- Construction of 4-Isochromanones through Cu(OTf)2-Catalysed Sequential C=O and C–O Bond Formation
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A new strategy for the facile and efficient synthesis of 4-isochromanones has been developed. The reaction involves a Cu(OTf)2-catalysed sequential reaction of epoxides carrying electron-deficient alkenes using the solvent DMSO as the oxidant.
- Xing, Siyang,Gu, Nan,Qin, Jiajing,Cui, Hong,Li, Yan,Wang, Kui,Tian, Dawei,Chen, Bo,Yu, Guo
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- Palladium-Catalyzed Tandem Hydrocarbonylative Lactamization and Cycloaddition Reaction for the Construction of Bridged Polycyclic Lactams
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The intramolecular hydroaminocarbonylation of alkenes is a compelling tool to rapidly access lactam, a privileged motif ubiquitous in natural products, pharmaceuticals, and agrochemicals. However, selective carbonylation to bridged polycyclic lactams with a lactam nitrogen at a bridgehead position is less explored. We herein report a modular palladium-catalyzed approach to perform a tandem hydrocarbonylative lactamization/Diels-Alder cycloaddition reaction with 2-vinyl aryl aldimines, alkenes, and CO, which offers convenient access to furnish the bridged polycyclic lactams in high yields with high selectivities.
- Xu, Pengcheng,Qian, Bo,Hu, Bin,Huang, Hanmin
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supporting information
p. 147 - 151
(2022/01/04)
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- Diastereoselective Synthesis of the ABCD Ring System of Rubriflordilactone B
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A novel nine-step diastereoselective route to the ABCD ring system of the natural product rubriflordilactone B is reported. Use of an α-substituted butenolide derived from maleic anhydride facilitated a 1,4-conjugate addition to provide a diene. The order in which a ringclosing metathesis and enolate oxidation were performed on this compound dictated the relative stereochemistry of the target. The final product exhibited anisotropic effects during roomerature NMR studies, requiring elevatederature experiments to confirm its identity.
- Roth, Hudson G.,Nicewicz, David A.
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supporting information
p. 48 - 51
(2021/11/09)
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- A Transient Directing Group Strategy Enables Enantioselective Multicomponent Organofluorine Synthesis
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The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed three-component coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6-trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds.
- Liu, Zhonglin,Oxtoby, Lucas J.,Liu, Mingyu,Li, Zi-Qi,Tran, Van T.,Gao, Yang,Engle, Keary M.
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supporting information
p. 8962 - 8969
(2021/07/01)
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- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
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We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
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supporting information
p. 9680 - 9683
(2021/09/30)
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- Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
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Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
- Maurya, Abhishek,Haldar, Chanchal
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- Construction of Partially Protected Nonsymmetrical Biaryldiols via Semipinacol Rearrangement of o-NQM Derived from Enynones
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The construction of partially protected nonsymmetrical biaryldiols catalyzed by AgBF4 has been achieved. The approach facilitates the formation of two new aryl rings and the introduction of two hydroxyl groups (one free and one TBS-protected) via the o-NQM generation/semipinacol rearrangement cascade, featuring high atom- and step-economy to afford a diverse array of partially protected nonsymmetrical biaryldiols under mild conditions.
- Wu, Feng,Cheng, Tairan,Zhu, Shifa
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supporting information
p. 71 - 75
(2021/01/09)
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- Copper(I)-Catalyzed Enyne Oxidation/Cyclopropanation: Divergent and Enantioselective Synthesis of Cyclopropanes
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An efficient copper(I)-catalyzed enyne oxidation/cyclopropanation for the modular synthesis of cyclopropane derivatives is described, which represents the first non-noble metal-catalyzed enynes oxidation/cyclopropanation by the in situ generated α-oxo copper carbenes. This protocol allows the assembly of valuable cyclopropane-γ-lactams in generally good to excellent yields with excellent diastereoselectivity. More significantly, the enantioselective version of enyne oxidation/cyclopropanation has been disclosed with chiral copper catalysts.
- Shen, Wen-Bo,Tang, Xiang-Ting,Zhang, Ting-Ting,Lv, Dong-Can,Zhao, Dan,Su, Tong-Fu,Meng, Lei
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supporting information
p. 1285 - 1290
(2021/02/20)
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- Carbonylative cycloaddition between two different alkenes enabled by reactive directing groups: Expedited construction of bridged polycyclic skeletons
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A novel palladium-catalyzed highly selective hydrocarbonylative cycloaddition reaction with two different alkenes in the presence of CO enabled by a reactive directing-group is developed, which offers efficient and convenient access to lactone-containing bridged polycyclic compounds in high yield with high chemo- and stereoselectivities.
