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Squaramide‐Catalyzed Synthesis of Enantioenriched Spirocyclic Oxindoles via Ketimine Intermediates with Multiple Active Sites
Author(s) -
Sun QiangSheng,
Zhu Hua,
Chen YongJian,
Yang XiaoDi,
Sun XingWen,
Lin GuoQiang
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201506206
Subject(s) - squaramide , bifunctional , chemistry , catalysis , mannich reaction , combinatorial chemistry , cascade reaction , stereoselectivity , organocatalysis , stereochemistry , organic chemistry , enantioselective synthesis
A new method for the construction of five‐membered spirocyclic oxindoles is based on a Michael–Mannich cascade reaction of a ketimine intermediated catalyzed by a bifunctional quinine‐derived squaramide. The desired products were obtained in excellent yields (up to 94 %) and stereoselectivities (up to >20:1 d.r., >99 % ee ). A scaled‐up variant also proceeded smoothly showing that the one‐pot reaction might find application in the synthesis of bioactive‐compound libraries.