Electrophilic Addition of Alcohols and Phenols

It is known that N-vinylindole [650-652] and N-vinylcarbazole [653-655], upon acid-catalyzed interaction with alcohols, give the corresponding N-(o-alkoxyethyl) derivatives (addition according to the Markovnikov rule). In the case of N-vinylindole, the HCl-catalyzed addition competes with the polymerization and considerably reduces the yields of adducts [650], N-Vinylpyrrolidone adds alcohols and phenols also according to the Markovnikov rule to afford N-[a-alk(ar)oxyethyl] pyrrolidones [647,656]. The benzene nucleus of phenols is reported to be alkylated by N-vinylpyrrolidone, the hydroxyl group remaining intact [647]. 

N-Vinylpyrroles provide ample opportunities for the synthesis of new families of pyrrole derivatives, in particular, via the reactions with hydroxyl function. 

SCHEME 2.194 Synthesis of N-(a-alkoxyethyl)pyrroles by electrophilic addition of alcohols to N-vinylpyrroles. 

N-vinylpyrroles add alcohols and phenols in the presence of acids or without the catalyst (in the case of phenols possessing higher acidity than alcohols) regiose-lectively according to the Markovnikov rule and in agreement with the electrophilic nature of the reaction. 

Reaction Products of N-Vinylpyrroles with the Participation of Vinyl Group 

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