A new method for the synthesis of trans-2,6-disubstituted piperidine derivatives is described. The transformation of cyclic α-methoxycarbamates 5 and 6 affords trans ketones 17 and 18. The synthesis of diols 1–4 from 17 and 18 has shown that the structure proposed in the literature for the piperidine alkaloid andrachamine is incorrect. A reexamination of the original spectral data of this alkaloid suggested that it is a meso 2,6-disubstituted piperidine derivative. Unambiguous syntheses of 23 and 24 and comparison with a sample of andrachamine have established that this alkaloid possesses structure 23. Key words: N-acyliminium, piperidine, alkaloid, andrachamine.