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本文研究了一类结构可调手性单齿亚磷酰胺配体DpenPhos在Rh(I)催化的E和Z型β-脱氢氨基酸酯的不对称催化氢化反应中的应用.经过系统的反应条件和配体结构优化,发现N原子上含有H的亚磷酰胺配体与Rh(I)形成的催化剂通常比N原子上不含H的配体表现出更高的反应活性.在E型β-脱氢氨基酸酯的不对称氢化反应中,催化剂(R,R)-3k/Rh(I)表现突出,可以实现底物的常压催化氢化,取得了92%～96%的对映选择性,催化剂用量可降低至0.2 mol%;对于Z型β-脱氢氨基酸酯的不对称氢化反应,则(R,R)-3l/Rh(I)为最优催化剂,可以获得92%～98%ee值的氢化产物,特别是对于β-芳基取代衍生物的氢化反应,相应氢化产物的ee值可以达到96%～98%.该类催化剂为天然或非天然光学活性β氨基酸的合成提供了一个简便、高效的方法.
In this paper, a class of structurally tunable chiral monodentate phosphoramidite ligands DpenPhos was applied to the asymmetric catalytic hydrogenation of Rh and β-dehydroamino esters catalyzed by Rh (I) .After systematic reaction conditions And ligand structure optimization, it was found that the phosphoramidite ligands containing H at N atom and Rh (I) usually show higher reactivity than the ligands containing no H atom at N. In the case of E-type β- (R, R) -3k / Rh (I) is outstanding in the asymmetric hydrogenation of dehydroabietic acid ester, which can achieve atmospheric catalytic hydrogenation of the substrate with an enantioselectivity of 92% -96% The amount of catalyst can be reduced to 0.2 mol%; (R, R) -3l / Rh (I) is the optimal catalyst for the asymmetric hydrogenation of Z-type β-dehydroamino ester, which can obtain 92% ~ 98% ee Value of the hydrogenated product, especially for the hydrogenation of the β-aryl substituted derivatives, the ee value of the corresponding hydrogenated product can reach 96% to 98%. Such catalysts provide a synthesis of natural or non-natural optically active β amino acids Simple and efficient way.