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.