Palladium-catalyzed intramolecular dearomative reductive-Heck reaction of C2-substituted indoles is developed, which provides access to structurally diverse 3,2′-spiropyrrolidine oxindoles. By changing the hydride source to AcONa base, direct C3-arylation products [2,3-b]quinolinones are achieved in good yields. The reaction of C2-substituted benzofuran is also realized, delivering the desired spiro-product
开发了钯催化的C2取代的吲哚分子内脱芳香性还原-Heck反应,该反应可提供结构上不同的3,2'-螺吡咯烷氧吲哚。通过将氢化物来源更改为AcONa碱,可以得到高产率的直接C3-芳基化产物[2,3- b ]喹啉酮。还实现了C 2-取代的苯并呋喃的反应,提供了所需的螺产物。
Radical dearomatising spirocyclisations onto the C-2 position of benzofuran and indole
作者:Afua S. Kyei、Kirill Tchabanenko、Jack E. Baldwin、Robert M. Adlington
DOI:10.1016/j.tetlet.2004.09.148
日期:2004.11
Spirolactams were obtained via an intramolecular radical ipso-type spirocyclisation in benzofuran and indole systems. Alkyl, vinyl and aryl radicals, tethered at the C-2 position of the heterocycle underwent radical cyclisation to produce novel tricyclic partially dearomatised heterocycles in moderate yields. Fragmentation of the furan ring was observed subsequent to spirocyclisation of a vinyl radical onto a