- Selective Synthesis of Substituted Pyridines and Pyrimidines through Cascade Annulation of Isopropene Derivatives
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Diverse substituted pyridines and pyrimidines with high selectivity were obtained using a concise and efficient protocol developed herein. The reaction proceeds via metal-free cascade annulation of isopropene derivatives. Using isopropene derivatives as C3 synthons, NH4I as the “N” source, and formaldehyde or dimethyl sulfoxide as the carbon source, this reaction realizes the efficient formation of intermolecular C-N and C-C bonds.
- Chen, Lu,He, Runfa,Huang, Yubing,Li, Jiaming,Li, Jian,Li, Yibiao,Liu, Jiasheng,Liu, Yang
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supporting information
p. 1620 - 1625
(2022/03/14)
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- Metal-Free Deoxygenation of Chiral Nitroalkanes: An Easy Entry to α-Substituted Enantiomerically Enriched Nitriles
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A metal-free, mild and chemodivergent transformation involving nitroalkanes has been developed. Under optimized reaction conditions, in the presence of trichlorosilane and a tertiary amine, aliphatic nitroalkanes were selectively converted into amines or nitriles. Furthermore, when chiral β-substituted nitro compounds were reacted, the stereochemical integrity of the stereocenter was maintained and α-functionalized nitriles were obtained with no loss of enantiomeric excess. The methodology was successfully applied to the synthesis of chiral β-cyano esters, α-aryl alkylnitriles, and TBS-protected cyanohydrins, including direct precursors of four active pharmaceutical ingredients (ibuprofen, tembamide, aegeline and denopamine).
- Pirola, Margherita,Faverio, Chiara,Orlandi, Manuel,Benaglia, Maurizio
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supporting information
p. 10247 - 10250
(2021/06/18)
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- 1,3-Difunctionalization of β-alkyl nitroalkenes via combination of Lewis base catalysis and radical oxidation
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Upon treatment with a Lewis base catalyst, β-alkyl-substituted nitroalkenes could be readily converted into allylic nitro compounds. Examples of either C-1 or C-3 functionalization methods have been reported through nitro-elimination, giving alkene products. In this work, successful 1,3-difunctionalization was achieved through a synergetic Lewis base catalysis and TBHP radical oxidation, giving vinylic alkoxyamines in good to excellent yields. This work further extended the general synthetic application of β-alkyl nitroalkenes.
- Wang, Ye,Zheng, Lei,Shi, Xiaodong,Chen, Yunfeng
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supporting information
p. 886 - 889
(2021/02/01)
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- Visible-Light-Induced Meerwein Fluoroarylation of Styrenes
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An unprecedented approach for assembling a broad range of 1,2-diarylethane derivatives with fluorine-containing fully substituted carbon centers was developed. The protocol features straightforward operation, proceeds under metal-free condition, and accommodates a large variety of synthetically useful functionalities. The critical aspect to the success of this novel transformation lies in using aryldiazonium salts as both aryl radical progenitor and also as single electron acceptor which elegantly enables a radical-polar crossover manifold.
- Tang, Hai-Jun,Zhang, Bin,Xue, Fei,Feng, Chao
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supporting information
p. 4040 - 4044
(2021/05/26)
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- Enantioselective Hydrothiolation: Diverging Cyclopropenes through Ligand Control
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In this article, we advance Rh-catalyzed hydrothiolation through the divergent reactivity of cyclopropenes. Cyclopropenes undergo hydrothiolation to provide cyclopropyl sulfides or allylic sulfides. The choice of bisphosphine ligand dictates whether the pathway involves ring-retention or ring-opening. Mechanistic studies reveal the origin for this switchable selectivity. Our results suggest the two pathways share a common cyclopropyl-Rh(III) intermediate. Electron-rich Josiphos ligands promote direct reductive elimination from this intermediate to afford cyclopropyl sulfides in high enantio- A nd diastereoselectivities. Alternatively, atropisomeric ligands (such as DTBM-BINAP) enable ring-opening from the cyclopropyl-Rh(III) intermediate to generate allylic sulfides with high enantio- A nd regiocontrol.
- Dong, Vy M.,Kuker, Erin L.,Lu, Alexander,Nie, Shaozhen
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supporting information
p. 6176 - 6184
(2021/05/07)
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- Palladium-Catalyzed Markovnikov Hydroaminocarbonylation of 1,1-Disubstituted and 1,1,2-Trisubstituted Alkenes for Formation of Amides with Quaternary Carbon
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Hydroaminocarbonylation of alkenes is one of the most promising yet challenging methods for the synthesis of amides. Herein, we reported the development of a novel and effective Pd-catalyzed Markovnikov hydroaminocarbonylation of 1,1-disubstituted or 1,1,2-trisubstituted alkenes with aniline hydrochloride salts to afford amides bearing an α quaternary carbon. The reaction makes use of readily available starting materials, tolerates a wide range of functional groups, and provides a facile and straightforward approach to a diverse array of amides bearing an α quaternary carbon. Mechanistic investigations suggested that the reaction proceeded through a palladium hydride pathway. The hydropalladation and CO insertion are reversible, and the aminolysis is probably the rate-limiting step.
