A general synthesis of five, six and seven-membered silasultones via dehydrative cyclisation

Five, six and seven-membered silasultones can be conveniently prepared in good yield by dehydrative cyclisation of siloxane disulphonic acids. The siloxanes are prepared by protodesilylation of the corresponding phenylsilane sulphonic acids. The sulphonate group is introduced either by free-radical sulphonation of vinyl silanes, or by SN2 sulphite displacement of a long chain alkyl chloride.