A Concise Synthesis of Substituted Stilbenes and Styrenes from Propargylic Phosphonium Salts by a Cobalt-Catalyzed Diels−Alder/Wittig Olefination Reaction Sequence
作者:Gerhard Hilt、Christoph Hengst
DOI:10.1021/jo701406d
日期:2007.9.1
single synthetical step starting from three variable starting materials. The E/Z stereoselectivities of the products revealed that the dihydroaromatic phosphonium ylides behave as semistabilized ylides giving predominantly the E-configured products. The application of unsymmetrical 1,3-dienes as well as internal phosphonium functionalized alkynes is also described.
炔丙基phospho盐和较长链炔烃官能化phospho盐与1,3-二烯的钴(I)催化Diels-Alder反应生成二氢芳族phospho盐中间体,可直接用于一锅Wittig型烯化反应中醛。随后的氧化导致在三种合成起始原料的单一合成步骤中,形成了三个新的碳-碳键,形成了苯乙烯和二苯乙烯型产品。产品的E / Z立体选择性表明,二氢芳族盐表现为半稳定化的ides化物,主要产生E配置的产品。还介绍了不对称1,3-二烯以及内部phospho官能化炔烃的应用。