Organocatalytic Asymmetric Decarboxylative Mannich Reaction of beta-Keto Acids with Cyclic alpha-Ketiminophosphonates: Access to Quaternary alpha-Aminophosphonates

An organocatalytic asymmetric decarboxylative Mannich reaction of beta-keto acids with cyclic alpha-ketiminophosphonates has been developed. By using saccharide-derived bifunctional amine-thiourea catalysts bearing an axial chiral binaphthyl scaffold, a wide range of quaternary alpha-amino-gamma-oxophosphonates were obtained in up to 93% yield and >99% ee. Furthermore, two interesting-aminophosphonate derivatives were synthesized from the corresponding decarboxylative Mannich product via simple transformations.