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Asymmetric Synthesis of Enantioenriched 2‐Aryl‐2,3‐Dihydrobenzofurans by a Lewis Acid Catalyzed Cyclopropanation/Intramolecular Rearrangement Sequence
Author(s) -
Pandit Rameshwar Prasad,
Kim Seung Tae,
Ryu Do Hyun
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201906954
Subject(s) - cyclopropanation , stereocenter , enantioselective synthesis , intramolecular force , chemistry , lewis acids and bases , aryl , stereoselectivity , stereochemistry , catalysis , medicinal chemistry , organic chemistry , alkyl
A cyclopropanation/intramolecular rearrangement initiated by the Michael addition of in situ generated ortho ‐quinone methides ( o ‐QMs) has been developed for the enantioselective synthesis of 2‐aryl‐2,3‐dihydrobenzofurans containing two consecutive stereogenic centers, including a quaternary carbon atom. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction proceeded in excellent yields (up to 95 %) with excellent stereoselectivity (up to >99 ee, up to >20:1 d.r.).