title: Carbolithiation of N-alkenyl ureas and N-alkenyl carbamates.
abstract: N-Alkenyl ureas and N-alkenyl carbamates, like other N-acyl enamines, are typically nucleophilic at their β-carbon. However, by incorporating an α-aryl substituent, we show that they will also undergo attack at the β-carbon by organolithium nucleophiles, leading to the products of carbolithiation. The carbolithiation of E and Z N-alkenyl ureas is diastereospecific, and N-tert-butoxycarbonyl N-alkenyl carbamates give carbolithiation products that may be deprotected in situ to provide a new connective route to hindered amines.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Julien
authors.initials: J
authors.lastname: Lefranc
authors.forename: Alberto
authors.initials: A
authors.lastname: Minassi
authors.forename: Jonathan
authors.initials: J
authors.lastname: Clayden
keywords: carbamate; carbolithiation; carbometallation; organolithium; stereospecificity; styrene; urea