1. For recent reviews, see:
2. Asymmetric Catalysis in Organic Synthesis Wiley-Interscience, New York, 1994 .
3. in: Comprehensive Asymmetric Catalysis (Eds.: Springer, Berlin, 1999 , p. 121.
4. in: Catalytic Asymmetric Synthesis 2nd ed. (Ed.: Wiley-Interscience, New York, 2000 , p. 1.