The first synthesis of aliphatic sulfines from thiono-esters

Facile Conversion of Dithioesters into Carboxylic Acids or Esters Using Alkaline Hydrogen Peroxide

“…By analogy to the previously postulated mechanism for the conversion of dithioesters into acids (Scheme 2), the transformation probably proceeds through the oxidation of the intermediate thionoester with hydrogen peroxide, leading to the corresponding sulfine (thionoester S-oxide), which is then desulfurized into the ester via the intermediate formation of an oxathiirane. 29 In summary, we reported a simple process for the direct conversion of dithioesters into either carboxylic acids or esters using a inexpensive and environmentally friendly oxidant, hydrogen peroxide, under alkaline conditions. In particular, this procedure is an interesting alternative to those involving heavy metals.…”

“…Unfortunately, whatever the conditions attempted, ester 5 was always contaminated with variable amounts of starting dithioester 3, acid 4, and/or Having previously shown that dithioester 3 could be cleanly converted into thionoester 7 under methanolic alkaline conditions (Table 1, entry 6) we thus envisaged a 'one-pot' stepwise procedure via thionoester 7 instead of thiolester 6. A variety of methods has been reported for the conversion of thionoesters into esters 1 including the use of tellurium, 7,24 chromate, 25 mercury, 26 or copper 27 species, hypochlorite, 28 peracid, 29 or Oxone 30 as reagents.…”