Enantioselective addition of diethylzinc to aromatic aldehydes catalyzed by Ti(IV) complexes of C2-symmetrical chiral BINOL derivatives

✍ Scribed by Shaohua Gou; Zaher M.A. Judeh

• Publisher: Elsevier Science
• Year: 2009
• Tongue: French
• Weight: 162 KB
• Volume: 50
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2008.10.149

✦ Synopsis

Enantioselective addition of diethylzinc to a series of aromatic aldehydes is developed using new chiral C 2 -symmetric ligand (S)-2,2 0 -(1,1 0 -binaphthyl-2,2 0 -diylbis(oxy))bis(methylene)bis(4-nitrophenol) (S)-2b. The catalytic system employing 10 mol % of (S)-2b and 120 mol % of Ti(OiPr) 4 was found to promote the addition of diethylzinc to a wide range of aromatic aldehydes with electron-donating and electronwithdrawing substituents, giving up to 89% ee and up to 95% yield of the corresponding secondary alcohol under mild conditions.