- Gao, Bingjian,Zou, Suchen,Yang, Guoqing,Ding, Yongzheng,Huang, Hanmin
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supporting information
p. 12198 - 12201
(2020/10/26)
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- Tandem Reaction Approaches to Isoquinolones from 2-Vinylbenzaldehydes and Anilines via Imine Formation-6π-Electrocyclization-Aerobic Oxidation Sequence
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Two distinctive transition-metal-promoted aerobic oxidation protocols have been developed for the synthesis of isoquinolones from 2-vinylbenzaldehydes and aniline derivatives. Thus, the one-pot tandem reaction sequence of imine formation, thermal 6π-electrocyclization, followed by either Cu(OAc)2-mediated or Pd(OAc)2-catalyzed aerobic oxidation protocol allowed the ready access to isoquinolone derivatives. The control experiments revealed that the 1,2-dihydroisoquinoline intermediates from the 6π-electrocyclization of 1-azatrienes were aerobically oxidized to isoquinolones in the presence of either Cu(OAc)2 or Pd(OAc)2 catalyst.
- Lee, Jiyeon,Kim, Hun Young,Oh, Kyungsoo
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supporting information
p. 474 - 478
(2020/01/21)
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- Catalyst-free photodecarbonylation ofortho-amino benzaldehyde
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It is almost a consensus that decarbonylation of the aldehyde group (-CHO) needs to not only be mediated by transition metal catalysts, but also requires severe reaction conditions (high temperature and long reaction time). In this work, inspired by the “conformational-selectivity-based” design strategy, we broke this consensus and discovered a catalyst-free photodecarbonylation of the aldehyde group. It revealed that decarbonylation can be easily achieved with visible light irradiation by introducing a tertiary amine into theortho-position of the aldehyde group. A diverse array of tertiary amines is tolerated by our photodecarbonylation under mild conditions. Furthermore, the (QM) computations of the mechanism and the experiments on well-designed special substrates revealed that our photodecarbonylation depends on the conformational specificity of the aldehyde group and tertiary amine, and occurs through an unusual [1,4]-H shift and a subsequent [1,3]-H shift.
- Li, Lamei,Wang, Songping,Wei, Wentao,Yan, Ming,Zhou, Jingwei
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supporting information
p. 3421 - 3426
(2020/06/25)
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- Stereoselective Convergent Synthesis of Tetrahydro-5 H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition
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The diene methyl ethers or acetates, constructed from the Li-Br exchange/addition reactions of 2-vinylbenzaldehydes and 2-(but-3-en-1-yl)bromoarenes followed by etherification or acetylation of the corresponding alcohols, smoothly underwent the ring-closi
- Lekky, Anek,Ruengsatra, Tanachote,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 5277 - 5291
(2019/05/10)
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- Trialkylborane-Mediated Multicomponent Reaction for the Diastereoselective Synthesis of Anti-δ,δ-Disubstituted Homoallylic Alcohols
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The trialkylborane/O2-mediated reaction of propargyl acetates having a tributylstannyl group at an alkyne terminus with aldehydes in a THF-H2O solvent system gave anti-δ,δ-disubstituted homoallylic alcohols with good to high diastereoselectivity. Intriguingly, two alkyl groups derived from trialkylborane were embedded into the reaction product. The trialkylborane plays a key role not only as a radical initiator but also as a source of alkyl radicals.
- Horino, Yoshikazu,Murakami, Miki,Aimono, Ataru,Lee, Jun Hee,Abe, Hitoshi
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supporting information
p. 476 - 480
(2019/01/14)
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- A Strategy To Obtain o-Naphthoquinone Methides: Ag(I)-Catalyzed Cyclization of Enynones for the Synthesis of Benzo[ h]chromanes and Naphthopyryliums
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A new strategy to obtain o-NQM intermediates through a ring-formation strategy by Ag(I)-catalyzed cyclization of 2-alkenylphenyl alkynyl ketones and its [4 + 2] annulations with styrenes has been developed. This reaction features high efficiency, mild reaction conditions, as well as flexible substitutions and atom economy. The obtained benzo[h]chromane products were further oxidized to naphthopyryliums, which displayed tunable photophysical properties.
- Wu, Feng,Zhu, Shifa
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supporting information
(2019/03/08)
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- Copper-Catalyzed Modular Amino Oxygenation of Alkenes: Access to Diverse 1,2-Amino Oxygen-Containing Skeletons
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Copper-catalyzed alkene amino oxygenation reactions using O-acylhydroxylamines have been achieved for a rapid and modular access to diverse 1,2-amino oxygen-containing molecules. This transformation is applicable to the use of alcohols, carbonyls, oximes, and thio-carboxylic acids as nucleophiles on both terminal and internal alkenes. Mild reaction conditions tolerate a wide range of functional groups, including ether, ester, amide, carbamate, and halide. The reaction protocol allows for starting with free amines as the precursor of O-benzoylhydroxylamines to eliminate their isolation and purification, contributing to broader synthetic utilities. Mechanistic investigations reveal the amino oxygenation reactions may involve distinct pathways, depending on different oxygen nucleophiles.
