(E)-1, 3-Dihydroxyhex-4-ene and (E)-1, 3-dihydroxy-4-methylhex-4-ene undergo epoxidation with peracetic acid and in situ cyclisation to give a mixture of tetrahydro-furans and-pyrans, whereas comparable compounds lacking the allylic hydroxyl group give predominantly or exclusively tetrahydrofurans. These reactions model the first cyclisation of prebrevetoxin polyepoxides and demonstrate the regio-directing effect of the hydroxy ...
