反应详情

With 1-phenylethylamine neither a satisfactory yield nor an adequate optical purity could be achieved. Quinine yielded enantiomer in good optical purity but poor yield, no yield was indicated for N-methylephedfine With 1,2-diphenylethylamine the yield is satisfactory and the optical purity very good but the reagent, as is also N-methylephedrine is very expensive. Further, it is known that 2,2-dimethylcyclopropanecarboxylic acid can be separated into the enantiomers by the diastereomeric menthyl esters, which can be obtained from the acid chloride with (+) or (-) menthol (U.S. Pat. No. 4,487,956). This process does provide usable yields and optical purities, but is relatively complicated in working up and requires the relatively expensive menthol.

1. customcan be separated into the enantiomers by the diastereomeric menthyl esters, which