Short synthesis of polyfunctional sp3-rich threonine-derived morpholine scaffolds

A convenient synthesis of novel complex morpholines was achieved by a two-step process involving a Petasis three-component coupling reaction of glycolaldehyde, organoboronic acid and different amines, followed by an acid- or base-mediated intramolecular cyclization. The use of threonine derivatives with glycolaldehyde in the Petasis reaction has been studied and successfully applied in the process, achieving morpholines with a higher fraction of sp(3) carbon atoms compared to blockbuster drugs.