ACS Publications. Most Trusted. Most Cited. Most Read
Stereo- and Enantioselective Syntheses of (Z)-1,3-Butadienyl-2-carbinols via Brønsted Acid Catalysis
My Activity
  • Open Access
Letter

Stereo- and Enantioselective Syntheses of (Z)-1,3-Butadienyl-2-carbinols via Brønsted Acid Catalysis
Click to copy article linkArticle link copied!

Open PDFSupporting Information (1)

Organic Letters

Cite this: Org. Lett. 2025, 27, 3, 887–891
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.orglett.4c04663
Published January 9, 2025

Copyright © 2025 The Author. Published by American Chemical Society. This publication is licensed under

CC-BY 4.0 .

Abstract

Click to copy section linkSection link copied!

A Brønsted acid-catalyzed enantioselective synthesis of (Z)-1,3-butadienyl-2-carbinols is developed. By employing a chiral phosphoric acid as the catalyst, a variety of 1,3-butadienyl-2-carbinols were obtained in good yields with excellent Z-selectivities and enantiopurities from α-alkyl-substituted homoallenyl boronates.

This publication is licensed under

CC-BY 4.0 .
  • cc licence
  • by licence
Copyright © 2025 The Author. Published by American Chemical Society

The 1,3-butadienyl-2-carbinols with a stereochemically defined 1,2-disubstituted alkene unit and their deoxy-analogs are important building blocks for a variety of natural products that are of great biological importance (Figure 1). (1) Several methods have been developed for stereoselective syntheses of these structural motifs in the context of complex molecule synthesis. (2,3) As shown in Scheme 1, the Nicolaou group utilized a sequential olefination approach to access diene C in the total synthesis of des-epoxy caribenolide I. (2a) Horner–Wadsworth–Emmons olefination of an aldehyde with β-ketophosphonate A was utilized to generate α,β-unsaturated ketone B. Subsequent Wittig olefination to install the methylene group gave diene C. In the total synthesis of pteriatoxin, (2b) Kishi showed that Nozaki–Hiyama–Kishi coupling of vinyl bromide D with the aldehyde furnished a diastereomeric mixture of allylic alcohols E. Acylation of the hydroxyl group of E followed by Pd-mediated elimination afforded diene C. An enyne metathesis approach to diene C was developed by the Trost group in their synthesis of des-epoxy-amphidinolide N. (2c) Enyne metathesis of enantioenriched propargylic ether F with the alkene substrate using Grubbs’ II catalyst formed an E/Z mixture of dienes G. (2d) The mixture equilibrated under the reaction conditions over time to form diene C with a high E-selectivity. The synthesis of racemic (Z)-1,3-butadienyl-2-carbinol K was reported by Diver and co-workers by employing a multistep reaction sequence. (2d) Vinyl bromide H was converted to allylic alcohol I using a Nozaki–Hiyama–Kishi coupling reaction. Alcohol I was transformed into aldehyde J in four steps, which reacted under the Wittig olefination conditions to give racemic diene K. With our research focus in organoboron chemistry, (4) we became interested in whether asymmetric aldehyde addition with homoallenyl boronate could generate enantioenriched 1,3-butadienyl-2-carbinols (bottom panel, Scheme 1). (5) Accordingly, we have developed and describe herein chiral phosphoric-acid-catalyzed enantioselective syntheses of Z-1,3-butadienyl-2-carbinols 2 from homoallenyl boronate 1.

Figure 1

Figure 1. Selected natural products containing the 1,3-butadienyl-2-carbinol motif or the deoxy-analog.

Scheme 1

Scheme 1. Approaches to 1,3-Butadienyl-2-carbinols

As shown in Scheme 2, homoallenyl boronates 1 were synthesized from pinanediol boronic esters 5 using the conditions developed by Matteson and co-workers. (6) Treatment of boronic ester 5 at −100 °C with lithiated dichloromethane followed by the addition of a solution of ZnCl2 gave an α-chloroboronate intermediate. Subsequent addition of allenyl Grignard reagents to the α-chloroboronate intermediate generated enantioenriched homoallenyl boronates 1 in 72–89% yield.

Scheme 2

Scheme 2. Syntheses of Boron Reagents 1 and Evaluation of the Conditions for Reactions with Boronate 1aa

aReaction conditions: boronate 1a (0.12 mmol, 1.2 equiv), benzaldehyde (0.1 mmol, 1.0 equiv), catalyst (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

bThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

cYields of isolated products are listed.

dThe enantiomeric excesses were determined by modified Mosher ester analyses.

eThe reaction was conducted at rt.

fThe reaction was conducted in CH2Cl2.

After successful preparation of reagents 1, we chose boronate 1a and benzaldehyde as the model system to study the reactions. As shown in Scheme 2, the reaction of 1a and benzaldehyde in the absence of any catalyst gave a 6:1 mixture of dienols 2a and 3a in a 92% combined yield (entry 1). The enantiomeric purity of major isomer 2a is excellent (95% ee). (7) The results indicate that without any catalyst, the reaction of reagent 1a and benzaldehyde has a 6:1 inherent Z-selectivity. Next we sought to identify suitable conditions to improve the Z-selectivity. It has been shown that addition of a Lewis acid can drastically affect the E/Z selectivities of aldehyde addition with α-substituted allylboronates. (8,9) However, the vast majority of prior studies focused on reactions with pinacol boronates. At the outset of our studies, it is not apparent whether these conditions will be applicable to boronates 1 bearing a pinanediol unit that is considerably larger than pinacol. Indeed, the reaction with BF3·OEt2 as the catalyst, which has been shown to promote highly stereoselective allylation with several α-substituted allylboronates, formed only a 1:1 mixture of 2a and 3a in a combined 69% yield (entry 2). Similar selectivities were observed with either Cu(OTf)2 or Sc(OTf)3 as the catalyst (entries 3 and 4). Brønsted acids, such as chiral phosphoric acids, have been utilized to catalyze aldehyde addition with a variety of unsaturated organoboronates with excellent enantioselectivities. (10−13) More recently, they have also been shown to affect the E/Z selectivity in reactions with α-substituted allylboronates. (14) Because pinanediol is much larger than pinacol, whether these acid catalysts will tolerate the large pinanediol group is the key to controlling the alkene geometry of alcohols 2 and 3. In the event, 5 mol % acid (R)-A was used as the catalyst for the reaction of 1a with benzaldehyde at −45 °C. Gratifyingly, the reaction generated alcohol 2a as the only product (Z:E > 30:1). Alcohol 2a was isolated in 86% yield with 98% ee (entry 5). By contrast, the reaction with enantiomeric acid (S)-A as the catalyst only formed a 1.5:1 mixture of 2a and 3a, slightly favoring Z-isomer 2a. These data indicate that the asymmetric induction from acid catalyst (R)-A is the same as the inherent selectivity of reagent 1a in the reaction with benzaldehyde. The reaction of 1a with acid (R)-A as the catalyst is a matched case, and therefore, alcohol 2a was produced with excellent selectivity. On the other hand, the reaction of 1a with (S)-A as the catalyst is mismatched, as the asymmetric induction from acid catalyst (S)-A is the opposite to the inherent selectivity of reagent 1a. Ultimately, the mismatched reaction led to the formation of a mixture of 2a and 3a with poor selectivity.

