Preparation of cis-Fused Tetrahydropyranyl Lactones via Palladium-Catalysed Cyclocarbonylation of Enediols

Abstract

The stereoselective palladium-catalysed cyclocarbonylation of hex-5-ene-1,4-diols affords cis-fused bicyclic lactones only. Ring-opening with N,O-dimethylhydroxylamine hydrochloride gives the corresponding Weinreb amides, and their subsequent recyclisation provides advanced synthons for the prospective synthesis of decarestrictine L. The relative configurations of all the prepared tetrahydropyrans are determined by NOESY. The attempted transformations of lactones into methyl ketones leads to an unexpected furan, the formation of which is discussed.