- Yang, Hui-Yi,Yao, Ya-Hong,Chen, Ming,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 7298 - 7305
(2021/05/26)
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- Ni-Catalyzed Reductive Allylation of α-Chloroboronates to Access Homoallylic Boronates
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The transition-metal-catalyzed allylation reaction is an efficient strategy for the construction of new carbon-carbon bonds alongside allyl or homoallylic functionalization. Herein we describe a Ni-catalyzed reductive allylation of α-chloroboronates to efficiently render the corresponding homoallylic boronates, which could be readily converted into valuable homoallylic alcohols or amines or 1,4-diboronates. This reaction features a broad substrate scope with good functional group compatibility that is complementary to the existing methods for the preparation of homoallylic boronates.
- Lou, Yixian,Qiu, Jian,Yang, Kai,Zhang, Feng,Wang, Chenglan,Song, Qiuling
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supporting information
p. 4564 - 4569
(2021/06/28)
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- Visible-light-promoted radical alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester: Synthesis of oxazolines
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An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.
- Ding, Hao,Huang, Panyi,Jin, Can,Su, Weike,Sun, Bin,Yan, Zhiyang,Zhao, Haiyun
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supporting information
(2021/10/29)
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- MnBr2 catalyzed regiospecific oxidative Mizoroki-Heck type reaction
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Herein, we report an unprecedented regiospecific oxidative Mizoroki-Heck type reaction for the synthesis of ɑ-difluoromethyl homoallylic alcohols. The reaction shows broad substrate scopes and high functional group tolerance. Late-stage functionalization of complex biologically active molecules demonstrates the synthetic potential of this transformation. Mechanistic study supports the involvement of MnBr2 catalyzed radical 1,2-silyl transfer.
- Chen, Xiang,Chen, Yi-Hung,Liu, Shanshan,Shen, Xiao,Zhu, Zhihong
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supporting information
(2021/11/27)
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- Early Drug-Discovery Efforts towards the Identification of EP300/CBP Histone Acetyltransferase (HAT) Inhibitors
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EP300 and CBP (KAT3A/3B) are two highly homologous, multidomain, epigenetic coregulators that play central roles in transcription through the acetylation of lysine residues on histones and other proteins. Both enzymes have been implicated in human diseases, especially cancer. From a high-throughput screen of 191 000 compounds searching for EP300/CBP histone acetyltransferase (HAT) inhibitors, 18 compounds were characterized by a suite of biochemical enzymatic assays and biophysical methods, including X-ray crystallography and native mass spectrometry. This work resulted in the discovery of three distinct mechanistic classes of EP300/CBP HAT inhibitors, including two classes not previously described. The profiles of an example of each class of inhibitor are described in detail. A subsequent medicinal chemistry effort led to the development of a novel class of orally bioavailable AcCoA-competitive EP300/CBP HAT inhibitors with in vivo activity. We believe that this work will prove to be a useful guide for other groups interested in the development of HAT inhibitors.
- Audia, James E.,Bommi-Reddy, Archana,Brucelle, Francois,Cantone, Nico,Cummings, Richard,Gardberg, Anna S.,Huhn, Annissa J.,Levell, Julian,Patel, Chirag,Patel, Gaurav,Poy, Florence,Sims, Robert,Vivat, Valerie,Wilson, Jonathan E.
-
supporting information
(2020/04/20)
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- Cationic nickel(II)-catalyzed hydrosilylation of alkenes: Role of p, n?type ligand scaffold on selectivity and reactivity
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Seven structurally similar cationic nickel(II)?alkyl complexes were synthesized by using a series of P, N ligands, and their reactivity was explored in the hydrosilylation of alkenes. More electron-rich phosphines enhanced the overall reactivity of the transformation; in contrast, groups on the imine donor had little impact. Overall, these catalysts displayed reactivity and selectivity that was previously unknown or very rare in nickel-catalyzed hydrosilylation. In reactions with Ph2SiH2, 1,2-disubstituted vinylarenes showed complete benzylic selectivity for silane addition, whereas terminal selectivity was observed for 1,1-disubstituted alkenes. The related PhSiH3 led to exclusively Markovnikov selectivity for monosubstituted vinylarenes with no competing double addition observed. Mechanistic investigations supported the hypothesis that a Ni?H functions as the active species in this catalytic hydrosilylation, which in turn also showed catalytic competence for the silane redistribution reaction, especially with sterically unhindered silanes.
