The effects of solvents, metals and structural variation of the substrates on the reactions between alkanesulphonic acid derivatives with organoalkali metal reagents have been examined and the formation and reactivity of α-sulphonylcarbanions are discussed. The formation of 4-membered cyclic sulphones from a sulpbonyl fluoride and the Claisen ester condensation type reaction in a sulphonic ester, which have been observed for the first ...