报道了一种前所未有的银促进的区域选择性 (4 + 1) 异氰乙酸酯与吡啶盐的环化。已建立的协议提供对一系列合成有用的 N-稠合杂环支架的受控、简便和模块化访问,这些支架包含吲哚嗪、吡咯并 [1,2- a ] 喹啉、吡咯并 [2,1- a ] 异喹啉和 1 H -咪唑[4,5 - a ]indolizin-2(3 H )-ones。提出了涉及亲核加成/质子化/消除/环异构化的机制途径。
Synthesis of indolizine-1-carboxylates through the Ortoleva-King reaction of 2-pyridylacetate followed by the Aldol condensation under mild reaction conditions has been described. This protocol is compatible with a broad range of functional groups, and it has been also successfully extended to unsaturated ketones, bringing about the regioselective formation of benzoyl-substituted indolizines through Michael addition followed by C-N bond formation, which are difficult to prepare by previous methods in a single step.