199166-26-2Relevant academic research and scientific papers
Novel Zn/ZnI2-promoted cross-coupling of acrylic acid esters with arylaldehydes to α-aroyladipic acid esters
Sakurai, Hidehiro,Takeuchi, Hiroki,Hirao, Toshikazu
, p. 3048 - 3049 (2002)
Cross-coupling of alkyl acrylates and arylaldehydes was achieved by treatment with metallic zinc and zinc(II) iodide in DMF, giving dialkyl α-aroyladipates in moderate yields.
Catalytic Enantioselective Addition of Prochiral Radicals to Vinylpyridines
Cao, Kangning,Jiang, Zhiyong,Yang, Songwei,Jia, Hongshao,Zhao, Xiaowei,Qiao, Baokun,Tan, Siu Min,Lee, Richmond
, p. 5437 - 5443 (2019)
Pyridine, one of the most important azaarenes, is ubiquitous in functional molecules. The electronic properties of pyridine have been exploited to trigger asymmetric transformations of prochiral species as a direct approach for accessing chiral pyridine derivatives. However, the full potential of this synthetic strategy for the construction of enantioenriched ?-functionalized pyridines remains untapped. Here, we describe the first enantioselective addition of prochiral radicals to vinylpyridines under cooperative photoredox and asymmetric catalysis mediated by visible light. The enantioselective reductive couplings of vinylpyridines with aldehydes, ketones, and imines were achieved by employing a chiral Br?nsted acid to activate the reaction partners and provide stereocontrol via H-bonding interactions. Valuable chiral γ-secondary/tertiary hydroxyl- and amino-substituted pyridines were obtained in high yields with good to excellent enantioselectivities.
Electrochemical Arylation of Aldehydes, Ketones, and Alcohols: from Cathodic Reduction to Convergent Paired Electrolysis
Zhang, Sheng,Li, Lijun,Li, Jingjing,Shi, Jianxue,Xu, Kun,Gao, Wenchao,Zong, Luyi,Li, Guigen,Findlater, Michael
supporting information, p. 7275 - 7282 (2021/03/01)
Arylation of carbonyls, one of the most common approaches toward alcohols, has received tremendous attention, as alcohols are important feedstocks and building blocks in organic synthesis. Despite great progress, there is still a great gap to develop an ideal arylation method featuring mild conditions, good functional group tolerance, and readily available starting materials. We now show that electrochemical arylation can fill the gap. By taking advantage of synthetic electrochemistry, commercially available aldehydes (ketones) and benzylic alcohols can be readily arylated to provide a general and scalable access to structurally diverse alcohols (97 examples, >10 gram-scale). More importantly, convergent paired electrolysis, the ideal but challenging electrochemical technology, was employed to transform low-value alcohols into more useful alcohols. Detailed mechanism study suggests that two plausible pathways are involved in the redox neutral α-arylation of benzylic alcohols.
Photocatalytic pinacol C-C coupling and jet fuel precursor production on ZnIn2S4nanosheets
Cao, Zhi,Han, Guanqun,Liu, Xingwu,Sun, Yujie
, p. 9346 - 9355 (2020/10/09)
Visible light-driven C-C bond formation has attracted increasing attention recently, thanks to the advance in molecular photosensitizers and organometallic catalysts. Nevertheless, these homogeneous methodologies typically necessitate the utilization of noble metal-based (e.g., Ir, Ru, etc.) photosensitizers. In contrast, solid-state semiconductors represent an attractive alternative but remain less explored for C-C bond-forming reactions driven by visible-light irradiation. Herein, we report that photocatalytic pinacol C-C coupling of benzaldehyde to hydrobenzoin can be achieved on two-dimensional ZnIn2S4 nanosheets upon visible-light irradiation in the presence of a sacrificial electron donor (e.g., triethylamine). We further demonstrate that it is feasible to take advantage of both excited electrons and holes in irradiated ZnIn2S4 for C-C coupling reactions in the absence of any sacrificial reagent if benzyl alcohol is utilized as the starting substrate, maximizing the energy efficiency of photocatalysis and circumventing any byproducts. In this case, industrially important benzoin and deoxybenzoin are formed as the final products. More importantly, by judiciously tuning the photocatalytic conditions, we are able to produce either benzoin or deoxybenzoin with unprecedented high selectivity. The critical species during the photocatalytic process were systematically investigated with various scavengers. Finally, such a heterogeneous photocatalytic pinacol C-C coupling strategy was applied to produce a jet fuel precursor (e.g., hydrofuroin) from biomass-derived furanics (e.g., furfural and furfural alcohol), highlighting the promise of our approach in practical applications.
