Total Syntheses of Conformationally Locked Difluorinated Pentopyranose Analogues and a Pentopyranosyl Phosphate Mimetic

Trifluoroethanol has been elaborated, via a telescoped sequence involving a metalated difluoroenol, a
difluoroallylic alcohol, [2,3]-Wittig rearrangement, and ultimately an RCM reaction and requiring minimal
intermediate purification, to a number of cyclooctenone intermediates. Epoxidation of these intermediates
followed by transannular ring opening or dihydroxylation, then transannular hemiacetalization delivers
novel bicyclic analogues of pentopyranoses, which were elaborated (in one case) to an analogue of a
glycosyl phosphate.