摘要/Abstract

报道了一个膦催化水杨醛亚胺与马来酰亚胺的[4+1]环化反应，以44%～99%收率生成螺[苯并呋喃-2，3'-吡咯烷]衍生物.产物包含一对可经硅胶柱层析分离的syn和anti异构体（dr 1.6∶1～5∶1），由此提供了合成螺[苯并呋喃-2，3'-吡咯烷]简单有效的方法.该反应起始于PPh₃与马来酰亚胺原位形成非烯丙基磷叶立德活性中间体，经亲核加成/分子内取代的串联过程完成，代表了新的一例经此类磷叶立德完成的膦催化[4+1]环化反应.
关键词: 膦, [4+1]环化反应, 亚胺, 马来酰亚胺, 合成
In this work, a phosphine-catalyzed[4+1] annulation between salicyl imines and maleimides has been successfully developed, which readily produces spiro[benzofuran-2,3'-pyrrolidine] derivatives in 44%~99% yields. The annulation products were obtained as a pair of syn-and anti-isomers with dr 1.6:1~5:1. The syn-and anti-isomers can be readily separated by column chromatography on silica gel. Thus, this reaction constitutes a simple and efficient method for the synthesis of spiro[benzofuran-2,3'-pyrrolidines]. Presumably, the reaction is initiated by in situ generated non-allylic P-ylide from maleimide and PPh₃, and proceeds through a cascade sequence of nucleophilic addition/intramolecular S_N2-like substitution. It accordingly represents a new example of the phosphine-catalyzed[4+1] annulation via in situ generated non-allylic P-ylides.
Key words: phosphine, [4+1]annulation reaction, imine, maleimide, synthesis


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