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.
Emma, M.G., Lombardo, M., Trombini, C., Quintavalla, A. (2016). The Organocatalytic α-Fluorination of Chiral γ-Nitroaldehydes: the Challenge of Facing the Construction of a Quaternary Fluorinated Stereocenter. EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 2016(19), 3223-3232 [10.1002/ejoc.201600378].
The Organocatalytic α-Fluorination of Chiral γ-Nitroaldehydes: the Challenge of Facing the Construction of a Quaternary Fluorinated Stereocenter
EMMA, MARCO GIUSEPPE;LOMBARDO, MARCO;TROMBINI, CLAUDIO;QUINTAVALLA, ARIANNA
2016
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
