Resolution of alpha-(phenoxy) phenylacetic acid derivatives with naphthyl-alkylamines
申请人:Cheng Peng
公开号:US20070073082A1
公开(公告)日:2007-03-29
The present invention provides a methods and compounds for producing an enantiomerically enriched α-(phenoxy)phenylacetic acid compound of the formula:
from a mixture of its enantiomers, where R
1
is alkyl or haloalkyl and X is halide.
Chiral Brønsted Acids Catalyze Asymmetric Additions to Substrates that Are Already Protonated: Highly Enantioselective Disulfonimide-Catalyzed Hantzsch Ester Reductions of NH–Imine Hydrochloride Salts
作者:Benjamin List、Vijay N. Wakchaure、Carla Obradors
DOI:10.1055/s-0040-1706413
日期:2020.10
are frequently used substrates in asymmetric Bronsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N–H imine
” conformation (“1,3,5-up/2,4,6-down” conformation) to avoid otherwise increased steric repulsion between the vicinal substituents of the benzene frame. Use of such sterically bulky subunits within a molecule to enable it to adopt a thermodynamically favored conformation with mini-mum steric interactions has been dubbed as “steric gearing.”