With suitable conditions identified, we explored the scope of the reaction. As summarized in Scheme 3, in the presence of 5 mol % acid (R)-A, the reactions worked well with a wide array of aldehydes to generate 1,3-butadienyl-2-carbinols 2 with excellent Z-selectivities and enantiopurities. For example, para-substituted aromatic aldehydes reacted smoothly with 1a to afford products 2bf in 74–92% yields with 96–99% ee. Aromatic aldehydes with a substituent at the meta- or ortho-position also reacted to form alcohols 2gj in 74–88% yields with 97–99% ee. The reactions with α,β-unsaturated aldehydes occurred to give products 2km in 71–78% yields with 95–99% ee. Aldehydes with a heterocycle, such as benzothiophene or Boc-protected indole, reacted with 1a to generate alcohols 2np in 73–91% yields with 94–98% ee. Moreover, reactions with aliphatic aldehydes also worked well, furnishing products 2qr in 74–77% yield with 94–99% ee. In all cases, Z-isomers were obtained with excellent selectivities (>30:1).

Scheme 3

Scheme 3. Scope of the Aldehyde for Acid (R)-A-Catalyzed Asymmetric Allylation with Boronate 1aad

aReaction conditions: boronate 1a (0.12 mmol, 1.2 equiv), aldehyde (0.1 mmol, 1.0 equiv), phosphoric acid (R)-A (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

bYields of isolated products 2 are listed.

cThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

dThe enantiomeric excesses were determined by modified Mosher ester analyses.

To evaluate whether homoallenyl boronates with a substituent other than the methyl group at the α-position could also react with aldehydes to form 1,3-butadienyl-2-carbinols with high Z-selectivities, reactions of reagents 1bd with several representative aldehydes were conducted. As summarized in Scheme 4, the reactions tolerate several alkyl groups, including ethyl, n-propyl, and i-butyl groups, at the α-position of homoallenyl boronates 1. Several aldehydes participated in the reactions with reagents 1bd, affording alcohol products 4ai in 73–94% yield with 97–99% ee. Again, the Z-isomers were obtained with excellent selectivities (>30:1) in all cases.

Scheme 4

Scheme 4. Chiral Phosphoric-Acid-Catalyzed Asymmetric Aldehyde Addition with Homoallenyl boronates 1bdad

aReaction conditions: allylboronate 1a (0.12 mmol, 1.2 equiv), aldehyde (0.1 mmol, 1.0 equiv), phosphoric acid (R)-A (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

bYields of isolated products are listed.

cThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

dThe enantiomeric excesses were determined by modified Mosher ester analysis.

The reaction of allylboronate 5 with benzaldehyde formed a 1.5:1 mixture of homoallylic alcohols 6 and 7. The observed 6:1 Z-selectivity in the uncatalyzed reaction with boronate 1a is somewhat unexpected (entry 1, Scheme 2). To establish the origin of such selectivity, we analyzed the transition states of these reactions. As depicted in Scheme 5, in transition state TS-2 that leads to E-isomer 7, the α-methyl group adopts a pseudoequatorial position. Such a spatial arrangement will suffer unfavorable gauche interactions between the methyl group of reagent 5 and the pinanediol group on boron (shown with a red arrow in TS-2). In comparison, in transition state TS-1 that forms Z-isomer 6, the methyl group is oriented in a pseudoaxial position, and A1,3 strain between the methyl group and the vinyl hydrogen is developed. (15) Two competing transition states, TS-1 and TS-2, are similar in energy. Therefore, the reaction forms a mixture of Z and E isomers, 6 and 7, with low selectivity. The energy difference of TS-1 and TS-2 is estimated to be 0.24 kcal/mol at 25 °C. The energy penalty for the A1,3 strain in TS-1 is about 1 kcal/mol. Therefore, the energy penalty for the gauche interactions in TS-2 is estimated to be 1.24 kcal/mol at 25 °C.

Scheme 5

Scheme 5. Transition State Analyses of Aldehyde Addition with Boron Reagents 5 and 1a

In the uncatalyzed reaction of 1a with benzaldehyde, two competing transition states, TS-3 and TS-4, lead to the formation of Z-isomer 2a and E-isomer 3a, respectively (Scheme 5). Close inspection of transition states TS-4 and TS-2 revealed that similar unfavorable gauche interactions also exist in TS-4. By contrast, the A1,3 strain as in TS-1 is not present in TS-3, owing to the lack of the vinyl hydrogen. Therefore, the energy difference of TS-3 and TS-4 is estimated to be 1.24 kcal/mol at 25 °C due to the gauche interactions in TS-4. The observed 6:1 selectivity of 2a and 3a in the reaction with 1a corresponds to a 1.06 kcal/mol energy difference at 25 °C, which is in good accord with the 1.24 kcal/mol caused by the gauche interactions.

In the chiral phosphoric acid (R)-A-catalyzed reaction of 1a, the asymmetric induction from the catalyst is the same as the inherent selectivity of reagent 1a as in transition state TS-5. The additive effect of these two stereodirecting factors is estimated to be at least 3 kcal/mol at 25 °C. Moreover, the steric interactions between the pinanediol group on boron and the acid catalyst (similar to the pinacol boronate case) further destabilize transition state TS-6 (Scheme 6). Therefore, acid (R)-A-catalyzed reaction of 1a with aldehydes proceeded with the favored transition state TS-5 to give Z-isomers 2 with excellent selectivities.

