C-H amination/cyclocarbonylation of allene carbamates: a versatile platform for the synthesis of α,β-unsaturated γ-lactams

Despite their utility as building blocks for the construction of a variety of nitrogen-containing heterocyclic scaffolds, the preparation of allenic amines 2 via the direct C-H amination of allenes of the general structure 1 has not been well-explored. In this report, we describe our preliminary studies on the factors that control the chemoselectivity of Rh-catalyzed aminations of allenes to give either bicyclic methylene aziridines or the desired allenic amines 2. Additionally, the conversion of selected allenic amines to alpha,beta-unsaturated gamma-lactam scaffolds via a facile Ru-3(CO)(12) catalyzed cyclocarbonylation is described. (C) 2011 Elsevier Ltd. All rights reserved.