Dual Gold/Silver Catalysis: Indolizines from 2-Substituted Pyridine Derivatives via a Tandem C(sp3)-H Alkynylation/Iminoauration.

A dual gold/silver-catalyzed cascade C(sp3)-H alkynylation/iminoauration of 2-substituted pyridines with hypervalent iodine(III) reagents for the synthesis of indolizines is described. This novel reaction involves the formation of an alkynyl Au(III) species, a dual gold/silver-catalyzed C(sp3)-H functionalization, and a subsequent iminoauration process. A number of indolizines bearing diverse functionalities were prepared in good to excellent yield. Furthermore, a gram-scale reaction was efficiently conducted.