含酯基的杂芳取代无引发剂自由基环化反应。

Barton esters for initiator-free radical cyclisation with heteroaromatic substitution.

机构信息

School of Chemistry, National University of Ireland Galway, University Road, Galway, Ireland.

出版信息

Org Biomol Chem. 2013 Feb 13;11(10):1672-82. doi: 10.1039/c3ob27313j.

Abstract

S-(1-Oxido-2-pyridinyl)-1,1,3,3-tetramethylthiouronium hexafluorophosphate (HOTT) facilitates the 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 required for cyclisation from carboxylic acid precursors.

摘要

S-(1-氧代-2-吡啶基)-1,1,3,3-四甲基硫代𬭸六氟磷酸盐（HOTT）通过 Barton 酯中间体促进了首例（杂）芳族取代的高效自由基环化反应。环丙基和烷基自由基可以得到五个、六个和七个成员的脂环族稠合杂环，包括抗癌剂环丙米特森、扩环和唑类似物的骨架，并且可以带有或不带有额外的稠合环丙烷。从羧酸前体进行环化反应不需要自由基引发剂。