Cesium effect: high chemoselectivity in direct N-alkylation of amines.
A novel method for the mono-N-alkylation of primary amines, diamines, and polyamines was developed using cesium bases in order to prepare secondary amines efficiently. A cesium base not only promoted alkylation of primary amines but also suppressed overalkylations of the produced secondary amines. Various amines, alkyl bromides, and alkyl sulfonates were examined, and the results demonstrated this methodology was highly chemoselective to favor mono-N-alkylation over dialkylation. In particular, use of either sterically demanding substrates or amino acid derivatives afforded the secondary amines exclusively, offering wide applications in peptidomimetic syntheses.
Salvatore
Ralph Nicholas
RN
Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620-5250, USA.
Nagle
Advait S
AS
Jung
Kyung Woon
KW
D000478:Alkylation; D000588:Amines / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D018716:Molecular Mimicry; D010455:Peptides / Q000737:chemistry
D000588:Amines; D010455:Peptides; D002586:Cesium