Anions formed from the lithiation of a variety of 1-(arylmethyl)-and 1-(heteroarylmethyl) benzotriazoles 1 with n-BuLi underwent addition to aliphatic and aromatic aldehydes and cyclic and acyclic ketones. Subsequent in situ thermal rearrangements of the intermediates in the presence of zinc bromide provided one-carbon chain-extended or ring-expanded α- aryl-and α-heteroaryl-substituted ketones 2 in moderate to excellent yields in simple one- ...