Both enantiomers of pseudoephedrine are inexpensive and can be N-acylated in high yields to form tertiary amides. In the presence of lithium chloride, the enolates of the corresponding pseudoephedrine amides undergo highly diastereoselective alkylations with a wide range of alkyl halides.
Advantages of using psuedoephedrine as chiral auxiliary,
• Enolate of pseudoephedrine amide undergo efficient and high diastreoselective alkylation with wide variety of alkyl halides.
• High enantiometrically enriched carboxylic acids, alcohols, aldehydes and ketones
• Large scale/ Preocess application ( low cost of auxiliary, crystallinity of starting materials and products, no carcinogenic solvents.)
Ref.: Myers, A.G. et al., J. Am. Chem. Soc., 1997, 119 , 6496