Déplacements homolytiques intramoléculaires. 2. Décomposition du perpentène-4 oate de tert-butyle dans les éthers

Abstract

The thermolysis of tert-butyl perpent-4-enoate 1 in THF led to several compounds; the main product, 5-(2-tetrahydrofuryl)-4-pentanolide (yield 42%) comes from an induced decomposition of the perester occurring with the addition of 2-tetrahydrofuryl radical to the double bond. A similar reaction was performed at a lower temperature, using butyl perdicarbonate as initiator, but did not define the mechanism (concerted or two-step). The thermolysis of 1 in ethers (THP, oxepane, 1,4-dioxane, dipropyl ether) appears to be a useful synthetic tool: several new γ-lactones have been obtained in this way.