- Hossain, Istiak,Schmidt, Joseph A.R.
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supporting information
p. 3441 - 3451
(2020/10/09)
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- 3 -trifluoromethyl -5 - aryl -1, 6 -dihydropyridazine compound and preparation method thereof (by machine translation)
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The invention relates to 3 - trifluoromethyl -5 - aryl -1, 6 -dihydropyridazine compound, and the structural formula of the compound is as follows. Ar refers to Ar. . . One of the following. , The invention also discloses a preparation method of the compound. To the invention, the oxidation/cyclization reaction of 4 - aryl substituted trifluoromethylhomoallylhydrazine is promoted by copper acetate, 3 - trifluoromethyl -5 - aryl -1 and 6 -dihydropyridazine compound with obvious aggregation-induced emission effect are obtained. (by machine translation)
- -
-
Paragraph 0048-0049; 0054-0055
(2020/08/25)
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- Aqueous ZnCl2 Complex Catalyzed Prins Reaction of Silyl Glyoxylates: Access to Functionalized Tertiary α-Silyl Alcohols
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An efficient Prins reaction of silyl glyoxylates in the presence of an aqueous ZnCl2 complex as a catalyst was developed, providing functionalized tertiary α-silyl alcohols in high yields under mild conditions. A preliminary investigation indicated that the aqueous ZnCl2 complex acted as a dual functional catalyst of Br?nsted and Lewis acid to activate the carbonyl groups of silyl glyoxylates via a dual-activation model.
- Han, Man-Yi,Pan, Hong,Li, Pinhua,Wang, Lei
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p. 5825 - 5837
(2020/05/22)
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- Additions of Aldehyde-Derived Radicals and Nucleophilic N-Alkylindoles to Styrenes by Photoredox Catalysis
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The consecutive addition of acyl radicals and N-alkylindole nucleophiles to styrenes was established, as well as some additional radical-nucleophile combinations. Both aryl and aliphatic aldehydes give reasonable yields. The reaction proceeds best for α-substituted styrenes, effectively creating a quaternary all-carbon center. Some iridium-based photoredox systems are catalytically active; furthermore, a base is needed in this transformation. Radicals are formed by reductive perester cleavage and hydrogen atom transfer.
- Klussmann, Martin,Lux, Marcel
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supporting information
(2020/04/30)
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- Rhodium-Catalyzed Intermolecular Cyclopropanation of Benzofurans, Indoles, and Alkenes via Cyclopropene Ring Opening
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The generation of metal carbenoids via ring opening of cyclopropenes by transition metals offers a simple entry into highly reactive intermediates. Herein, we describe a diastereoselective intermolecular rhodium-catalyzed cyclopropanation of heterocycles and alkenes using cyclopropenes as carbene precursors with a low loading of a commercially available rhodium catalyst. The reported method is scalable and could be performed with catalyst loadings as low as 0.2 mol %, with no impact to the reaction yield or selectivity.
- Jeyaseelan, Rubaishan,Lautens, Mark,Ross, Rachel J.
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supporting information
(2020/06/29)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Stereoselective Synthesis of Vinylcyclopropa[ b]indolines via a Rh-Migration Strategy
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A mild rhodium catalytic system has been developed to synthesize vinylcyclopropa[b]indolines through cyclopropanation of indoles with vinyl carbenoids generated from ring opening of cyclopropenes in situ. By employing a Rh-migration strategy, the products can be obtained with good to excellent E:Z ratios (≤99:1) and complete diastereoselectivity (≤99:1). This method is easy, has a low catalyst loading, and works for a broad range of functionalities.
- Guo, Pan,Sun, Wangbin,Liu, Yu,Li, Yong-Xin,Loh, Teck-Peng,Jiang, Yaojia
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supporting information
p. 5978 - 5983
(2020/08/05)
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- Synthesis of 2-Substituted Propenes by Bidentate Phosphine-Assisted Methylenation of Acyl Fluorides and Acyl Chlorides with AlMe3
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Bidentate phosphine-assisted methylenation of acyl fluorides and acyl chlorides with substituted with aryl, alkenyl, and alkyl groups trimethylaluminum afforded an array of 2-substituted propene derivatives. The addition of a catalytic amount of DPPM increased an efficiency of the reactions. Trimethylaluminum as the methylenation reagent not only eliminates the presynthesis of methylene transfer reagent, but provides an efficient method for the synthesis of a series of 2-substituted propenes.
