Topology-Based Functionalization of Robust Chiral Zr-Based Metal–Organic Frameworks for Catalytic Enantioselective Hydrogenation
作者:Hong Jiang、Wenqiang Zhang、Xing Kang、Ziping Cao、Xu Chen、Yan Liu、Yong Cui
DOI:10.1021/jacs.0c00637
日期:——
strong acidic and weak basic aqueous solutions. The two flu MOFs featuring the dihydroxyl groups of biphenol in open and large cages, after sequential post-synthetic modification with P(NMe2)3 and [Ir(COD)Cl]2, can be high efficient and recyclable heterogeneous catalysts for hydrogenation of α-dehydroaminoacidesters with up to 98% ee, whereas the three ith MOFs featuring the dihydroxyl groups in small
设计和开发具有高活性和选择性的坚固且多孔的负载型催化剂对于精细化学品和药物的生态友好合成非常重要,但非常具有挑战性。我们在此报告了具有不同拓扑结构的高度稳定的手性 Zr(IV) 基 MOF 的设计和合成,以支持 Ir 配合物并证明其依赖于网络结构的不对称催化性能。在调制合成和等网状扩展策略的指导下,五个具有flu或ith拓扑结构的手性Zr-MOFs由对映纯的1,1'-联苯酚衍生的四羧酸酯接头和Zr6、Zr9或Zr12簇构建而成。所得MOFs在沸水、强酸性和弱碱性水溶液中均表现出较高的化学稳定性。两种以双酚二羟基为特征的开放笼和大笼中的flu MOF,经过P(NMe2)3和[Ir(COD)Cl]2的连续后合成修饰,可以成为高效且可回收的α加氢多相催化剂具有高达 98% ee 的脱氢氨基酸酯,而在小笼中具有二羟基基团的第三个 MOF 不能与 P(NMe2)3 一起安装以支持 Ir 络合物。将 Ir-磷催化剂掺入
Chiral bisphosphine ligands based on quinoline oligoamide foldamers: application in asymmetric hydrogenation
A series of chiral bisphosphine ligands were designed and synthesized based on single-handed quinoline oligoamidefoldamers. The bisphosphine ligands can coordinate with Rh(cod)2BF4 in a 1 : 1 stoichiometry and the resulted chiral Rh(I) catalysts were applied in the asymmetric hydrogenation of α-dehydroamino acid esters, in which excellent conversions and promising levels of enantioselectivity were
Brine-Stabilized 2,2,2-Trifluorodiazoethane and Its Application in the Synthesis of CF<sub>3</sub>–Substituted Cyclopropane α-Amino Acids
作者:Chuan-Le Zhu、Li-Jun Yang、Shen Li、Yan Zheng、Jun-An Ma
DOI:10.1021/acs.orglett.5b01450
日期:2015.7.17
CF3CHN2 in CH3CN is realized. This method shows excellent generality, affording a wide range of trifluoromethyl-substituted cyclopropanes bearing azlactone rings in good to high yields and diastereoselectivities. With the products in hand, the trifluoromethyl-substituted cyclopropane α-amino acids and relative peptide derivatives could be readily obtained.
Asymmetric Synthesis of Unnatural Amino Acids and Tamsulosin Chiral Intermediate
作者:Veera Reddy Arava、Srinivasulu Reddy Amasa、Bharat Kumar Goud Bhatthula、Laxmi Srinivas Kompella、Venkata Prasad Matta、M. C. S. Subha
DOI:10.1080/00397911.2012.748075
日期:2013.11.2
An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resource: Full experimental and spectral details.]
Cation-Triggered Switchable Asymmetric Catalysis with Chiral Aza-CrownPhos
作者:Guang-Hui Ouyang、Yan-Mei He、Yong Li、Jun-Feng Xiang、Qing-Hua Fan
DOI:10.1002/anie.201411593
日期:2015.3.27
AbstractAn aza‐crown ether, modified phosphoramidite ligand, has been designed and synthesized. The ON/OFF reversible switch of catalytic activity for its rhodium catalyst was thoroughly investigated in the asymmetric hydrogenation of dehydroamino acid esters modulated by host–guest interactions. In the OFF state, the catalyst is almost inactive (less than 1 % conversion) because of the formation of an intermolecular sandwich complex by two aza‐crown ether moities and the cationic rhodium metal center. In using alkali‐metal‐cations as the trigger, the catalytic activity was turned ON and consequently resulted in full conversions and excellent enantioselectivities (up to 98 % ee).