Asymmetric Phenol Oxidation. Stereospecific and Stereoselective Oxidative Coupling of a Chiral Tetrahydronaphthol

Article abstract of DOI:10.1021/jo00325a022

The study of the factors which determine the intermolecular asymmetric phenol oxidation shows the importance of the stereochemical control exerted by asymmetry in the substrate.The oxidative coupling of (S)-(+)-2-hydroxy-3,4,8-trimethyl-5,6,7,8-tetrahydronaphthalene ((S)-(+)-1) resulted in the completely stereoselective formation of the optically active dinaphthol (S,S)-(+)-trans-2a.The results argue against the necessity of an asymmetric oxidant in intermolecular phenol coupling reactions.The synthesis of enantiomerically pure (S)-(+)-1 was completed by a six-step route from racemic 7-methoxy-5,6-dimethyl-1,2,3,4-tetrahydro-1-naphthoic acid ((R,S)-16), which was resolved via its (+)-dehydroabietylamine salts.The chiroptical data of the tetrahydronaphthols 1, 10, 16, and 23-25 and of dinaphthol 2a are presented.Diastereomeric charge-transfer interactions, which resulted in long-range asymmetric influences, were observed in amides 27 and 29.