- Hemric, Brett N.,Chen, Andy W.,Wang, Qiu
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supporting information
p. 1468 - 1488
(2019/01/25)
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- Enantioselective Copper-Catalyzed Desymmetrization of 1,3-Diketones Involving Borylation of Styrenes
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A copper-catalyzed intramolecular enantioselective and diastereoselective borylative coupling of styrenes and ketones was achieved by merging desymmetrization strategy and olefin difunctionalization. The reaction proceeds through an initial enantioselective borylcupration of styrenes, followed by a highly selective direct addition to 1,3-diketones. The bicyclic scaffolds with three chiral carbon centers, including two tetrasubstituted carbons, were generated in excellent yields, diastereoselectivities, and enantioselectivities. This catalytic tandem reaction has great potential for further synthetic application of the chiral polycyclic compounds, because of the versatility of the functional groups in the products.
- Zheng, Purui,Han, Xiaoyu,Hu, Jiao,Zhao, Xiaoming,Xu, Tao
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supporting information
p. 6040 - 6044
(2019/08/27)
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- Palladium-catalysed O-Allylation of α-Hydroxyphosphonates: An Expedient Entry into Phosphono-oxaheterocycles
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We report here an unprecedented palladium-catalysed O-allylation of α-hydroxyphosphonates. The method was eventually included in a sequential Pudovik/Tsuji-Trost type O-allylation/Ring-Closing Metathesis to afford a variety of phosphorylated heterocycles
- Kerim, Mansour Dolé,Cattoen, Martin,Fincias, Nicolas,Dos Santos, Aurélie,Arseniyadis, Stellios,El Ka?m, Laurent
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supporting information
p. 449 - 454
(2017/12/04)
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- C- ARYL GLYCOSID DERIVATIVES, PHARMACEUTICAL COMPOSITION, PREPARATION PROCESS AND USES THEREOF
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This invention relates to a kind of C-aryl glycoside derivatives, its pharmaceutical compositions, preparation methods, and uses thereof. The preparation method comprises: method 1: in a solvent, deprotecting the acetyl protecting groups of compound 1-f in the presence of a base; method 2: 1) compound 2-g reacts with via Mitsunobu reaction; 2) deprotecting the acetyl protecting groups of compound 2-f obtained from step 1; method 3: 1) compound 2-g reacts with via nucleophilic substitution reaction; 2) deprotecting the acetyl protecting groups of compound 3-f obtained from step 1. The pharmaceutical composition comprises a kind of C-aryl glycoside derivatives; it's pharmaceutically acceptable salts and/or prodrugs thereof and excipient thereof. This invention further relates to a kind of C-aryl glycoside derivatives, it's pharmaceutically acceptable salts or pharmaceutical compositions thereof for the use in preparation of a SGLT inhibitor. The C-aryl glycoside derivatives of this invention provides a new direction for the study of SGLT inhibitors.
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Paragraph 0096; 0147; 0148
(2017/04/19)
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- Palladium-Catalyzed Ring-Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation
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A palladium-catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition-state, is the turnover-limiting step in which the inherent β-hydride elimination of the key Csp3?Pd species was controlled by the confined conformation and the nucleophilicity of the Csp3?Pd bond was enhanced by the strong electron-donating effect of the nitrogen atom.
- Hu, Yue,Xie, Yinjun,Shen, Zhiqiang,Huang, Hanmin
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supporting information
p. 2473 - 2477
(2017/02/23)
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- AgOTf-catalyzed sequential synthesis of 4-isoquinolones: Via oxidative ring opening of aziridines and aza-Michael addition
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An efficient AgOTf-catalyzed sequential reaction involving the oxidative ring-opening of aziridines by DMSO and aza-Michael addition has been developed. A series of 2,3-dihydro-4(1H)-isoquinolones were afforded in moderate to good yields by the formation of one new CO bond and one new C-N bond. The features of this sequential reaction include high bonding efficiency, use of a catalytic amount of catalysts, a broad substrate scope and mild conditions. This methodology provides a good choice for constructing the libraries of 2,3-dihydro-4(1H)-isoquinolones.