Scheme 6

Scheme 6. Transition State Analyses of Chiral Phosphoric-Acid-Catalyzed Aldehyde Addition with Reagent 1a

In summary, we developed a chiral phosphoric acid (R)-A-catalyzed reaction of homoallenyl boronates with aldehydes. A variety of 1,3-butadienyl-2-carbinols were obtained with excellent Z-selectivities and enantioselectivities. Synthetic applications of the method will be reported in due course.

Data Availability

Click to copy section linkSection link copied!

The data underlying this study are available in the published article and its Supporting Information.

Supporting Information

Click to copy section linkSection link copied!

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.orglett.4c04663.

  • Experimental procedures, spectra for all new compounds (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

Click to copy section linkSection link copied!

Acknowledgments

Click to copy section linkSection link copied!

Financial support provided by the National Science Foundation (CAREER Award CHE-2426500) is gratefully acknowledged.

References

Click to copy section linkSection link copied!

This article references 15 other publications.

  1. 1
    (a) Kobayashi, J.; Tsuda, M.; Ishibashi, M.; Shigemori, H.; Yamasu, T.; Hirota, H.; Sasaki, T. Amphidinolide F, a new cytotoxic macrolide from the marine dinoflagellate Amphidinium sp. J. Antibiot. 1991, 44, 1259,  DOI: 10.7164/antibiotics.44.1259
    (b) Bauer, I.; Maranda, L.; Shimizu, Y.; Peterson, R. W.; Cornell, L.; Steiner, J. R.; Clardy, J. The structures of amphidinolide B isomers: strongly cytotoxic macrolides produced by a free-swimming dinoflagellate, Amphidinium sp. J. Am. Chem. Soc. 1994, 116, 2657,  DOI: 10.1021/ja00085a071
    (c) Areche, C.; Sepulveda, B.; Martin, A. S.; Garcia-Beltran, O.; Simirgiotis, M.; Cañete, A. An unusual mulinane diterpenoid from the Chilean plant Azorella trifurcata (Gaertn) Pers. An unusual mulinane diterpenoid from the Chilean plant Azorella trifurcata (Gaertn) Pers. Org. Biomol. Chem. 2014, 12, 6406,  DOI: 10.1039/C4OB00966E
  2. 2
    (a) Nicolaou, K. C.; Bulger, P. G.; Brenzovich, W. E. Synthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures. Revised strategy and final stages. Org. Biomol. Chem. 2006, 4, 2158,  DOI: 10.1039/b602021f
    (b) Matsuura, F.; Peters, R.; Anada, M.; Harried, S. S.; Hao, J.; Kishi, Y. Unified total synthesis of pteriatoxins and their diastereomers. J. Am. Chem. Soc. 2006, 128, 7463,  DOI: 10.1021/ja0618954
    (c) Trost, B. M.; Bai, W. J.; Stivala, C. E.; Hohn, C.; Poock, C.; Heinrich, M.; Xu, S.; Rey, J. Enantioselective synthesis of des-epoxy-amphidinolide N. J. Am. Chem. Soc. 2018, 140, 17316,  DOI: 10.1021/jacs.8b11827
    (d) Giessert, A. J.; Diver, S. T. Equilibrium control in enyne metathesis: crossover studies and the kinetic reactivity of (E,Z)-1,3-disubstituted-1,3-dienes. J. Org. Chem. 2005, 70, 1046,  DOI: 10.1021/jo0482209
  3. 3
    (a) Trost, B. M.; Papillon, J. P. N. Alkene–Alkyne Coupling as a Linchpin: An efficient and convergent synthesis of amphidinolide P. J. Am. Chem. Soc. 2004, 126, 13618,  DOI: 10.1021/ja045449x
    (b) Zhang, W.; Carter, R. G. Synthetic studies toward amphidinolide B1: Synthesis of the C9–C26 fragment. Org. Lett. 2005, 7, 4209,  DOI: 10.1021/ol051544e
    (c) Va, P.; Roush, W. R. Total synthesis of amphidinolide E. J. Am. Chem. Soc. 2006, 128, 15960,  DOI: 10.1021/ja066663j
    (d) Clark, J. S.; Yang, G.; Osnowski, A. P. Synthesis of the C1–C17 fragment of amphidinolides C, C2, C3, and F. Org. Lett. 2013, 15, 1460,  DOI: 10.1021/ol4004838
  4. 4
    (a) Wang, M.; Gao, S.; Chen, M. Stereoselective syntheses of (E)-γ′,δ-bisboryl-substituted syn-homoallylic alcohols via chemoselective aldehyde allylboration. Org. Lett. 2019, 21, 2151,  DOI: 10.1021/acs.orglett.9b00461
    (b) Gao, S.; Chen, J.; Chen, M. (Z)-α-Boryl-crotylboron reagents via Z-selective alkene isomerization and application to stereoselective syntheses of (E)-δ-boryl-syn-homoallylic alcohols. Chem. Sci. 2019, 10, 3637,  DOI: 10.1039/C9SC00226J
    (c) Liu, J.; Gao, S.; Chen, M. Development of α-borylmethyl-(Z)-crotylboronate reagent and enantioselective syntheses of (E)-δ-hydroxymethyl-syn-homoallylic alcohols via highly stereoselective allylboration. Org. Lett. 2021, 23, 9451,  DOI: 10.1021/acs.orglett.1c03628
    (d) Chen, J.; Miliordos, E.; Chen, M. Highly diastereo- and enantioselective synthesis of 3,6’-bisboryl-anti-1,2-oxaborinan-3-enes: an entry to enantioenriched homoallylic alcohols with a stereodefined trisubstituted alkene. Angew. Chem., Int. Ed. 2021, 60, 840,  DOI: 10.1002/anie.202006420
