Activation Parameters for the Epoxidation of Substitutedcis/trans Pairs of 1,2-Dialkylalkenes by Dimethyldioxirane
作者:Brian S. Crow、W. Rucks Winkeljohn、Angela Navarro-Eisenstein、Elba Michelena-Baez、Paul J. Franklin、Pedro C. Vasquez、Al Baumstark
DOI:10.1002/ejoc.200600427
日期:2006.10
the corresponding cis isomers. The ΔH‡ terms mirrored trends observed in ΔG‡ because ΔS‡ terms for all ten of the compounds were roughly identical. The ΔΔG‡ values, a comparison of the trans to the cis isomer data, yielded positive values of 1.2 to 1.8 kcal/mol for the five sets of data and appeared to be dependent on relative steric interactions. The experimental activation parameter data, consistent
报告了二甲基二环氧乙烷 (1) 与五个顺式/反式烯烃对反应的第一个活化参数数据。顺式-1,2-二烷基烯烃的环氧化(2顺式:R1 = Me,R2 = iPr;3顺式:R1 = Me,R2 = tBu;4顺式:R1 = R2 = Et;5顺式:R1 = Et,R2 = iPr;6顺式:R1 = Et,R2 = tBu)和反式-1,2-二烷基烯烃(2trans:R1 = Me,R2 = iPr;3trans:R1 = Me,R2 = tBu;4trans:R1 = R2 = Et;5trans:R1 = Et, R2 = iPr; 6trans: R1 = Et, R2 = tBu) 通过 1 产生相应的环氧化物,定量和立体定向,作为唯一可观察的产物。使用 Arrhenius 方法确定五对烯烃,2cis-6cis 和 2trans-6trans,1 环氧化的活化参数。在较低温度下观察到顺式与反式