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The Organocatalytic α‐Fluorination of Chiral γ‐Nitroaldehydes: the Challenge of Facing the Construction of a Quaternary Fluorinated Stereocenter
Author(s) -
Emma Marco Giuseppe,
Lombardo Marco,
Trombini Claudio,
Quintavalla Arianna
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600378
Subject(s) - stereocenter , chemistry , organocatalysis , stereoselectivity , enamine , combinatorial chemistry , organic chemistry , michael reaction , enantioselective synthesis , catalysis
Chiral γ‐nitroaldehydes 1 are easily accessible by the organocatalytic Michael addition of aldehydes to nitroalkenes. In this paper, we report the organocatalytic fluorination of 1 with N ‐fluorobenzenesulfonimide (NFSI) leading to the highly stereoselective construction of a challenging quaternary fluorinated stereocenter at the α position of α,α‐dialkyl aldehydes. The reaction takes place via a chiral trisubstituted enamine, so far rather unexplored in the field of organocatalysis. Fluorinated products 3 are direct precursors of chiral monofluorinated 3,4‐polysubstituted pyrrolidines. Mechanistic details are discussed with the aid of computational results.