(E)-1,3-Dihydroxyhex-4-ene and (E)-1,3-dihydroxy-4-methylhex-4-ene undergo epoxidation with peracetic acid and in situ cyclisation to give a mixture of tetrahydro-furans and -pyrans, whereas comparable compounds lacking the allylic hydroxyl group give predominantly or exclusively tetrahydrofurans. These reactions model the first cyclisation of prebrevetoxin polyepoxides and demonstrate the regio-directing effect of the hydroxy group adjacent to the epoxide. (C) 1999 Elsevier Science Ltd. All rights reserved.
(E)-1,3-二羟基-4-烯六氢和(E)-1,3-二羟基-4-甲基-4-烯六氢在过
二氯乙酸作用下进行氧化,随后在离子环境下 cyclization生成多种
四氢呋喃和
四氢呋喃类似物,而类似物中缺少邻位羟基的化合物主要或完全生成
四氢呋喃。这些反应模型化了预 Brieftoxin 多
环氧化物的首次环合,同时证明了邻近氧化环的羟基对环的邻位诱导效应。(C) 1999 Elsevier Science Ltd. 专利权所有。