- Xing, Siyang,Cui, Hong,Gu, Nan,Li, Ying,Wang, Kui,Tian, Dawei,Qin, Jiajing,Liu, Qiaoyang
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supporting information
p. 8308 - 8312
(2017/10/23)
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- Photoredox-Catalyzed Three-Component Tandem Process: An Assembly of Complex Trifluoromethylated Phthalans and Isoindolines
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A novel photoredox-mediated tandem three-component process afforded a wide variety of CF3-containing phthalans and isoindolines in respectable yields and with moderate to excellent diastereoselectivity.
- Jarrige, Lucie,Carboni, Aude,Dagousset, Guillaume,Levitre, Guillaume,Magnier, Emmanuel,Masson, Géraldine
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supporting information
p. 2906 - 2909
(2016/07/06)
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- Photochemical approach to functionalized benzobicyclo[3.2.1]octene structures via fused oxazoline derivatives from 4-and 5-(o-vinylstyryl) oxazoles
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Novel cis/trans-4- and cis/trans -5-(2-vinylstyryl)oxazoles have been synthesized by Wittig reactions from the diphosphonium salt of α,α'- o -xylene dibromide, formaldehyde and 4- and 5-oxazolecarbaldehydes, respectively. In contrast, trans -5-(2-vinylsty
- agud, Ivana,Boiae, Simona,Mariniae, eljko,indler-Kulyk, Marija
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p. 2222 - 2229
(2015/01/09)
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- Direct intramolecular conjugate addition of simple alkenes to α,β-unsaturated carbonyls catalyzed by Cu(OTf)2
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An unprecedented intramolecular conjugate addition of simple alkenes to α,β-unsaturated carbonyl compounds has been developed. A simple Lewis acid such as Cu(OTf)2 was found to effectively catalyze the reaction, and six- and five-membered cycli
- Qin, Yan,Lv, Jian,Luo, Sanzhong,Cheng, Jin-Pei
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supporting information
p. 5032 - 5035
(2014/12/11)
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- Enantioselective allylation of selected ortho-substituted benzaldehydes: A comparative study
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We report a systematic study of the allylation of ortho-substituted benzaldehydes under catalysis of a Lewis base (N, Ndioxide), a Lewis acid (Keck allylation), and a Bronsted acid. ortho-Halobenzaldehydes were used as the aldehydic substrates, and specia
- Hessler, Filip,Betk, Robert,Kadlkov, Aneta,Belle, Roman,Kotora, Martin
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supporting information
p. 7245 - 7252
(2015/01/09)
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- Preparation of amino-substituted indenes and 1,4-dihydronaphthalenes using a one-pot multireaction approach: Total synthesis of oxybenzo[c]phenanthridine alkaloids
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Allylic trichloroacetimidates bearing a 2-vinyl or 2-allylaryl group have been designed as substrates for a one-pot, two-step multi-bond-forming process leading to the general preparation of aminoindenes and amino-substituted 1,4-dihydronaphthalenes. The synthetic utility of the privileged structures formed from this one-pot process was demonstrated with the total synthesis of four oxybenzo[c]phenanthridine alkaloids, oxychelerythrine, oxysanguinarine, oxynitidine, and oxyavicine. An intramolecular biaryl Heck coupling reaction, catalyzed using the Hermann-Beller palladacycle was used to effect the key step during the synthesis of the natural products.
- Calder, Ewen D. D.,McGonagle, Fiona I.,Harkiss, Alexander H.,McGonagle, Grant A.,Sutherland, Andrew
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p. 7633 - 7648
(2014/09/17)
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- Unexpected pyrolytic behaviour of substituted benzo[c]thiopyran and thieno[2,3-c]thiopyran s,s-dioxides
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Flash vacuum pyrolysis (FVP) of benzo[c]thiopyran S,S-dioxide (1) results in formation of indene and 2-vinylbenzaldehyde as previously described. A range of eight analogues with various substitution patterns are found to behave differently. In general, there is no extrusion of SO2 to give products analogous to indene, but unsaturated carbonyl products analogous to 2-vinylbenzaldehyde are formed in most cases by way of ring expansion to a 7-membered ring sultine, extrusion of SO, and intramolecular hydrogen atom transfer. Other processes observed include formation of anthracene via an isomeric 7-membered sultine with loss of SO, CO and methane or butane, and formation of 4-ethylidene-4,5- dihydrocyclobuta[b]thiophenes by way of SO loss, a radical rearrangement, and extrusion of acetone. The analogues with a halogen substituent at position 8 on the benzene ring require a higher temperature to react and give naphthalene resulting from net elimination of HX and SO2. The X-ray crystal structure of 1 is also reported.
- Aitken, R. Alan,Hauduc, Clemence,Hossain, M. Selim,McHale, Emily,Schwan, Adrian L.,Slawin, Alexandra M. Z.,Stewart, Colin A.
