Superacid-promoted additions involving vinyl-substituted pyrimidines, quinoxalines, and quinazolines: mechanisms correlated to charge distributions.

The superacid-promoted reactions of vinyl-substituted N-heterocycles have been studied. Diprotonated pyrimidines, quinoxalines, and quinazolines exhibit an unusual regioelectronic effect that controls the type of addition reaction observed. Depending on the ring position of the vinyl substituent, either conjugate addition or Markovnikov addition occurs.

Superelectrophilic chemistry of imidazoles.

The mechanistic and synthetic chemistry of imidazole-based superelectrophiles has been studied. The protonated imidazole ring, or imidazolium group, is shown to enhance the electrophilic reactivity of an adjacent carboxonium group (compared to a related monocationic species). This leads to efficient condensation reactions between imidazole aldehydes and ketone with arenes in the Brønsted superacid CF3SO3H.