Hydrostannylation of sulphur- and nitrogen-substituted phenylacetylenes: NMR characterisation of the reaction products

Both non-catalysed and Pd-catalysed hydrostannylations of methylthiophenyl- acetylene and N,N-dimethylaminophenylacetylene by triphenyltin hydride were performed. In the case of PhC equivalent to CSMe (la), both reactions are quite selective affording (Z)-and (E)-2-methylthio-2-triphenylstannyl-1-phe nylethene (2,3), respectively. In the case of PhC equivalent to CNMe2 (Ib), the non-catalysed reaction affords (Z)-2-(N,N-dimethylamino)-1-triphenysta nnyl-1-phenylethene(4) nearly quantitatively, whereas the Pd-catalysed reac tion affords a mixture of compounds only. The compounds 2-4 were completely identified using H-1 - C-13 gs HMQC, 1D INADEQUATE and NOESY experiments.