Catalytic enantioselective Michael addition in the synthesis of α-aminophosphonates

Enantioenriched (S)-phosphoglutaminic acid derivatives with up to 72% ee were obtained in the catalytic enantioselective Michael reaction of the achiral phosphoglycine synthon. The scope and limitation of the process in terms of the catalyst (diverse (R,R)-TADDOL derivatives) and the base (solid alkali metal tert-butoxides) were examined. The nature of the transition complex was also investigated.