Effectiveness and Mechanism of the Ene(amido) Group in Activating Iron for the Catalytic Asymmetric Transfer Hydrogenation of Ketones
作者:Qingquan Xue、Rongliang Wu、Di Wang、Meifang Zhu、Weiwei Zuo
DOI:10.1021/acs.organomet.0c00636
日期:2021.1.25
1 and 2 reduced the catalytic activity but led to undiminished enantioselectivity as reaction proceeded. In comparison to the iron complexes 1–3 with a 5,5,5-coordination geometry, the complex 4 derived from the new (R,R)-P-NH-NH2 tridentate ligand showed high reactivity comparable to that of I but was unfortunately not enantioselective. The catalytic reactivity of 1, 2, and 4 illustrates the effectiveness
二膦酰氨基-烯(酰胺基)型的π-相互作用的配体可有效地活化铁,使其类似于酮在催化的不对称转移氢化中的贵金属性能。为了进一步验证该烯基(酰氨基)基团的有效性,我们合成了4种胺(亚胺)铁二膦配合物预催化剂与α的取代基,并且相对于亚氨基(β位置1 - 3)或用放大螯合环大小(5,5- ,6-元环)(4)。与母体比较反式- (- [R ,- [R的[Fe(CO)(CL)(PPH - )2 CH 2 CH═NCHPhCHPhNHCH 2 CH 2 PPH 2)] BF如图4(I)所示,在1和2中引入甲基降低了催化活性,但是随着反应的进行导致对映选择性的降低。相比于铁络合物1 - 3用5,5,5-协调的几何形状,该复合物4从新的派生([R ,- [R)-P-NH-NH 2三齿配体显示出高的反应性比得上我但不幸的是没有对映选择性。的催化活性1,2,和4说明了烯(酰胺)基团的有效性。对重要的催化中间体酰胺