Syntheses of selectively fluorinated cyclodecenones: the first deployment of the neutral oxy-Cope rearrangement in organofluorine chemistry
作者:Gianluca DiMartino、Michael B. Hursthouse、Mark E. Light、Jonathan M. Percy、Neil S. Spencer、Malcolm Tolley
DOI:10.1039/b311261f
日期:——
Metallated haloalkenes were used to open epoxides in moderate to good yield. The homoallylic alcohols obtained underwent Swern oxidation to afford three γ,γ-difluorinated β,γ-enones, which reacted with either vinyllithium, 2-lithio-2H-dihydropyran or another metallated haloalkene to afford substituted trans-1,2-divinylcyclohexanols of different degrees of stability. These intermediates underwent neutral thermal oxy-Cope rearrangements when heated in xylene in Ace® tubes. The first-formed enols ketonised without loss of HF to afford a range of cyclodecenones in moderate to good yield; X-ray crystallography was used extensively for product characterisation. All substrates rearranged more rapidly than a cis/trans mixture of 1,2-divinylcyclohexanols.
使用金属卤代烯打开环氧化物的收率为中等到良好。得到的均烯丙基醇经过 Swern 氧化反应得到三种 γ,γ-二氟化 β,γ-烯酮,它们与乙烯基锂、2-二硫代-2H-二氢吡喃或另一种金属化卤代烃反应,得到不同稳定度的取代反式-1,2-二乙烯基环己醇。这些中间体在 Ace® 管中的二甲苯中加热时会发生中性热氧-科普重排。第一次生成的烯醇在不损失 HF 的情况下发生酮化,从而得到一系列环癸烯酮,收率从中等到良好;X 射线晶体学被广泛用于产品特征描述。与 1,2-二乙烯基环己醇的顺式/反式混合物相比,所有底物的重排速度都更快。