Rh(III)-Catalyzed Domino [4 + 2] Annulation/Aza-Michael Addition of N-(Pivaloyloxy)benzamides with 1,5-Enynes via C-H Activation: Synthesis of Functionalized Aromathecins.

Reported herein are the Rh(III)-catalyzed cascade annulation reactions of N-(pivaloyloxy)benzamides with 1,5-enynes to access diversely substituted aromathecin derivatives involving C-H activation. The developed procedure offers an efficient synthetic tool for the assembly of a wide range of N-(pivaloyloxy)benzamides and 1,5-enynes with good atom economy and functional group tolerance. The key reactions involved in this annulation are alkyne insertion and aza-Michael addition under oxidant-free mild reaction conditions.