Hexitol derivatives containing a 1,4-oxathiane ring—III : Rearrangement of a sulfone on treatment with LAH

Treatment of 2,5 - anhydro - 3,4 - di -O- mesyl - 1,6 - thioanhydro - D - glucitol S,S-dioxide (1) with LAH afforded (1S,6R)-2-thiabicyclo4.1.0]heptane S,S-dioxide (2) and its (4R) - 4 -hydroxy derivative 3 in a ratio of 46:6. Sodium - dihydro - bis(2 - methoxy - ethoxy) - aluminate afforded the same compounds in a ratio of 15:22. The corresponding sulfide 5 underwent no rearrangement under similar conditions. The structure of the products was established by IR, PMR, CMR and MS. A probable reaction mechanism is discussed.