The improved synthesis of gamma-, delta- and epsilon-lactones using a dinuclear N-heterocyclic carbene (NHC)-gold(I) catalyst is reported. This solvent-free process provides access to gamma- and delta-lactones in high regio- and stereoselectivity. Reactions were performed at low catalyst loadings and without the need for any additives. The use of a digold pre-catalyst provides a new synthetic route to functionalised epsilon-lactones, poorly accessible using previous methodologies.
- gold catalysis
- low catalyst loading