Palladium-Catalyzed Aerobic Oxidative Kinetic Resolution of Alcohols with an Achiral Exogenous Base
作者:Sunil K. Mandal、Matthew S. Sigman
DOI:10.1021/jo034717r
日期:2003.9.1
(-)-sparteine for a more practical achiral base in the aerobic oxidativekineticresolution of secondary alcohols is described. Carbonate bases are the most effective of those screened and allow for effective kineticresolution of benzylic, allylic, and aliphatic substrates. The procedure was also successfully extended to the oxidative desymmetrization of meso diols.
Scope of Enantioselective Palladium(II)-Catalyzed Aerobic Alcohol Oxidations with (−)-Sparteine
作者:Sunil K. Mandal、David R. Jensen、Jacob S. Pugsley、Matthew S. Sigman
DOI:10.1021/jo0269161
日期:2003.5.1
Evaluation of the substrate scope for Pd(II)/ (-)-sparteine catalyzed aerobic oxidative kinetic resolution of secondary alcohols is disclosed. An improved system is found with use of tert-butyl alcohol solvent in which benzylic and aliphatic alcohols as well as alcohols containing olefins are effectively oxidatively resolved. For substrates that successfully undergo oxidative kinetic resolution, k(rel) values
Chiral 1,3-oxazolidines are readily prepared from methyl ketones and chiral norephedrine. Formation of stannous azaenolates from the oxazolidines and reaction with aldehydes followed by removal of the chiral auxiliary lead to the aldol products in high level of enantiomeric purity.