Where does Au coordinate to N-(2-pyridiyl)benzotriazole: gold-catalyzed chemoselective dehydrogenation and borrowing hydrogen reactions

Abstract

Where does Au coordinate to N-(2-pyridiyl)benzotriazole? Here, pyridyltriazole gold(I) complexes were synthesized, whereby it was revealed that the triazole part coordinated to gold(I). Compared to the Ph₃PAuCl/AgOTf catalyst, pyridyltriazole gold(I) complexes proved to be an efficient pre-catalyst for the most challenging gold-catalyzed borrowing hydrogen reaction and dehydrogenation of alcohols and amines, which provided an efficient method to selectively synthesize imines, substituted amines and functionalized ketones in excellent yields with high chemoselectivity. This indicated that triazole ligands are helpful in forming gold nanoparticles and delaying agglomeration in these reactions. Importantly, this kind of air and moisture stable complex was effective for allene synthesis through the 3,3-rearrangement of propargyl ethers with good yields under wet conditions with a reduced catalyst loading by a silver-free protocol. Furthermore, the synthesis of 1,5-enyne derivatives was realized from propargyl alcohols with pyridyltriazole gold(I) complexes as the catalyst.