Du X,
Fan H,
*,
Liu S,
Zhang ZC.
*
Dalian Institute of Chemical Physics and Changzhou University, P. R. of China
Selective Nucleophilic α-C Alkylation of Phenols with Alcohols via Ti=Cα Intermediate on Anatase TiO
2 Surface.
Nat. Commun. 2023;
14: 4479
DOI:
10.1038/s41467-023-40101-7
Key words
aromatic alkylation - anatase TiO
2
- nucleophilic aromatic functionalization
Significance
C-alkylation of phenols with alcohols was promoted by anatase TiO2 at 300 °C. Phenol reacted with n-propyl alcohol to give 2-propylphenol with 87% selectivity. Rutile TiO2, a stable polymorphs titania, did not promote the C-alkylation (ca. 0% phenol conversion). Phenols bearing 3-chloro and 3-methyl substituents showed a similar trend of selectivity for the alkylation, although they have opposite electronic effects.
Comment
DFT calculations as well as experimental observations indicate that the main reaction pathway of C-alkylation is different from the conventional Friedel-Crafts alkylation. The authors have proposed that the reaction proceeds via a Ti=C intermediate which reacted with a Ti-activated phenol nucleophilically at the ortho-position.
