Self-Assembled Heterodimer Complexes for Asymmetric Hydroboration

Significance

The authors describe the synthesis of chiral, non-symmetric bisoxazoline hetero­dimeric zinc complexes from the corresponding chiral homodimers. Previously, they had observed rapid equilibration to the heterodimeric metal complex upon mixing racemic or two non-equal bisoxazoline ligands. Using this method, a library of various self-assemblied heterodimeric zinc complexes possessing phosphite moieties were synthesized and evaluated in the rhodium-catalyzed hydroboration of various styrenes. Several ligand systems employing various rhodium ­sources afforded corresponding benzylic alcohols in high regio- and enantioselectivities.