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排序方式: 共有1345条查询结果,搜索用时 15 毫秒
1.
Xi‐Sha Zhang Yun‐Fei Zhang Zhao‐Wei Li Fei‐Xian Luo Zhang‐Jie Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(18):5568-5572
A rhodium(III)‐catalyzed cross‐coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (C H, C S, O H) and the formation of two bonds (C C, C O). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double C H activation, the first of such examples in cross‐oxidative coupling. 相似文献
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Jie Li Prof. Dr. Shuanglin Qu Prof. Dr. Wanxiang Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(6):2380-2384
A rhodium-catalyzed remote C(sp3)−H borylation of silyl enol ethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional-group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derived from aldehydes and ketones, and provides direct access to a broad range of structurally diverse 1,n-borylethers in excellent regioselectivities and good yields. These compounds are precursors to various valuable chemicals, such as 1,n-diols and aminoalcohols. 相似文献
6.
Wen-Wen Zhang Prof. Dr. Bi-Jie Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202214534
Despite the advances in the area of catalytic alkene hydrosilylation, the enantioselective hydrosilylation of alkenes bearing a heteroatom substituent is scarce. Here we report a rhodium-catalyzed hydrosilylation of β,β-disubstituted enamides to directly afford valuable α-aminosilanes in a highly regio-, diastereo-, and enantioselective manner. Stereodivergent synthesis could be achieved by regulating substrate geometry and ligand configuration to generate all the possible stereoisomers in high enantio-purity. 相似文献
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Dr. Yuting Li Prof. Dr. Yu Tang Prof. Dr. Franklin Tao 《Angewandte Chemie (International ed. in English)》2023,62(15):e202214332
C−N coupling is significant for the synthesis of fine chemicals toward various applications. Hydroaminoalkylation of olefins is a tandem reaction of C−N coupling involving first the formation of an aldehyde through hydroformylation of an olefin and then the production of amine through reductive amination of the aldehyde. Here we report a stable, supported catalyst of singly dispersed Rh1 atoms anchored on TiO2 (P25) nanoparticles designated as Rh1/P25. Its high activity for C−N coupling was demonstrated by six hydroaminoalkylations of olefins and amines with selectivity of higher than 90% for producing tertiary amines. The singly dispersed Rh1O4 on P25 exhibit activity and selectivity for hydroaminoalkylation comparable or even higher than some reported molecular catalysts. In contrast to molecular catalysts, the Rh-based single-atom Rh heterogeneous catalysis (Rh1/P25) can be readily separated from reactants and products, reused for multiple runs of hydroaminoalkylation, and recycled with a low cost. 相似文献
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Dr. Liselle Atkin Dr. Daniel L. Priebbenow 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302175
Investigations into C−H amidation reactions catalysed by cationic half-sandwich d6 metal complexes revealed that the indenyl-derived catalyst [Ind*RhCl2]2 significantly accelerated the directed ortho C−H amidation of benzoyl silanes using 1,4,2-dioxazol-5-ones. Ring slippage involving a haptotropic η5 to η3 rearrangement of the indenyl complex proposedly enables ligand substitution at the metal centre to proceed via associative, rather than dissociative pathways, leading to significant rate and yield enhancements. Intriguingly, this phenomenon appears specific for C−H amidation reactions involving weakly coordinating carbonyl-based directing groups with no acceleration observed for the corresponding reactions involving strongly coordinating nitrogen-based directing groups. 相似文献
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Yaxin Zeng Prof. Dr. Ying Xia 《Angewandte Chemie (International ed. in English)》2023,62(32):e202307129
Direct synthesis of gem-difluorinated carbocyclic molecules represents a longstanding challenge in organic chemistry. Herein, a Rh-catalyzed [3+2] cycloaddition reaction between readily available gem-difluorinated cyclopropanes (gem-DFCPs) and internal olefins has been developed, enabling the efficient synthesis of gem-difluorinated cyclopentanes with good functional group compatibility, excellent regioselectivity and good diastereoselectivity. The resulting gem-difluorinated products can undergo downstream transformations to access various mono-fluorinated cyclopentenes and cyclopentanes. This reaction demonstrates the use of gem-DFCPs as a type of “CF2” C3 synthon for cycloaddition under transition metal catalysis, which provides potential strategy for synthesizing other gem-difluorinated carbocyclic molecules. 相似文献
10.
Hongpu Huang Dr. Kai Liu Dr. Fulin Yang Junlin Cai Shupeng Wang Weizhen Chen Dr. Qiuxiang Wang Dr. Luhong Fu Prof. Zhaoxiong Xie Prof. Shuifen Xie 《Angewandte Chemie (International ed. in English)》2023,62(52):e202315752
Breaking atomic monogeneity of catalyst surfaces is promising for constructing synergistic active centers to cope with complex multi-step catalytic reactions. Here, we report a defect-derived strategy for creating surface phosphorous vacancies (P-vacancies) on nanometric Rh2P electrocatalysts toward drastically boosted electrocatalysis for alkaline hydrogen oxidation reaction (HOR). This strategy disrupts the monogeneity and atomic regularity of the thermodynamically stable P-terminated surfaces. Density functional theory calculations initially verify that the competitive adsorption behavior of Had and OHad on perfect P-terminated Rh2P{200} facets (p-Rh2P) can be bypassed on defective Rh2P{200} surfaces (d-Rh2P). The P-vacancies enable the exposure of sub-surface Rh atoms to act as exclusive H adsorption sites. Therein, the Had cooperates with the OHad on the peripheral P-sites to effectively accelerate the alkaline HOR. Defective Rh2P nanowires (d-Rh2P NWs) and perfect Rh2P nanocubes (p-Rh2P NCs) are then elaborately synthesized to experimentally represent the d-Rh2P and p-Rh2P catalytic surfaces. As expected, the P-vacancy-enriched d-Rh2P NWs catalyst exhibits extremely high catalytic activity and outstanding CO tolerance for alkaline HOR electrocatalysis, attaining 5.7 and 14.3 times mass activity that of p-Rh2P NCs and commercial Pt/C, respectively. This work sheds light on breaking the surface atomic monogeneity for the development of efficient heterogeneous catalysts. 相似文献