Palladium-catalyzed reaction of 2-alkynylhalobenzene with 2-alkynylbenzamide: an efficient approach to indeno[1,2-c]azepin-3(2H)-ones.

A novel and efficient route for rapid access to indeno[1,2-c]azepin-3(2H)-ones is described, which proceeds through a palladium-catalyzed tandem reaction of 2-alkynylhalobenzene with 2-alkynylbenzamide in the presence of PPh(3) or PCy(3). The indeno[1,2-c]azepin-3(2H)-ones which incorporate both indene and unsaturated seven-membered ring lactam skeletons are obtained in good to excellent yields.