Fast racemisation and slow epimerisation of laterally lithiated amides: stereochemical evidence for the mechanism of inversion of amide-substituted benzyllithiums.
Tertiary 1-naphthamides racemise much more slowly than their laterally lithiated derivatives, and the relative rates of racemisation and epimerisation of these derivatives indicate that the lithium-bearing stereogenic centre inverts via a "conducted tour" mechanism, in which the lithium cation is delivered from one face to the other by coordination to the rotating amide group.
Clayden
Jonathan
J
Department of Chemistry, University of Manchester, Oxford Road, Manchester, UKM13 9PL. j.p.clayden@man.ac.uk
Stimson
Christopher C
CC
Keenan
Martine
M
Wheatley
Andrew E H
AE