N to C aryl migration in lithiated carbamates: alpha-arylation of benzylic alcohols.
We report a new mode of reactivity displayed by lithiated O-benzyl carbamates carrying an N-aryl substituent: upon lithiation, the N-aryl group is transferred cleanly from N to C. An arylation of the carbamate results, providing a route to alpha,alpha-arylated secondary or tertiary alcohols. We also report density functional theory calculations supporting the proposal that arylation proceeds through a dearomatizing attack on the aromatic ring, a significantly lower energy pathway than the 1,2-acyl transfer observed with related N-alkyl carbamates.
Clayden
Jonathan
J
School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK. clayden@man.ac.uk
Farnaby
William
W
Grainger
Damian M
DM
Hennecke
Ulrich
U
Mancinelli
Michele
M
Tetlow
Daniel J
DJ
Hillier
Ian H
IH
Vincent
Mark A
MA