Synthesis of enantiopure β-amino alcohols via AKR/ARO of epoxides using recyclable macrocyclic Cr(III) salen complexes
作者:Rukhsana Ilays Kureshy、K. Jeya Prathap、Manish Kumar、Prasanta Kumar Bera、Noor-ul Hasan Khan、Sayed Hasan Razi Abdi、Hari Chandra Bajaj
DOI:10.1016/j.tet.2011.08.077
日期:2011.10
A series of chiral macrocyclic Cr(III) salen complexes 1–8 were synthesized and characterized. These complexes were found to be highly active, regio-, diastereo-, and enantioselective catalysts in aminolytic kinetic resolution (AKR) of racemic trans-epoxides as well as asymmetric ring opening (ARO) of prochiral meso-epoxides with various anilines as nucleophiles at room temperature in 18–24 h. Excellent
一系列大环的手性的Cr(III)络合物沙仑的1 - 8被合成和表征。这些复合物被认为是高度活性的,区域选择性,diastereo-,和外消旋的aminolytic动力学拆分(AKR)的对映选择性催化剂的反式环氧化物的前手性和不对称环开口(ARO)内消旋环氧化物与各种苯胺亲核在室温在18–24小时内。获得了具有高对映体选择性(ee,> 99%)的手性抗-β-氨基醇的极佳收率(相对于亲核试剂> 99%),同时伴随着高ee(最高> 99%)的相应环氧化物的回收。配合物1还催化内消旋的ARO-环氧化物以高产率(99%)和ee(高达91%)提供相应的顺-β-氨基醇。由于催化剂中内置了碱性位点,因此无需外部碱(作为添加剂)即可促进AKR和ARO反应。催化剂1在保持其性能的情况下方便地循环几次。使用催化剂1在相对较高的规模(10 mmol)下成功地证明了反式二苯乙烯与苯胺的AKR 。