title: Ring-selective functionalization of N,N'-diarylureas by regioselective N-alkylation and directed ortho metalation.
abstract: [reaction: see text]. Unsymmetrical N,N'-diarylureas may be alkylated regioselectively at the more sterically congested nitrogen atom. The resulting mono-N-alkylated ureas undergo directed metalation (ortholithiation) with sec-BuLi to yield, on electrophilic quench, products functionalized regioselectively at the ring bearing the alkylated nitrogen atom.
authors: School of Chemistry, University of Manchester, UK. j.p.clayden@man.ac.uk
authors: Jonathan
authors: J
authors: Clayden
authors: Hazel
authors: H
authors: Turner
authors: Mark
authors: M
authors: Pickworth
authors: Thomas
authors: T
authors: Adler
mesh_terms: D000478:Alkylation; D018360:Crystallography, X-Ray; D003500:Cyclization; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism; D014508:Urea / Q000032:analysis / Q000737:chemistry*
chemical_list: D014508:Urea