Chiral Cyclometalated Oxazoline Gold(III) Complex-Catalyzed Asymmetric Carboalkoxylation of Alkynes
作者:Jia-Jun Jiang、Jian-Fang Cui、Bin Yang、Yulu Ning、Nathanael Chun-Him Lai、Man-Kin Wong
DOI:10.1021/acs.orglett.9b02171
日期:2019.8.16
O′-chelated 4,4′-biphenol cyclometalated oxazoline gold(III) complexes has been developed. A high yield (≤89%) and a high enantioselectivity (≤90% ee) were achieved in asymmetric carboalkoxylation of alkynes. Enantioselectivity could be significantly improved from 19% to 90% ee by increasing the steric size of the substituent on the chiral oxazoline ligand. Catalytically active AuIII species and the origin
Generation and Ring Opening of Aziridines in Telescoped Continuous Flow Processes
作者:Nathanael Hsueh、Guy J. Clarkson、Michael Shipman
DOI:10.1021/acs.orglett.5b01777
日期:2015.7.17
A simple method for the preparation of a variety of N-sulfonyl aziridines (10 examples) from 1,2-amino alcohols under continuous flow conditions is described. Using flow based methods, the aziridines can be further ring opened with oxygen, carbon, and halide nucleophiles or ring expanded to imidazolines by Lewis acid promoted reaction with nitriles. Telescoping the aziridine generation and ring opening steps together in a microfluidic reactor allows the chemistry to be undertaken with limited exposure to the potentially hazardous aziridine intermediates.