Intra- and Intermolecular Hydrogen Bonding Effects in Cycloadditions between Nitrile Oxides and 4-Benzoylamino-2-cyclopenten-1-ol and Its Derivatives
作者:Paolo Quadrelli、Vera Fassardi、Annamaria Cardarelli、Pierluigi Caramella
DOI:10.1002/1099-0690(200207)2002:13<2058::aid-ejoc2058>3.0.co;2-z
日期:2002.7
Cycloadditions between nitrile oxides and cis-4-benzoylamino-2-cyclopenten-1-ol offer an example in which a strong intramolecular hydrogen bond completely offsets the syn-directing ability of the cyclopentene substituents. Solvents affected the conformational equilibrium of the cyclopentene dipolarophile but did not sizeably influence the cycloaddition selectivity, showing the absence of directing
腈氧化物和顺式-4-苯甲酰氨基-2-环戊烯-1-醇之间的环加成反应提供了一个例子,其中强大的分子内氢键完全抵消了环戊烯取代基的顺式定向能力。溶剂会影响亲环戊烯偶极试剂的构象平衡,但不会显着影响环加成选择性,表明加数之间不存在导向效应。通过 OH 保护或氧化去除分子内氢键激活了酰胺取代基的顺式定向能力,并为顺式立体选择提供了方便的途径。(© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)