posted on 2012-12-04, 14:15authored byRobert G. Giles
Trimethyloxonium fluoroborate rapidly reacts with nitriles at
elevated temperatures, to afford N-methylnitrilium salts. Subsequent reaction with π-excessive heterocyclic aromatic systems
has been shown to give rise to iminium salts in moderate to excellent
yields. The related imines may be obtained by deprotonation, and these
compounds can be converted further by reduction or hydrolysis to secondary
amines or ketones respectively. The reactions studied provide access to
acylated indoles and pyrroles which are obtainable by other methods in
inferior yields. The related reactions with carbocyclic aromatic systems were studied
in an attempt to determine the range of heteroatom ring substituents which
may be used.