Reciprocal Tests of Steric Opposition to Down-Disrotatory ThermalDecyclization of [3.2.1] Propellanes. The Cycloreversion Stereochemistry of the 6,7,8-Trimethyltricyclo[3.2.1.01,5] octanes
作者:Lauren Lee Stevens、Jerome A. Berson
DOI:10.1016/s0040-4039(00)80621-8
日期:1988.1
isomeric title compounds are described. The cis, endo isomers undergo down-disrotatory cycloreversion to E,E-2-methyl-1,3-bis-(ethylidene)-cyclohexane with high stereospecificity, regardless of the stereochemistry of the C8-methyl group. Both 8-syn - and 8-anti - 6,7-trans -trimethyl isomers decyclize with low stereochemical preference,suggesting that the orbital overlap factors favoring the down-disrotatory
描述了异构标题化合物的合成和热分解。无论C 8-甲基的立体化学如何,顺式内消旋异构体都经历下旋转环还原成具有高立体特异性的E,E -2-甲基-1,3-双-(亚乙基)-环己烷。8-顺-和8-反-6,7-反式-三甲基异构体都以较低的立体化学偏好性脱环,这表明在顺式情况下,有利于下旋转路径的轨道重叠因子很容易被空间效应克服。