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The role of β-cyclodextrin in mediating regioselective dimethylaminomethylation of phenol
- Wu, Wen-Hai, Duan, Jiang, Wei, Ting, Tu, Hai-Yang, Zhang, Ai-Dong
- Tetrahedron 2018 v.74 pp. 360-365
- beta-cyclodextrin, chemical reactions, chemical structure, dimethylamine, formaldehyde, nuclear magnetic resonance spectroscopy, phenol, regioselectivity
- Regioselective reactions with supramolecular control are of great interest. Herein, the para-regioselectivity in the Mannich reaction of phenol with formaldehyde and dimethylamine was achieved with the use of β-cyclodextrin (β-CD), giving 4-(N,N-dimethylaminomethyl)phenol (p-AP) as major product. ¹H NMR and ITC measurements of the binding of β-CD with the reactants and the products o- and p-AP revealed a new mechanism, in which β-CD includes p-AP instead of phenol to control the reaction regioselectivity. This product-inclusion mechanism is remarkably different to the known reactant-inclusion process.