Synthesis of β‐Hydroxyaldehydes with Stereogenic Quaternary Carbon Centers by Direct Organocatalytic Asymmetric Aldol Reactions

Abstract

A fluorescence detection system was used to identify effective chiral-amine/acid combinations as bifunctional catalysts for asymmetric direct catalytic aldol reactions of α,α-dialkyl aldehydes with aryl aldehydes (see scheme). With the optimized catalyst system, the reaction of isobutyraldehyde with p-nitrobenzaldehyde provided the α,α-dimethyl aldol product in 92 % yield with 96 % ee. R1, R2=alkyl; X=NO2, CN, Br, Cl, OMe, H. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53546_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.