Cyclobutane-fused dihydropyrans and methylenetetrahydrofurans are highly interesting cores found in numerous natural products. Both these cores are selectively prepared from a common alkynylcyclobutane precursor bearing an appended hydroxyl group herein. Thus, cyclobutane-fused dihydropyrans can be obtained by a selective 6-endo-dig iodocyclization, whereas gold-catalyzed 5-exo-dig cycloisomerization
环丁烷稠合的二氢
吡喃和亚甲基
四氢呋喃是在许多
天然产物中发现的非常有趣的核心。这两个核都是由本文带有附加羟基的普通炔基
环丁烷前体选择性制备的。因此,可以通过选择性的6-endo-dig
碘环化获得
环丁烷稠合的二氢
吡喃,而
金催化的5-exo-dig环异构化提供了包含亚甲基
四氢呋喃部分作为主要产物的双环核。按照报道的方法,合成了几个具有不同取代基的
环丁烷稠合的O-杂环。