- Mechanical metal activation for Ni-catalyzed, Mn-mediated cross-electrophile coupling between aryl and alkyl bromides
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Liquid-assisted grinding has been successfully applied to eliminate the requirements of chemical activators and anhydrous solvents in nickel-catalyzed, manganese-mediated cross-electrophile coupling between aryl and alkyl bromides. In addition to the traditional reaction parameters, mechanical ones,e.g.the rotational speed of mill, the filling degree of jar and ball size, have been found to affect the catalytic efficiency remarkably, implying the involvement of the regeneration of nickel(0) species in the rate-determining steps. A combined evaluation of the reaction and mechanical parameters led to an optimal condition under which a variety ofn-alky aromatics with various functional groups could be readily obtained in good yields with a 1 mol% catalyst loading. The practical application of liquid-assisted grinding-enabled aryl/alkyl cross-electrophile coupling has been demonstrated in the gram-scale synthesis of 6-methoxytetralone.
- Wu, Sisi,Shi, Weijia,Zou, Gang
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supporting information
p. 11269 - 11274
(2021/07/02)
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- Radical-Mediated Strategies for the Functionalization of Alkenes with Diazo Compounds
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One of the most common reactions of diazo compounds with alkenes is cyclopropanation, which occurs through metal carbene or free carbene intermediates. Alternative functionalization of alkenes with diazo compounds is limited, and a methodology for the addition of the elements of Z-CHR2 (with Z = H or heteroatom, and CHR2 originates from N2 CR2) across a carbon-carbon double bond has not been reported. Here we report a novel reaction of diazo compounds utilizing a radical-mediated addition strategy to achieve difunctionalization of diverse alkenes. Diazo compounds are transformed to carbon radicals with a photocatalyst or an iron catalyst through PCET processes. The carbon radical selectively adds to diverse alkenes, delivering new carbon radical species, and then forms products through hydroalkylation by thiol-assisted hydrogen atom transfer (HAT), or forms azidoalkylation products through an iron catalytic cycle. These two processes are highly complementary, proceed under mild reaction conditions, and show high functional group tolerance. Furthermore, both transformations are successfully performed on a gram-scale, and diverse γ-amino esters, γ-amino alcohols, and complex spirolactams are easily prepared with commercially available reagents. Mechanistic studies reveal the plausible pathways that link the two processes and explain the unique advantages of each.
- Su, Yong-Liang,Liu, Geng-Xin,Liu, Jun-Wen,Tram, Linh,Qiu, Huang,Doyle, Michael P.
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supporting information
p. 13846 - 13855
(2020/09/21)
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- Copper(II)-catalyzed preparation of alkylindium compounds and applications in cross-coupling reactions both in aqueous media
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An efficient water-based method for the synthesis of alkylindium compound in the presence of a catalytic amount of cheap and readily available CuSO4·5H2O (10 mol%) was developed. The thus-generated alkylindium compounds effectively underwent palladium-catalyzed cross-coupling reactions with a myriad of aryl halides in aqueous media, leading to the cross-coupled products in modest to high yields. The mildness of the formed alkyl organometallics allowed the tolerance to various important functional groups incorporated in both substrates of alkyl iodides and aryl halides.
- Wang, Peng,Chen, Bing-Zhi,Guo, Yi-Cong,Rao, Weidong,Shen, Zhi-Liang
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supporting information
(2019/11/11)
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- Cobalt(II)-catalyzed preparation of alkylindium reagents and applications in cross-coupling with aryl halides
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The direct insertion of indium powder into alkyl iodides was found to be efficiently catalyzed by a catalytic amount of cobalt(II) bromide (10 mol%). Upon subjection of the thus-formed alkylindium compounds to palladium-catalyzed cross-coupling reactions with a wide range of aryl halides, a series of cross-coupled products could be obtained in moderate to good yields with the tolerance to many important functional groups.
- Wang, Peng,Song, Xuan-Di,Chen, Bing-Zhi,Rao, Weidong,Shen, Zhi-Liang
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- Preparation of Alkyl Indium Reagents by Iodine-Catalyzed Direct Indium Insertion and Their Applications in Cross-Coupling Reactions
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An efficient method for the synthesis of alkyl indium reagent by means of an iodine-catalyzed direct indium insertion into alkyl iodide in THF is reported. The thus-generated alkyl indium reagents effectively underwent Pd-catalyzed cross-coupling reactions with various aryl halides, exhibiting good compatibility to a variety of sensitive functional groups. By replacing THF with DMA and using 0.75 equiv of iodine, less reactive alkyl bromide could be used as substrate for indium insertion with equal ease.
