Abstract: The present invention relates to a tandem process of reduction and host-guest complexation using metal-hydride complexes to reduce chemical entities bearing carbonyl groups or their equivalents, and host-guest complexation to achieve improved optical resolution of the reduction product. In the complexation step, the reduction product is optically resolved via inclusion into the crystalline complex where it resides as guest and another complex component acts as host. Additional crystallization stages are performed if further improvements in the enantiomeric excess is desired.

Abstract: Novel chiral boron and aluminum hydride complexes, compositions comprising the chiral hydride complexes, and methods for their synthesis and use are described. The novel chiral hydride complexes are of the formulas:MBH.sub.4-n-a (R*).sub.n (R').sub.a ;MBH.sub.2-b (R**) (R').sub.b ;MBH(R***);MBH(R*) (R");MAlH.sub.4-n-a (R*).sub.n (R').sub.a ;MAlH.sub.2-b (R**)(R').sub.b ;MAlH(R***); andMAlH(R*) (R"),whereinM is Na.sup.+, Li.sup.+ or K.sup.+ ;each R* is independently a monodentate chiral ligand;R** is a bidentate chiral ligand;R*** is a tridentate chiral ligand;R' is a monodentate achiral ligand;R" is a bidentate achiral ligand;n is 1-3;a is 0-2; andb is 0-1,with the proviso that n+a.ltoreq.3, and with the further proviso that when R** is S-BINOL, M is not Li.sup.+.