Web Release Date: August 21,
Enantioselective [3 + 2]-Cycloadditions Catalyzed by a Protected,
Multifunctional Phosphine-Containing 
-Amino Acid
Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107
Received May 14, 2007
Abstract:
Catalytic asymmetric [3 + 2]-cycloaddition reactions between -allenic esters and enones are presented. We have found that a simple phosphine-containing protected -amino acid derivative is capable of promoting such cycloadditions in high yields with significant levels of regioselectivity and enantioselectivity. Furthermore, employing chiral racemic 
-substituted allenoates in the cycloaddition with chalcone substrates results in a "deracemization" reaction furnishing cyclopentenes in high yields with up to 93% ee.
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