A Highly Efficient Gold-Catalyzed Photoredox α-C(sp3) -H Alkynylation of Tertiary Aliphatic Amines with Sunlight

A new alpha-C(sp(3))-H alkynylation of unactivated tertiary aliphatic amines with 1-iodoalkynes as radical alkynylating reagents in the presence of [Au-2(mu-dppm)(2)](2+) in sunlight provides propargylic amines. Based on mechanistic studies, a C C coupling of an alpha-aminoalkyl radical and an alkynyl radical is proposed for the C(sp(3))-C(sp) bond formation. The mild, convenient, efficient, and highly selective C(sp(3))-H alkynylation reaction shows excellent regioselectivity and good functional-group compatibility. A scale-up to gram quantities is possible with sunlight used as a clean and sustainable energy source.