Palladium hydride promoted stereoselective isomerization of unactivated di(exo)methylenes to endocyclic dienes

Abstract

The exomethylenes of 2,6-disubstituted bicyclo[3.3.1]nonan-9-ones 2 are readily isomerized over a palladium catalyst under an atmosphere of hydrogen to predominantly form the isomer 3 with C2 symmetry with very little formation of the analogous product with Cs symmetry. A hydrogen source is essential to effect the rearrangement. © 2014 American Chemical Society.