Enantioselective Organocatalytic Michael Addition of Aldehydes to Nitroethylene: Efficient Access to γ<sup>2</sup>-Amino Acids
作者:Yonggui Chi、Li Guo、Nathan A. Kopf、Samuel H. Gellman
DOI:10.1021/ja800345r
日期:2008.4.1
EnantioselectiveorganocatalyticMichaeladdition of aldehydes to nitroethylene catalyzed by (S)-diphenylprolinol silyl ether provides beta-substituted-delta-nitroalcohols in nearly optically pure form (96-99% ee). The Michael adducts bear a single substituent adjacent to the carbonyl and can be efficiently converted to protected gamma2-amino acids, which are essential for the systematic conformational
Stereospecific Synthesis of Conformationally Constrained γ-Amino Acids: New Foldamer Building Blocks That Support Helical Secondary Structure
作者:Li Guo、Yonggui Chi、Aaron M. Almeida、Ilia A. Guzei、Brian K. Parker、Samuel H. Gellman
DOI:10.1021/ja907233q
日期:2009.11.11
A highly stereoselective synthesis of novel cyclically constrained gamma-amino acid residues is presented. The key step involves organocatalytic Michael addition of an aldehyde to 1-nitrocyclohexene. After aldehyde reduction, this approach provides optically active beta-substituted delta-nitro alcohols (96-99% ee), which can be converted to gamma-amino acid residues with a variety of substituents at
CONCISE BETA2-AMINO ACID SYNTHESIS VIA ORGANOCATALYTIC AMINOMETHYLATION
申请人:CHI Yonggui
公开号:US20080058548A1
公开(公告)日:2008-03-06
The present invention provides a method for the synthesis of β
2
-amino acids. The method also provides methods yielding α-substituted β-amino aldehydes and β-substituted γ-amino alcohols. The present method according to this invention allows for increased yield and easier purification using minimal chromatography or crystallization. The methods described herein are based on an aldehyde aminomethylation which involves a Mannich reaction between an aldehyde and a formaldehyde-derived N,O-acetal (iminium precursor) and a catalyst, such as, for example, L-proline or a pyrrolidine. The invention allows for large scale, commercial preparation of β
2
-amino acids.