First reactions of dialkoxycarbenium tetrafluoroborates with pyrroles, 5<i>H</i>‐dibenz[<i>b,f</i>]azepines, and electron‐rich arenes

Abstract

Abstract Pyrrole ( 2a ) and 2,5‐dimethylpyrrole ( 2b ) react with the dialkoxycarbenium tetrafluoroborates 1a‐1c under kinetic control to yield the corresponding acylpyrrole derivatives. 5 H ‐Dibenz[ b,f ]azepine ( 9a ) and the 10,11‐dihydro derivative 9b react only with the most electrophilic of the series of electrophiles tested, namely, diethoxycarbenium tetrafluoroborate ( 1a ), to furnish the corresponding formyl derivatives. Similarly, in arene chemistry, the highly electron‐rich N,N ‐dimethylaniline ( 13a ) and 1,3,5‐trimethoxybenzene ( 13b ) are formylated by reaction with 1a .