Oxidation of toluene-p-sulfonates derived from 1-substituted-1,5-syn-5
-benzyloxyhex-3-enols using osmium tetraoxide gives stereoselective ac
cess to xyalkyl)-3-hydroxy-5-substituted-tetrahydrofurans. This proced
ure has been applied to synthesize bis-tetrahydrofurans.