Synthesis of (−)-coniine and (−)-pipecoline using ruthenium catalyzed ring closing metathesis

Ring closing metathesis employing the well-known Grubbs’ ruthenium catalyst has been used as the key step in the synthesis of piperidine alkaloids, (−)-coniine and (−)-pipecoline, and the asymmetric induction has been performed by using (R)-α-methyl benzylamine as an auxiliary.