A novel reaction of coordinated vinylidenes: coupling with hydrogen sulfide to give a η1-thioaldehyde

Abstract

The RuII fragment [(PNP)RuCl2] assists the coupling of phenylacetylene with H2S to give 2-phenylethanethial [PNP = CH3CH2CH2N(CH2CH2PPh2)2] in a reaction that is initiated by alk-1-yne to vinylidene tautomerism at ruthenium, followed by electrophilic attack of H2S on the vinylidene ligand; 2-phenylethanethial is recovered as either η1-S-ligand or endo-6-benzyl-1-thiabicyclo[2.2.1]hept-3-ene ligand, and the latter molecule is formed via a stereoselective Diels–Alder reaction between cyclopentadiene and the η1-2-phenylethanethial complex.