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

摘要

Fluorous chiral BINOLs were prepared and used as the ligands for the titanium catalyzed asymmetric addition of Et2Zn 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. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 29]