    (e) Liu, J.; Gao, S.; Miliordos, E.; Chen, M. Asymmetric syntheses of (Z)- or (E)-β,γ-unsaturated ketones via silane-controlled enantiodivergent catalysis. J. Am. Chem. Soc. 2023, 145, 19542,  DOI: 10.1021/jacs.3c02595
    (f) Gao, S.; Liu, J.; Troya, D.; Chen, M. Copper-catalyzed asymmetric acylboration of 1,3-butadienylboronate with acyl fluorides. Angew. Chem., Int. Ed. 2023, 62, e202304796  DOI: 10.1002/anie.202304796
  5. 5
    (a) Lachance, H.; Hall, D. G. Allylboration of carbonyl compounds. Org. React. 2009, 73, 1,  DOI: 10.1002/0471264180.or073.01
    (b) Yus, M.; González-Gómez, J. C.; Foubelo, F. Catalytic enantioselective allylation of carbonyl compounds and imines. Chem. Rev. 2011, 111, 7774,  DOI: 10.1021/cr1004474
    (c) Yus, M.; González-Gómez, J. C.; Foubelo, F. Diastereoselective allylation of carbonyl compounds and imines: application to the synthesis of natural products. Chem. Rev. 2013, 113, 5595,  DOI: 10.1021/cr400008h
  6. 6
    (a) Matteson, D. S.; Ray, R. alpha-Chloro boronic esters from homologation of boronic esters. J. Am. Chem. Soc. 1980, 102, 7590,  DOI: 10.1021/ja00545a046
    (b) Matteson, D. S.; Sadhu, K. M.; Peterson, M. L. 99% Chirally selective synthesis via pinanediol boronic esters: insect pheromones, diols, and an amino alcohol. J. Am. Chem. Soc. 1986, 108, 810,  DOI: 10.1021/ja00264a039
  7. 7
    (a) Dale, J. A.; Mosher, H. S. Nuclear magnetic resonance enantiomer regents. Configurational correlations via nuclear magnetic resonance chemical shifts of diastereomeric mandelate, O-methylmandelate, and.alpha.-methoxy-.alpha.-trifluoromethylphenyl-acetate (MTPA) esters. J. Am. Chem. Soc. 1973, 95, 512,  DOI: 10.1021/ja00783a034
    (b) Ohtani, I.; Kusumi, T.; Kashman, Y.; Kakisawa, H. High-field FT NMR application of Mosher’s method. The absolute configurations of marine terpenoids. J. Am. Chem. Soc. 1991, 113, 4092,  DOI: 10.1021/ja00011a006
  8. 8
    (a) Kennedy, J. W. J.; Hall, D. G. Dramatic rate enhancement with preservation of stereospecificity in the first metal-catalyzed additions of allylboronates. J. Am. Chem. Soc. 2002, 124, 11586,  DOI: 10.1021/ja027453j
    (b) Ishiyama, T.; Ahiko, T.; Miyaura, N. Acceleration effect of Lewis acid in allylboration of aldehydes: catalytic, regiospecific, diastereospecific, and enantioselective synthesis of homoallyl alcohols. J. Am. Chem. Soc. 2002, 124, 12414,  DOI: 10.1021/ja0210345
  9. 9
    (a) Peng, F.; Hall, D. G. Simple, stable, and versatile double-allylation reagents for the stereoselective preparation of skeletally diverse compounds. J. Am. Chem. Soc. 2007, 129, 3070,  DOI: 10.1021/ja068985t
    (b) Liu, J.; Gao, S.; Chen, M. Asymmetric syntheses of (E)-δ-hydroxymethyl-anti-homoallylic alcohols via highly enantio- and stereoselective aldehyde allylation with α-borylmethyl-(E)-crotyl-boronate. Org. Lett. 2021, 23, 7808,  DOI: 10.1021/acs.orglett.1c02831
    (c) Liu, J.; Chen, M. Highly stereoselective syntheses of (E)-δ-boryl-anti-homoallylic alcohols via allylation with α-boryl-(E)-crotylboronate. Chem. Commun. 2021, 57, 10799,  DOI: 10.1039/D1CC04058H
  10. 10
    (a) Jain, P.; Antilla, J. C. Chiral Brønsted acid-catalyzed allylboration of aldehydes. J. Am. Chem. Soc. 2010, 132, 11884,  DOI: 10.1021/ja104956s
    (b) Miura, T.; Nishida, Y.; Morimoto, M.; Murakami, M. Enantioselective synthesis of anti-homoallylic alcohols from terminal alkynes and aldehydes based on concomitant use of a cationic iridium complex and a chiral phosphoric acid. J. Am. Chem. Soc. 2013, 135, 11497,  DOI: 10.1021/ja405790t
    (c) Incerti-Pradillos, C. A.; Kabeshov, M. A.; Malkov, A. V. Highly stereoselective synthesis of Z-homoallylic alcohols by kinetic resolution of racemic secondary allyl boronates. Angew. Chem., Int. Ed. 2013, 52, 5338,  DOI: 10.1002/anie.201300709
    (d) Huang, Y.; Yang, X.; Lv, Z.; Cai, C.; Kai, C.; Pei, Y.; Feng, Y. Asymmetric synthesis of 1,3-butadienyl-2-carbinols by the homoallenylboration of aldehydes with a chiral phosphoric acid catalyst. Angew. Chem., Int. Ed. 2015, 54, 7299,  DOI: 10.1002/anie.201501832
    (e) Gao, S.; Chen, M. Enantioselective syn- and anti-alkoxyallylation of aldehydes via Brønsted acid catalysis. Org. Lett. 2018, 20, 6174,  DOI: 10.1021/acs.orglett.8b02653
    (f) Gao, S.; Chen, M. Enantioselective syntheses of 1, 4-pentadien-3-yl carbinols via Brønsted acid catalysis. Org. Lett. 2020, 22, 400,  DOI: 10.1021/acs.orglett.9b04089
