A PEGylated N-heterocyclic carbene-gold(i) complex: an efficient catalyst for cyclization reaction in water

Abstract

Here we describe an efficient method for the synthesis of a PEGylated N-heterocyclic carbene(NHC)–gold(I) complex. This PEGylated NHC–gold(I) complex exhibited high reactivity and regio-selectivity in the cyclization of various alkynoic acids and cascade reaction of tryptamine and alkynoic acids in water. A systematic study of double cyclization of dialkynoic acids to construct spiro enol lactones was first reported. Importantly, this water-soluble catalyst could be recycled seven times while maintaining good catalytic activity.