Synthesis of Cyclic Amidines by Iridium-Catalyzed Deoxygenative Reduction of Lactams and Tandem Reaction with Sulfonyl Azides.

An efficient and convenient synthesis of various cyclic amidines has been achieved via iridium-catalyzed deoxygenative reduction of lactams with a silane followed by a one-pot cycloaddition reaction with sulfonyl azides. Using the novel tandem procedure, a large array of cyclic amidines bearing various sized rings were synthesized in good yields from readily available lactams. This methodology has been successfully utilized in the late stage diversification of complex architectures bearing a lactam moiety.