- Wang, Xiu,Wang, Zhenhua,Asanuma, Yuya,Nishihara, Yasushi
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supporting information
p. 3640 - 3643
(2019/05/17)
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- Catalyst-Free Enantiospecific Olefination with In Situ Generated Organocerium Species
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Described is the in situ formation of triorganocerium reagents and their application in catalyst-free Zweifel olefinations. These unique cerium species were generated through novel exchange reactions of organohalides with n-Bu3Ce reagents. The adequate electronegativity of cerium allowed for compensating the disadvantages of both usually functional-group-sensitive organolithium species and less reactive organomagnesium reagents. Exchange reactions were performed on aryl and alkenyl bromides, enabling enantiospecific transformations of chiral boron pinacol esters. Finally, these new organocerium species were engaged in selective 1,2-additions onto enolisable and sterically hindered ketones.
- Music, Arif,Hoarau, Clément,Hilgert, Nicolas,Zischka, Florian,Didier, Dorian
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supporting information
p. 1188 - 1192
(2019/01/04)
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- Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2- a]pyridin-5-ones through Pummerer-Type Reactions
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N-Alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride-activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride-activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.
- Huang, Jingjia,Hu, Gang,An, Shaoyu,Chen, Dongding,Li, Minglei,Li, Pingfan
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p. 9758 - 9769
(2019/08/08)
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- Palladium/Acid Relay Catalyzed Tandem Heck Coupling/6-Endo Cyclization between ortho-Halogenated Benzoates and Unactivated Terminal Alkenes for the Synthesis of 1-Isochromanones
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We report a unique and expeditious route to synthesize 1-isochromanone derivatives through palladium catalyzed tandem Heck coupling/6-endo hydroacyloxylation cyclization between readily available ortho-halogenated benzoates and unactivated alkenes. Various 2-bromo or 2-iodo benzoates can be coupled efficiently with a broad range of alkenes to afford functionalized 1-isochromanones in high yields. Significantly, this cost-efficient and easy-to-handle synthetic methodology will have great prospect application in the synthetic and medicinal chemistry. (Figure presented.).
- Wen, Zhen-Kang,Ge, Xiao-Min,Zhao, Ze-Kai,Chao, Jian-Bin
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supporting information
p. 983 - 988
(2019/01/30)
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- A convenient access to allylic triflones with allenes and triflyl chloride in the presence of (EtO)2P(O)H
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A simple method for the preparation of allylic triflones from allenes and triflyl chloride in the presence of (EtO)2P(O)H has been developed. The features of this reaction are catalyst-free and simple starting substrates. This method tolerates diverse functional groups and substituted allylic triflones are obtained in moderate to good yields.
- Ni, Jixiang,Jiang, Yong,An, Zhenyu,Lan, Jingfeng,Yan, Rulong
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supporting information
p. 7343 - 7345
(2019/06/27)
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- Chiral Br?nsted Acid Catalyzed Dynamic Kinetic Asymmetric Hydroamination of Racemic Allenes and Asymmetric Hydroamination of Dienes
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The first highly efficient and practical chiral Br?nsted acid catalyzed dynamic kinetic asymmetric hydroamination (DyKAH) of racemic allenes and asymmetric hydroamination of unactivated dienes with both high E/Z selectivity and enantioselectivity are described herein. The transformation proceeds through a new catalytic asymmetric model involving a highly reactive π-allylic carbocationic intermediate, generated from racemic allenes or dienes through a proton transfer mediated by an activating/directing thiourea group. This method affords expedient access to structurally diverse enantioenriched, potentially bioactive alkenyl-containing aza-heterocycles and bicyclic aza-heterocycles.
- Lin, Jin-Shun,Li, Tao-Tao,Jiao, Guan-Yuan,Gu, Qiang-Shuai,Cheng, Jiang-Tao,Lv, Ling,Liu, Xin-Yuan
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supporting information
p. 7092 - 7096
(2019/04/26)
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- Synthesis of Functionalized α-Vinyl Aldehydes from Enaminones
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An efficient RhII-catalyzed synthesis of functionalized α-vinyl aldehydes with high E/Z stereoselectivity was developed. The reaction mediates the cyclopropanation of enaminones with vinyl carbenoids that are generated from cyclopropenes in situ to give the aminocyclopropane intermediates. Selective C?C bond cleavage of the cyclopropane intermediates leads to formation of α-vinyl aldehyde derivatives with high E/Z selectivity. This method proceeds at room temperature under very mild reaction conditions and works with a broad substrate scope.
- Chen, Jie,Guo, Pan,Zhang, Jianguo,Rong, Jiaxin,Sun, Wangbin,Jiang, Yaojia,Loh, Teck-Peng
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supporting information
p. 12674 - 12679
(2019/08/07)
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- Highly Enantioselective Iridium-Catalyzed Hydrogenation of 2-Aryl Allyl Phthalimides
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The iridium-catalyzed asymmetric hydrogenation of 2-aryl allyl phthalimides to afford enantioenriched β-aryl-β-methyl amines is presented. Recently developed Ir-MaxPHOX catalysts are used for this enantioselective transformation. The mild reaction conditions and the feasible removal of the phthalimido group makes this catalytic method easily scalable and of great interest to afford chiral amines. The importance of this new methodology is exemplified by the formal synthesis of (R)-Lorcaserin, OTS514, and enantiomerically enriched 3-methyl indolines.
