The stereochemistry of new spiro-1,3-oxathiane derivatives has been explore
d by NMR methods and the molecular structure of one compound established vi
a single crystal by X-ray diffractometry. The investigations revealed flexi
ble, semi-flexible and anancomeric structures and the ring-chain tautomeris
m of the 1,3-oxathiane heterocycle. (C) 2001 Elsevier Science Ltd. All righ
ts reserved.