Appendix

Relative prices of some chiral reagents per mole as compared with that of (R,R)-tartaric acid (taken as 1 .OO). * D-Alanine 83 L-Alanine 12 (R )-2-Aminobutane 6 000 (S)-2-Aminobutane 5 400 (R)-2-Amino-l -butanol