- Enantioselective [3 + 2] Cycloaddition Reaction of Ethynylethylene Carbonates with Malononitrile Enabled by Organo/Metal Cooperative Catalysis
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The first catalytic asymmetric decarboxylative [3 + 2] cycloaddition reaction of ethynylethylene carbonates with malononitrile has been developed successfully by an organo/copper cooperative system. This strategy led to a series of optically active polysu
- Zhang, Yu-Chen,Zhang, Bo-Wen,Geng, Rui-Long,Song, Jin
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- Ruthenium(0) Catalyzed Endiyne-α-Ketol [4 + 2] Cycloaddition: Convergent Assembly of Type II Polyketide Substructures via C-C Bond Forming Transfer Hydrogenation
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Upon exposure of 3,4-benzannulated 1,5-diynes (benzo-endiynes) to α-ketols (α-hydroxyketones) in the presence of Ru(0) catalysts derived from Ru3(CO)12 and RuPhos or CyJohnPhos, successive redox-triggered C-C coupling occurs to gener
- Saxena, Aakarsh,Perez, Felix,Krische, Michael J.
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- Chiral Bidentate Phosphoramidite-Pd Catalyzed Asymmetric Decarboxylative Dipolar Cycloaddition for Multistereogenic Tetrahydrofurans with Cyclic N-Sulfonyl Ketimine Moieties
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An asymmetric [3 + 2] cycloaddition of vinyl ethylenecarbonates (VECs) and (E)-3-arylvinyl substituted benzo[d] isothiazole 1,1-dioxides has been developed using the Pd complex of a bidentate phosphoramidite (Me-BIPAM) as the catalyst, providing a wide variety of chiral multistereogenic vinyltetrahydrofurans in good yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, 99% ee).
- Lv, Hao-Peng,Yang, Xiao-Peng,Wang, Bai-Lin,Yang, Hao-Di,Wang, Xing-Wang,Wang, Zheng
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p. 4715 - 4720
(2021/06/28)
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- Palladium-Catalyzed [5 + 2] Annulation of Vinylethylene Carbonates with Barbiturate-Derived Alkenes
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A palladium/XantPhos-catalyzed [5 + 2] annulation of VECs with electron-deficient alkenes having an isolated carbon-carbon double bond has been developed to afford spirobarbiturate-tetrahydrooxepines. This study provides an expedient assembly of biologically interesting spirobarbiturate-tetrahydrooxepines. The easy scalability and versatile transformability of the reaction products were also exhibited.
- Chen, Yuehua,Deng, Hao,Gao, Xing,Guo, Hongchao,Jiang, Feng,Wang, Wei,Wu, Yongjun,Zhu, Dongyu
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supporting information
p. 7158 - 7163
(2020/10/02)
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- Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
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The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
- Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
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p. 9982 - 9992
(2020/06/27)
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- Vinylethylene Carbonates as α,β-Unsaturated Aldehyde Surrogates for Regioselective [3 + 3] Cycloaddition
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Herein, we report a novel stepwise addition-controlled ring size method, to access tetrahydropyrimidines through an operationally simple [3 + 3] cycloaddition of vinylethylene carbonates with triazinanes. Interestingly, we could also use this method for a [3 + 3] oxidative cycloaddition, which allows the facile synthesis of polysubstituted terphenyls under mild conditions. Mechanistic studies suggest that vinylethylene carbonates could generate α,β-unsaturated aldehydes as 3-carbon synthons for cycloaddition via a combination process of Pd-catalyzed decarboxylation and β-H elimination.
- Xu, Yi,Chen, Lu,Yang, Yu-Wen,Zhang, Zhiqiang,Yang, Weibo
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p. 6674 - 6678
(2019/09/03)
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- Divergent synthesis of N-heterocycles by Pd-catalyzed controllable cyclization of vinylethylene carbonates
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Here, we report a palladium-catalyzed controllable cyclization of vinyl ethylene carbonates that proceeds through formal migration [2+3] and [5+2] cycloadditions, respectively, under mild conditions. The transformation described here affords a series of synthetically versatile 5,7-membered N-heterocycles which are found in natural products and pharmaceuticals with biological and medicinal properties.
- Yang, Yuwen,Yang, Weibo
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p. 12182 - 12185
(2018/11/21)
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- Diversity-Orientated Stereoselective Synthesis through Pd-Catalyzed Switchable Decarboxylative C?N/C?S Bond Formation in Allylic Surrogates
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Switchable catalytic transformation of reactants can be a powerful approach towards diversity-orientated synthesis from easily available molecular synthons. Herein, an endogenous ligand-controlled, Pd-catalyzed allylic substitution allowing for either selective C?N or C?S bond formation using vinylethylene carbonates (VECs) and N-sulfonylhydrazones as coupling partners has been developed. This versatile methodology provides a facile, divergent route for the highly chemo- and stereoselective synthesis of functional allylic sulfones or sulfonohydrazides. The newly developed protocol features wide substrate scope (nearly 80 examples), broad functional group tolerance, and potential for the late-stage functionalization of bioactive compounds. The isolation and crystallographic analysis of a catalytically competent π-allyl Pd complex suggests that the pathway leading to the allylic products proceeds through a different manifold as previously proposed for the functionalization of VECs with nucleophiles.
