Manganese “Picnic Basket” Porphyrins: Cytochrome P-450 Active Site Analogues

Abstract

Abstract This paper describes studies of a new class of cytochrome P-450 model compounds called the “picnic basket porphyrins.” The picnic basket porphyrins are unsymmetrical porphyrins with one face sterically protected by a superstructure and the other unhindered. The manganese(III) porphyrins have been investigated as shape selective catalysts using oxygen atom donors in the presence of a sterically bulky imidazole. This paper presents ligand binding studies and competitive olefin epoxidations which lead to the surprising conclusion that catalysis by the manganese picnic basket porphyrins occurs exclusively on the sterically unhindered face indicating reaction by the minor catalyst component and not the selective major catalyst component.