Deplacements homolytiques intramoleculaires-I : Etude de la decomposition du perpentene-4 oate de t-butyle dans les cyclanes. synthese de cycloalkyl-5 pentanolides-4

The thermolysis of t-butyl-4-peroxypentenoate 1, in cyclohexane led to several compounds; the main product was 5-cyclohexyl-4-pentanolide (yield 35%). Hypotheses are proposed to explain their formation. The lactone could be obtained by two different mechanisms: a concerted one and a two-step one (cyclohexyl radical addition to the double bond of the perester leading to a discrete radical followed by an intramolecular displacement of a t-butoxyl radical). The thermolysis of 1 has synthetic interest: several original 5-cycloalkyl-4-pentanolides have been obtained by this way.