37580-83-9Relevant academic research and scientific papers
Metal-free thermal organocatalytic pinacol coupling of arylaldehydes using an isonicotinate catalyst with bis(pinacolato)diboron
Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi,Yasui, Masamichi
, p. 24652 - 24655 (2021/07/29)
The metal-free thermal organocatalytic pinacol coupling of arylaldehydes has been developed. The intermolecular coupling of arylaldehydes catalyzed byt-butyl isonicotinate with bis(pinacolato)diboron as the co-reducing agent afforded 1,2-diphenylethane-1,2-diols. This reaction was also applicable to the intramolecular coupling of 1,1′-biphenyl-2,2′-dicarbaldehydes to afford 9,10-dihydrophenanthrene-9,10-diols. Various functional groups were tolerated under this coupling condition.
Reductive Coupling of Aromatic Aldehydes and Ketones under Electrochemical Conditions
Li, Qian-Yu,Swaroop, Toreshettahally R.,Wang, Heng Shan,Wang, Zi-Qiang
, (2020/04/27)
Reductive coupling of o-substituted carbonyl compounds and m-substituted carbonyl compounds by the direct transfer of electron to carbonyl group respectively gave 1-(4-(1-hydroxy-1-phenylethyl/methyl)phenyl)ethanones/methanones and 2,3-bis(3-substitutedph
Stereoselective Barbier-Type Allylations and Propargylations Mediated by CpTiCl3
López-Martínez, Josefa L.,Torres-García, Irene,Rodríguez-García, Ignacio,Mu?oz-Dorado, Manuel,álvarez-Corral, Miriam
, p. 806 - 816 (2019/01/24)
CpTiCl2, prepared in situ by manganese reduction of CpTiCl3, is an excellent new system for the Barbier-type allylation and propargylation of carbonyl compounds. It can be used in catalytic amounts when combined with Et3N·HBr/TMSBr, which acts as a regenerating system. The high regio- and stereoselectivity shown by this system makes it useful for prenylation and crotylation processes in the synthesis of natural products.
Implementing Hydrogen Atom Transfer (HAT) Catalysis for Rapid and Selective Reductive Photoredox Transformations in Continuous Flow
Steiner, Alexander,Williams, Jason D.,Rincón, Juan A,de Frutos, Oscar,Mateos, Carlos,Kappe, C. Oliver
supporting information, p. 5807 - 5811 (2019/08/01)
The reductive transformation of aryl halides and carbonyl compounds is a key step in many photoredox transformations. By combining a highly reducing organic photocatalyst with a thiol hydrogen atom transfer (HAT) catalyst, we showcase rapid and highly selective reactions of these synthetically important starting materials in continuous flow. The fast reduction of aryl iodides, bromides and chlorides has been demonstrated with residence times in some cases below one minute. Selectivity between mono- and di-dehalogenation could also be achieved in some cases. Aryl ketones, aldehydes and imines were shown to undergo facile pinacol couplings, and the coupling of an aryl chloride with a styrene was also successful.
Biginelli reaction of vicinal diols: A new route for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives
Jagadishbabu, Narasashetty,Shivashankar, Kalegowda
, p. 330 - 336 (2017/07/26)
Background: 3,4-Dihydropyrimidin-2(1H)-one derivatives are an important class of nitrogen heterocycles. These compounds present a wide range of biological activities viz antibacterial, antifungal, and antidiabetic. Although many synthetic methods are available in the literature for the synthesis of these molecules, many of these methods have their own limitations such as use of excess of expensive catalyst and poor yields. Methods: The synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives is developed through the reaction of 1,2-diols, ethyl acetoacetate and urea in the presence of lead tetraacetate in dry ethanol under reflux conditions. Results: A series of 3,4-dihydropyrimidin-2(1H)-one derivatives were synthesized in good yields (82-95%) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This protocol is an alternative to existing procedure for the synthesis of Biginelli compounds. The present methodology reduces the number of steps in total synthesis.
First pinacol coupling in emulsified water: Key role of surfactant and impact of alternative activation technologies
Billamboz, Muriel,Len, Christophe
, p. 1664 - 1675 (2015/06/02)
For the first time, the influence of surfactants on the radical pinacol coupling reaction is investigated. The rate and selectivity of this reductive C-C coupling are compared under three different activation technologies: thermal activation, microwave irradiation, and sonication. The use of IgepalCO520, a neutral surfactant, led to the successful conversion of aromatic or α,β-unsaturated aliphatic carbonyl compounds in moderate to excellent yield (55-90 %). An insight on the potential mechanism involved in the reaction is also proposed, based on microscopic observations and particle size measurement.
Biocatalyzed asymmetric reduction of benzils to either benzoins or hydrobenzoins: pH dependent switch
Pal, Mohan,Srivastava, Gautam,Sharma, Amar Nath,Kaur, Suneet,Jolly, Ravinder S.
, p. 4017 - 4028 (2015/08/03)
Enantiopure benzoins and hydrobenzoins are precursors of various pharmaceuticals and biologically active compounds. In addition, hydrobenzoins are precursors of chiral ligands and auxiliaries in stereoselective organic synthesis. Biocatalytic reduction of benzils is a straightforward approach to prepare these molecules. However, known methods are not selective and lead to formation of a mixture of benzoin and hydrobenzoin, requiring expensive separation procedures. Here, we describe an enzyme system Talaromyces flavus, which exhibited excellent pH dependent selectivity for the conversion of benzil to either benzoin or hydrobenzion in high ee. Thus, (S)-benzoin was the exclusive product at pH 5.0 (ee >99%), whereas at pH 7.0, (S,S)-hydrobenzoin (ee >99%, dl/meso 97 : 3) was the exclusive product. The observed pH dependent selectivity was shown to be due to the presence of multiple enzymes in Talaromyces flavus, which specifically accepted either benzil or benzoin as a substrate and exhibited different pH profiles of their activity. The biocatalyst efficiently reduced a variety of symmetrical and unsymmetrical benzils. Moreover, a 36.4 kDa benzoin reductase was purified, the N-terminal sequence of which did not show a significant similarity to any of the known reductase/dehydrogenase in the database. The protein therefore appears to be a novel reductase.
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.
The scalable pinacol coupling reaction utilizing the inorganic electride [Ca2N]+·e- as an electron donor
Kim, Ye Ji,Kim, Sun Min,Hosono, Hideo,Yang, Jung Woon,Kim, Sung Wng
supporting information, p. 4791 - 4794 (2014/05/06)
The scalable pinacol coupling reaction is realized utilizing the inorganic electride [Ca2N]+·e- as an electron donor in organic solvents. The bond cleavages of the [Ca2N] + layers by methanol play a vital role in transferring anionic electrons to electrophilic aldehydes, accompanying the formation of Ca(OMe) 2 and ammonia. The Royal Society of Chemistry 2014.
