- Potassium Persulfate Mediated Oxidative Radical Cyclization of 1,3-Dicarbonyl Compounds with Styrenes for the Synthesis of Dihydrofurans
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A potassium persulfate promoted tandem radical addition/cyclization of 1,3-dicarbonyl compounds with styrenes has been developed. This transition-metal-free procedure provides an efficient approach to a diverse set of substituted dihydrofurans in moderate to good yields.
- Wang, Shun,He, Lin-Ye,Guo, Li-Na
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- Mn-Catalyzed Electrochemical Chloroalkylation of Alkenes
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The heterodifunctionalization of alkenes is an efficient method for synthesizing highly functionalized organic molecules. In this report, we describe the use of anodically coupled electrolysis for the catalytic chloroalkylation of alkenes - a reaction that constructs vicinal C-C and C-Cl bonds in a single synthetic operation - from malononitriles or cyanoacetates and NaCl. Knowledge of the persistent radical effect guided the reaction design and development. A series of controlled experiments, including divided-cell electrolysis that compartmentalized the anodic and cathodic events, allowed us to identify the key radical intermediates and the pathway to their electrocatalytic formation. Cyclic voltammetry data further support the proposed mechanism entailing the parallel, Mn-mediated generation of two radical intermediates in an anodically coupled electrolysis followed by their selective addition to the alkene.
- Fu, Niankai,Shen, Yifan,Allen, Anthony R.,Song, Lu,Ozaki, Atsushi,Lin, Song
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p. 746 - 754
(2019/01/11)
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- Organocatalytic Cloke-Wilson Rearrangement: DABCO-Catalyzed Ring Expansion of Cyclopropyl Ketones to 2,3-Dihydrofurans
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An organocatalytic Cloke-Wilson rearrangement of cyclopropyl ketones to 2,3-dihydrofurans is exploited utilizing the homoconjugate addition process. With 1,4-diazabicyclo[2.2.2]octane as the catalyst, the rearrangement in DMSO at 120 °C proceeded in gener
- Zhang, Jingfang,Tang, Yuhai,Wei, Wen,Wu, Yong,Li, Yang,Zhang, Junjie,Zheng, Yuansuo,Xu, Silong
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p. 3043 - 3046
(2017/06/23)
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- Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3-Dicarbonyls and Styrenes: Construction of Five-Membered Heterocycles
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A cooperative indium(III)/silver(I) system for the synthesis of various five-membered heterocycles, including dihydrofurans, pyrroles, spirolactones, and spiroiminolactones, through the sequential oxidative coupling/annulation reaction of 1,3-dicarbonyl compounds with styrenes has been developed. Four different heterocyclic systems were successfully synthesized depending on the substitution pattern of the substrates using readily available starting materials. This system has the advantages of a broad substrate scope, moderate to good chemical yields, an operationally easy and simple procedure, and short reaction times. (Figure presented.) .
- Ko, Tae Yun,Youn, So Won
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supporting information
p. 1934 - 1941
(2016/07/06)
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- Non-decarbonylative photochemical versus thermal activation of Bu4N[Fe(CO)3(NO)] - the Fe-catalyzed Cloke-Wilson rearrangement of vinyl and arylcyclopropanes
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The base metal complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the rearrangement of vinyl and arylcyclopropanes both under thermal or photochemical conditions to give the corresponding vinyl or aryldihydrofurans in good to excellent yi
- Lin, Che-Hung,Pursley, Dominik,Klein, Johannes E. M. N.,Teske, Johannes,Allen, Jennifer A.,Rami, Fabian,K?hn, Andreas,Plietker, Bernd
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p. 7034 - 7043
(2015/11/17)
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- Domino [3+3] annulation/ring-cleavage reactions of 1,3- bis(trimethylsilyloxy)-1,3-butadienes with 5-aryl- and 5-vinyl-3-acyl-4,5- dihydrofurans: Efficient synthesis of 5-(4-chlorobut-2-en-1-yl)- and 5-(2-aryl-2-chloroethyl)salicylates
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The domino "[3+3] cyclization-ring-opening" reactions of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-acetyl-5vinyl-4, 5-dihydrofurans afforded 5-(4-halobut-2-en-1-yl)salicylates. The reactions of 1,3-bis(trimethylsilyloxy)-1,3butadienes with 3-acetyl
- Lau, Matthias,Sher, Muhammad,Villinger, Alexander,Fischer, Christine,Langer, Peter
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experimental part
p. 3743 - 3753
(2010/09/03)
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- Mn(III)-mediated in-cell electrochemical addition of active methylene compounds to olefins: synthetic and mechanistic aspects
