A highly efficient approach to vanillin starting from 4-cresol
作者:Jian-An Jiang、Cheng Chen、Ying Guo、Dao-Hua Liao、Xian-Dao Pan、Ya-Fei Ji
DOI:10.1039/c4gc00003j
日期:——
A highly efficient approach to the famous flavor and fragrance compound vanillin has been developed starting from 4-cresol with the attention focused on improving the sustainability of all the reactions. The approach involves a three-step sequence of the quasi-quantitative selective clean oxybromination of 4-cresol, the high-yield selective aerobic oxidation of 2-bromo-4-cresol, and the quantitative methoxylation of 3-bromo-4-hydroxybenzaldehyde with the recovery of pure methanol. Herein, the pivotal oxidation and methoxylation reactions are logically investigated and developed into two concise methodologies. As a green alternative, the approach holds significant value for the sustainable manufacturing of vanillin.
Cu(OAc)<sub>2</sub>-catalyzed remote benzylic C(sp<sup>3</sup>)–H oxyfunctionalization for CO formation directed by the hindered para-hydroxyl group with ambient air as the terminal oxidant under ligand- and additive-free conditions
作者:Jian-An Jiang、Cheng Chen、Jian-Gang Huang、Hong-Wei Liu、Song Cao、Ya-Fei Ji
DOI:10.1039/c3gc41946k
日期:——
A hindered para-hydroxyl group-directed remotebenzylicC(sp3)–H oxyfunctionalization has been developed for the straightforward transformation of 2,6-disubstituted 4-cresols, 4-alkylphenols, 4-hydroxybenzyl alcohols and 4-hydroxybenzyl alkyl ethers into various aromatic carbonyl compounds. The ligand- and additive-free Cu(OAc)2-catalyzed atmospheric oxidation mediated by ethylene glycol unlocks a