Synthesis of iridium and rhodium complexes with new chiral phosphine-NHC ligands based on 1,1′-binaphthyl framework and their application in asymmetric hydrogenation
Synthesis of iridium and rhodium complexes with new chiral phosphine-NHC ligands based on 1,1′-binaphthyl framework and their application in asymmetric hydrogenation
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DOI：
10.1039/c3dt51141c
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发表时间：
2013-01-01
影响因子：
4
通讯作者：
Shi, Min
中科院分区：
文献类型：
--
作者：
Gu, Peng;Zhang, Jun;Shi, Min
以（R）-2-胺-2 '-（二苯基膦基）-1，1'-联萘（1）为起始原料，经四步反应合成了第一系列基于1，1 '-联萘骨架的手性膦咪唑卡宾配体。用（LiOBu）-Bu-t脱质子后，与[Ir（COD）Cl]（2）络合，再与NaBArF进行阴离子交换，得到膦卡宾螯合铱配合物（R）-6a和（R）-6b。通过核磁共振和X-射线衍射对其结构进行了表征。通过类似的合成方法也获得了NHC-膦铑配合物（R）-6c。这些铱配合物已被应用于催化烯烃的不对称氢化，在温和的条件下，以中等至优异的转化率（高达99%）和中等的对映选择性（高达61%ee）得到相应的产品。
The first series of chiral phosphine-imidazole carbene ligands based on a 1,1'-binaphthyl framework were synthesized from (R)-2-amine-2'-(diphenylphosphino)-1,1'-binaphthyl (1) in a four-step pathway. After deprotonation of these phosphine-imidazolium salts with (LiOBu)-Bu-t, and subsequent complexation with [Ir(COD)Cl](2) and anion exchange with NaBArF, phosphine-carbene chelated iridium complexes (R)-6a and (R)-6b were obtained. Their structures have been characterized by NMR and X-ray diffraction analysis. The NHC-phosphine rhodium complex (R)-6c has been also obtained by a similar synthetic method. These iridium complexes have been applied to catalyze the asymmetric hydrogenation of alkenes to give the corresponding products in moderate to excellent conversion (up to 99%) and moderate enantioselectivities under mild conditions (up to 61% ee).