Synthesis and catalytic properties of manganese complexes of substituted tetraphenylporphyrins in the stereoselective hydroxylation of cholesterol
摘要:
Manganese(III) complexes of 5-(p-aminophenyl)-10,15,20-triphenylporphyrin, 2-(2-carboxyvinyl)-5,10,15,20-tetraphenylporphyrin, and their derivatives containing electron-donor and electron-acceptor substituents have been synthesized. Manganese(III) porphyrinates (PMn) are catalytically active in the stereoselective hydroxylation of cholesterol to form 3 beta,5 alpha-cholestanediol. The influence of substitutents in the porphyrin ring on the ability of PMn to associate in solution, the hydroxylation rate constants, and the turnover number of the catalyst are discussed.