- Cabré, Albert,Romagnoli, Elia,Martínez-Balart, Pol,Verdaguer, Xavier,Riera, Antoni
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supporting information
p. 9709 - 9713
(2019/11/19)
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- Copper-Catalyzed Enantio- and Diastereoselective Addition of Silicon Nucleophiles to 3,3-Disubstituted Cyclopropenes
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A highly stereocontrolled syn-addition of silicon nucleophiles across cyclopropenes with two different geminal substituents at C3 is reported. Diastereomeric ratios are excellent throughout (d.r.≥98:2) and enantiomeric excesses usually higher than 90 %, even reaching 99 %. This copper-catalyzed C?Si bond formation closes the gap of the direct synthesis of α-chiral cyclopropylsilanes.
- Zhang, Liangliang,Oestreich, Martin
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supporting information
p. 14304 - 14307
(2019/11/13)
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- Regioselective Diboron-Mediated Semireduction of Terminal Allenes
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A method for the regioselective reduction of the terminal double bond of 1,1-disubstituted allenes has been developed. In the presence of a palladium catalyst, tetrahydroxydiboron and stoichiometric water, allene semireduction proceeds in high yield to afford Z-alkenes selectively.
- Gates, Ashley M.,Santos, Webster L.
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supporting information
p. 4619 - 4624
(2019/12/11)
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- Iridium-Catalyzed Isomerization of N-Sulfonyl Aziridines to Allyl Amines
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The Crabtree's reagent catalyzes the isomerization of N-sulfonyl 2,2-disubstituted aziridines to allyl amines. The selectivity of allyl amine vs imine is very high (up to 99/1). The unprecedented isomerization takes place in mild conditions without activation of the catalyst by hydrogen. The mechanism has been studied computationally by DFT calculations; instead of the usual hydrogenation of COD, the catalytic species is formed by a loss of the pyridine ligand. Approaching of aziridine to this unsaturated species leads to a carbocation intermediate through a low energy barrier. A metal-mediated tautomerization involving sequentially γ-H elimination and N-H reductive elimination affords selectively the allyl amine. The readiness of the CγH bond to participate in the H elimination step accounts for the selectivity toward the allyl amine product.
- Cabré, Albert,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
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supporting information
p. 5747 - 5751
(2018/09/21)
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- Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: Synthesis of vicinal-dichlorides and chlorodienes
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Allyl and vinyl chlorides represent important structural motifs in organic chemistry. Herein is described the chemoselective and regioselective reaction of aryl- and α-substituted phenylallenes with the hypervalent iodine (HVI) reagent 1-chloro-1,2-benz-iodoxol-3-one. The reaction typically results in vicinal dichlorides, except with proton-containing α-alkyl substituents, which instead give chlorinated dienes as the major product. Experimental evidence suggests that a radical mechanism is involved.
- Zhao, Zhensheng,Murphy, Graham K.
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supporting information
p. 796 - 802
(2018/04/16)
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- Rhodium-Catalyzed Enantioconvergent Isomerization of Homoallylic and Bishomoallylic Secondary Alcohols
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We present herein an unprecedented enantioselective isomerization of homoallylic and bishomoallylic secondary alcohols, catalyzed by a commercially available rhodium-complex and a base. This catalytic redox-neutral process provides an effective access to chiral ketones in high efficiency and enantioselectivity, without the use of any stoichiometric reagent or generation of any waste. For the reaction of homoallylic alcohols, this system achieved not only a stereoconvergent access to chiral ketones bearing a β-stereocenter (up to 95%, 86% ee) but also a concomitant oxidative kinetic resolution of the alcohol substrates (S > 20). In the case of bishomoallylic alcohols, an intriguing ligand-induced divergent reactivity was observed. A terminal-to-internal alkene isomerization promoted by Rh/L7 followed by redox isomerization using Rh/BINAP system produced chiral ketones bearing a γ-stereocenter with high yield and enantioselectivity. Mechanistic studies provided strong support for the redox-isomerization pathway with chain walking of the key alkyl-Rh intermediate.
- Huang, Rui-Zhi,Lau, Kai Kiat,Li, Zhaofeng,Liu, Tang-Lin,Zhao, Yu
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supporting information
p. 14647 - 14654
(2018/11/06)
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- Oxygen Activated, Palladium Nanoparticle Catalyzed, Ultrafast Cross-Coupling of Organolithium Reagents
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The discovery of an ultrafast cross-coupling of alkyl- and aryllithium reagents with a range of aryl bromides is presented. The essential role of molecular oxygen to form the active palladium catalyst was established; palladium nanoparticles that are highly active in cross-coupling reactions with reaction times ranging from 5 s to 5 min are thus generated in situ. High selectivities were observed for a range of heterocycles and functional groups as well as for an expanded scope of organolithium reagents. The applicability of this method was showcased by the synthesis of the [11C]-labeled PET tracer celecoxib.
