Methane-Derived Polyanionic Synthons from Bis(Phenylthio)Methane

Successive treatment of bis(phenylthio)methane (1) with (a) n-butyllithium at 0°C, (b) a carbonyl compound [tBuCHO, Me2CO, Et2CO, (CH2)5CO] at −40°C, (c) lithium and a catalytic amount of DTBB (5%) and (d) a second carbonyl compound [iPrCHO, tBuCHO, Me2CO, Et2CO, (CH2)5CO], both at −78°C, leads, after hydrolysis, to the expected dihydroxy thioethers 5. When, after step (d), a second DTBB-catalysed lithiation is performed at temperatures ranging between −78 and 20°C, the corresponding allylic alcohols 7 are isolated. Finally, treatment of compounds 7 with 6 M hydrochloric acid give 1,3-dienes 10 in almost quantitative yield.