Visible Light-Induced α-C(sp)-H Acetalization of Saturated Heterocycles Catalyzed by a Dimeric Gold Complex.

Saturated heterocyclic acetals are useful fragments in organic synthesis and other fields. Herein, C(sp)-H dehydrogenative cross-couplings of ethers, tetrahydrothiophenes, and pyrrolidines were achieved under visible light irradiation by using iodobenzene and an in situ-formed gold complex. The broad functional group compatibility and substrate scope indicate that our strategy is a promising way to synthesize acetal analogues. The method was successfully applied in late-stage modifications of bioactive molecules. Gram scale syntheses and mechanistic studies are also presented.