The direct enantioselective chiral calcium(II)·phosphate complex (Ca[CPA]₂)-catalyzed conjugate addition of unprotected alkyl amines to maleimides was developed. This mild catalytic system represents a significant advance towards the general convergent asymmetric amination of α,β-unsaturated electrophiles, providing medicinally relevant chiral aminosuccinimide products in high yields and enantioselectivities. Furthermore, the catalyst can be reused directly from a previously chromatographed reaction and still maintain both high yield and selectivity.

中文翻译：

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钙（ii）催化的胺的对映选择性共轭加成† ‡

开发了将未保护的烷基胺直接对映选择性手性钙（II）·磷酸酯络合物（Ca [CPA] ₂）催化的共轭加成到马来酰亚胺的方法。这种温和的催化体系代表了朝一般聚合的α，β-不饱和亲电试剂的不对称胺化的重大进展，从而以高收率和对映选择性提供了与医学相关的手性氨基琥珀酰亚胺产品。此外，该催化剂可以直接从先前的色谱反应中重复使用，并且仍然保持高收率和选择性。