- Heijnen, Dorus,Tosi, Filippo,Vila, Carlos,Stuart, Marc C. A.,Elsinga, Philip H.,Szymanski, Wiktor,Feringa, Ben L.
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supporting information
p. 3354 - 3359
(2017/03/17)
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- Regiocontrolled synthesis of α-sulfonylmethyl o-nitrostyrenes via ZnI2-mediated sulfonylation and AgNO2/Pd(PPh3)4-promoted o-nitration
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We report herein the AgNO2/Pd(PPh3)4-promoted regiocontrolled o-nitration of α-sulfonylmethylstyrenes in MeNO2 with good yields. The o-nitration process provides a series of sulfonyl o-nitrostyrenes. Substituted α-sulfonylmethylstyrenes were synthesized from ZnI2-mediated sulfonylation of substituted α-methylstyrenes and sodium sulfinates (RSO2Na) in MeCN with good to excellent yields. The structures of the key products were confirmed by X-ray crystallography. A plausible mechanism has been proposed herein.
- Chang, Meng-Yang,Chen, Han-Yu,Wang, Heui-Sin
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p. 10601 - 10610
(2018/05/31)
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- Rapid access to cyclopentadiene derivatives through gold-catalyzed cycloisomerization of ynamides with cyclopropenes by preferential activation of alkenes over alkynes
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In this communication, gold-catalyzed intermolecular cycloisomerization of cyclopropenes and ynamides is investigated. The current transformation displayed an activation priority of double bonds over triple bonds by the cationic gold catalyst, giving the corresponding cyclopentadienes in good to excellent yields. Additionally, this protocol can be expanded to a one-pot two-step procedure for the synthesis of substituted cyclopentanones.
- Cheng, Xing,Zhu, Lei,Lin, Meijun,Chen, Jianxin,Huang, Xueliang
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supporting information
p. 3745 - 3748
(2017/04/03)
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- Iodine-Catalyzed Facile Approach to Sulfones Employing TosMIC as a Sulfonylating Agent
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A novel iodine-catalyzed functionalization of a variety of olefins and alkynes and direct decarboxylative functionalization of cinnamic and propiolic acids with TosMIC to provide access to various vinyl, allyl, and β-iodo vinylsulfones is described. This simple, efficient, and environmentally benign approach employing inexpensive molecular iodine as a catalyst demonstrates a versatile protocol for the synthesis of highly valuable sulfones, rendering it attractive to both synthetic and medicinal chemistry.
- Kadari, Lingaswamy,Palakodety, Radha Krishna,Yallapragada, Lakshmi Prapurna
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supporting information
p. 2580 - 2583
(2017/05/24)
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- Visible-Light Photocatalytic Bicyclization of 1,7-Enynes toward Functionalized Sulfone-Containing Benzo[a]fluoren-5-ones
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A new visible-light photocatalytic arylsulfonylation and bicyclization of C(sp3)-tethered 1,7-enynes with sulfinic acids has been developed, delivering functionalized sulfone-containing benzo[a]fluoren-5-ones with generally good yields. This Eosin Y-catalyzed approach makes use of visible light as a safe and eco-friendly energy source to drive cascade cyclization reactions, resulting in continuous multiple bond-forming events including C–S and C–C bonds to efficiently construct polycyclic-linked alkyl aryl sulfones. (Figure presented.).
- Huang, Min-Hua,Zhu, Yi-Long,Hao, Wen-Juan,Wang, Ai-Fang,Wang, De-Cai,Liu, Feng,Wei, Ping,Tu, Shu-Jiang,Jiang, Bo
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supporting information
p. 2229 - 2234
(2017/07/07)
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- Asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by Pd(II)-SunPhos complex
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An efficient asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by chiral Pd(II)/(S)-SunPhos complex was developed. A series of optically active homoallylic alcohols containing a CF3 group were obtained with high yields and excellent ee under mild conditions. Particularly, the reaction of isobutylene and trifluoropyruvate gave the desired product (90% yield, 98% ee) with catalyst loading as low as 0.01 mol% in dichloroethane/toluene.
