Rh(iii)-catalyzed regioselective intermolecular -methylene Csp-H bond carbenoid insertion.

A Rh(iii)-catalyzed regioselective intermolecular carbenoid insertion into the -methylene Csp-H bond of acyclic aliphatic amides has been achieved, taking advantage of bidentate-chelation assistance. This methodology has been successfully applied to a broad range of linear and branched-chain -alkylamides, thus providing a practical method for the assembly of diverse beta-amino esters. Mechanism studies and density functional theory (DFT) calculations revealed that a singlet Fischer type carbene insertion an outer-sphere pathway was involved in this -methylene Csp-H bond carbenoid insertion.