Enantioselective fluoride ring opening of aziridines enabled by cooperative Lewis acid catalysis
摘要:
The enantioselective ring opening of aziridines using a latent source of HF is described. A combination of two Lewis acids, (salen)Co and an achiral Ti(IV) cocatalyst, provided optimal reactivity and enantioselectivity for the trans beta-fluoroamine product. The use of a chelating aziridine protecting group was crucial. Acyclic and cyclic meso N-picolinamide aziridines underwent fluoride ring opening in up to 84% ee, and the kinetic resolution of a piperidine-derived aziridine was performed with k(rel)=6.6. The picolinamide group may be readily removed without epimerization of the fluoroamine. Preliminary studies revealed a bimetallic mechanism wherein the chiral (salen)Co catalyst delivers the nucleophile and the Ti(IV) cocatalyst activates the aziridine. (C) 2013 Elsevier Ltd. All rights reserved.
Aziridines. XIV. 3-Oxa-6-azabicyclo[3.1.0]hexane<sup>1</sup>
作者:Paul E. Fanta、Edward N. Walsh
DOI:10.1021/jo01339a011
日期:1966.1
Enantioselective fluoride ring opening of aziridines enabled by cooperative Lewis acid catalysis
作者:Julia A. Kalow、Abigail G. Doyle
DOI:10.1016/j.tet.2013.01.062
日期:2013.7
The enantioselective ring opening of aziridines using a latent source of HF is described. A combination of two Lewis acids, (salen)Co and an achiral Ti(IV) cocatalyst, provided optimal reactivity and enantioselectivity for the trans beta-fluoroamine product. The use of a chelating aziridine protecting group was crucial. Acyclic and cyclic meso N-picolinamide aziridines underwent fluoride ring opening in up to 84% ee, and the kinetic resolution of a piperidine-derived aziridine was performed with k(rel)=6.6. The picolinamide group may be readily removed without epimerization of the fluoroamine. Preliminary studies revealed a bimetallic mechanism wherein the chiral (salen)Co catalyst delivers the nucleophile and the Ti(IV) cocatalyst activates the aziridine. (C) 2013 Elsevier Ltd. All rights reserved.
Enantioselective ring-opening of aziridines
申请人:Antilla Jon C.
公开号:US20090030212A1
公开(公告)日:2009-01-29
A process for the preparation of a nucleophilic addition product of an aziridine and a nucleophile, the process comprising treating the arizidine with the nucleophile in the presence of a biaryl phosphoric acid catalyst