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p. 1288 - 1295
(2014/11/07)
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- Pd-catalyzed ring assembly by vinylation and intramolecular heck coupling: A versatile strategy towards functionalized azadibenzocyclooctynes
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A new modular approach based on Pd-catalyzed C-C bond formation is presented for the assembly of a benzannulated azocine scaffold, the key intermediate in the synthesis of functionalized azadibenzocyclooctynes (aza-DIBOs). The intramolecular ring-closing Heck coupling was investigated by variation of the C-X bond. The reaction rate is limited by the initial oxidative addition step and the regiochemistry strongly depends on the auxiliary phosphine. Under optimized conditions, the 8-endo regioisomer was obtained in 71 % yield over two steps (with no protecting group chemistry) or in one pot, inclusive of C-N bond formation. The practical generation of the octyne triple bond of a prototypical N-benzoyl aza-DIBO, without the need for chromatographic purification, is also described. The structural features, including those of the ring-strained cyclic octyne, were elucidated by NMR spectroscopy and X-ray crystallographic analysis. The high reactivity of the N-benzoyl aza-DIBO synthesized is demonstrated in a strain-promoted azide-alkyne cycloaddition reaction with an alkyl azide (k=0.38 M-1 s-1). Copyright
- J?ger, Michael,G?rls, Helmar,Günther, Wolfgang,Schubert, Ulrich S.
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supporting information
p. 2150 - 2157
(2013/03/28)
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- Relay catalysis: Enantioselective synthesis of cyclic benzo-fused homoallylic alcohols by chiral bronsted acid-catalyzed allylboration/ring closing metathesis
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Six- and seven-membered benzo-fused cyclic homoallylic alcohols can be readily synthesized by a tandem chiral Bronsted acid-catalyzed allyl (crotyl)boration/ring closing metathesis sequence performed under orthogonal relay catalysis conditions. Excellent enantio- and diastereoselectivities are obtained in most of the cases. In addition, the parent crotylboration/RCM process is also described. The required substrates, ortho-vinylbenzaldehydes, are readily available in one step from commercially available starting materials. Both catalysts and reactants are also available from commercial suppliers. The reaction shows broad functional group compatibility and is also suitable for heteroaromatic substrates. Substitution at any position of the aromatic ring is tolerated; however, substitution at position 6 results in a substantial drop in enantioselectivity. Copyright
- Fustero, Santos,Rodriguez, Elsa,Lazaro, Ruben,Herrera, Lidia,Catalan, Silvia,Barrio, Pablo
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supporting information
p. 1058 - 1064
(2013/05/21)
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- New synthesis of A-ring aromatic strigolactone analogues and their evaluation as plant hormones in pea (pisum sativum)
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A new general access to A-ring aromatic strigolactones, a new class of plant hormones, has been developed. The key transformations include in sequence ring-closing metathesis, enzymatic kinetic resolution and a radical cyclization with atom transfer to install the tricyclic ABC-ring system. The activity as plant hormones for the inhibition of shoot branching in pea of various analogues synthesized by this strategy is reported. Inhibiting shoot branching: A new general access to A-ring aromatic strigolactones (see scheme), a new class of plant hormones, has been developed. The biological activity of various analogues synthesized by this strategy for inhibiting bud outgrowth in pea was evaluated. Copyright
- Chen, Victor X.,Boyer, Fran?ois-Didier,Rameau, Catherine,Pillot, Jean-Paul,Vors, Jean-Pierre,Beau, Jean-Marie
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supporting information
p. 4849 - 4857
(2013/05/22)
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- Catalytic asymmetric synthesis of (S)-laudanosine by hydroamination
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Lithium amide-chiral bisoxazoline-catalyzed asymmetric intramolecular hydroamination was examined with respect to the structural variants of starting aminoalkenes. Substituents on the nitrogen and olefin of aminoalkenes were found to be important factors affecting reaction efficiency as well as enentioselectivity in the production of chiral tetrahydroisoquinolines and isoindolines. The catalytic asymmetric total synthesis of (S)-laudanosine highlights the utility of the asymmetric hydroamination.
- Ogata, Tokutaro,Kimachi, Tetsutaro,Yamada, Ken-Ichi,Yamamoto, Yasutomo,Tomioka, Kiyoshi
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p. 469 - 485
(2013/08/23)
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- Efficient entry to the [2.2.2]-diazabicyclic ring system via diastereoselective domino reaction sequence
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A domino reaction sequence involving aldol condensation, alkene isomerization, and intramolecular hetero-Diels-Alder cycloaddition for the synthesis of [2.2.2]-diazabicyclic structures is reported. Excellent diastereofacial control during the cycloaddition is enforced with a removable chiral phenyl aminal diketopiperazine substituent. The reaction sequence rapidly generates molecular complexity and is competent with both enolizable and nonenolizable aldehyde substrates (nine examples total). Progress toward the synthesis of malbrancheamide B, a protypical member of the [2.2.2]-diazabicyclic natural product family, is also disclosed.