- Zhi, Man-Ling,Chen, Bing-Zhi,Deng, Wei,Chu, Xue-Qiang,Loh, Teck-Peng,Shen, Zhi-Liang
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p. 3017 - 3023
(2019/02/26)
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- Cesium carbonate-catalyzed indium insertion into alkyl iodides and their synthetic utilities in cross-coupling reactions
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A catalytic amount of cesium carbonate (10?mol%) was found to be capable of effectively catalyzing the insertion of indium powder into alkyl iodides. The thus-generated alkyl indium reagents could readily undergo palladium-catalyzed cross-coupling reactions with a wide variety of aryl halides, showing compatibility to a range of important functional groups.
- Feng, Xue-Xin,Wu, Zhen,Wang, Qing-Dong,Chen, Bing-Zhi,Rao, Weidong,Yang, Jin-Ming,Shen, Zhi-Liang
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- Synthesis of Alkyl Indium Reagents by Using Unactivated Alkyl Chlorides and Their Applications in Palladium-Catalyzed Cross-Coupling Reactions with Aryl Halides
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An efficient method for the preparation of alkyl indium reagents by using unactivated and cheap alkyl chlorides as substrates in the presence of indium and LiI was developed. The thus-formed alkyl indium species effectively underwent palladium-catalyzed cross-coupling reactions with aryl halides with wide functional group tolerance.
- Chen, Bing-Zhi,Zhi, Man-Ling,Wang, Chuang-Xin,Chu, Xue-Qiang,Shen, Zhi-Liang,Loh, Teck-Peng
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supporting information
p. 1902 - 1905
(2018/04/16)
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- Discovery of DSP-1053, a novel benzylpiperidine derivative with potent serotonin transporter inhibitory activity and partial 5-HT1A receptor agonistic activity
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We have previously shown that SMP-304, a serotonin uptake inhibitor with weak 5-HT1A partial agonistic activity, may act under high serotonin levels as a 5-HT1A antagonist that improves the onset of paroxetine in the rat swimming test. However, SMP-304 is mostly metabolized by CYP2D6, indicating limited efficacy among individuals and increased side effects. To reduce CYP2D6 metabolic contribution and enhance SERT/5-HT1A binding affinity, we carried out a series of substitutions at the bromine atom in the left part of the benzene ring of SMP-304 and replaced the right part of SMP-304 with a chroman-4-one. This optimization work led to the identification of the antidepressant candidate DSP-1053 as a potent SERT inhibitor with partial 5-HT1A receptor agonistic activity. DSP-1053 showed low CYP2D6 metabolic contribution and a robust increase in serotonin levels in the rat frontal cortex.
- Yoshinaga, Hidefumi,Nishida, Tomoaki,Sasaki, Izumi,Kato, Taro,Oki, Hitomi,Yabuuchi, Kazuki,Toyoda, Tomohiro
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supporting information
p. 1614 - 1627
(2018/02/21)
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- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
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- Direct synthesis of ester-containing indium homoenolate and its application in palladium-catalyzed cross-coupling with aryl halide
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An efficient method for the synthesis of ester-containing indium homoenolate via a direct insertion of indium into β-halo ester in the presence of CuI/LiCl was described. The synthetic utility of the indium homoenolate was demonstrated by palladium-cataly
- Shen, Zhi-Liang,Goh, Kelvin Kau Kiat,Wong, Colin Hong An,Yang, Yong-Sheng,Lai, Yin-Chang,Cheong, Hao-Lun,Loh, Teck-Peng
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supporting information; experimental part
p. 4778 - 4780
(2011/05/15)
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- One-pot Negishi cross-coupling reactions of in situ generated zinc reagents with aryl chlorides, bromides, and triflates
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(Chemical Equation Presented) In situ generated aryl, heteroaryl, alkyl, or benzylic poly-functional zinc reagents obtained by the addition of zinc and LiCl to the corresponding organic iodides undergo smooth Pd(0)-catalyzed cross-coupling reactions with
- Sase, Shohei,Jaric, Milica,Metzger, Albrecht,Malakhov, Vladimir,Knochel, Paul
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supporting information; experimental part
p. 7380 - 7382
(2009/05/07)
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- Facile preparation of organozinc bromides using electrogenerated highly reactive zinc and its use in cross-coupling reaction
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Highly reactive zinc was readily prepared by electrolysis of a DMF solution containing pyrene as a mediator with a platinum cathode and a zinc anode. Preferential reduction of pyrene occurred to generate the corresponding radical anion, which reduced zinc ions generated from anodic dissolution to give zero valent zinc with high reactivity. The reactive zinc was successfully used for an efficient transformation of bromoalkanes into the corresponding organozinc bromides. Organozinc bromides obtained were further used successfully in Pd-catalyzed cross-coupling reaction with various aryl iodides and bromides.
