Rational Combination of Two Privileged Chiral Backbones: Highly Efficient Organocatalysts for Asymmetric Direct Aldol Reactions between Aromatic Aldehydes and Acylic Ketones

• Published in: Journal of organic chemistry Vol. 73; no. 15; pp. 6006 - 6009
• Main Authors: Chen, Jia-Rong, An, Xiao-Lei, Zhu, Xiao-Yu, Wang, Xu-Fan, Xiao, Wen-Jing
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.08.2008; Amer Chemical Soc
• Subjects: Aldehydes - chemistry; Amines - chemistry; Catalysis; Catalysts: preparations and properties; Chemistry; Chemistry, Organic; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Ketones - chemistry; Molecular Structure; Nitrobenzenes - chemistry; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; Stereoisomerism; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; ORGANIC CATALYSIS; CINCHONA ALKALOIDS; THIOUREA; VERSATILE CATALYSTS; STEREOSELECTIVE ORGANOCATALYST; MANNICH REACTIONS; AMINO-ACIDS; PROLINE; DERIVATIVES; MICHAEL ADDITION; Quinuclidine derivatives; Enantioselectivity; Nitrogen heterocycle; Quinoline derivatives; Proline; Chiral compound; Aldehyde; Ketone; Aldol condensation; 2-Butanone; α-Aminoacid; Alkaloid; Amine; Asymmetric synthesis; Aminoacid; Enantiomeric excess; Aromatic compound; Chemical synthesis; Catalyst; Acetone; Hydrogen bond
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo800910s

A new class of organocatalysts has been designed by rational combination of proline with cinchona alkaloids. The chiral amine 3a, prepared from l-proline and cinchonidine, has been found to be an efficient catalyst for the direct aldol reactions of acetone or 2-butanone with a wide range of aldehydes (up to 98% ee). The cinchonidine backbone is essential to the reaction efficiency and enantioselectivity.