A Highly Efficient Gold-Catalyzed Photoredox α-C(sp(3))-H Alkynylation of Tertiary Aliphatic Amines with Sunlight.

A new α-C(sp(3))H alkynylation of unactivated tertiary aliphatic amines with 1-iodoalkynes as radical alkynylating reagents in the presence of [Au2(μ-dppm)2](2+) in sunlight provides propargylic amines. Based on mechanistic studies, a C-C coupling of an α-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.