- Margrey, Kaila A.,Chinn, Alex J.,Laws, Stephen W.,Pike, Robert D.,Scheerer, Jonathan R.
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supporting information; experimental part
p. 2458 - 2461
(2012/07/27)
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- Ring-closure reactions of 1,2-diaza-4,5-benzoheptatrienyl metal compounds: Experiment and theory
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2-Alkenylbenzylidene hydrazones 5a-m, which are accessible in good to excellent yields in a four-step synthesis, are converted into 1,2-diaza-4,5-benzoheptatrienyl metal compounds 1a-m by treatment with KO-t-Bu as base. These metal compounds undergo the various types of reactions in good yields and exclusively depending on the nature of substituents R1 and R3. Thus, metal compounds 1a-c carrying alkyl substituents R 1 and R3 form 3H-benzodiazepines 6a-c after electrophilic quench of the intermediate cyclic anion 7 in a 7-endo-trig electrocyclic reaction with a moebius aromatic transition structure 1--TS. Similarly, a benzothienyl derivative 5n is converted into diazepine 6d. Potassium compounds 1d-h, which are N-methyl and aryl substituted at R 3, form 1,2-dihydrophthalazines 8a-e in a predominantly charge-controlled 6-exo-trig cyclization reaction. In contrast, aryl-aryl-substituted systems 5i-m did not lead to cyclic products upon deprotonation, but the intermediate open-chain metal compounds 1i-m were trapped by acid chlorides at N1 to yield the hydrazides 10a-e. We interpret thermodynamics and kinetics of these reactions in the context of the Baldwin rules on the basis of quantum chemical calculations and discuss the transition structures considering the results of NICS and NBO-charge calculations. Examples of the products 6, 8, and 10 could be characterized by X-ray diffraction.
- Kleine, Tillmann,Bergander, Klaus,Froehlich, Roland,Wibbeling, Birgit,Wuerthwein, Ernst-Ulrich
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scheme or table
p. 1979 - 1991
(2011/05/07)
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- High chemoselectivity in the phenol synthesis
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Efforts to trap early intermediates of the gold-catalyzed phenol synthesis failed. Neither inter- nor intramolecularly offered vinyl groups, ketones or alcohols were able to intercept the gold carbenoid species. This indicates that the competing steps of
- Rudolph, Matthias,McCreery, Melissa Q.,Frey, Wolfgang,Hashmi, A. Stephen K.
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scheme or table
p. 794 - 801
(2011/08/03)
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- Inter- and intramolecular hydroacylation of alkenes employing a bifunctional catalyst system
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Based on a conceptually innovative bifunctional P,N ligand, an efficient protocol for the rhodium-catalyzed inter- and intramolecular hydroacylation of alkenes has been developed.
- Vautravers, Nicolas R.,Regent, Damien D.,Breit, Bernhard
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supporting information; experimental part
p. 6635 - 6637
(2011/06/27)
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- AuI-catalyzed intramolecular cyclization of 2-alkenylphenyl carbonyl compounds: Exploring the oxophilic Lewis acidity of AuI species
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A AuI-catalyzed intramolecular cyclization reaction of 2-alkenylphenyl carbonyl compounds to afford a variety of indene, indenol, and indanone ring systems was developed. In this process, AuI serves to activate the carbonyl group of β-keto esters, aldehydes, and ketones, preferentially exhibiting oxophilicity in the presence of C-C multiple bonds. Furthermore, β-keto esters could participate as the electrophilic partner in reactions with carbon nucleophile such as alkenes. Copyright
- Jagdale, Arun R.,Youn, So Won
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supporting information; experimental part
p. 3904 - 3910
(2011/09/15)
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- Stereoselective synthesis of chiral IBR2 analogues
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Two stereoselective routes were developed to synthesize optically pure IBR2 analogues 1-16. The first features addition of N-Boc-3-bromoindole 26 to the sulfinamide 25, providing a 1:1 ratio of the separable diasteroisomers 27 and 28 in good yield. In a s
- Qiu, Xiao-Long,Zhu, Jiewen,Wu, Guikai,Lee, Wen-Hwa,Richard Chamberlin
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supporting information; experimental part
p. 2018 - 2027
(2009/08/07)
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- Direct vinylation and difluorovinylation of arylboronic acids using vinyl- and 2,2-difluorovinyl tosylates via the Suzuki-Miyaura cross coupling
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(Chemical Equation Presented) General reaction conditions were developed for the Pd(0)-catalyzed Suzuki-Miyaura coupling reaction of aryl boronic acids with a simple electrophilic vinylation reagent, vinyl tosylate, providing access to styrene derivatives in good yields. The easily accessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology was expanded to provide a facile and straightforward approach for the introduction of a gem-difluorovinyl substituent onto an aromatic ring using the similar and also readily available 2,2-difluorovinyl tosylate as the electrophilic complement.
