Highly selective mild stepwise allylation of N-methoxybenzamides with allenes.

An efficient Rh(III)-catalyzed stepwise ortho allylation of N-methoxybenzamides 1 with polysubstituted allenes is reported. This C-H functionalization involving allenes is conducted under very mild conditions (-20 °C or room temperature) and compatible with ambient air and moisture, and it can be applied to terminal or internal allenes with different synthetically attractive functional groups. Highly efficient axial chirality transfer has been realized, yielding optically active lactones.