Diastereoselective, large-scale synthesis of β-amino acids via asymmetric aza-Michael addition as α2δ ligands for the treatment of generalized anxiety disorder and insomnia

Scalable synthetic routes to β-amino acids 1 and 2 are presented. These two compounds, which bind to the α2δ subunit of calcium channels and have important medical applications, have been prepared on kilogram scale in our pilot plant through an improved synthesis that avoids the use of highly toxic reagents and hazardous chemistry present in the original Medicinal Chemistry route. The two chiral centers are introduced through asymmetric Michael and aza-Michael reactions with excellent diastereoselectivity.