method has been developed for the preparation of new Tröger base derivatives by an exchange reaction with the methano bridge of rac-Tröger base derivatives with carbonylcompounds in the presence of TiCl4 or POCl3. The use of chiral (S,S)-N,N-bis(α-methylbenzyl)formamide as a carbonylcompound gave the corresponding methano Tröger base derivatives with the diastereomeric ratios of up to 77:23.
intermolecular reaction of Tröger bases with N‐sulfonyl‐1,2,3‐triazoles. Under RhII catalysis, α‐imino carbenes are generated and a subsequent cascade of [1,2]‐Stevens, Friedel–Crafts, Grob, and aminal formationreactions yield the polycyclic heterocycles as single isomers (d.r.>49:1, four stereocenters including two bridgehead N atoms). Further ring expansion by insertion of a second α‐imino carbene leads