Superacid-catalyzed reactions of olefinic pyrazines: an example of anti-Markovnikov addition involving superelectrophiles.
[reaction: see text] Olefinic pyrazines are found to react with benzene in CF3SO3H and give anti-Markovnikov-type addition products. We propose that this is caused by two effects: destabilization of the carbocationic intermediates that would lead to Markovnikov-type products and the generation of a considerable amount of positive charge at the terminal carbon of the olefinic groups. This suggests that acid-catalyzed addition reactions can give anti-Markovnikov-type products when a multiply charged (i.e., superelectrophilic) group is adjacent to the olefinic site.
Zhang
Yiliang
Y
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA.
Briski
Jason
J
Zhang
Yun
Y
Rendy
Rendy
R
Klumpp
Douglas A
DA
D000475:Alkenes / Q000737:chemistry; D001554:Benzene / Q000737:chemistry; D002384:Catalysis; D004563:Electrochemistry; D007202:Indicators and Reagents; D015394:Molecular Structure; D011719:Pyrazines / Q000737:chemistry*
D000475:Alkenes; D007202:Indicators and Reagents; D011719:Pyrazines; D001554:Benzene