1718-50-9Relevant academic research and scientific papers
Synthesis of hydroxyphthioceranic acid using a traceless lithiation-borylation-protodeboronation strategy
Rasappan, Ramesh,Aggarwal, Varinder K.
, p. 810 - 814 (2014)
In planning organic syntheses, disconnections are most often made adjacent to functional groups, which assist in C-C bond formation. For molecules devoid of obvious functional groups this approach presents a problem, and so functionalities must be installed temporarily and then removed. Here we present a traceless strategy for organic synthesis that uses a boronic ester as such a group in a one-pot lithiation-borylation-protodeboronation sequence. To realize this strategy, we developed a methodology for the protodeboronation of alkyl pinacol boronic esters that involves the formation of a boronate complex with a nucleophile followed by oxidation with Mn(OAc) 3 in the presence of the hydrogen-atom donor 4-tert-butylcatechol. Iterative lithiation-borylation- protodeboronation allows the coupling of smaller fragments to build-up long alkyl chains. We employed this strategy in the synthesis of hydroxyphthioceranic acid, a key component of the cell-wall lipid of the virulent Mycobacterium tuberculosis, in just 14 steps (longest linear sequence) with full stereocontrol.
Air-Stable PdI Dimer Enabled Remote Functionalization: Access to Fluorinated 1,1-Diaryl Alkanes with Unprecedented Speed
Kundu, Gourab,Opincal, Filip,Schoenebeck, Franziska,Sperger, Theresa
supporting information, (2021/11/30)
While remote functionalization via chain walking has the potential to enable access to molecules via novel disconnections, such processes require relatively long reaction times and can be in need of elevated temperatures. This work features a remote arylation in less than 10 min reaction time at room temperature over a distance of up to 11 carbons. The unprecedented speed is enabled by the air-stable PdI dimer [Pd(μ-I)(PCy2tBu)]2, which in contrast to its PtBu3 counterpart does not trigger direct coupling at the initiation site, but regioconvergent and chemoselective remote functionalization to yield valuable fluorinated 1,1-diaryl alkanes. Our combined experimental and computational studies rationalize the origins of switchability, which are primarily due to differences in dispersion interactions.
Bola-type PAH-based fluorophores/chemosensors: Synthesis via an unusual clemmensen reduction and photophysical studies
Charushin, V. N.,Chupakhin, O. N.,Gorbunov, E. B.,Grzhegorzhevskii, K. V.,Kovalev, I. S.,Minin, A. S.,Sadieva, L. K.,Taniya, O. S.,Tsurkan, M. V.,Volkova, N. N.,Zyryanov, G. V.
, (2021/08/21)
Bola-type organic scaffolds are of key importance for application in a wide variety of fields. In this manuscript we wish to report our results on construction of polycyclic aromatic hydrocarbon (PAH, PAH = 9-antracenyl, 1-pyrenyl)-based bola-type fluorophores/chemosensors via an unusual Clemmensen reduction of the corresponding penta-1,4-dien-3-ones. In aqueous solutions the thus obtained bola-type molecules demonstrate intensive excimer emission at 500 nm, as well as well-pronounced “turn-off” fluorescence response towards common nitro-explosive components, such as 2,4-dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT), as well as, hard-to-detect pentaerythritol tetranitrate (PETN).
Hydrodecyanation of Secondary Alkyl Nitriles and Malononitriles to Alkanes using DiMeImd-BH3
Kawamoto, Takuji,Oritani, Kyohei,Kawabata, Atsushi,Morioka, Tsubasa,Matsubara, Hiroshi,Kamimura, Akio
, p. 6137 - 6142 (2020/05/22)
The decyanation of secondary aliphatic nitriles and the 2-fold decyanation of malononitriles leading to alkanes in the presence of 1,3-dimethylimidazol-2-ylidene borane (diMeImd-BH3) are reported. These reactions proceed via a radical mechanism that involves the addition of a borane radical to the nitrile to form an iminyl radical, followed by cleavage of a carbon-carbon bond. Theoretical calculations suggest that the β-cleavage of these iminyl radicals, which affords NHC-BH2CN and the corresponding alkyl radicals, is the rate-determining step in this reaction.
Photoinduced Radical Borylation of Alkyl Bromides Catalyzed by 4-Phenylpyridine
Zhang, Li,Wu, Zhong-Qian,Jiao, Lei
supporting information, p. 2095 - 2099 (2019/12/24)
Utilizing pyridine catalysis, we developed a visible-light-induced transition-metal-free radical borylation reaction of unactivated alkyl bromides that features a broad substrate scope and mild reaction conditions. Mechanistic studies revealed a novel nucleophilic substitution/photoinduced radical formation pathway, which could be utilized to trigger a variety of radical processes.
