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Enantioselective Organocatalytic Four‐Atom Ring Expansion of Cyclobutanones: Synthesis of Benzazocinones
Author(s) -
Zhou Yirong,
Wei YunLong,
Rodriguez Jean,
Coquerel Yoann
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201810184
Subject(s) - enantioselective synthesis , bifunctional , chemistry , ring (chemistry) , amide , aryl , catalysis , organocatalysis , stereochemistry , combinatorial chemistry , organic chemistry , alkyl
An enantioselective Michael addition– four‐atom ring expansion cascade reaction involving cyclobutanones activated by a N ‐aryl secondary amide group and ortho ‐amino nitrostyrenes has been developed for the preparation of functionalized eight‐membered benzolactams using bifunctional aminocatalysts. Taking advantage of the secondary amide activating group, the eight‐membered cyclic products could be further rearranged into their six‐membered isomers having a glutarimide core under base catalysis conditions without erosion of optical purity, featuring an overall ring expansion– ring contraction strategy.