An efficient reaction of the (2R,1'S)-or (2S,1'S)-N,N-bis(p-methoxybenzyl)-2-(1-amino-A C H T U N G T R E N N U N G alkyl)epoxides, derived from a-amino acids, with boron trifluoride-phosphoric acid complex is described. This process affords highly elaborated enantiopure tricyclic a,b-enones in high yields, through an ipso-Friedel-Crafts/Michael addition cascade.Keywords: amino acids; boron; enones; FriedelCrafts reaction; Michael addition; quaternary centersThe synthetic design of complex compounds bearing quaternary stereocenters is a challenging task for synthetic organic chemists.[1] The construction of quaternary stereocenters employing the methods used for preparing tertiary ones is not straightforward.[1f] For this reason, asymmetric procedures aiming to obtain fully substituted carbon centers are of great value.In this communication we report the synthesis of new amino acid-derived enantiopure tricyclic a,benones bearing an asymmetric quaternary center. Similar structures have found applications such as novel alkaloid natural products [2] and were also evaluated for their anti-HBV (hepatitis B virus) activity.[3]