Unusual endoperoxide isomerizations:: a convenient entry into 2-vinyl-2-cyclopentenones from saturated fulvene endoperoxides

Abstract

An unusual peroxide base-promoted isomerization is uncovered. Saturated endoperoxides derived from fulvenes give rise to 2-vinyl-2-cyclopentenones upon treatment with DBU in CH2CL2 in a one-pot reaction. This methodology is applied to a convenient synthesis of dihydrojasmone. Moreover, functional groups placed on the side chain at C-6 participate in the base-catalyzed isomerizations via conjugate attack at the enone moiety to give 2-cyclopentenones carrying oxygen heterocycles at C-2. (c) 2006 Elsevier Ltd. All rights reserved.