Combining palladium and ammonium halide catalysts for Morita–Baylis–Hillman carbonates of methyl vinyl ketone: from 1,4-carbodipoles to ion pairs
作者:Yang Yang、Bo Zhu、Lei Zhu、Ying Jiang、Chun-Ling Guo、Jing Gu、Qin Ouyang、Wei Du、Ying-Chun Chen
DOI:10.1039/d1sc03517g
日期:——
Morita–Baylis–Hillman carbonates from diverse aldehydes and methyl vinyl ketones can be directly utilised as palladium-trimethylenemethane 1,4-carbodipole-type precursors, and both reactivity and enantioselectivity are finely regulated by adding a chiral ammonium halide as the ion-pair catalyst. The newly assembled intermediates, proposed to contain an electronically neutral π-allylpalladium halide complex and a reactive
在这里,我们报道了来自不同醛和甲基乙烯基酮的Morita-Baylis-Hillman碳酸酯可以直接用作钯-三亚甲基甲烷1,4-碳二极型前体,并且通过添加手性卤化铵作为前体,可以精细调节反应性和对映选择性。离子对催化剂。新组装的中间体含有电子中性的 π-烯丙基卤化钯络合物和反应性紧致离子对,可有效地与不同的活化烯烃或靛红进行不对称 [4 + 2] 环化,通常具有高区域性、非对映性和对映性通过调节基底或催化剂组件,可以很好地实现选择性,甚至可切换的区域发散或非对映发散环化。进行了一系列控制实验,包括紫外/可见光吸收研究和密度泛函理论计算,以合理化这种结合钯配合物和卤化铵作为离子对催化剂的新型双活化模式。