Highly Diastereo‐ and Enantioselective Synthesis of α‐Alkyl Norstatine Derivatives: Catalytic Asymmetric Mannich Reactions of 5 H ‐Oxazol‐4‐ones

Going Mannich : The title reaction results in the first catalytic asymmetric synthesis of syn ‐α‐alkyl norstatine derivatives. Excellent enantioselectivities and diastereoselectivities were achieved with a series of N ‐diphenylphosphinoyl‐protected imines and 5 H ‐oxazol‐4‐ones by using the catalyst 1 /Zn. Importantly, the involvement of the diethyl phosphoramidate 2 was critical to achieve good enantioselectivities in the present Mannich reaction.