Toluenes reactions with xenon difluoride

Trimethylsilyl ethers of several steroidal ketones were a-fluorinated by 4-(difluoroiodo)toluene, in moderate yield because of concomitant elimination, accompanied by the formation of other by-products from nucleophilic substitution to a phenyliodonium intermediate. The analogous reaction with xenon difluoride resulted in much better yields but different stereochemistry [50],... 

Fhiorination of aromatics. The reagent reacts with toluene to form benzyl fluoride as the major product ( 65% yield). It is also useful for fluorination of phenols- and of alkyl ethers of phenols the or/Ao-isomcr is formed as the major product. Reactions with this reagent thus differ from those with xenon difluoride, which generally favors formation of paro-isomers. 

The magnitude of the alkoxy group in raeta-substituted toluenes does not significantly influence the regiospecificity of substitution in xenon difluoride fluorinations, while reaction with l-methoxy-2-methylbenzene gave 4-fluoro- and 6-fluoro-l-methoxy-2-methylbenzene in 3 to 1 ratio89,90 (Scheme 30). 

---