Sterically demanding binaphthol-based chiral diboranes for metal-free and isotactic poly(propylene oxide).

Chiral diborane polymerization catalysts with 3,3'-disubstituted binaphthol-backbones are presented. These compounds deliver isotactic poly(propylene oxide) from racemic monomer with isotactoc diad ( m ) and triad ( mm ) placements of up to 92% and >80%, respectively. The resulting polyether is well-defined, of high molar mass and semi-crystalline.