Umpoled Vilsmeier reagents. The chemistry of aminochlorocarbenes derived from Vilsmeier reagents by the action of bases1

Abstract

Vilsmeier reagents such as N-methyl-N-phenylchloroiminium chloride are readily deprotonated by tert-amines even in POCl₃ solution. The resulting transient intermediates, aminochlorocarbenes, are nucleophilic (i.e. umpoled Vilsmeier reagents) and are trapped with electrophiles. In this way dimers [1,2-bis(N-methylanilino)-1,2-dichloroethanes] 3, ‘trimers’ (indolo[3,2-b]quinolininium chlorides) 4 and 5, ‘tetramers’ (2,2′-bis-indoles) 11 and isatins 9 and 10 are accessible in one-pot processes from the formanilide.