- Gogsig, Thomas M.,Sobjerg, Lina S.,Lindhardt, Anders T.,Jensen, Kim L.,Skrydstrup, Troels
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p. 3404 - 3410
(2008/09/21)
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- Domino ring-closing enyne-metathesis-cross-metathesis approach to 1-phosphonylated benzazepines
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A short approach was developed towards phosphonylated benzazepines. Aminophosphonates containing an 'yne' and an 'ene' moiety were synthesised via phosphonylation of the corresponding imines. The key step in the reaction sequence is a domino enyne-metathesis-cross-metathesis. Georg Thieme Verlag Stuttgart.
- Dieltiens, Nicolai,Stevens, Christian V.
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p. 2771 - 2776
(2008/02/11)
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- Suzuki cross-coupling reactions between alkenylboronic acids and aryl bromides catalysed by a tetraphosphane-palladium catalyst
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A range of alkenylboronic acids undergo Suzuki cross-coupling with aryl bromides in good yields in the presence of [PdCl(C3H 5)]2/cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphanyl) methyl]cyclopentane as a catalyst. A wide variety of 1-arylprop-1-enes, 2-arylprop-1-enes, 2-arylbut-1-enes and 1,1-diarylethylene or styrene derivatives have been prepared. Moreover, the reaction tolerates several functions, such as acetyl, formyl, nitrile or nitro. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Peyroux, Eugenie,Berthiol, Florian,Doucet, Henri,Santelli, Maurice
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p. 1075 - 1082
(2007/10/03)
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- Liquid phase oxidation of alkenes with nitrous oxide to carbonyl compounds
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A variety of substrates including linear, cyclic, heterocyclic alkenes and their derivatives were tested in the liquid phase non-catalytic oxidation with nitrous oxide (N2O). The structure and composition of the alkenes have a significant effect on the reaction selectivity. With many alkenes, N 2O oxidation provides a selective way for the preparation of carbonyl compounds. The generation of carbene (or diazomethane) species is a remarkable feature of the oxidation of terminal alkenes.
- Starokon,Dubkov,Babushkin,Parmon,Panov
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p. 268 - 274
(2007/10/03)
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- Polymeric nitrons. 2. Synthesis, irradiation and waveguide mode spectroscopy of polymeric nitrons derived from polymeric benzaldehydes and N-isopropylhydroxylamine
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Various vinylbenzaldehydes were prepared using the Heck reaction: 4-vinylbenzaldehyde (14), 3-vinylbenzaldehyde (15), 2-vinylbenzaldehyde (18a), 2-hydroxy-4-vinylbenzaldehyde (16) and 4-[(4-vinylbenzyl)oxy]benzaldehyde (6). The four monomers (6, 14, 15, 16) were polymerized using AIBN as initiator at 70 °C for 24 h to yield the corresponding homopolymers (7, 19, 23, 25) and a copolymer (20) with styrene. The molecular weights are about 10 000. The polymer analogous condensation of the aldehyde groups with an excess of N-isopropylhydroxylamine (8) at room temperature produces polymeric nitrons (9, 21, 22, 24, 26) in almost quantitative yields. All nitron functions were irradiated, and the intramolecular cyclization of the nitrons to the corresponding oxaziridines was examined. Waveguide mode spectroscopy of poly(4-vinylbenzaldehyde-N-isopropylnitron) (21) shows that the changes in film thickness are low but the changes in refractive indices are significant after irradiation. Oxaziridine 10 has high thermal stability with respect to ring opening. No structural change was detected after irradiation of the hydrexyphenyl-modified polynitron (26). A low molecular weight model compound (2-hydroxybenzaldehyde-N-methylnitron, 28) was prepared id order to examine this abnormal photochemical behavior and also showed that it is highly resistant to UV irradiation.
- Heinenberg, Michael,Menges, Bernhard,Mittler, Silvia,Ritter, Helmut
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p. 3448 - 3455
(2007/10/03)
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- Generation of substituted styrenes via Suzuki cross-coupling of aryl halides with 2,4,6-trivinylcyclotriboroxane
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The synthesis of functionalized styrene derivatives can be readily achieved utilizing a Suzuki cross-coupling protocol between aryl halides and 2,4,6-trivinylcyclotriboroxane-pyridine complex. The scope and limitations of the procedure were demonstrated by investigation of an array of ortho-substituted aryl halides.
