Formation of keto-carbeniums from 1,2,2-triarylacenaphthen-1-ols by breaking a long CC bond: unusual alcohol protonolysis accompanied by formal hydride abstraction

Oxidation of 1,2,2-tris(4-dimethylaminophenyl)- and 2,2-bis(4-dimethylaminophenyl)-1-phenylacenaphthen-1-ols 1a,b with I2 induced the C1C2 bond fission to give 8-aroylnaphthalen-1-yl-bis(4-dimethylaminophenyl)carbenium derivatives 2a,b+, the intramolecular Lewis acid–base pairs. Treatment of 1 with HBF4 did not induce the expected COH bond heterolysis but caused fission of COH and C1C2 bonds to give exactly the same carbenium 2+.