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.

以三氟乙醇（Trifluoroethanol）为起始原料，通过包含金属化二氟烯醇（metalated difluoroenol）、二氟烯丙醇（difluoroallylic alcohol）、[2,3]-维蒂希重排（[2,3]-Wittig rearrangement）以及最终的闭环复分解（RCM）反应的串联反应序列，且仅需极少量中间体纯化步骤，即可合成多种环辛烯酮（cyclooctenone）中间体。对上述中间体进行环氧化反应（epoxidation）后，经跨环开环（transannular ring opening）或二羟基化反应（dihydroxylation），再进行跨环半缩醛化（transannular hemiacetalization），即可得到一系列新颖的戊吡喃糖双环类似物（bicyclic analogues of pentopyranoses）；其中一例该类似物可进一步衍生得到糖基磷酸酯（glycosyl phosphate）类似物。