High percentages of substitution meta to oxygen in electrophilic benzylation of 2,6-dialkylphenols and aryl ethers
✍ Scribed by Michael P. McLaughlin; Virginia Creedon; Bernard Miller
- Book ID
- 104246011
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- French
- Weight
- 289 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
Hydmw and alkoxy groups on aromatic rings are powerful ortho-w directing substituents in -electrophlllc substitution reactions. We have confirmed, for instance, previous reports1 that Friedel-Crafts benzylatlcm of phenol, anisole, snd orthc-cresol gives solely products of substltution at positions ortho and para to the oxygen substituents. Even In reactions of 2,6-dimethylphenol (&) snd 2,64inethylsnisole (.&I, in which both methyl groups would direct substitution to positions meta to the hydroxy and methoxy functions, a wide variety of.electrophilic reagents have been reported to give exclusively the products of substitution para to the oxygens2, with no reported examples of xneta substitution. A Ham&t treatment of the data of Olah and co-workers3 suggested that TlCl,, catslyzed benzylation of & and & should give just 0.5 and 2.4X, respectlve-