An Experimental and Computational Study of 1,2-Hydrogen Migrations in 2-Hydroxycyclopentylidene and Its Conjugate Base
作者:Kathleen M. Morgan、Matthew J. O'Connor、Jonathan L. Humphrey、Kerry E. Buschman
DOI:10.1021/jo001038x
日期:2001.3.1
decomposition of alpha-hydroxydiazirine 2 gives primarily cyclopentanone and some allylic alcohol, in similar amounts as the known cyclohexyl analogue 1. Calculations (B3LYP/6-31+G) also show cyclopentanone to be the major product of this carbene rearrangement. Diazirine 2 and the lithium salt of the corresponding conjugate base 3 were decomposed by photolysis. The proportion of ketone formed increases with
α-羟基重氮2的热分解主要产生环戊酮和一些烯丙醇,其量与已知的环己基类似物1相似。计算(B3LYP / 6-31 + G)也显示环戊酮是这种卡宾重排的主要产物。通过光解分解重氮二嗪2和相应的共轭碱3的锂盐。酮的形成比例随着去质子化而增加,这种趋势也在计算机上发现。相比之下,碱诱导的环戊烯氧化物的异构化(通过α消除反应进行到类似于从3中获得的类胡萝卜素中间体)主要产生了烯丙基醇,而不是酮。因此,无论是环尺寸还是电荷,都不能解释观察到的异常产品分布。有趣的是,这些计算表明,在没有抗衡离子的气相中,单线态,氧阴离子卡宾和α-去质子化的环氧化物是相同的,而不是离散的结构。分子内络合使氧阴离子卡宾稳定在20-25 kcal / mol。