A novel aza-Prins-Friedel-Crafts reaction for the synthesis of 4-arylpiperidines

Aldehyde, homoallylic amine and arene undergo smooth cyclization in the presence of BF3·OEt2 to afford 4-arylpiperidines in good yields and with high trans-selectivity. This is the first report on the preparation of 4-arylpiperidines via aza-Prins-Friedel-Crafts reaction.