Thiol-Catalyzed Radical Decyanation of Aliphatic Nitriles with Sodium Borohydride
Kawamoto, Takuji,Oritani, Kyohei,Curran, Dennis P.,Kamimura, Akio
supporting information, p. 2084 - 2087 (2018/04/16)
Radical decyanation of aliphatic nitriles was achieved in the presence of NaBH4 and a thiol. The reaction proceeds via a radical mechanism involving borane radical anion addition to nitrile to form an iminyl radical, which undergoes carbon-carbon cleavage. Reductive radical addition to acrylonitrile is followed by decyanation to give a two-carbon homologated product in a net radical ethylation reaction.
Synthesis of Elongated Esters from Alkenes
Miura, Tomoya,Funakoshi, Yuuta,Nakahashi, Junki,Moriyama, Daisuke,Murakami, Masahiro
, p. 15455 - 15459 (2018/10/31)
A convenient method for synthesizing elongated aliphatic esters from alkenes is reported. An (alkoxycarbonyl)methyl radical species is generated upon visible-light irradiation of an ester-stabilized phosphorus ylide in the presence of a photoredox catalyst. This radical species adds onto the carbon–carbon double bond of an alkene to produce an elongated aliphatic ester.
A novel route to the synthesis of α,Ω-diphenylalkanes
Chen, Hui,Chen, Yancai,Zhang, Yinlong,Yang, Zhenqiang,Li, Ji,Yang, Ruina,Wang, Wenxin
, p. 473 - 474 (2017/08/18)
A novel route to the synthesis of α,ω-diphenylalkanes is reported. Toluene was metalated in the benzylic position by n-butyllithium with THF as an activating reagent, and then directly reacted with α,ω-dichloroalkanes to obtain the target product. This process provides a facile and efficient route to the synthesis of α,Ω-diphenylalkanes.
A novel iron complex for cross-coupling reactions of multiple C-Cl bonds in polychlorinated solvents with grignard reagents
Gartia, Yashraj,Pulla, Sharon,Ramidi, Punnamchandar,Farris, Carolina Costa,Nima, Zeid,Jones, Darin E.,Biris, Alexandru S.,Ghosh, Anindya
, p. 1397 - 1404 (2013/01/15)
A novel iron(III) complex (2) of a pincer ligand [1, N2,N6-bis(2,6- diisopropylphenyl)pyridine-2,6-dicarboxamide] was developed and used for remediation of polychlorinated solvents via sp3-sp3 coupling of Grignard reagents with C-Cl bonds. The use of an iron catalyst for such coupling reactions is highly desirable due to its greener and more economical nature. Complex 2 was characterized using various spectroscopic techniques: electrospray ionization mass spectrometer (ESI-MS, m/z 575.1), cyclic voltammetry (E 1/2, 0.03 V and ΔE, 0.97 V), and ultraviolet visible (UV/Vis) spectroscopic techniques. The iron(III) complex showed efficient activation of multiple C-Cl bonds and catalyzing C-C coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents under ambient reaction conditions. Complex 2 showed exceptional activity with reactions approaching near completion in about 5 min. With the required catalyst loading as low as 0.2 mol%, considerably high turnover numbers (TON = 483) and turnover frequency (TOF = 5,800 h-1) were obtained. None of the products detected during the reaction contained any chlorine, indicating an efficient dechlorination method while synthesizing products of synthetic and commercial interest. Interestingly, the catalyst was capable of replacing all chlorine atoms in each polychlorinated solvent under the investigations with high conversion. Springer Science+Business Media, LLC 2012.
Cross coupling reactions of multiple CCl bonds of polychlorinated solvents with Grignard reagent using a pincer nickel complex
Gartia, Yashraj,Nasini, Udaya Bhasker,Ghosh, Anindya,Biswas, Abhijit,Stadler, Matthew
, p. 322 - 327,6 (2020/07/30)
The nickel(II) complex of a bulky pincer-type ligand, N,N′-bis(2,6- diisopropylphenyl)-2,6-pyridinedicarboxamido, was examined for sp 3-sp3 coupling of Grignard reagents with polychlorinated solvents. The nickel(II) complex catalyzed CC coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents. The effective activation of multiple CCl bonds proceeded under ambient reaction conditions and within a short time (20 min). This catalyst displays the highest activity yet reported for this reaction type, with catalyst loading as low as 0.4 mol% and turnover frequency (TOF) as high as 724 h-1. The catalyst is capable of replacing all chlorine atoms with CC bond formations for all of the polychlorinated solvents under investigation. The catalytic process could prove to be an efficient method of remediation of toxic polychlorinated solvents while generating synthetically and commercially important chemicals.
