Recyclable fluorous chiral ligands and catalysts: asymmetric addition of diethylzinc to aromatic aldehydes catalyzed by fluorous BINOL–Ti complexes

Abstract

Fluorous chiral BINOLs were prepared and used as the ligands for the titanium catalyzed asymmetric addition of Et 2Zn to aromatic aldehydes. Consecutive reactions were examined by utilizing fluorous–organic biphase and fluorous solid phase extraction techniques. Enantioselectivities were similar in consecutive reactions and were close to that attained in the non-fluorous system. The solid phase extraction method also enabled us to perform a simultaneous screening procedure.