    (g) Liu, J.; Chen, M. Enantioselective anti- and syn-(borylmethyl)allylation of aldehydes via Brønsted acid catalysis. Org. Lett. 2020, 22, 8967,  DOI: 10.1021/acs.orglett.0c03366
    (h) Gao, S.; Duan, M.; Liu, J.; Yu, P.; Houk, K. N.; Chen, M. Stereochemical control via chirality pairing: stereodivergent syntheses of enantioenriched homoallylic alcohols. Angew. Chem., Int. Ed. 2021, 60, 24096,  DOI: 10.1002/anie.202107004
    (i) Gao, S.; Liu, J.; Chen, M. Catalytic asymmetric transformations of racemic α-borylmethyl-(E)-crotylboronate via kinetic resolution or enantioconvergent reaction pathways. Chem. Sci. 2021, 12, 13398,  DOI: 10.1039/D1SC04047B
    (j) Gao, S.; Duan, M.; Andreola, L. R.; Yu, P.; Wheeler, S. E.; Houk, K. N.; Chen, M. Unusual enantiodivergence in chiral Brønsted acid-catalyzed asymmetric allylation with β-alkenyl allylic boronates. Angew. Chem., Int. Ed. 2022, 61, e202208908  DOI: 10.1002/anie.202208908
  11. 11
    (a) Jain, P.; Wang, H.; Houk, K. N.; Antilla, J. C. Brønsted acid catalyzed asymmetric propargylation of aldehydes. Angew. Chem., Int. Ed. 2012, 51, 1391,  DOI: 10.1002/anie.201107407
    (b) Reddy, L. R. Chiral Brønsted acid catalyzed enantioselective propargylation of aldehydes with allenylboronate. Org. Lett. 2012, 14, 1142,  DOI: 10.1021/ol300075n
    (c) Chen, M.; Roush, W. R. Enantioselective synthesis of anti- and syn-homopropargyl alcohols via chiral Brønsted acid catalyzed asymmetric allenylboration reactions. J. Am. Chem. Soc. 2012, 134, 10947,  DOI: 10.1021/ja3031467
    (d) Tsai, A. S.; Chen, M.; Roush, W. R. Chiral Brønsted acid catalyzed enantioselective synthesis of anti-homopropargyl alcohols via kinetic resolution-aldehyde allenylboration using racemic allenylboronates. Org. Lett. 2013, 15, 1568,  DOI: 10.1021/ol4003459
    (e) Wang, M.; Khan, S.; Miliordos, E.; Chen, M. Enantioselective syntheses of homopropargylic alcohols via asymmetric allenylboration. Org. Lett. 2018, 20, 3810,  DOI: 10.1021/acs.orglett.8b01399
  12. 12
    (a) Reddy, L. R. Chiral Brønsted acid catalyzed enantioselective allenylation of aldehydes. Chem. Commun. 2012, 48, 9189,  DOI: 10.1039/c2cc34371a
    (b) Wang, M.; Khan, S.; Miliordos, E.; Chen, M. Enantioselective allenylation of aldehydes via Brønsted acid catalysis. Adv. Synth. Catal. 2018, 360, 4634,  DOI: 10.1002/adsc.201801080
  13. 13
    (a) Grayson, M. N.; Pellegrinet, S. C.; Goodman, J. M. Mechanistic insights into the BINOL-derived phosphoric acid-catalyzed asymmetric allylboration of aldehydes. J. Am. Chem. Soc. 2012, 134, 2716,  DOI: 10.1021/ja210200d
    (b) Wang, H.; Jain, P.; Antilla, J. C.; Houk, K. N. Origins of stereoselectivities in chiral phosphoric acid catalyzed allylborations and propargylations of aldehydes. J. Org. Chem. 2013, 78, 1208,  DOI: 10.1021/jo302787m
    (c) Grayson, M. N.; Goodman, J. M. Understanding the mechanism of the asymmetric propargylation of aldehydes promoted by 1,1’-bi-2-naphthol-derived catalysts. J. Am. Chem. Soc. 2013, 135, 6142,  DOI: 10.1021/ja3122137
  14. 14
    (a) Miura, T.; Nakahashi, J.; Zhou, W.; Shiratori, Y.; Stewart, S. G.; Murakami, M. Enantioselective synthesis of anti-1,2-oxaborinan-3-enes from aldehydes and 1,1-di(boryl)alk-3-enes using ruthenium and chiral phosphoric acid catalysts. J. Am. Chem. Soc. 2017, 139, 10903,  DOI: 10.1021/jacs.7b06408
    (b) Miura, T.; Oku, N.; Murakami, M. Diastereo- and enantioselective synthesis of (E)-δ-boryl-substituted anti-homoallylic alcohols in two steps from terminal alkynes. Angew. Chem., Int. Ed. 2019, 58, 14620,  DOI: 10.1002/anie.201908299
    (c) Gao, S.; Duan, M.; Houk, K. N.; Chen, M. Chiral phosphoric acid dual-function catalysis: asymmetric allylation with α-vinyl allylboron reagents. Angew. Chem., Int. Ed. 2020, 59, 10540,  DOI: 10.1002/anie.202000039
    (d) Gao, S.; Duan, M.; Shao, Q.; Houk, K. N.; Chen, M. Development of α, α-disubstituted crotylboronate reagents and stereoselective crotylation via Brønsted or Lewis acid catalysis. J. Am. Chem. Soc. 2020, 142, 18355,  DOI: 10.1021/jacs.0c04107
    (e) Chen, J.; Chen, M. Enantioselective syntheses of (Z)-6′-boryl-anti-1,2-oxaborinan-3-enes via a dienylboronate protoboration and asymmetric allylation reaction sequence. Org. Lett. 2020, 22, 7321,  DOI: 10.1021/acs.orglett.0c02657
    (f) Zhang, Z.; Liu, J.; Gao, S.; Su, B.; Chen, M. Highly stereoselective syntheses of α,α-disubstituted (E)- and (Z)-crotylboronates. J. Org. Chem. 2023, 88, 3288,  DOI: 10.1021/acs.joc.2c02606
  15. 15
    Hoffmann, R. W. Allylic 1,3-strain as a controlling factor in stereoselective transformations. Chem. Rev. 1989, 89, 1841,  DOI: 10.1021/cr00098a009

