Chiral phosphine-phosphoramidite ligands for highly enantioselective hydrogenation of N-arylimines
作者:Qing Li、Chuan-Jin Hou、Xiao-Ning Liu、De-Zhi Huang、Yan-Jun Liu、Rui-Feng Yang、Xiang-Ping Hu
DOI:10.1039/c4ra16062b
日期:——
The asymmetrichydrogenation of N-arylimines with the chiral phosphine-phosphoramidite ligand, (Sc,Sa)-PEAPhos 2b, has been developed. The results revealed that the presence of the substituents on the 3,3′-positions of the binaphthyl backbone significantly improved the enantioselectivity. The utility of this methodology was demonstrated in the synthesis of the chiral fungicide (R)-metalaxyl.
A Frustrated Lewis Pair Catalyzed Asymmetric Transfer Hydrogenation of Imines Using Ammonia Borane
作者:Songlei Li、Gen Li、Wei Meng、Haifeng Du
DOI:10.1021/jacs.6b07245
日期:2016.10.5
Lewis acid and base together. Piers' borane and chiral tert-butylsulfinamide were chosen as the FLP, and a metal-free asymmetrictransferhydrogenation of imines was realized with high enantioselectivities. Significantly, with ammonia borane as hydrogen source, a catalytic asymmetric reaction using 10 mol % of Piers' borane, chiral tert-butylsulfinamide, and pyridine additive, has been successfully
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‐Symmetric Bicyclic Bisborane Catalysts: Kinetic or Thermodynamic Products of a Reversible Hydroboration of Dienes
作者:Xian‐Shuang Tu、Ning‐Ning Zeng、Ru‐Ye Li、Yu‐Quan Zhao、De‐Zhen Xie、Qian Peng、Xiao‐Chen Wang
DOI:10.1002/anie.201808289
日期:2018.11.12
C2‐symmetric bicyclic bisborane catalysts by addition reactions of internal dienes with the Piers borane, HB(C6F5)2, and an analogue, HB(p‐C6F4H)2. The dependence of the addition pattern on the reaction temperature allowed us to selectively prepare two diastereomericcatalysts from a single diene precursor. The bisboranes prepared in situ exhibited excellent activity (turnover numbers up to 200 at −40 °C)
我们通过内部二烯与Piers硼烷HB(C 6 F 5)2和类似物HB(p- C 6 F 4 H)2的加成反应制备了新型的手性C 2对称双环双硼烷催化剂。加料方式对反应温度的依赖性使我们能够从单一的二烯前体中选择性地制备两种非对映体催化剂。原位制备的双硼烷在亚胺加氢反应中表现出出色的活性(在-40°C时的转换数高达200)和对映选择性(高达95% ee)。
Synthesis of Planar Chiral Shvo Catalysts for Asymmetric Transfer Hydrogenation
作者:Xiaowei Dou、Tamio Hayashi
DOI:10.1002/adsc.201501162
日期:2016.3.31
solely on different substitution flanking the CO function, was prepared and used for transfer hydrogenation of imines and ketones. The reduction of ketimines represented by N‐(1‐phenylethylidene)aniline and prochiral ketones such as phenyl trifluoromethyl ketone with 2‐propanol was efficiently catalyzed by 0.5 mol% of the chiral Shvo catalyst to give high yields of the corresponding reduction products
A Method for the Asymmetric Hydrosilylation of <i>N</i>-Aryl Imines
作者:Marcus C. Hansen、Stephen L. Buchwald
DOI:10.1021/ol005583w
日期:2000.3.1
[GRAPHICS]The asymmetric reduction of N-aryl imines to yield chiral amines with enantiomeric excesses above 90% was achieved. Ethylenebis(eta(5)-tetrahydroindenyl)titanium difluoride ((EBTHI)TiF2, 1) was employed as the precatalyst with polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent. A variety of N-aryl imines derived from nonaromatic ketones were reduced with high ee.