Reductive Coupling of Carbon Dioxide and an Aldehyde Mediated by a Copper(I) Complex toward the Synthesis of α-Hydroxycarboxylic Acids
Masada, Koichiro,Kusumoto, Shuhei,Nozaki, Kyoko
supporting information, p. 4922 - 4926 (2020/04/21)
Copper-mediated reductive coupling between CO2 and an aldehyde to form α-hydroxycarboxylic acid was achieved using silylborane as a reductant. CO2 cleanly inserted into a copper-carbon bond that was formed by the reaction between a silylcopper-NHC complex
β-Selective Reductive Coupling of Alkenylpyridines with Aldehydes and Imines via Synergistic Lewis Acid/Photoredox Catalysis
Lee, Katarzyna N.,Lei, Zhen,Ngai, Ming-Yu
supporting information, p. 5003 - 5006 (2017/05/04)
Umpolung (polarity reversal) strategies of aldehydes and imines have dramatically expanded the scope of carbonyl and iminyl chemistry by facilitating reactions with non-nucleophilic reagents. Herein, we report the first visible light photoredox-catalyzed β-selective reductive coupling of alkenylpyridines with carbonyl or iminyl derivatives with the aid of a Lewis acid co-catalyst. Our process tolerates complex molecular scaffolds (e.g., sugar, natural product, and peptide derivatives) and is applicable to the preparation of compounds containing a broad range of heterocyclic moieties. Mechanistic investigations indicate that the key step involves single-electron-transfer reduction of aldehydes or imines followed by the addition of resulting ketyl or α-aminoalkyl radicals to Lewis acid-activated alkenylpyridines.
Transition-metal-free and chemoselective NaOtBu-O 2-mediated oxidative cleavage reactions of vic-1,2-diols to carboxylic acids and mechanistic insight into the reaction pathways
Kim, Sun Min,Kim, Dong Wan,Yang, Jung Woon
supporting information, p. 2876 - 2879 (2014/06/23)
A method for efficient oxidative cleavage of vic-1,2-diols using a NaO tBu-O2 system resulted in the formation of carboxylic acids in high yields. The present protocol is an eco-friendly alternative to a conventional transition-metal-based method. This new strategy allows large-scale production with nonchromatographic purification while also suppressing competitive reaction pathway such as benzilic acid rearrangement.
Synthesis of ferrocene derivatives with planar chirality via palladium-catalyzed enantioselective C-H bond activation
Pi, Chao,Cui, Xiuling,Liu, Xiuyan,Guo, Mengxing,Zhang, Hanyu,Wu, Yangjie
supporting information, p. 5164 - 5167 (2014/12/11)
The first catalytic and enantioselective C-H direct acylation of ferrocene derivatives has been developed. A series of 2-acyl-1-dimethylaminomethylferrocenes with planar chirality were provided under highly efficient and concise one-pot conditions with up to 85% yield and 98% ee. The products obtained could be easily converted to various chiral ligands via diverse transformations.
Catalytic enantioselective alkylation and arylation of aldehydes by using grignard reagents
Muramatsu, Yusuke,Kanehira, Shinichi,Tanigawa, Masato,Miyawaki, Yuta,Harada, Toshiro
experimental part, p. 19 - 32 (2010/03/25)
We have developed an efficient and practical method for the catalytic enantioselective alkylation and arylation of aldehydes by using Grignard reagents in combination with titanium tetraisopropoxide. Grignard reagents and titanium tetraisopropoxide are mixed in a molar ratio of ca. 1:2. In the presence of catalyst (24mol%), which is formed in situ from a BINOL ligand 4a and 4b and titanium tetraisopropoxide, the resulting mixed titanium reagents undergo addition to aldehydes with high enantioselectivities (typically >90% ee) and high yields. The method is applicable to various combination of aldehydes (R1CHO; R1 = aryl, heteroaryl, 1-alkenyl, and alkyl) and Grignard reagents (R2MgX; R2 = primary alkyl and aryl). Thus, a variety of enantiomerically enriched secondary alcohols (R1CH*(OH)R2) can be prepared. It has also been demonstrated that functionalized aryl Grignard reagents can be employed to generate highly functionalized diarylmethanols. The preparative utility of the method has been shown by the fact that the reaction is operationally simple, can be carried out on a 10-mmol scale without any difficulty, and the ligands can be readily recovered.
Reaction of secondary and tertiary aliphatic halides with aromatic aldehydes mediated by chromium(II): a selective cross-coupling of alkyl and ketyl radicals
Wessjohann, Ludger A.,Schmidt, Gisela,Schrekker, Henri S.
, p. 2134 - 2142 (2008/09/18)
Takai-Utimoto reactions with secondary and tertiary aliphatic halides usually failed according to previous reports. Now, significant improvements could be achieved, and especially secondary aliphatic halides can be coupled to aromatic aldehydes in yields of up to >95%. A variety of processes are competing with the desired one, and thus conditions must be adapted to the nature of the aldehyde as well as the aliphatic halide used, as the outcome of these reactions is strongly affected by the putative radical intermediates.
