Efficient C_2-Symmetric Chiral Schiff Bases for Lanthanide-catalyzed Asymmetric Hydrogenation of Ace

• 出 处: Chinese Chemical Letters
• 发表日期: 2006年10期
• 关键词: catalyzed Schiff hydrogenation chiral alcohols selectivity asymmetric lanthanide

An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde (1R, 2R)-1, 2-cyclohexanediamine and (R)-(+)-2, 2’-diamino-1, 1’-binaphthalene, incorporated with lanthanide complexes, have been applied as catalysts for asymmetric hydrogenation of acetophenone for the first time. Highly enantioselective product with 90% enantiomeric excess (e.e.) was obtained when the catalyst, hybridized by the bulky electron-donating 3, 5-di-tert-butyl substituted Schiff base (2) and SmCl3·4THF, was employed.

An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde (1R, 2R) -1, 2- cyclohexanediamine and (R) - (+) - 2, 2’-diamino- 1, 1’-binaphthalene, incorporated with lanthanide complexes , have been applied as catalysts for asymmetric hydrogenation of acetophenone for the first time. Highly enantioselective product with 90% enantiomeric excess (ee) was obtained when the catalyst, hybridized by the bulky electron-donating 3, 5-di-tert- Schiff base (2) and SmCl3 · 4THF, was employed.