C2-Symmetric Bicyclic Diols as Chiral Ligands in the Titanate-Catalyzed Enantioselective Addition of Alkylzinc Reagents to Aldehydes

Article abstract of DOI:10.1002/hlca.19940770803

Enantiomerically pure C₂-symmetric 1,4-diols embodying bicyclic C-frameworks were synthesized by means of asymmetric carbo-Diels-Alder reactions as key steps (Scheme 1).They were investigated as chiral ligands in the enantioselective addition of ZnEt2 to aromatic aldehydes.In the presence of 20-40 mol-percent of the titanates formed from these diols and at -78 deg C, the respective 1-arylpropanols were obtained with enantiomer ratios up to 93:7 (Scheme 2, Table).