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Cooperative Tertiary Amine/Chiral Iridium Complex Catalyzed Asymmetric [4+3] and [3+3] Annulation Reactions
Author(s) -
Chen ZhiChao,
Chen Zhi,
Yang ZhenHong,
Guo Li,
Du Wei,
Chen YingChun
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201907797
Subject(s) - annulation , organocatalysis , chemistry , stereoselectivity , allylic rearrangement , catalysis , iridium , enantioselective synthesis , kinetic resolution , combinatorial chemistry , lewis acids and bases , organic chemistry
Asymmetric reactions merging organocatalysis and metal catalysis significantly broaden the scope of organic synthesis. Nevertheless, the accomplishment of stereoselective annulations combining two types of dipole species, independently generated from the activations of organocatalysts and metal complexes, still remains as a challenging task. Now, Morita–Baylis–Hillman carbonates from isatins and carbamate‐functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes. The zwitterionic allylic ylides and 1,4‐π‐allyliridium dipoles formed in situ are assembled in a highly stereoselective [4+3] annulation pattern. Similar cooperative catalytic strategy could be applied for the reactions of Morita–Baylis–Hillman carbonates and vinyl aziridines, furnishing an asymmetric [3+3] annulation reaction also with excellent stereocontrol.