Barton esters for initiator-free radical cyclisation with heteroaromatic substitution
作者:Robert Coyle、Karen Fahey、Fawaz Aldabbagh
DOI:10.1039/c3ob27313j
日期:——
first examples of efficient radical cyclisation with (hetero)aromatic substitution via Barton ester intermediates. Cyclopropyl and alkyl radicals allow access to five, six and seven-membered alicyclic-ring fused heterocycles with and without an additional fused cyclopropane, including the skeleton of the anti-cancer agent, cyclopropamitosene, expanded, and diazole analogues. Radical initiators are not
S-(1-Oxido-2-pyridinyl)-1,1,3,3-tetramethylthiouronium hexafluorophosphate(HOTT)促进了通过Barton酯中间体进行(杂)芳香取代的有效自由基环化的第一个例子。环丙基和烷基可与五个,六个和七元脂环族稠合杂环一起使用,无论是否有其他稠合环丙烷,包括抗癌药环丙烷酰胺的骨架,展开的和 二唑类似物。自由基引发剂是不需要用于从羧酸前体的环化。