1,3,5‐Cyclohexatrien‐1,4‐diyl und 2,4‐Cyclohexadien‐1,4‐diyl

Abstract

Abstract The Energy Well of Diradicals, V [1] . — 1,3,5‐Cyclohexatriene‐1,4‐diyl and 2,4‐Cyclohexadiene‐1,4‐diyl The energy profile of the Bergman rearrangement of (Z)‐3‐hexene‐1,5‐diyne ( 4 ) has been established from the NO and oxygen dependance of the trapping rate of the intermediate diradical 1 which leads to a heat of formation for 1,4‐didehy‐drobenzene ( 1 ) of δ H O f = 138.0 ± 1.0 kcal . morl −1 . By the same technique the heat of formation of 1,2,4‐cyclohexatriene ( 2 ), generated by thermolysis of (Z)‐1,3‐hexadien‐5‐yne ( 10 ), gives δ H O f = 105.1 ± 1.0 kcal . mol −1 which indicates a high diradical character for 2 .