Brønsted Acid Catalysis of Achiral Enamine for Regio- and Enantioselective Nitroso Aldol Synthesis
摘要:
Two types of chiral Brønsted acid catalysts have been shown to catalyze regio- and enantioselective nitroso aldol synthesis between nitrosobenzene and achiral enamine. The combination of Brønsted acidity and amine moiety of enamine realizes complete regioselectivity with high enantioselectivity. After a survey of Brønsted acid catalysts, 1-naphthyl glycolic acid is found to be optimal in the O-nitroso aldol pathway, while 1-naphthyl TADDOL is the best catalyst for the N-nitroso aldol pathway. This is based on our finding on the control of regioselectivity by changing the amine moiety of enamine and the choice of Brønsted acidity.
Asymmetric reduction of arylglyoxylic acids via host-guest complex formation with optically active paracyclophanes.
作者:Ichiro Takahashi、Kazunori Odashima、Kenji Koga
DOI:10.1248/cpb.33.3571
日期:——
Reduction of 1-naphthylglyoxylic acid (2c) by inclusion complex formation with optically active paracyclophane (1a) followed by treatment with sodium borohydride in acidic water gave, after esterification with diazomethane, (R)-1-naphthylglycolic acid methyl ester (4c) in 9.7% ee. A working hypothesis is proposed to describe the mechanism of this reaction.
An Enzyme Library Approach to Biocatalysis: Development of Nitrilases for Enantioselective Production of Carboxylic Acid Derivatives
作者:Grace DeSantis、Zuolin Zhu、William A. Greenberg、Kelvin Wong、Jenny Chaplin、Sarah R. Hanson、Bob Farwell、Lawrence W. Nicholson、Cynthia L. Rand、David P. Weiner、Dan E. Robertson、Mark J. Burk
DOI:10.1021/ja0259842
日期:2002.8.1
and diverse set of nitrilases is reported. The utility of this nitrilaselibrary for identifying enzymes that catalyze efficient production of valuable hydroxy carboxylicacidderivatives is demonstrated. Unprecedented enantioselectivity and substrate scope are highlighted for three newly discovered and distinct nitrilases. For example, a wide array of (R)-mandelic acidderivatives and analogues were
Nitrilases, Nucleic Acids Encoding Them and Methods for Making and Using Them
申请人:DeSantis Grace
公开号:US20100009426A1
公开(公告)日:2010-01-14
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
Nitrilases, Nucleic Acids Encoding Them and Methods For Making and Using Them
申请人:Desantis Grace
公开号:US20120009637A1
公开(公告)日:2012-01-12
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.