[sweet memo]

hello..

I have questions that I don't understand could anyone please help me....

I'm reading these days about vilsmeier reaction and I understand the mechanism of the reaction of it with activated aromatic rings , but I don't know if Vilsmeier reagent react with benzene ring?

 and why when Vilsmeier reagent reacts with enolizable ketone, Chlorovinyl aldehydes formed?? what is the mechanism??? and does the reagent react with ketone that doesn't contain α-hydrogen???


I searched in many books but I didn't find answer???

[Dan]

but I don't know if Vilsmeier reagent react with benzene ring?

It's a sliding scale. The key intermediate iminium cation is an electrophile, and the aromatic ring is the nucleophile. The reaction is faster if the ring is more electron rich (a better nucleophile). I don't think it works for benzene (or at least not well) and it doesn't work for electron deficient aromatics as far as I know.

and why when Vilsmeier reagent reacts with enolizable ketone, Chlorovinyl aldehydes formed??

The key intermediate iminium cation in the Vilsmeier is an electrophile. It reacts with nucleophiles. How can a nucleophile be generated from an enolisable ketone (clue is in the name)?