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The Mn-mediated in-cell electrochemical addition of active methylene compounds is an interesting alternative to usual chemical methods notably with respect to the amount of manganese salt used.The electrochemical approach however requires the reagent to be readily oxidized in order to be associated with an efficient in situ anodic regeneration process.We have used amperometric measurements to show that the rate constants for the Mn(III)-oxidation of active methylene compounds at 60 deg C range between 10-2 and 1.2 L mol-1 s-1.In this study we show that the addition reaction occurs in the coordination sphere of Mn; this requires the active methylene compound and the olefin to be coordinated to the Mn salt.This aspect can be critical in the electrochemical process insofar as the catalytic manganese salt can sometimes be fully coordinated by only one reagent, either the active methylene compound (eg, 2,4-pentanedione) or the olefin (eg, styrene). - Key words: electrochemistry; manganese(III); addition reaction; free radical
- Nedelec, Jean-Yves,Lachaise, Isabelle,Nohair, Khaddouj,Paugam, Jean Paul,Hakiki, Marjouba
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p. 843 - 849
(2007/10/02)
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- Electronic and Steric Effects in the Addition of Electrophilic 1,3-Dicarbonylalkyl Radicals to Styrenes
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The addition reactions of 1,3-dicarbonylalkyl radicals to ring-substituted styrenes have been kinetically investigated in MeOH and/or MeCN.It has been observed that the rate effect of ring substituents is nearly identical in the reactions of MeCOCHCOMe (1), MeOCOCHCOMe (2) and MeOCOCHCOOMe (4), the ρ value, in MeOH being -0.96, -1.01 and -1.06, respectively.Since the three radicals are relatively strong oxidants and have similar reduction potentials, an important contribution of the transfer structure RCOCHCOR(1-)*CH2CHAr(1+) to the addition transition state is suggested.It has also be found that in the reactions of 1 and 4 with α-alkyl-substituted styrenes the rate of additions is strongly influenced by the nature of the alkyl group, decreasing in the order: Me > Et > i-Pr > t-Bu.The observed effects are much larger than those reported for the corresponding reactions of the nucleophilic cyclohexyl radical.It is suggested that the α-alkyl substituents exert an effect of steric inhibition of resonance thereby ring delocalization of the charge and/or unpaired electron in the transition state is significantly reduced.Delocalization may be more important in the reactions of 1 and 4 than in those of the cyclohexyl radical since it is possible that the former utilizes a transition state occurring later along the reaction coordinate and/or characterized by a larger extent of charge transfer.
- Baciocchi, Enrico,Ruzziconi, Renzo
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p. 4772 - 4778
(2007/10/02)
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- Oxidative Addition of 1,3-Dicarbonyl Compounds to Conjugated Olefins
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A convenient one step synthesis of the 5-aryl- or 5-(1-alkenyl)-4,5-dihydrofurans from 1,3-dicarbonyl compounds and conjugated olefins in the presence of copper(II) chloride/pyridine or copper(II) chloride/pyridine/oxygen is reported.
- Vinogradov, Maxim G.,Kondorsky, Alexander E.,Nikishin, Gennady I.
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- Regioselective Synthesis of Dihydrofurans from 2,2-Dibromo 1,3-Diones and Olefins Using Copper
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2,2-Dibromo 1,3-diones reacted with copper powder and olefin to give 2,3-dihydrofuran derivatives in a highly regioselective fashion.Acetylenes and 1,3-dienes also reacted with 2,2-dibromo 1,3-diones and copper to afford furan derivatives and 2-vinyl-2,3-
- Yoshida, Jun-ichi,Yano, Shinji,Ozawa, Tadahiro,Kawobata, Nariyoshi
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p. 3467 - 3473
(2007/10/02)
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- The Facile Synthesis of Dihydrofurans by the Oxidation of Olefins with Tris(2,4-pentanedionato)manganese(III)
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Eleven olefins were oxidized with tris(2,4-pentanedionato)manganese(III) at the reflux temperature to give the corresponding 3-acetyl-2-methyl-4,5-dihydrofurans in good yields.The oxidation of 9-benzylidene-9,10-dihydroanthracene under the same reaction conditions did not produce the corresponding dihydrofuran, but 9--9,10-dihydroxyanthracene.When 1,1-diphenylethene was oxidized at room temperature, 3-acetyl-2-hydroperoxy-2-methyl-5,5-diphenyltetrahydrofuran was obtained in a high yield.The effects of the solvent and the additives on the yield of dihydrofuran, the comparable reactivities of other (2,4-pentanedionato)metal complexes, such as Co(III), Cr(III), Fe(III), and Cu(II), and the reaction mechanism are discussed.
- Nishino, Hiroshi
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p. 1922 - 1927
(2007/10/02)
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- REGIOSELECTIVE SYNTHESIS OF DIHYDROFURANS FROM 2,2-DIBROMO-1,3-DIKETONE AND OLEFIN USING COPPER
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2,2-Dibromo-1,3-diketones reacted with copper powder and olefin to give 4,5-dihydrofuran derivatives in a highly regioselective fashion.
- Yoshida, Jun-ichi,Yano, Shinji,Ozawa, Tadahiro,Kawabata, Nariyoshi
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p. 2817 - 2820
(2007/10/02)
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