Gold Catalysis – Steadily Increasing in Importance

1 Since the beginning of the millennium the field of gold catalysis has emerged as one of the top subjects in organic chemistry. Analysis of the chemical databases clearly documents this evolution and the subject is listed among the "Hot Topics" in major journals. If the activity in gold catalysis would have followed a normal "life cycle", one could have expected a slow decay in the numbers of publications after about a decade. The opposite is the case; the interest is not decreasing but rather continues to grow. One can observe that the success in catalysis research has provided important impulses for other sectors of gold chemistry, too. Many of the new complexes of gold developed for catalysis find interesting new applications in other fields. Many of the mechanisms initially proposed for gold-catalyzed reactions have provided new impulses for the stoichiometric organometallic chemistry of gold; the recent efforts in the field of oxidative addition to gold(I) and reductive elimination at gold(III) are good examples. Overall, gold catalysis triggered a revival of all aspects of gold chemistry, ranging from gold nanoparticles to applications of gold-catalyzed reactions in the total synthesis of complex natural targets. In this special issue "Gold Catalysis: Quo Vadis" a series of publications on subjects with high potential for the future of gold catalysis have been collected. The issue contains two timely reviews: one on gold-catalyzed reactions of diyne substrates, with a focus on the use of carbonates and esters, the other covering N- and O-functionalizations of alkynes with a focus on reagents with NO bonds. A series of communications cover diverse subjects ranging from the preparation of gold-nanocrystals as catalysts, heterogeneous gold-catalyzed reactions to a diverse family of cycloadditions providing pharmaceutically interesting heterocycles, a borrowing hydrogen strategy and a total synthesis. Full papers on solvent-free gold-catalyzed conversions, micellar gold catalysts, access to heterobimetallic species, gold-functionalized platinum nanospheres as well as heterogeneous catalysts for the selective oxidation of amines are included in the issue, too. Furthermore, four updates round out the picture; examples here describe access to strained bicyclic compounds, visible light photoredox catalysis and powerful gold-catalyzed cascade reactions. Overall, "Gold Catalysis: Quo Vadis" demonstrates how the field now is quickly moving beyond classic topics of early gold catalysis, like nucleophilic addition reactions or reactions of carbene intermediates. The new topics show how gold catalysis will continue to play an important role in organic synthesis and organometallic chemistry.