A NOVEL REACTION OF COORDINATED VINYLIDENES - COUPLING WITH HYDROGEN-SULFIDE TO GIVE A ETA(1)-THIOALDEHYDE

The Ru-II fragment [(PN P)RuCl2] assists the coupling of phenylacetylene with H2S to give 2-phenylethanethial [PNP = CH3CH2CH2N(CH(2)CH(2)PPh(2))(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; P-phenylethanethial is recovered as either eta(1)-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 eta(1)-2-phenylethanethial complex.