Hydrogen Transfer from Alcohols to Carbonyl Compounds Catalyzed by Aluminum Porphyrins. Stereochemical Aspects

Article abstract of DOI:10.1021/jo00290a008

Highly diastereoselective reductions of methylcyclohexanones with alcohols such as 2-propanol, (-)-borneol, or (+/-)-isoborneol were brought about by using chloroaluminium porphyrins, (5,10,15,20-tetraphenylporphinato)aluminium chloride or (etioporphinato)aluminium chloride, as catalysts.When an optically active alcohol such as (-)-isoborneol was used, enantioselective reductions of prochiral ketones such as isopropyl or cyclohexyl phenyl ketone took place. 1H NMR and UV-vis studies demonstrated coordination of ketone and alcohol to the central aluminium atom of the catalyst.