Gold Catalysis: 2,3‐ or 1,4‐Addition to Butadiynes

In the past, numerous impressive methodologies have been developed in homogeneous gold catalysis, typically using alkynes, allenes, or different non‐conjugated diyne systems as starting materials. While there are applications catalyzed by other transition metals, the use of 1,3‐butadiyne derivatives has been largely neglected in gold catalysis. In this work we present an efficient gold‐catalyzed method focusing on the functionalization of this specific type of diynes. The starting materials can be synthesized via simple Glaser Coupling, starting from cheap, highly variable, terminal alkynes. These homocoupling products, which are often observed as undesirable side‐products in Sonogashira reactions, can be converted into versatile 1,3‐butadiene derivatives in alcohol as a solvent and nucleophile under mild conditions. The possible field of application of the 1,3‐butadiene derivatives known from the literature is very broad and ranges from a use as transistor or OLED material to a use as an enzyme inhibitor. The approach presented here offers an attractive and highly effective way to versatile functionalized 1,3‐butadiene derivatives.