- Kerins, Fergal,O'Shea, Donal F.
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p. 4968 - 4971
(2007/10/03)
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- Palladium-catalyzed coupling reaction of alkenylgalliums with aryl halides
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Treatment of aryl halides with alkenylgallium dichloride, prepared from GaCl3 and alkenylmagnesium bromide, in the presence of a catalytic amount of palladium provided cross-coupling products in good yields.
- Mikami, Satoshi,Yorimitsu, Hideki,Oshima, Koichiro
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p. 1137 - 1139
(2007/10/03)
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- Suzuki cross-coupling reactions of potassium alkenyltrifluoroborates
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(formula presented) The palladium-catalyzed coupling reaction of potassium alkenyltrifluoroborates with aryl or alkenyl halides or triflates proceeds readily with good yields. The trifluoroborates are air-and moisture-stable solids that can be stored indefinitely. The cross-coupling can be effected using PdCl2(dppf)-CH2Cl2 as the catalyst in n-PrOH in the presence of Et3N. A variety of functional groups are tolerated. ? Dedicated to Professor Herbert C. Brown on the occasion of his 90th birthday.
- Molander, Gary A.,Rivero, Marta Rodriguez
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p. 107 - 109
(2007/10/03)
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- X-ray-induced transformation of o-vinylbenzaldehyde and 2-methylbenzocyclobutenone to an o-quinoid ketene and its radical cation
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Upon ionization in argon matrices by X-irradiation, o-vinylbenzaldehyde (VBA) partially undergoes transfer of the formyl hydrogen atom to the vinylic CH2 group, thereby forming a quinoketene radical cation of the type previously described (Bally, T.; Michalak, J. J. Photochem. Photobiol. A: Chem. 1992, 69, 185). This process does not manifest itself clearly in the optical spectra because the transitions of the quinoketene cation coincide with the much more intense ones of VBA.+ and are mostly obscured by those. However, the IR spectra show unambiguously that the rearrangement occurs rather efficiently. Also they show that in the course of the X-irradiation, the tautomerized cations are reneutralized to form the quinoketene tautomer of VBA in good yield. The quinoketene and its radical cation were independently obtained from 2-methylbenzocyclobutenone which undergoes spontaneous ring-opening on photolysis and/or ionization. The optical spectra of the radical cations are assigned on the basis of CASPT2 calculations and the different species involved in this study are characterized at the B3LYP/6-31G* level.
- Huben, Krzysztof,Zhu, Zhendong,Bally, Thomas,Gebicki, Jerzy
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p. 2825 - 2831
(2007/10/03)
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- Synthesis of spirononane system present in fredericamycin A
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Two different approaches for the construction of spirononane system present in fredericamycin A (1) have been reported.In the first approach (2-(β-haloethyl)phenyl)-indane-1,3-dione-methyl enolate (17) was subjected to trimethylsilyliodide reaction
- Rao, A. V. Rama,Rao, B. Venkateswara,Reddy, D. Reddappa
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p. 723 - 727
(2007/10/02)
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- Transition Metal Catalyzed Grignard Cross-Coupling to Ortho-Halogenated Aryl Imines. An Efficient Synthesis of Ortho-Substituted Aryl Aldehydes
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N-(o-Halogenated benzylidene)cyclohexylamines 2 were successfully reacted with reducing and nonreducing Grignard reagents in a transition metal catalyzed cross-coupling reaction resulting in an efficient single-step synthesis of ortho-substituted benzaldehydes after acidic workup.The dihalogenated benzylidene amines reacted regioselectively at the amine-activated ortho position to yield ortho-substituted halogenated benzaldehydes.
- Pridgen, N. Lendon,Snyder, L.,Prol, J.
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p. 1523 - 1526
(2007/10/02)
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- THE ALTERNATIVE SYNTHESIS OF ISOQUINOLINE NUCLEUS USING THE THERMAL ELECTROCYCLIC REACTION OF 1-AZAHEXA-1,3,5-TRIENE SYSTEM
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The thermal electrocyclic reaction of 2-alkenylbenzaldoximes or their derivatives having conjugated 1-azahexatriene system in o-dichlorobenzene gave isoquinolines in moderate to good yields except the reaction of unsubstituted 2-alkenylbenzaldoxime and its oxime ethers.
- Hibino, Satoshi,Sugino, Eiichi,Adachi, Yukiko,Nomi, Kazuhiko,Sato, Kohichi,Fukumoto, Keiichiro
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p. 275 - 282
(2007/10/02)
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