Thermolysis of the tricyclic 1,2-dioxetanes 3,4:3,4-dipropano-, 3,4-pentano-3,4-propano-, and 3,4-butano-3,4-propano-1,2-dioxetane

Abstract

The title compounds have been isolated in crystalline form by cyclization of the corresponding bromo- or iodohydroperoxides. The activation parameters for thermolysis are, respectively (Ea, kcal/mol, ΔS≠, eu): 25.6 ± 0.6, 4 ± 2; 29.8 ± 0.4, 4 ± 2; 26.3 ± 0.5, 1 ± 2. The singlet [Formula: see text] and triplet [Formula: see text] excited state product yields produced on thermolysis of these compounds are, respectively: 0.011, 0.10; 0.0019, 0.18; 0.0013, 0.11. These yields are relative to a value of 0.31 for [Formula: see text] of tetramethyl-l,2-dioxetane. The cyclic 1,5-diones from thermolysis of the last two title compounds cyclized before isolation to give the bicyclic hydroxyketones.