Ethylenic compounds reactivity: bromination—XLI: Relative reactivities of R1CMeCH2 and R1CHCMe2 series as a criterion for distinguishing between bridged and acyclic transition states. Degree of symmetry of the bromonium ion-like transition state |
| |
Authors: | Elisabeth Bienvenue-Goëtz Jacques-Emile Dubois |
| |
Affiliation: | Laboratoire de Chimie Organique Physique de l''Université Paris VII, associé au C.N.R.S., l rue Guy de la Brosse, 75005 Paris, France |
| |
Abstract: | Reactivities of homogeneous series of ethylenic compounds R1CHCH21, trans R1CHCHMe 2, R1MeCCH23 and R1CHCMe24 have been measured in methanol at 25°C (R1 Me, Et, n-Pr, -CH2C6H5-CH2OCOCH3, -CH2Cl). The criterion developed to decide between a bridged and a carbonium ion-like transition state is based on an internal comparison of the series and avoids resorting to external structural scales. Even in the case of alkenes 3 and 4 which are very dissymmetric with respect to polarity, the sensitivity to polar effects remains constant and the transition state behaves like a symmetric entity; only a slight secondary effect, attributed to hyperconjugation, is detectable. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|