Allylic oxofunctionalization of cyclic olefins with homogeneous and heterogeneous catalysts

Heterogeneous catalysis and heterogenization of homogeneous catalysts are catch phrases of modern chemistry. Here we attempt to trace the development from homogeneous to heterogeneous catalysis in the allylic oxofunctionalization of cyclic olefins. The utility of this oxidative conversion is highlighted succinctly in the allylic oxidation of isophorone to ketoisophorone, which is a useful intermediate in the synthesis of carotenoids and fragrances. Competitive allylic oxidation and epoxidation are discussed briefly for the structurally simpler cyclohexene. Allylic oxidation of bicyclic cu-pinene to verbenone is used as an example to illustrate that upon progressing to more complex cyclic olefins, competitive isomerization and structural rearrangements often result in very poor selectivity to the desired or,P-unsaturated ketone. (C) 2000 Elsevier Science B.V. All rights reserved.