25574-04-3Relevant academic research and scientific papers
2,2′-Bipyridine-α,α′-trifluoromethyl-diol ligand: Synthesis and application in the asymmetric Et2Zn alkylation of aldehydes
Lauzon, Samuel,Ollevier, Thierry
supporting information, p. 11025 - 11028 (2021/11/03)
A chiral 2,2′-bipyridine ligand (1) bearing α,α′-trifluoromethyl-alcohols at 6,6′-positions was designed in five steps affording either the R,R or S,S enantiomer with excellent stereoselectivities, i.e. 97% de, >99% ee and >99.5% de, >99.5% ee, respectively. The key step for reaching high levels of stereoselectivity was demonstrated to be the resolution of the α-CF3-alcohol using (S)-ibuprofen as the resolving agent. An initial application for the 2,2′-bipyridine-α,α′-CF3-diol ligand was highlighted in the ZnII-catalyzed asymmetric ethylation reaction of aromatic, heteroaromatic, and aliphatic aldehydes. Synergistic electron deficiency and steric hindrance properties of the newly developed ligand afforded the corresponding alcohols in good to excellent yields (up to 99%) and enantioselectivities (up to 95% ee). As observed from single crystal diffraction analysis, the complexation of the 2,2′-bipyridine-α,α′-CF3-diol ligand generates an unusual hexacoordinated ZnII.
Copper-Catalyzed Enantioconvergent Cross-Coupling of Racemic Alkyl Bromides with Azole C(sp2)?H Bonds
Chang, Xiao-Yong,Chen, Ji-Jun,Gu, Qiang-Shuai,Jiang, Sheng-Peng,Li, Zhong-Liang,Liu, Lin,Liu, Xiao-Dong,Liu, Xin-Yuan,Su, Xiao-Long,Wang, Fu-Li,Yang, Chang-Jiang,Ye, Liu
supporting information, p. 380 - 384 (2020/10/30)
The development of enantioconvergent cross-coupling of racemic alkyl halides directly with heteroarene C(sp2)?H bonds has been impeded by the use of a base at elevated temperature that leads to racemization. We herein report a copper(I)/cinchona-alkaloid-derived N,N,P-ligand catalytic system that enables oxidative addition with racemic alkyl bromides under mild conditions. Thus, coupling with azole C(sp2)?H bonds has been achieved in high enantioselectivity, affording a number of potentially useful α-chiral alkylated azoles, such as 1,3,4-oxadiazoles, oxazoles, and benzo[d]oxazoles as well as 1,3,4-triazoles, for drug discovery. Mechanistic experiments indicated facile deprotonation of an azole C(sp2)?H bond and the involvement of alkyl radical species under the reaction conditions.
Half-sandwich rhodium complexes with phenylene-based SCS ligands: Synthesis, characterization and catalytic activities for transfer hydrogenation of ketones
Jia, Wei-Guo,Gao, Li-Li,Zhi, Xue-Ting,Li, Xiao-Dong,Wang, Zhi-Bao,Sun, Ying
, (2020/12/30)
A series of half-sandwich rhodium complexes with tridentate phenylene-based bis(thione) (SCS) ligand have been synthesized and characterized. Both half-sandwich rhodium complexes and phenylene-based bis(thione) compounds were fully characterized by 1H and 13C NMR spectra, mass spectrometry and single-crystal X-ray diffraction method. The catalytic activities of half-sandwich rhodium complexes toward the transfer hydrogenation of ketones to their corresponding alcohols were explored using 2-propanol as hydrogen source and solvent. And the half-sandwich rhodium complexes exhibited high catalytic activity for transfer hydrogenation of ketones with a broad functional group tolerance.
Pincerlike molybdenum complex and preparation method thereof, catalytic composition and application thereof, and alcohol preparation method
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Paragraph 0125-0130, (2021/08/11)
The invention discloses a clamp-type molybdenum complex, a preparation method, a corresponding catalyst composition and application. The method comprises the steps: obtaining 9 molybdenum complexes with different structures through coordination reaction of 2-(substituent ethyl)-(5, 6, 7, 8-tetrahydroquinolyl) amine and a corresponding carbonyl molybdenum metal precursor; and catalyzing a ketone compound transfer hydrogenation reaction through a molybdenum complex to generate 40 alcohol compounds. The preparation method of the molybdenum complex is simple, high in yield and good in stability. For a transfer hydrogenation reaction of ketone, the molybdenum-based catalytic system has high catalytic activity and small molybdenum loading capacity, is used for production of aromatic and aliphatic alcohols, and has the advantages of simple method, small environmental pollution and high yield.
