A Stereochemical Reaction Cycle with Chiral Phosphorus

Cholesteryl and menthyl methylphenylphosphinates diastereomerically pure gave IV-phenyl methylphenyl-phosphinic amide of the same rotation. The lithium salt of a-phenylethylamine with the same phosphinate esters gave the corresponding diastereomerically pure phosphinic amide of the same rotation. Treatment of these same esters with benzyl Grignard reagent gave benzylmethylphenylphosphine oxide of the same rotation. These results, coupled with reactions and configurational assignments of others, completed a three-reaction stereochemical cycle with three chiromers. The two reactions reported here proceed with inversion of configuration and high stereospecificity. Cholesteryl methylphenylphosphinate, absorbed on a solid support, failed to separate a series of racemates in a glc column.