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Communication

Synthesis of 2,3-Disubstituted Benzofurans by Platinum−Olefin-Catalyzed Carboalkoxylation of o-Alkynylphenyl Acetals

Supporting Info

Itaru Nakamura, Yuya Mizushima, and Yoshinori Yamamoto*

Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan

J. Am. Chem. Soc., 2005, 127 (43), pp 15022–15023

DOI: 10.1021/ja055202f

Publication Date (Web): October 8, 2005

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, yoshi@yamamoto1.chem.tohoku.ac.jp

Abstract

The PtCl₂-catalyzed cyclization reaction of o-alkynylphenyl acetals 1 in the presence of 1,5-cyclooctadiene produces 3-(α-alkoxyalkyl)benzofurans 2 in good to high yields. For example, the reaction of acetaldehyde ethyl 2-(1-octynyl)phenyl acetal (1a), acetaldehyde ethyl 2-(cyclohexylethynyl)phenyl acetal (1c), and acetaldehyde ethyl 2-(phenylethynyl)phenyl acetal (1f) in the presence of 2 mol % of platinum(II) chloride and 8 mol % of 1,5-cyclooctadiene in toluene at 30 °C gave the corresponding 2,3-disubstituted benzofurans 2a, 2c, and 2f in 91, 94, and 88% yields, respectively.

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Published In Issue November 02, 2005
Received August 1, 2005

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Communication

Synthesis of 2,3-Disubstituted Benzofurans by Platinum−Olefin-Catalyzed Carboalkoxylation of o-Alkynylphenyl Acetals