A facile synthetic approach has been adopted towards the synthesis of (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine via demetalation of its dichloro Zn(II) complex, which itself was separated from a mixture of diastereomeric Zn(II) complexes by fractional crystallization. The synthesized chiral 1,2-diamine ligand was evaluated as a chiral auxiliary for the Cu(II)-catalysed asymmetric Henry reaction of 3-phenylpropanal and nitromethane, yielding (S)-1-nitro-4-phenylbutan-2-ol in excellent yields (up to 99%) and enantioselectivities (up to 97%). A facile synthetic approach towards (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine (2b) via fractional crystallization and demetalation of its Zn(II) complex has been adopted. 2b served as a highly enantioselective pro-ligand with Cu(OAc)2 for asymmetric Henry reaction of 3-phenylpropanal and nitromethane in the presence of base with 97% > ee and 99% yield.

中文翻译：

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通过金属化和去金属化合成 (2R,3R)-N2,N3-双((S)-1-苯乙基)丁烷-2,3-二胺的单一非对映体的有效合成方法

已采用一种简便的合成方法通过其二氯 Zn(II) 配合物的脱金属来合成 (2R,3R)-N2,N3-双((S)-1-苯乙基)丁烷-2,3-二胺，其中通过分级结晶将 Zn(II) 络合物与非对映体 Zn(II) 络合物的混合物分离。合成的手性 1,2-二胺配体被评估为 Cu(II) 催化的 3-苯基丙醛和硝基甲烷的不对称亨利反应的手性助剂，生成 (S)-1-nitro-4-phenylbutan-2-ol优异的产率（高达 99%）和对映选择性（高达 97%）。采用了一种简便的合成方法（2R,3R）-N2,N3-双（（S）-1-苯乙基）丁烷-2,3-二胺（2b），通过其Zn（II）配合物的分级结晶和脱金属.