The stereospecific synthesis of cis and trans 1-oxabicyclo[4,4,0]decanes and 9-methoxycarbonyl-1-oxabicyclo[4,3,0] nonanes

Article abstract of DOI:10.1016/S0040-4020(99)00532-3

The allylic sulphoxides 1b and 1e reacted with 1- pyrrolidinylcyclohexene and 2-ethoxycarbonyl cyclopentanone to yield the 2- substituted keto-sulphoxides 10 and 14 respectively, which on reduction followed by oxidation yielded in each case a mixture of cis and trans sulphones that were separated by column chromatography. Base induced cyclisation followed by reductive desulphurisation of the cyclised sulphones yielded the corresponding bicyclic compounds 6, 7, 8 and 9 in good yields.