The development of chiral borane Lewis acid catalysts opened the door for transition-metal-free
catalyzed asymmetric organic reactions. Herein, we have summarized our work on the
preparation of two classes of novel chiral bicyclic bisborane Lewis acid catalysts
derived from C
2-symmetric [3.3.0] dienes and [4.4] dienes, respectively. These catalysts not only
form frustrated Lewis pairs with Lewis bases to catalyze asymmetric hydrogenation
reactions but also activate Lewis basic functional groups in traditional Lewis acid
catalyzed asymmetric reactions.
4 Other Types of Asymmetric Reactions Promoted by Chiral Bicyclic Bisborane Catalysts
Key words
chiral borane - Lewis acid - frustrated Lewis pair - asymmetric catalysis -
C
2-symmetric - hydrogenation