Linear β-amino alcohol catalyst anchored on functionalized magnetite nanoparticles for enantioselective addition of dialkylzinc to aromatic aldehydes
Ciprioti, Stefano Vecchio,De Angelis, Martina,Di Pietro, Federica,Iannoni, Marika,Pilloni, Luciano,Primitivo, Ludovica,Ricelli, Alessandra,Righi, Francesco,Righi, Giuliana,Sappino, Carla,Suber, Lorenza
, p. 29688 - 29695 (2020/10/26)
A linear β-amino alcohol ligand, previously found to be a very efficient catalyst for enantioselective addition of dialkylzinc to aromatic aldehydes, has been anchored on differently functionalized superparamagnetic core-shell magnetite-silica nanoparticles (1a and 1b). Its catalytic activity in the addition of dialkylzinc to aldehydes has been evaluated, leading to promising results, especially in the case of 1b for which the recovery by simple magnetic decantation and reuse was successfully verified. This journal is
Binaphthyl-based chiral ligands: Design, synthesis and evaluation of their performance in enantioselective addition of diethylzinc to aromatic aldehydes
Yao, Chao,Wu, Piao,Huang, Yue,Chen, Yaoqi,Li, Lin,Li, Yue-Ming
supporting information, p. 9712 - 9725 (2020/12/28)
The design strategy and the performance of binaphthyl-based chiral ligands were evaluated with computation and enantioselective addition of diethylzinc to aromatic aldehydes. Under optimized conditions, enantioselective addition of diethylzinc to aromatic aldehydes provided the desired optically active secondary alcohols in high isolated yields (up to 91%) and excellent enantiomeric excesses (up to 98% ee).
Isosterically designed chiral catalysts: Rationale, optimization and their application in enantioselective nucleophilic addition to aldehydes
Gao, En,Li, Qiao,Duan, Lili,Li, Lin,Li, Yue-Ming
supporting information, (2020/10/20)
Proline-based N,N′-dioxide ligands were designed on the basis of isosteric approach, and were successfully applied in enantioselective nucleophilic addition to aldehydes. In the presence of 10 mol% of chiral ligand 1b, enantioselective addition of diethylzinc to aldehydes provided the corresponding secondary alcohols in up to 90% isolated yield and up to 99% ee. Similarly, using 3e as chiral ligand, enantioselective arylation and alkynylation of aldehydes also proceeded readily, leading to the desired chiral alcohols in up to 92% isolated yield at 99% ee and 80% isolated yields and up to 84% ee, respectively. The current work would shed light on expanding the structure diversity in the design of chiral ligands and chiral catalysts.
Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
supporting information, p. 14286 - 14294 (2020/09/15)
A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
Rhodium coordination compound as well as preparation method and application thereof
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Paragraph 0133-0135, (2020/09/09)
The invention discloses a rhodium coordination compound as well as a preparation method and application thereof. The structure of the rhodium coordination compound is shown as a formula I which is described in the specification, wherein R is one of H and C1-C6 alkyl, and X is halogen. The rhodium coordination compound can efficiently catalyze a carbonyl transfer hydrogenation reaction to obtain corresponding alcohol, and meanwhile, the preparation method has the advantages of simple process and simplicity and convenience in operation.
Aza-crown compounds synthesised by the self-condensation of 2-amino-benzyl alcohol over a pincer ruthenium catalyst and applied in the transfer hydrogenation of ketones
Zhang, Shanshan,Wang, Zheng,Cao, Qianrong,Yue, Erlin,Liu, Qingbin,Ma, Yanping,Liang, Tongling,Sun, Wen-Hua
supporting information, p. 15821 - 15827 (2020/11/24)
A well-defined PNN-Ru catalyst was revisited to self-condense 2-aminobenzyl alcohol in forming a series of novel aza-crown compounds [aza-12-crown-3 (1), aza-16-crown-4 (2) and aza-20-crown-5 (3)]. All aza-crown compounds are separated and determined by NMR, IR, and ESI-MS spectroscopy as well as X-ray crystallography, indicating the saddle structure of 1 and the twisted 1,3-alternate conformation structure of 3. These aza-crown compounds have been explored to study ferric initiation of transfer hydrogenation (TH) of ketones into their corresponding secondary alcohols in the presence of 2-propanol with a basic t-BuOK solution, achieving a high conversion (up to 95%) by a ferric complex with 2 in a low loading (0.05 mol%). This journal is
