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Catalytic Asymmetric 6π Electrocyclization: Enantioselective Synthesis of Functionalized Indolines
Author(s) -
Maciver Eleanor E.,
Thompson Sam,
Smith Martin D.
Publication year - 2009
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200905169
Subject(s) - enantioselective synthesis , catalysis , delocalized electron , yield (engineering) , aryl , chemistry , combinatorial chemistry , organic chemistry , materials science , alkyl , metallurgy
How to close a ring: An approach to catalytic asymmetric 6π electrocyclization leads to a highly enantioselective process that was used in the synthesis of chiral indolines (see scheme). Treatment of N ‐aryl imines under phase transfer conditions in the presence of N ‐benzyl cinchonidinium chloride generates a delocalized 2‐aza‐pentadienyl anion system that cyclizes in up to 99 % yield and 98 % ee.