- Rapid assembly of 3-azidomethylfurans from 2-(1-alkynyl)-2-alken-1-ones enabled by silver catalysis
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A rapid access to useful 3-azidomethylfurans is developed via Ag(I)-catalyzed cascade annulation/azidation of 2-(1-alkynyl)-2-alken-1-ones. The salient features of the protocol include mild reaction conditions, high efficiency, broad substrate scope, and
- Qian, Lei-Lei,Yi, Ruxia,Min, Xiang-Ting,Hu, Yan-Cheng,Wan, Boshun,Chen, Qing-An
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- Gold(I)-Catalyzed Highly Diastereo- and Enantioselective Cyclization–[4+3] Annulation Cascades between 2-(1-Alkynyl)-2-alken-1-ones and Anthranils
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This work reports gold-catalyzed [4+3]-annulations of 2-(1-alkynyl)-2-alken-1-ones with anthranils to yield epoxybenzoazepine products with excellent exo-diastereoselectivity (dr>25:1). The utility of this new gold catalysis is manifested by applicable substrates over a broad scope. More importantly, the enantioselective versions of these [4+3]-cycloadditions have been developed satisfactorily with chiral gold catalysts under ambient conditions (DCM, 0 °C); the ee levels range from 88.0–99.9 %. With DFT calculations, we postulate a stepwise pathway to rationalize the preferable exo-stereoselection.
- Chao, Tzu-Hsuan,Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Liu, Rai-Shung
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supporting information
p. 10396 - 10400
(2020/04/29)
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- Gold(I)-Catalyzed Reactions between 2-(1-Alkynyl)-2-alken-1-ones and Vinyldiazo Ketones for Divergent Synthesis of Nonsymmetric Heteroaryl-Substituted Triarylmethanes: N-versus C-Attack Paths
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Gold-catalyzed synthesis of nonsymmetrical heteroaryl-substituted triarylmethanes using 2-(1-alkynyl)-2-alken-1-ones and vinyldiazo ketones is described. In this catalytic sequence, vinyldiazo ketones attack gold-containing 3-furylbenzyl cations to form the observed C(1)-addition products. We also note that vinyldiazo ketones can be thermally cyclized to yield pyrazole derivatives, which can react with 3-furylbenzyl cations to afford pyrazole-containing triarylmethanes, corresponding to a N(5)-addition path.
- Kardile, Rahul Dadabhau,Liu, Rai-Shung
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supporting information
p. 8229 - 8233
(2020/11/03)
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- Organocatalytic Formation of Chiral Trisubstituted Allenes and Chiral Furan Derivatives
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A novel reaction that provides chiral allenes by amino catalytic activation of either aldehydes or α,β-unsaturated aldehydes for reaction with alkynyl-substituted enones is presented. The reaction forms a variety of trisubstituted allenes in high yields a
- Poulsen, Pernille H.,Li, Yang,Lauridsen, Vibeke H.,J?rgensen, Danny K. B.,Palazzo, Teresa A.,Meazza, Marta,J?rgensen, Karl Anker
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supporting information
p. 10661 - 10665
(2018/07/30)
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- Sc(OTf)3-Catalyzed Diastereoselective Formal [3+2] Cycloaddition Reactions of Alkynylcyclopropane Ketones with Electron-Rich Aromatic Aldehydes to Yield 2,5-trans-Tetrahydrofurans
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In contast to the general [4+2] cycloaddition reactions of alkynylcyclopropane ketones reported in the literature, we report herein a Sc(OTf)3-catalyzed formal intermolecular [3+2] cycloaddition reaction of alkynylcyclopropane ketones with elec
- Zhang, Chi,Xu, Muyun,Ren, Jun,Wang, Zhongwen
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p. 2467 - 2478
(2016/06/01)
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- Experimental and Theoretical Study of an Intramolecular CF3-Group Shift in the Reactions of α-Bromoenones with 1,2-Diamines
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The reactions of trifluoromethylated 2-bromoenones and N,N′-dialkyl-1,2-diamines have been studied. Depending on the structures of the starting compounds, the formation of 2-trifluoroacetylpiperazine or 3-trifluoromethylpiperazine-2-ones was observed. The mechanism of the reaction is discussed in terms of multistep processes involving sequential substitution of bromine in the starting α-bromoenones and intramolecular cyclization of the captodative aminoenones as key intermediates to form the target heterocycles. The results of theoretical calculations are in perfect agreement with the experimental data. The unique role of the trifluoromethyl group in this reaction is demonstrated.
