α-Phosphoryl sulfoxides. XI. Sulfenylation of α-phosphoryl sulfoxides and a general synthesis of optically active ketene dithioacetal mono-S-oxides

Article abstract of DOI:10.1016/S0040-4020(96)01175-1

Sulfenylation and selenenylation of α-phosphoryl sulfoxides 1 with S-methyl methanethiosulfonate and phenylselenenyl bromide, respectively, affording α-methylsulfenyl- and α-phenylselenenyl-α-phosphoryl sulfoxides 8 and 9 are described. Sulfenylation of (+)-(S)- dimethoxyphosphorylmethyl p-tolyl sulfoxide 2 gave a mixture of optically active diastereoisomers of the sulfoxide 8a which is a key substrate in the Horner-Wittig synthesis of enantiomeric ketene dithioacetal mono-S-oxides 10. The E/Z ratio of geometrical isomers of 10 was determined and briefly discussed. The crystal and molecular structure of E-1-p-tolylsulfinyl- 1-methylsulfenyl-2-phenyl-ethene 10a is reported.