Nitrone cycloadditions: synthesis of (±)-andrachamine

Abstract
The usefulness of the cycloaddition of alkenes to 2-alkyl-2,3,4,5-tetrahydropyridine oxides for the preparation of trans-2,6-dialkylpiperidines is confirmed by a stereoselective synthesis of (±)-andrachamine. Peroxy acid oxidation of 9-oxa-1-azabicyclo[4.3.0]nonanes does not lead regioselectively to the corresponding 2-alkyl-2,3,4,5-tetrahydropyridine oxide, as had previously been claimed.