Liu Y, * Xi X, Ye C, Gong T, Yang Z, Cui Y. * Shanghai Jiao Tong University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P. R. of China
Chiral Metal-Organic Frameworks Bearing Free Carboxylic Acids for Organocatalyst Encapsulation.
Angew. Chem. Int. Ed. 2014;
53: 13821-13825
Key words
aldol reaction - heterogeneous catalysis - metal-organic framework - organocatalysis
Significance
Carboxylic acid functionalized micro- and mesoporous metal-organic frameworks (MOFs) were developed for the organocatalyst encapsulation via acid–base interactions. The reaction of aldehydes 1 with ketones 2 in the presence of 4@MOF (encapsulated 4 in acid-functionalized MOF) proceeded in water to give the aldol products 3 in 68–77% yield with 66–80% ee.
Comment
The MOF-based catalyst 4@MOF gave higher enantioselectivity than the combination of 4 and benzoic acid as homogeneous counterparts. Thus, the reaction of 4-nitrobenzaldehyde and acetone in the presence of 4 with benzoic acid (1 mol equiv) afforded the corresponding product 3 in 79% yield with 64% ee (cf. 4@MOF: 77% yield, 80% ee).
