PSEUDOEPHEDRINE AS A PRACTICAL CHIRAL AUXILIARY FOR THE SYNTHESIS OF HIGHLY ENANTIOMERICALLY ENRICHED CARBOXYLIC-ACIDS, ALCOHOLS, ALDEHYDES, AND KETONES

The use of pseudoephedrine as a practical chiral auxiliary for asymmet ric synthesis is described in full. Both enantiomers of pseudoephedrin e are inexpensive commodity chemicals and fan be N-acylated in high yi elds to form tertiary amides. In the presence of lithium chloride, the enolates of the corresponding pseudoephedrine amides undergo highly d iastereoselective alkylations with a wide range of alkyl halides to af ford cl-substituted products in high yields. These products can then b e transformed in a single operation into highly enantiomerically enric hed carboxylic acids, alcohols, aldehydes, and ketones.