Synthesis of some thietanoprostanoids

Abstract

Four isomers of 2-(hydroxymethyl)-3-(6-methoxycarbonylhexyl)-4-methylthietan 1-oxide have been prepared by way of intramolecular sulphenic acid–olefin additions. The sulphenic acids were generated by thermolysis of erythro- and threo-(methyl 10-hydroxy-9-t-butylsulphinyl-8-vinyldecanoate), which were synthesized in eleven steps from 6-bromohexanol. Oxidation of the thietan 1-oxide derivatives to the corresponding 1,1-dioxides, followed by oxidation of the hydroxymethyl groups, furnished (±)-2β-formyl-3α-(6-methoxycarbonyl)-4β-methylthietan 1,1-dioxide and its 4α-isomer, which were converted into thietanoprostanoids by standard methods. Configurations were assigned throughout by comparison with analogous compounds derived from four isomers of 6-hexyl-2-(hydroxymethyl)-4-methylthietan 1-oxide of established stereochemistry.