A series of calcium complexes supported by chiral bisimidazoline ligands have been studied in the catalytic intramolecular hydroamination/cyclisation of amino-olefins. The complexes [Ca(R-BIM)N(SiMe3)2}(THF)] (R = 4-C6H4Me, 5a, 4-C6H4F, 5b and tBu, 5c) have given competitive enantioselectivities (up to 12%) when compared to current literature studies involving calcium. Bisimidazolines offer a significant advance over similar bisoxazoline ligands, by allowing a greater structural variance through a modular synthetic pathway.
一系列由手性
双咪唑啉
配体支持的
钙复合物已被研究用于
氨基烯烃的催化分子内
氢胺化/环化反应。复合物 [Ca(R-BIM)N(SiMe3)2}(THF)](R = 4-C6H4Me, 5a;4-
C6H4F, 5b 和 tBu, 5c)在与当前文献中涉及的
钙相比时,表现出竞争性的对映选择性(最高可达 12%)。
双咪唑啉在结构变异方面相较于类似的双
噁唑啉
配体提供了显著的进展,因为它通过模块化合成途径允许更大的结构多样性。