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Aryloxide‐Facilitated Catalyst Turnover in Enantioselective α,β‐Unsaturated Acyl Ammonium Catalysis
Author(s) -
Matviitsuk Anastassia,
Greenhalgh Mark D.,
Antúnez DiegoJavier Barrios,
Slawin Alexandra M. Z.,
Smith Andrew D.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201706402
Subject(s) - enantioselective synthesis , catalysis , acylation , chemistry , yield (engineering) , ammonium , substrate (aquarium) , organic chemistry , kinetics , materials science , oceanography , metallurgy , geology , physics , quantum mechanics
A new general concept for α,β‐unsaturated acyl ammonium catalysis is reported that uses p‐nitrophenoxide release from an α,β‐unsaturated p‐nitrophenyl ester substrate to facilitate catalyst turnover. This method was used for the enantioselective isothiourea‐catalyzed Michael addition of nitroalkanes to α,β‐unsaturated p‐nitrophenyl esters in generally good yield and with excellent enantioselectivity (27 examples, up to 79 % yield, 99:1 er). Mechanistic studies identified rapid and reversible catalyst acylation by the α,β‐unsaturated p‐nitrophenyl ester, and a recently reported variable‐time normalization kinetic analysis method was used to delineate the complex reaction kinetics.