Superelectrophilic carbocations: preparation and reactions of a substrate with six ionizable groups

Abstract

A substrate has been prepared having two triarylmethanol centers and four pyridine-type substituent groups. Upon ionization in the Brønsted superacid CF3SO3H, the substrate undergoes two types of reactions. In the presence of only the superacid, the highly ionized intermediate(s) provide a double cyclization product having two pyrido[1,2-a]indole rings. With added benzene, an arylation product is obtained. A mechanism is proposed involving tetra-, penta-, or hexacationic species.

Superelectrophiles: Recent Advances

“…Our research group has studied a class of superelectrophiles in which very high levels of cationic charge are formed on the ion, including tri-, tetra-, penta-, and hexacationic structures [ 47 , 48 , 49 ]. Thus, compound 45 reacts in superacid with benzene to provide compound 46 in good yield, as a product from remote functionalization ( Scheme 12 ) [ 48 ].…”