A FRUSTRATED COPE REARRANGEMENT - THERMAL INTERCONVERSION OF 2,6-DIPHENYLHEPTA-1,6-DIENE AND 1,5-DIPHENYLBICYCLO[3.2.0]HEPTANE

被引：62

作者：

ROTH, WR ^{[1
]}

LENNARTZ, HW ^{[1
]}

DOERING, WV ^{[1
]}

BIRLADEANU, L ^{[1
]}

GUYTON, CA ^{[1
]}

KITAGAWA, T ^{[1
]}

机构：

[1] HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 1990年 / 112卷 / 05期

关键词：

D O I：

10.1021/ja00161a011

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

The title reaction constitutes a reliable model of a nonconcerted, diradical mechanism closely related to a Cope rearrangement. Its activation parameters relate to a transition state approximated by 1,5-diphenylcyclohepta-1,5-diyl (7). Force field calculations of various conformations of the diradical model the reaction path and reproduce the “experimental” enthalpy of formation of the rate-determining transition state. The experimental enthalpy of activation of the “degenerate” Cope rearrangement of 2,5-diphenylhexa-1,5-diene-1,6-13C2 (2) is essentially identical with an enthalpy of activation calculated by force field for the model 1,4-diphenylcyclohexa-1,4-diyl (6). Strong support is there by provided for this Cope rearrangement proceeding by a mechanism of the “continuous diradical” or “diradical-as-transition-state” type. © 1990, American Chemical Society. All rights reserved.

引用

页码：1722 / 1732

页数：11

共 64 条

[1] CONFORMATIONAL-ANALYSIS .130. MM2 - HYDROCARBON FORCE-FIELD UTILIZING V1 AND V2 TORSIONAL TERMS [J].