- Jiang, Lili,Hu, Bei,Xie, Xiaomin,Zhang, Zhaoguo
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supporting information
p. 6901 - 6905
(2017/10/31)
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- Enantioselective synthesis of cyclobutenes by intermolecular [2+2] cycloaddition with non-c2 symmetric digold catalysts
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The enantioselective intermolecular gold-(I)-catalyzed [2+2] cycloaddition of terminal alkynes and alkenes has been achieved using non-C2-chiral Josiphos digold(I) complexes as catalysts, by the formation of the monocationic complex. This new approach has been applied to the enantioselective total synthesis of rumphellaone A.
- García-Morales, Cristina,Ranieri, Beatrice,Escofet, Imma,López-Suarez, Laura,Obradors, Carla,Konovalov, Andrey I.,Echavarren, Antonio M.
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supporting information
p. 13628 - 13631
(2017/11/06)
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- Water-Enabled Catalytic Asymmetric Michael Reactions of Unreactive Nitroalkenes: One-Pot Synthesis of Chiral GABA-Analogs with All-Carbon Quaternary Stereogenic Centers
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Water enables new catalytic reactions for otherwise unreactive substrate systems. Under the “on water” reaction conditions, extremely unreactive β,β-disubstituted nitroalkenes smoothly underwent enantioselective Michael addition reactions with dithiomalonates using a chiral squaramide catalyst, affording both enantiomers of highly enantioenriched Michael adducts with all-carbon-substituted quaternary centers. The developed “on water” protocol was successfully applied for the scalable one-pot syntheses of chiral GABA analogs with all-carbon quaternary stereogenic centers at the β-position, which might show highly interesting pharmaceutical properties.
- Sim, Jae Hun,Song, Choong Eui
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supporting information
p. 1835 - 1839
(2017/02/05)
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- Towards nitrile-substituted cyclopropanes-a slow-release protocol for safe and scalable applications of diazo acetonitrile
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Diazo acetonitrile has long been neglected despite its high value in organic synthesis due to a high risk of explosions. Herein, we report our efforts towards the transient and safe generation of this diazo compound, its applications in iron catalyzed cyclopropanation and cyclopropenation reactions and the gram-scale synthesis of cyclopropyl nitriles.
- Hock, Katharina J.,Spitzner, Robin,Koenigs, Rene M.
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supporting information
p. 2118 - 2122
(2017/07/24)
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- Tandem Hydroalumination/Cu-Catalyzed Asymmetric Vinyl Metalation as a New Access to Enantioenriched Vinylcyclopropane Derivatives
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Herein, we report the first enantio- and diastereoselective addition of stereodefined vinyl organometallic reagents to cyclopropenes. The operationally simple tandem hydroalumination and copper-catalyzed vinylmetalation allows for the unique access of a diverse set of enantioenriched vinylcyclopropane derivatives.
- Müller, Daniel S.,Werner, Veronika,Akyol, Sema,Schmalz, Hans-Günther,Marek, Ilan
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supporting information
p. 3970 - 3973
(2017/08/14)
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- Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes
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Phenylallenes undergo fluorinative rearrangement upon the action of (difluoroiodo)toluene in the presence of 20 mol % BF3?OEt2 to yield α-difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl- and α-allenyl substituents, and diphenylallenes were investigated, and good functional-group compatibility was observed throughout. The ease with which allenes can be prepared on a large scale, and the operational simplicity of this reaction allowed us to rapidly access fluorine-containing building blocks that have not been accessed by conventional deoxyfluorination strategies.
- Zhao, Zhensheng,Racicot, Léanne,Murphy, Graham K.
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supporting information
p. 11620 - 11623
(2017/09/11)
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- Asymmetric Nitrone Synthesis via Ligand-Enabled Copper-Catalyzed Cope-Type Hydroamination of Cyclopropene with Oxime
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We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetric cyclopropene "hydronitronylation" process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic studies corroborate a CuI-catalytic profile featuring an olefin metalla-retro-Cope aminocupration process as the key C-N bond forming event. This conceptually novel reactivity enables the first example of highly enantioselective catalytic nitrone formation process and will likely spur further developments that may significantly expedite chiral nitrone synthesis.
- Li, Zhanyu,Zhao, Jinbo,Sun, Baozhen,Zhou, Tingting,Liu, Mingzhu,Liu, Shuang,Zhang, Mengru,Zhang, Qian
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supporting information
p. 11702 - 11705
(2017/09/07)
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
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supporting information
p. 12634 - 12637
(2017/12/02)
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- Palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane: Synthesis of homoallylic boronic esters
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A palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane to afford the corresponding homoallylic organoboronic esters with moderate to excellent yields is reported. This novel transformation provides an efficient strategy for the construction of homoallylic organoboronic esters in one step with a broad substrate scope. It is proposed that the palladium-catalyzed oxidative allylic C-H bond activation process may be involved in the catalytic cycle.
