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Brønsted Base‐Catalyzed Formal Reductive [3+2] Annulation of 4,4,4‐Trifluorocrotonate and α‐Iminoketones
Author(s) -
Kondoh Azusa,
Terada Masahiro
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002943
Subject(s) - annulation , phosphazene , chemistry , trifluoromethyl , catalysis , diastereomer , moiety , imine , base (topology) , tandem , combinatorial chemistry , michael reaction , quaternary carbon , medicinal chemistry , stereochemistry , organic chemistry , enantioselective synthesis , mathematics , mathematical analysis , alkyl , materials science , composite material , polymer
A formal reductive [3+2] annulation of 4,4,4‐trifluorocrotonate and α‐iminoketones was developed under Brønsted base catalysis. A single phosphazene base efficiently catalyzes the one‐pot tandem reaction involving two mechanistically different elementary processes, namely the chemoselective reduction of an imine moiety of α‐iminoketones with thiols as the reductant and the subsequent intermolecular Michael addition of an enolate of α‐aminoketones concomitant with lactam formation. This operationally simple method provides β‐trifluoromethyl‐substituted γ‐lactams with a tetrasubstituted carbon as a single diastereomer.