21071-39-6

Reaction of trithiocarbonates with meta-chloroperoxybenzoic acid in CH2Cl2 at 0°C affords the corresponding S-oxides. These sulfines are relatively stable comppounds which can be purified by chromatography. They react readily with organolithiums in THF at -78°C in a thiophilic manner to give carbanions which are stabilized by three sulfur groups. Hydrolysis affords trithioorthoester oxides. The thermal behaviour of these hindered products has been investigated and new rearrangenrent processes have been evidenced. The former carbanions are soft nucleophiles: 1,4-addition of these intermediates to α-enones was achieved selectively to lead to β-oxo ketenedithioacetals, which are easily transformed into 4-oxoalkanethioates. This 'Umpolung' route allows the formal use of the (alkylthio)carbonyl anion. A thiophilic addition was also observed with allylsilanes in the presence of n-Bu4NF furnishing allyl sulfoxides.

The direction of the homolytic transformations in 2-ethoxy-1,3-dithiolane and 2-ethoxy-1,3-oxathiolane was investigated. 1,3-Dithiolane and 1,3-dithiolan-2-one are formed from 2-ethoxy-1,3-dithiolane, and 1,3-oxathiolane-2-one, 1,3-oxathiolane, ethyl thioformate, and diethyl monothiocarbonate are formed from 2-ethoxy-1,3-oxathiolane.The temperature dependence of the yield and ratio of the reaction products was determined.