(-)-Menthone, an inexpensive chiral auxiliary, was used to prepare both enantiomers of alpha-amino acids, aminoalcohols, or oxazolidinones. The sequence includes the S(N)2' displacement by a cuprate reagent and a Curtius rearrangement as key steps.
Catalytic, Enantioselective N-Acylation of Lactams and Thiolactams Using Amidine-Based Catalysts
作者:Xing Yang、Valentina D. Bumbu、Peng Liu、Ximin Li、Hui Jiang、Eric W. Uffman、Lei Guo、Wei Zhang、Xuntian Jiang、K. N. Houk、Vladimir B. Birman
DOI:10.1021/ja306766n
日期:2012.10.24
contrast to alcohols and amines, racemic lactams and thiolactams cannot be resolved directly via enzymatic acylation or classical resolution. Asymmetric N-acylation promoted by amidine-based catalysts, particularly Cl-PIQ 2 and BTM 3, provides a convenient method for the kinetic resolution of these valuable compounds and often achieves excellent levels of enantioselectivity in this process. Density
An asymmetric transfer hydrogenation of 2-oxazolones in the presence of a chiral diamine ruthenium catalyst with potassium formate as a hydrogen source and potassium carbonate as an additive in 2,2,2-trifluoroethanol is described. A series of chiral 2-oxazolidinones were obtained with 29%–95% yields and 86%–>99% ee's. Furthermore, gram-scale synthesis of chiral 2-oxazolidinone and its downstream derivatizations