Catalysis by gold has rapidly become a hot topic in chemistry, with a new discovery being made almost every week. Gold is equally effective as a heterogeneous or a homogeneous catalyst and in this Review we attempt to marry these two facets to demonstrate this new found and general efficacy of gold. The latest discoveries are placed within a historical context, but the main thrust is to highlight the new catalytic possibilities that gold‐catalyzed reactions currently offer the synthetic chemist, in particular in redox reactions and nucleophilic additions to π systems. Indeed gold has proved to be an effective catalyst for many reactions for which a catalyst had not been previously identified, and many new discoveries are still expected.
Although gold is generally regarded as a very unreactive metal, nanoscale gold has been found to be exceptionally active as a catalyst. But the precise nature of the active sites and the mechanisms of the catalysed reactions of gold are as yet unknown.