- Kurono, Nobuhito,Inoue, Tomio,Tokuda, Masao
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p. 11125 - 11131
(2007/10/03)
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- One-step cross-coupling reaction of functionalized alkyl iodides with aryl halides by the use of an electrochemical method
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Organozinc compounds of functionalized alkyl iodide carrying an alkoxycarbonyl, cyano or alkenyl group were prepared in high yields under mild conditions (0°C-r.t., 10min in DMF) by the reaction of iodides with an electrogenerated reactive zinc (EGZn). Cross-coupling of the organozinc compounds with various aryl halides in the presence of 5 mol% Pd(P(o- Tol)3)2Cl2 in THF gave the corresponding cross-coupled products in moderate to high yields. These cross-coupling reactions can be also achieved in one step and in one pot by the use of an electrochemical method utilizing a Pt cathode and Zn anode.
- Kurono, Nobuhito,Sugita, Kazuya,Takasugi, Shingo,Tokuda, Masao
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p. 6097 - 6108
(2007/10/03)
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- Palladium catalyzed cross-coupling reaction of functionalized alkyltrifluorosilanes with aryl halides
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A variety of alkyltrifluorosilanes were found to couple with aryl halides in the presence of Pd(PPh3)4 catalyst and tetrabutylammonium fluoride (TBAF) to give the corresponding cross-coupled products in moderate to good yields.
- Matsuhashi, Hayao,Kuroboshi, Manabu,Hatanaka, Yasuo,Hiyama, Tamejiro
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p. 6507 - 6510
(2007/10/02)
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- Selective κ-opioid agonists: Synthesis and structure-activity relationships of piperidines incorporating an oxo-containing acyl group
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This study describes the synthesis and the structure-activity relationships (SARs) of the (S)-(-)-enantiomers of a novel class of 2- (aminomethyl)piperidine derivatives, using κ-opioid binding affinity and antinociceptive potency as the indices of biological activity. Compounds incorporating the 1-tetralon-6-ylacetyl residue (30 and 34-45) demonstrated an in vivo antinociceptive activity greater than predicted on the basis of their κ-binding affinities. In particular, (2S)-2-[(dimethylamino)methyl]- 1-[(5,6,7,8-tetrahydro-5-oxo-2-naphthyl)acetyl]piperidine (34) was found to have a potency similar to spiradoline in animal models of antinociception after subcutaneous administration, with ED50s of 0.47 and 0.73 μmol/kg in the mouse and in the rat abdominal constriction tests, respectively. Further in vivo studies in mice and/or rats revealed that compound 34, compared to other selective κ-agonists, has a reduced propensity to cause a number of κ-related side effects, including locomotor impairment/sedation and diuresis, at antinociceptive doses. For example, it has an ED50 of 26.5 μmol/kg sc in the rat rotarod model, exhibiting a ratio of locomotor impairment/sedation vs analgesia of 36. Possible reasons for this differential activity and its clinical consequence are discussed.
- Giardina,Clarke,Dondio,Petrone,Sbacchi,Vecchietti
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p. 3482 - 3491
(2007/10/02)
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- The Direct Formation of Functionalized Alkyl(aryl)zinc Halides by Oxidative Addition of Highly Reactive Zinc with Organic Halides and Their Reactions with Acid Chlorides, α,β-Unsaturated Ketones, and Allylic, Aryl, and Vinyl Halides
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Highly reactive zinc, prepared by the lithium naphthalenide reduction of ZnCl2, readily undergoes oxidative addition to alkyl, aryl, and vinyl halides under mild conditions to generate the corresponding organozinc compounds in excellent yields.Significantly, the reaction will tolerate a spectrum of functional groups on the organic halides.Accordingly, this approach can now be used to prepare a wide variety of highly functionalized organozinc compounds.In the presence of Cu(I) salts, the organozinc compounds cross-couple with acid chlorides, conjugatively add to α,β-unsaturated ketones, and regioselectively undergo SN2' substitution reactions with allylic halides.They also cross-couple with aryl or vinyl halides with Pd(0) catalysts.
- Zhu, Lishan,Wehmeyer, Richard M.,Rieke, Reuben D.
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p. 1445 - 1453
(2007/10/02)
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