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4904001 
Journal Article 
Pyridine Improves Aluminum Triiodide Induced Selective Cleavage of Alkyl o-Hydroxyphenyl Ethers: A Practical and Efficient Procedure for the Preparation of Hydroxychavicol by Demethylation of Eugenol 
Sang, D; Yao, M; Tian, J; Chen, X; Li, Li; Zhan, H; You, L 
2017 
1 
Synlett
ISSN: 0936-5214
EISSN: 1437-2096 
28 
1 
138-142 
WOS:000392511600028 
Demethylation of eugenol with aluminum triiodide is complicated by an unexpected hydrogenation side reaction. The hydrogenation proceeds through a cascade deprotonation, hydroiodination, and hydrogen-halogen exchange process, and can be prevented by suppressing the hydroiodination in advance. A practical demethylation procedure is thus developed that delivers hydryoxychavicol in essentially quantitative yield by using pyridine as an additive. The method is selective towards cleaving alkyl o-hydroxyphenyl ethers and is compatible with a variety of functional groups. 
eugenol; demethylation; hydroxychavicol; hydroiodination; hydrogen-halogen exchange; alkyl o-hydroxyphenyl ether; aluminum triidodide-pyridine