Cited By

Click to copy section linkSection link copied!

This article has not yet been cited by other publications.

Organic Letters

Cite this: Org. Lett. 2025, 27, 3, 887–891
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.orglett.4c04663
Published January 9, 2025

Copyright © 2025 The Author. Published by American Chemical Society. This publication is licensed under

CC-BY 4.0 .

Article Views

1006

Altmetric

-

Citations

-
Learn about these metrics

Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.

  • Abstract

    Figure 1

    Figure 1. Selected natural products containing the 1,3-butadienyl-2-carbinol motif or the deoxy-analog.

    Scheme 1

    Scheme 1. Approaches to 1,3-Butadienyl-2-carbinols

    Scheme 2

    Scheme 2. Syntheses of Boron Reagents 1 and Evaluation of the Conditions for Reactions with Boronate 1aa

    aReaction conditions: boronate 1a (0.12 mmol, 1.2 equiv), benzaldehyde (0.1 mmol, 1.0 equiv), catalyst (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

    bThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

    cYields of isolated products are listed.

    dThe enantiomeric excesses were determined by modified Mosher ester analyses.

    eThe reaction was conducted at rt.

    fThe reaction was conducted in CH2Cl2.

    Scheme 3

    Scheme 3. Scope of the Aldehyde for Acid (R)-A-Catalyzed Asymmetric Allylation with Boronate 1aad

    aReaction conditions: boronate 1a (0.12 mmol, 1.2 equiv), aldehyde (0.1 mmol, 1.0 equiv), phosphoric acid (R)-A (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

    bYields of isolated products 2 are listed.

    cThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

    dThe enantiomeric excesses were determined by modified Mosher ester analyses.

    Scheme 4

    Scheme 4. Chiral Phosphoric-Acid-Catalyzed Asymmetric Aldehyde Addition with Homoallenyl boronates 1bdad

    aReaction conditions: allylboronate 1a (0.12 mmol, 1.2 equiv), aldehyde (0.1 mmol, 1.0 equiv), phosphoric acid (R)-A (5 mol %), 4 Å molecular sieves (50 mg), toluene (0.3 mL), −45 °C.

    bYields of isolated products are listed.

    cThe Z/E ratios were determined by 1H NMR analyses of the crude reaction products.

    dThe enantiomeric excesses were determined by modified Mosher ester analysis.

    Scheme 5

    Scheme 5. Transition State Analyses of Aldehyde Addition with Boron Reagents 5 and 1a

    Scheme 6

    Scheme 6. Transition State Analyses of Chiral Phosphoric-Acid-Catalyzed Aldehyde Addition with Reagent 1a
  • References


    This article references 15 other publications.