- Muzalevskiy, Vasily M.,Ustynyuk, Yury A.,Gloriozov, Igor P.,Chertkov, Vyacheslav A.,Rulev, Alexander Yu.,Kondrashov, Evgeniy V.,Ushakov, Igor A.,Romanov, Alexey R.,Nenajdenko, Valentine G.
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p. 16982 - 16989
(2015/11/16)
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- Chemoselective C-C bond cleavage of epoxide motifs: Gold(I)-catalyzed diastereoselective [4+3] cycloadditions of 1-(1-Alkynyl)oxiranyl ketones and nitrones
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Cutting carbon! A novel facile strategy for the C-C bond cleavage of oxiranyl ketones has been developed. Carbophilic gold(I) activation of the alkyne side chain mediates a heterocyclization and subsequent C-C bond cleavage (see scheme).
- Wang, Tao,Zhang, Junliang
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- Cascade palladium-catalyzed direct intramolecular arylation/alkene isomerization sequences: Synthesis of indoles and benzofurans
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One route, two cycles: A palladium-catalyzed intramolecular direct arylation reaction combined with an isomerization step provided a straightforward synthetic route to both indoles and benzofurans (see scheme). Isolation and functionalization of intermedi
- Yagoubi, Myriam,Cruz, Ana C. F.,Nichols, Paula L.,Elliott, Richard L.,Willis, Michael C.
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supporting information; experimental part
p. 7958 - 7962
(2011/01/11)
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- Solvolytic stereoselective debromination of vic-dibromides with HMPA
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A simple and efficient procedure for the debromination of vic-dibromides has been reported with hexamethylphosphoric triamide at 155-160°C under a nitrogen atmosphere without the aid of any reagent.
- Khurana,Bansal,Chauhan
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p. 1089 - 1091
(2007/10/03)
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- New Derivatives of N-Vinyltriazoles: 1,3-Diaryl-3-(1H-1,2,4-triazol-1-yl)-2-propen-1-ones
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We have synthesized previously unknown N-vinyltriazoles: 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)-2-propen-1-ones.We discusss a hypothesis for a probable reaction mechanism.
- Rekhter, M. A.,Grushetskaya, G. N.,Panasenko, A. A.,Krimer, M. Z.
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p. 792 - 796
(2007/10/03)
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- Methoxide-induced fragmentation of 2,2,3-trihalogeno- and 2,2-dihalogeno-3-methoxy-1,3-diphenylpropanones
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The reaction of 2,2,3-trihalogeno-1,3-diphenylpropanones with sodium methoxide in methanol occurs with exclusive formation of fragmentation products.Kinetic and stereochemical evidence is interpreted in terms of a concerted intramolecular process promoted by initial attack of methoxide anion at the carbonyl carbon.In the case of 2,2-dihalogeno-3-methoxy-1,3-diphenylpropanones the reaction gives fragmentation, rearrangement, and elimination products.The former products are believed to be formed through competing reactions involving an intermediate formed on addition of methoxide to the substrate.For the fragmentation pathway the results are consistent with a carbanionic-intermediate mechanism.
- Montani, Rosana S.,Garay, Raul O.,Cabaleiro, Mercedes C.
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p. 1125 - 1130
(2007/10/02)
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- E1cB Elimination from 2-Halogeno-3-methoxy-1,3-diphenylpropan-2-ones
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Kinetic and stereochemical evidence has been obtained from the dehydromethoxylation of 2-halogeno-3-methoxy-1,3-diphenylpropan-2-ones with isopropoxide in isopropyl alcohol that is consistent with an E1cB reversible mechanism.The influence of the halogen both on the deprotonation rate and upon the methoxy-group expulsion has been evaluated.
- Cabaleiro, Mercedes C.,Garay, Raul O.
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p. 179 - 180
(2007/10/02)
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- SOLVENT SHIFTS INDUCED BY DIMETHYLSULPHOXIDE IN α-PROTON MAGNETIC RESONANCES OF CARBONYL COMPOUNDS
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The chemical shifts of α- and β-proton resonances of a number of carbonyl compounds in carbon tetrachloride and dimethylsulphoxide have been determined.The magnitude of the effect of the solvent change on the α-proton resonances seems to vary directly wit
- Cabaliero, M. C.,Giagante, N. N.
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p. 1829 - 1832
(2007/10/02)
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