- Deng, Lei,Kleij, Arjan W.,Yang, Weibo
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p. 19156 - 19161
(2018/11/30)
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- Chiral Ion-Pair Organocatalyst-Promoted Efficient Enantio-selective Reduction of α-Hydroxy Ketones
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The enantioselective reduction of α-hydroxy ketones with catecholborane has been developed employing 5 mol% of an 1,1′-bi-2-naphthol (BINOL)-derived ion-pair organocatalyst. This methodology provides a straightforward access to the corresponding aromatic 1,2-diols in high yields (up to 90%) with excellent enantioselectivities (up to 97%). Furthermore, the α-amino ketones also could be reduced with moderate ee values under mild reaction condition. (Figure presented.).
- Zhang, Yiliang,He, Li,Shi, Lei
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supporting information
p. 1926 - 1931
(2018/03/27)
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- Direct Aerobic Oxidative Reactions of 2-Hydroxyacetophenones
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Valuable and direct aerobic oxidation reactions of 2-hydroxyacetophenones were explored. The concept was based on the in situ treatment of small quantities of aerobically formed α-keto aldehydes that drove the reactions to the corresponding products. This new strategy was applied for a variety of oxidative reactions of 2-hydroxyacetophenones, and valuable products such as phthalides, quinoxalines, and α-keto amides were obtained in good to high yields.
- Sahoo, Subas Chandra,Nath, Utpal,Pan, Subhas Chandra
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supporting information
p. 4434 - 4438
(2017/08/23)
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- Neurotrophin production secretion promoting agent
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A neurotrophin production/secretion promoting agent which comprises an azole derivative of the formula: wherein R1represents a halogen atom, a heterocyclic group which may optionally be substituted, a hydroxy group which may optionally be substituted, a thiol group which may optionally be substituted, or an amino group which may optionally be substituted; A represents an acyl group which may optionally be substituted, a heterocyclic group which may optionally be substituted, a hydroxy group which may optionally be substituted, or a carboxyl group which may optionally be esterified or amidated; B represents an aromatic group which may optionally be substituted; X represents oxygen atom, sulfur atom, or nitrogen atom which may optionally be substituted; and Y represents a divalent hydrocarbon group or heterocyclic group, or a salt thereof; which is useful as an agent for preventing or treating neuropathy.
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- PROCESS FOR THE PREPARATION OF OXAZOLE DERIVATIVES
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A production method of a compound represented by the formula wherein R1 and R2 are each a hydrogen atom, an optionally substituted hydrocarbon group or an optionally substituted heterocyclic group, R3 is an electron-withdr
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- Synthesis of new 2,4-diamino-7H-pyrrolo[2,3-d]pyrimidines via the Taylor ring transformation/ring annulation strategy
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Selected examples 2,4-diamino-7H-pyrrolo[2,3-d]pyrimidines with a phenyl or benzyl group at the 5-position were synthesized as inhibitors of dihydrofolate reductase (DHFR) from Pneumocystis carinii and Toxoplasma gondii, two potentially life-threatening opportunistic pathogens associated with AIDS and other disorders of the immune system. Aldol condensation of paraformaldehyde with substituted benzaldehydes or with phenylacetaldehyde afforded α-hydroxyketones with a phenyl or benzyl group at the 4-position. Further reaction of the hydroxyketones with malononitrile afforded 2-aminofuran-3-carbonitriles, which upon heating with guanidine underwent ring transformation/ring annulation to produce 2,4-diamino-7H-pyrrolo[2,3-d]pyrimidines rather than 2,4-diaminofuro[2,3-d]pyrimidines. One of the target compounds obtained in this manner, 2,4-diamino-5-(3,4,5-trimethoxyphenyl)-7H-pyrrolo [2,3 -d]pyrimidine (1d), may be viewed as a conformationally restricted analogue of trimethoprim, an antimicrobial agent widely used in combination with a sulfa drug to treat P. carinii and T. gondii opportunistic infections in patients with AIDS. Compound 1d inhibited P. carinii and T. gondii DHFR with IC50 values of 8.3 and 14 μM, respectively. This potency was somewhat greater than that of trimethoprim. However, because this compound was also more potent than trimethoprim against mammalian (rat liver) DHFR rat liver it lacked species selectivity. The other 2,4-diamino-7H-pyrrolo[2,3-d]pyrimidines synthesized were neither potent nor selective.
- Rosowsky,Fu,Queener
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p. 1197 - 1202
(2007/10/03)
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- INVESTIGATIONS ON REACTIONS OF CHLORINE DIOXIDE AND SODIUM CHLORITE WITH ORGANIC COMPOUNDS. PART XXXV. REACTIONS OF CHLORINE DIOXIDE WITH RING-SUBSTITUTED STYRENES
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Reactions of chlorine dioxide with ring substituted styrenes (1a-n) in carbon tetrachloride at 52-54 deg C were studied.The reaction products were isolated and characterised.It has been found that methyl-, chloro-, nitrostyrenes and 4-methoxystyrene are attacked by chlorine dioxide exclusively on the vinyl group, to yield the corresponding α-chloroacetophenones (2), diastereoisomers of β-chlorostyrene (6,7), oxidation products (8,9) and some polymers.Oxidation of its phenolic hydroxyl groups and vinyl polymerization took place in hydroxystyrenes.
- Kwiecien, Halina,Jalowiczor, Jozef
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p. 811 - 824
(2007/10/02)
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