    1. 1
      (a) Kobayashi, J.; Tsuda, M.; Ishibashi, M.; Shigemori, H.; Yamasu, T.; Hirota, H.; Sasaki, T. Amphidinolide F, a new cytotoxic macrolide from the marine dinoflagellate Amphidinium sp. J. Antibiot. 1991, 44, 1259,  DOI: 10.7164/antibiotics.44.1259
      (b) Bauer, I.; Maranda, L.; Shimizu, Y.; Peterson, R. W.; Cornell, L.; Steiner, J. R.; Clardy, J. The structures of amphidinolide B isomers: strongly cytotoxic macrolides produced by a free-swimming dinoflagellate, Amphidinium sp. J. Am. Chem. Soc. 1994, 116, 2657,  DOI: 10.1021/ja00085a071
      (c) Areche, C.; Sepulveda, B.; Martin, A. S.; Garcia-Beltran, O.; Simirgiotis, M.; Cañete, A. An unusual mulinane diterpenoid from the Chilean plant Azorella trifurcata (Gaertn) Pers. An unusual mulinane diterpenoid from the Chilean plant Azorella trifurcata (Gaertn) Pers. Org. Biomol. Chem. 2014, 12, 6406,  DOI: 10.1039/C4OB00966E
    2. 2
      (a) Nicolaou, K. C.; Bulger, P. G.; Brenzovich, W. E. Synthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures. Revised strategy and final stages. Org. Biomol. Chem. 2006, 4, 2158,  DOI: 10.1039/b602021f
      (b) Matsuura, F.; Peters, R.; Anada, M.; Harried, S. S.; Hao, J.; Kishi, Y. Unified total synthesis of pteriatoxins and their diastereomers. J. Am. Chem. Soc. 2006, 128, 7463,  DOI: 10.1021/ja0618954
      (c) Trost, B. M.; Bai, W. J.; Stivala, C. E.; Hohn, C.; Poock, C.; Heinrich, M.; Xu, S.; Rey, J. Enantioselective synthesis of des-epoxy-amphidinolide N. J. Am. Chem. Soc. 2018, 140, 17316,  DOI: 10.1021/jacs.8b11827
      (d) Giessert, A. J.; Diver, S. T. Equilibrium control in enyne metathesis: crossover studies and the kinetic reactivity of (E,Z)-1,3-disubstituted-1,3-dienes. J. Org. Chem. 2005, 70, 1046,  DOI: 10.1021/jo0482209
    3. 3
      (a) Trost, B. M.; Papillon, J. P. N. Alkene–Alkyne Coupling as a Linchpin: An efficient and convergent synthesis of amphidinolide P. J. Am. Chem. Soc. 2004, 126, 13618,  DOI: 10.1021/ja045449x
      (b) Zhang, W.; Carter, R. G. Synthetic studies toward amphidinolide B1: Synthesis of the C9–C26 fragment. Org. Lett. 2005, 7, 4209,  DOI: 10.1021/ol051544e
      (c) Va, P.; Roush, W. R. Total synthesis of amphidinolide E. J. Am. Chem. Soc. 2006, 128, 15960,  DOI: 10.1021/ja066663j
      (d) Clark, J. S.; Yang, G.; Osnowski, A. P. Synthesis of the C1–C17 fragment of amphidinolides C, C2, C3, and F. Org. Lett. 2013, 15, 1460,  DOI: 10.1021/ol4004838
    4. 4
      (a) Wang, M.; Gao, S.; Chen, M. Stereoselective syntheses of (E)-γ′,δ-bisboryl-substituted syn-homoallylic alcohols via chemoselective aldehyde allylboration. Org. Lett. 2019, 21, 2151,  DOI: 10.1021/acs.orglett.9b00461
      (b) Gao, S.; Chen, J.; Chen, M. (Z)-α-Boryl-crotylboron reagents via Z-selective alkene isomerization and application to stereoselective syntheses of (E)-δ-boryl-syn-homoallylic alcohols. Chem. Sci. 2019, 10, 3637,  DOI: 10.1039/C9SC00226J
      (c) Liu, J.; Gao, S.; Chen, M. Development of α-borylmethyl-(Z)-crotylboronate reagent and enantioselective syntheses of (E)-δ-hydroxymethyl-syn-homoallylic alcohols via highly stereoselective allylboration. Org. Lett. 2021, 23, 9451,  DOI: 10.1021/acs.orglett.1c03628
      (d) Chen, J.; Miliordos, E.; Chen, M. Highly diastereo- and enantioselective synthesis of 3,6’-bisboryl-anti-1,2-oxaborinan-3-enes: an entry to enantioenriched homoallylic alcohols with a stereodefined trisubstituted alkene. Angew. Chem., Int. Ed. 2021, 60, 840,  DOI: 10.1002/anie.202006420
      (e) Liu, J.; Gao, S.; Miliordos, E.; Chen, M. Asymmetric syntheses of (Z)- or (E)-β,γ-unsaturated ketones via silane-controlled enantiodivergent catalysis. J. Am. Chem. Soc. 2023, 145, 19542,  DOI: 10.1021/jacs.3c02595
      (f) Gao, S.; Liu, J.; Troya, D.; Chen, M. Copper-catalyzed asymmetric acylboration of 1,3-butadienylboronate with acyl fluorides. Angew. Chem., Int. Ed. 2023, 62, e202304796  DOI: 10.1002/anie.202304796
    5. 5
      (a) Lachance, H.; Hall, D. G. Allylboration of carbonyl compounds. Org. React. 2009, 73, 1,  DOI: 10.1002/0471264180.or073.01
      (b) Yus, M.; González-Gómez, J. C.; Foubelo, F. Catalytic enantioselective allylation of carbonyl compounds and imines. Chem. Rev. 2011, 111, 7774,  DOI: 10.1021/cr1004474
      (c) Yus, M.; González-Gómez, J. C.; Foubelo, F. Diastereoselective allylation of carbonyl compounds and imines: application to the synthesis of natural products. Chem. Rev. 2013, 113, 5595,  DOI: 10.1021/cr400008h
    6. 6
      (a) Matteson, D. S.; Ray, R. alpha-Chloro boronic esters from homologation of boronic esters. J. Am. Chem. Soc. 1980, 102, 7590,  DOI: 10.1021/ja00545a046
      (b) Matteson, D. S.; Sadhu, K. M.; Peterson, M. L. 99% Chirally selective synthesis via pinanediol boronic esters: insect pheromones, diols, and an amino alcohol. J. Am. Chem. Soc. 1986, 108, 810,  DOI: 10.1021/ja00264a039
    7. 7
      (a) Dale, J. A.; Mosher, H. S. Nuclear magnetic resonance enantiomer regents. Configurational correlations via nuclear magnetic resonance chemical shifts of diastereomeric mandelate, O-methylmandelate, and.alpha.-methoxy-.alpha.-trifluoromethylphenyl-acetate (MTPA) esters. J. Am. Chem. Soc. 1973, 95, 512,  DOI: 10.1021/ja00783a034
      (b) Ohtani, I.; Kusumi, T.; Kashman, Y.; Kakisawa, H. High-field FT NMR application of Mosher’s method. The absolute configurations of marine terpenoids. J. Am. Chem. Soc. 1991, 113, 4092,  DOI: 10.1021/ja00011a006
    8. 8
      (a) Kennedy, J. W. J.; Hall, D. G. Dramatic rate enhancement with preservation of stereospecificity in the first metal-catalyzed additions of allylboronates. J. Am. Chem. Soc. 2002, 124, 11586,  DOI: 10.1021/ja027453j
      (b) Ishiyama, T.; Ahiko, T.; Miyaura, N. Acceleration effect of Lewis acid in allylboration of aldehydes: catalytic, regiospecific, diastereospecific, and enantioselective synthesis of homoallyl alcohols. J. Am. Chem. Soc. 2002, 124, 12414,  DOI: 10.1021/ja0210345
    9. 9
      (a) Peng, F.; Hall, D. G. Simple, stable, and versatile double-allylation reagents for the stereoselective preparation of skeletally diverse compounds. J. Am. Chem. Soc. 2007, 129, 3070,  DOI: 10.1021/ja068985t
      (b) Liu, J.; Gao, S.; Chen, M. Asymmetric syntheses of (E)-δ-hydroxymethyl-anti-homoallylic alcohols via highly enantio- and stereoselective aldehyde allylation with α-borylmethyl-(E)-crotyl-boronate. Org. Lett. 2021, 23, 7808,  DOI: 10.1021/acs.orglett.1c02831
