Reaction of Tröger’s base analogues with Vilsmeier reagents

As part of a program aimed at introducing functionality onto the Tröger’s base framework post-synthesis, we investigated the formylation reaction of Tröger’s base analogues with Vilsmeier reagents. We found that rather than the anticipated reaction at the aryl rings, these compounds react with Vilsmeier reagents to afford compounds with a modified strap, whereby the apical methylene group is replaced by a methylene strap bearing an N,N-disubstituted amine.