Reaction of <i>N</i>-Vinylic Phosphazenes with α,β-Unsaturated Aldehydes. Azatriene-Mediated Synthesis of Dihydropyridines and Pyridines Derived from β-Amino Acids
作者:Francisco Palacios、Esther Herrán、Concepción Alonso、Gloria Rubiales、Begoña Lecea、Mirari Ayerbe、Fernando P. Cossío
DOI:10.1021/jo060775b
日期:2006.8.1
Aza-Wittig reaction of N-vinylic phosphazenes (1,2 addition), derived from diphenylmethylphosphine or derived from trimethylphosphine with α,β-unsaturated aldehydes, leads to the formation of 3-azatrienes through a [2 + 2]-cycloaddition−cycloreversion sequence. The presence of an alkyl substituent in position 3 of N-vinylic phosphazenes increases the steric interactions, and [4 + 2] periselectivity
衍生自二苯基甲基膦或衍生自三甲基膦的N-乙烯基磷腈的Aza-Wittig反应(1,2加成)与α,β-不饱和醛反应,通过[2 + 2]-环加成-环还原反应生成3-氮杂烯顺序。N-乙烯基磷腈的3位上存在烷基取代基会增加空间相互作用,并且观察到[4 + 2]的选择性(1,4加成)。氮杂三烯与α,β-不饱和醛的反应产生吡啶。