      (c) Liu, J.; Chen, M. Highly stereoselective syntheses of (E)-δ-boryl-anti-homoallylic alcohols via allylation with α-boryl-(E)-crotylboronate. Chem. Commun. 2021, 57, 10799,  DOI: 10.1039/D1CC04058H
    10. 10
      (a) Jain, P.; Antilla, J. C. Chiral Brønsted acid-catalyzed allylboration of aldehydes. J. Am. Chem. Soc. 2010, 132, 11884,  DOI: 10.1021/ja104956s
      (b) Miura, T.; Nishida, Y.; Morimoto, M.; Murakami, M. Enantioselective synthesis of anti-homoallylic alcohols from terminal alkynes and aldehydes based on concomitant use of a cationic iridium complex and a chiral phosphoric acid. J. Am. Chem. Soc. 2013, 135, 11497,  DOI: 10.1021/ja405790t
      (c) Incerti-Pradillos, C. A.; Kabeshov, M. A.; Malkov, A. V. Highly stereoselective synthesis of Z-homoallylic alcohols by kinetic resolution of racemic secondary allyl boronates. Angew. Chem., Int. Ed. 2013, 52, 5338,  DOI: 10.1002/anie.201300709
      (d) Huang, Y.; Yang, X.; Lv, Z.; Cai, C.; Kai, C.; Pei, Y.; Feng, Y. Asymmetric synthesis of 1,3-butadienyl-2-carbinols by the homoallenylboration of aldehydes with a chiral phosphoric acid catalyst. Angew. Chem., Int. Ed. 2015, 54, 7299,  DOI: 10.1002/anie.201501832
      (e) Gao, S.; Chen, M. Enantioselective syn- and anti-alkoxyallylation of aldehydes via Brønsted acid catalysis. Org. Lett. 2018, 20, 6174,  DOI: 10.1021/acs.orglett.8b02653
      (f) Gao, S.; Chen, M. Enantioselective syntheses of 1, 4-pentadien-3-yl carbinols via Brønsted acid catalysis. Org. Lett. 2020, 22, 400,  DOI: 10.1021/acs.orglett.9b04089
      (g) Liu, J.; Chen, M. Enantioselective anti- and syn-(borylmethyl)allylation of aldehydes via Brønsted acid catalysis. Org. Lett. 2020, 22, 8967,  DOI: 10.1021/acs.orglett.0c03366
      (h) Gao, S.; Duan, M.; Liu, J.; Yu, P.; Houk, K. N.; Chen, M. Stereochemical control via chirality pairing: stereodivergent syntheses of enantioenriched homoallylic alcohols. Angew. Chem., Int. Ed. 2021, 60, 24096,  DOI: 10.1002/anie.202107004
      (i) Gao, S.; Liu, J.; Chen, M. Catalytic asymmetric transformations of racemic α-borylmethyl-(E)-crotylboronate via kinetic resolution or enantioconvergent reaction pathways. Chem. Sci. 2021, 12, 13398,  DOI: 10.1039/D1SC04047B
      (j) Gao, S.; Duan, M.; Andreola, L. R.; Yu, P.; Wheeler, S. E.; Houk, K. N.; Chen, M. Unusual enantiodivergence in chiral Brønsted acid-catalyzed asymmetric allylation with β-alkenyl allylic boronates. Angew. Chem., Int. Ed. 2022, 61, e202208908  DOI: 10.1002/anie.202208908
    11. 11
      (a) Jain, P.; Wang, H.; Houk, K. N.; Antilla, J. C. Brønsted acid catalyzed asymmetric propargylation of aldehydes. Angew. Chem., Int. Ed. 2012, 51, 1391,  DOI: 10.1002/anie.201107407
      (b) Reddy, L. R. Chiral Brønsted acid catalyzed enantioselective propargylation of aldehydes with allenylboronate. Org. Lett. 2012, 14, 1142,  DOI: 10.1021/ol300075n
      (c) Chen, M.; Roush, W. R. Enantioselective synthesis of anti- and syn-homopropargyl alcohols via chiral Brønsted acid catalyzed asymmetric allenylboration reactions. J. Am. Chem. Soc. 2012, 134, 10947,  DOI: 10.1021/ja3031467
      (d) Tsai, A. S.; Chen, M.; Roush, W. R. Chiral Brønsted acid catalyzed enantioselective synthesis of anti-homopropargyl alcohols via kinetic resolution-aldehyde allenylboration using racemic allenylboronates. Org. Lett. 2013, 15, 1568,  DOI: 10.1021/ol4003459
      (e) Wang, M.; Khan, S.; Miliordos, E.; Chen, M. Enantioselective syntheses of homopropargylic alcohols via asymmetric allenylboration. Org. Lett. 2018, 20, 3810,  DOI: 10.1021/acs.orglett.8b01399
    12. 12
      (a) Reddy, L. R. Chiral Brønsted acid catalyzed enantioselective allenylation of aldehydes. Chem. Commun. 2012, 48, 9189,  DOI: 10.1039/c2cc34371a
      (b) Wang, M.; Khan, S.; Miliordos, E.; Chen, M. Enantioselective allenylation of aldehydes via Brønsted acid catalysis. Adv. Synth. Catal. 2018, 360, 4634,  DOI: 10.1002/adsc.201801080
    13. 13
      (a) Grayson, M. N.; Pellegrinet, S. C.; Goodman, J. M. Mechanistic insights into the BINOL-derived phosphoric acid-catalyzed asymmetric allylboration of aldehydes. J. Am. Chem. Soc. 2012, 134, 2716,  DOI: 10.1021/ja210200d
      (b) Wang, H.; Jain, P.; Antilla, J. C.; Houk, K. N. Origins of stereoselectivities in chiral phosphoric acid catalyzed allylborations and propargylations of aldehydes. J. Org. Chem. 2013, 78, 1208,  DOI: 10.1021/jo302787m
      (c) Grayson, M. N.; Goodman, J. M. Understanding the mechanism of the asymmetric propargylation of aldehydes promoted by 1,1’-bi-2-naphthol-derived catalysts. J. Am. Chem. Soc. 2013, 135, 6142,  DOI: 10.1021/ja3122137
    14. 14
      (a) Miura, T.; Nakahashi, J.; Zhou, W.; Shiratori, Y.; Stewart, S. G.; Murakami, M. Enantioselective synthesis of anti-1,2-oxaborinan-3-enes from aldehydes and 1,1-di(boryl)alk-3-enes using ruthenium and chiral phosphoric acid catalysts. J. Am. Chem. Soc. 2017, 139, 10903,  DOI: 10.1021/jacs.7b06408
      (b) Miura, T.; Oku, N.; Murakami, M. Diastereo- and enantioselective synthesis of (E)-δ-boryl-substituted anti-homoallylic alcohols in two steps from terminal alkynes. Angew. Chem., Int. Ed. 2019, 58, 14620,  DOI: 10.1002/anie.201908299
      (c) Gao, S.; Duan, M.; Houk, K. N.; Chen, M. Chiral phosphoric acid dual-function catalysis: asymmetric allylation with α-vinyl allylboron reagents. Angew. Chem., Int. Ed. 2020, 59, 10540,  DOI: 10.1002/anie.202000039
      (d) Gao, S.; Duan, M.; Shao, Q.; Houk, K. N.; Chen, M. Development of α, α-disubstituted crotylboronate reagents and stereoselective crotylation via Brønsted or Lewis acid catalysis. J. Am. Chem. Soc. 2020, 142, 18355,  DOI: 10.1021/jacs.0c04107
      (e) Chen, J.; Chen, M. Enantioselective syntheses of (Z)-6′-boryl-anti-1,2-oxaborinan-3-enes via a dienylboronate protoboration and asymmetric allylation reaction sequence. Org. Lett. 2020, 22, 7321,  DOI: 10.1021/acs.orglett.0c02657
      (f) Zhang, Z.; Liu, J.; Gao, S.; Su, B.; Chen, M. Highly stereoselective syntheses of α,α-disubstituted (E)- and (Z)-crotylboronates. J. Org. Chem. 2023, 88, 3288,  DOI: 10.1021/acs.joc.2c02606
    15. 15
      Hoffmann, R. W. Allylic 1,3-strain as a controlling factor in stereoselective transformations. Chem. Rev. 1989, 89, 1841,  DOI: 10.1021/cr00098a009
  • Supporting Information

    Supporting Information


    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.orglett.4c04663.

    • Experimental procedures, spectra for all new compounds (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.