- Li, Chunsheng,Li, Meng,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 66 - 69
(2017/12/27)
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- Substrate Scope Evaluation of the Enantioselective Reduction of β-Alkyl-β-arylnitroalkenes by Old Yellow Enzymes 1-3 for Organic Synthesis Applications
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The substrate scope of the old yellow enzyme catalyzed reduction of β-alkyl-β-arylnitroalkenes is investigated. Compounds bearing either alkyl chains of increasing length at the carbon atom in position β to the nitro group or different substituents on the aromatic ring are prepared and submitted to bioreduction, to define the synthetic potential of this enantioselective reaction in the preparation of chiral fine chemicals. The versatility of the resulting nitroalkanes as chiral building blocks is shown by reducing the nitro group into a primary amine and by converting it into a carboxylic acid moiety by Meyer reaction. An "explosion" of chiral products can be observed by combining the highly enantioselective ene-reductase-mediated reduction of nitroalkenes with the chemical versatility of the nitro group.
- Bertolotti, Mattia,Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Santangelo, Sara
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p. 577 - 583
(2016/02/23)
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- Copper(i)-mediated synthesis of β-hydroxysulfones from styrenes and sulfonylhydrazides: An electrochemical mechanistic study
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Copper(i) halides were used as mediators in the synthesis of β-hydroxysulfones via the oxysulfonylation of styrenes using sulfonylhydrazides. The feature of the developed process lies in the combination of a copper(i) salt with oxygen - the stoichiometric oxidant. Copper(ii) species are responsible for the oxidation of sulfonylhydrazides, they are generated in small amounts in the O2/Cu(i)/Cu(ii) redox system, which is formed during the reaction. The combination of these three components enables one to obtain in the case of α-methylstyrenes only β-hydroxysulfones and in the case of α-unsubstituted styrenes, β-hydroxysulfones as the main products and β-ketosulfones as the by-products. With good yields β-hydroxysulfones were prepared by reduction of the reaction mixture containing both products β-hydroxysulfones and β-ketosulfones with NaBH4. An electrochemical study revealed that the Cu(i)/Cu(II) pair can serve as an effective mediator of β-hydroxysulfones formation via redox processes.
- Terent'Ev, Alexander O.,Mulina, Olga M.,Pirgach, Dmitry A.,Demchuk, Dmitry V.,Syroeshkin, Mikhail A.,Nikishin, Gennady I.
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p. 93476 - 93485
(2016/10/17)
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- Organic base-catalysed solvent-tuned chemoselective carbotrifluoromethylation and oxytrifluoromethylation of unactivated alkenes
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An unprecedented and efficient organic base-catalysed highly chemoselective carbo- and oxytrifluoromethylation of unactivated alkenes with Togni's reagent was developed. The switchable chemoselectivity was tuned by simply changing the organic base catalyst and solvent. Mechanistic studies indicated that a radical cyclization pathway for carbotrifluoromethylation in DMSO and a carbocation pathway for oxytrifluoromethylation in DCE were probably involved.
- Yang, Ning-Yuan,Li, Zhong-Liang,Ye, Liu,Tan, Bin,Liu, Xin-Yuan
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supporting information
p. 9052 - 9055
(2016/07/21)
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- Iodothiocyanation/Nitration of Allenes with Potassium Thiocyanate/Silver Nitrite and Iodine
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Direct strategies for the iodothiocyanation and iodonitration of allenes have been developed. In this process, potassium thiocyanate/silver nitrite and molecular iodine are used as the source of SCN, ONO2and iodine to provide the desired products in moderate to good yields with high stereoselectivity. (Figure presented.).
- Yang, Xiaodong,She, Yue,Chong, Ya,Zhai, Huichun,Zhu, He,Chen, Baohua,Huang, Guosheng,Yan, Rulong
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supporting information
p. 3130 - 3134
(2016/10/09)
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- A rhodium(I)-catalysed formal intramolecular C-C/C-H bond metathesis
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Phenylcyclobutanes underwent skeletal reorganisation in the presence of Wilkinson's catalyst to afford indanes through a cascade process involving chelation-assisted C-C bond cleavage and intramolecular C-H bond cleavage.
- Matsuda, Takanori,Yuihara, Itaru
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supporting information
p. 7393 - 7396
(2015/04/27)
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- Synthesis of 2,5-Diaryl-1,5-dienes from Allylic Bromides Using Visible-Light Photoredox Catalysis
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Visible-light photoreductive coupling of 2-arylallyl bromides in the presence of the photocatalyst Ru(bpy)3(PF6)2, a Hantzsch ester, and i-Pr2NEt gives 2,5-diaryl-1,5-dienes in high yield. This method avoids the use of stoichiometric metal reductants and is compatible with the presence of halogen, alkyl, electron-donating, and electron-withdrawing substituents on the aromatic ring.
- Pratsch, Gerald,Overman, Larry E.
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p. 11388 - 11397
(2015/12/01)
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