-oxodithioacetals 2a-m are shown to undergo facile one pot thermal dehydration and dethioacetalization in the presence of dimethyl sulphoxide to afford the corresponding ene- and polyene aldehydes 5a-m and 6a-b in good yields. The probable mechanism of dethioacetalization with dimethyl sulphoxide has also been discussed.
Theα-oxoketene dithioacetals are shown to undergo conjugate 1,4-reduction in highly regio- and chemoselective manner with sodium borohydride in acetic acid to afford the corresponding β-oxodithioacetals in good yields. These results have been rationalized according to HSAB principle in terms of 'hard soft affinity inversion' concept. The reduction of with sodium cyanoborohydride also proceeds in 1