Useful Enantioselective Bicyclization Reactions Using an N-Protonated Chiral Oxazaborolidine as Catalyst
作者:Gang Zhou、Qi-Ying Hu、E. J. Corey
DOI:10.1021/ol035542a
日期:2003.10.1
[reaction: see text] Nine examples are reported of enantioselective [4 + 2] cycloaddition reactions of achiral, acyclic substrates to form chiral bicyclo[4.3.0]nonane or bicyclo[4.4.0]decane derivatives.
Iminium ion cascade reactions: stereoselective synthesis of quinolizidines and indolizidines
作者:Shawn M. Amorde、Ivan T. Jewett、Stephen F. Martin
DOI:10.1016/j.tet.2008.10.074
日期:2009.4
A noveliminiumion cascade reaction has been developed that allows for the stereoselective synthesis of a variety of substituted aza-fused bicycles. The combination of amino allylsilanes and aldehydes (or ketones) was used to synthesize a number of quinolizidines and indolizidines in a one-pot reaction sequence. This technology has been used to effect the facile syntheses of several indolizidine and
[3+2] Cycloadditions of Aryl Cyclopropyl Ketones by Visible Light Photocatalysis
作者:Zhan Lu、Meihua Shen、Tehshik P. Yoon
DOI:10.1021/ja107849y
日期:2011.2.9
We report a new method for the formal [3+2] reaction of aryl cyclopropyl ketones with olefins to generate highly substituted cyclopentane ring systems. The key initiation step in this process is the one-electron reduction of the ketone to the corresponding radical anion, which is accomplished using a photocatalytic system comprising Ru(bpy)(3)(2+), La(OTf)(3), and TMEDA.
Stereodefined α-iodovinyl sulfoxides bearing a sulfinyl group and an iodo group were prepared by a one-pot iodination/Horner–Wadsworth–Emmons reaction protocol. This reaction can be applied to a wide range of aldehydes, and further application was demonstrated.
Nitrilases, nucleic acids encoding them and methods for making and using them
申请人:Diversa Corporation
公开号:US20040014195A1
公开(公告)日:2004-01-22
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.