Oxidative cyclization of 3-oxopropanenitriles with α,β-unsaturated amides by manganese(III) acetate. Regio- and stereoselective synthesis of 4-cyano-2,3-dihydrofuran-3-carboxamides
TL;DR: In this article, 4-Cyano-2,3-dihydrofuran-3-carboxamides were obtained from the oxidative cyclization of 3-oxopropanenitriles with unsaturated amides using manganese(III) acetate.
About: This article is published in Tetrahedron.The article was published on 2007-07-23. It has received 53 citations till now. The article focuses on the topics: Manganese(III) acetate & Acrylamide.
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TL;DR: H NMR spectroscopy and single-crystal analysis demonstrated that the obtained 2,3-dihydrofurans are trans isomers.
Abstract: An efficient synthetic procedure for the preparation of fused 2,3-dihydrofuran derivatives was developed with the assistance of pyridinium ylide. A sequential one-pot, two-step tandem reaction starting from pyridine, aromatic aldehyde, dimedone, or 4-hydroxycoumarin and alpha-phenacyl bromide or p-nitrobenzyl bromide with triethylamine as catalyst proceeded smoothly in acetonitrile. (1)H NMR spectroscopy and single-crystal analysis demonstrated that the obtained 2,3-dihydrofurans are trans isomers.
139 citations
TL;DR: A review of manganese(III) acetate mediated free-radical reactions can be found in this paper, where a wide range of protocols have been developed for the synthesis of biologically active and important organic molecules through oxidation, addition and cyclization reactions, which are in general difficult to achieve by the established synthetic operations.
Abstract: The preceding four decades have witnessed a major expansion in the field of free-radical assisted reactions, as they are becoming a key tool in organic, polymer and complex natural product chemistry. This progress has clearly changed the traditional idea of free-radical reactions being “extremely uncontrollable”, thereby allowing chemists to deal with free radicals in a more accurate and controlled way. Manganese(III) acetate mediated radical reactions have reached distinction in this field, as a wide range of protocols involving manganese(III) acetate under mild and efficient reaction conditions have been developed for the synthesis of biologically active and important organic molecules through oxidation, addition and cyclization reactions, which are in general difficult to achieve by the established synthetic operations. The present review focuses on manganese(III) acetate mediated oxidative free-radical reactions that have been developed and adapted during the last five years. It includes the advancements made in the field of free-radical promoted carbon–carbon and carbon–oxygen bond forming reactions, illustrating the examples of furans, hydrofurans, pyrroles, bicyclic lactones, biaryls, oxepins, indole-alkaloids, 1,2-benzanthracene and C60-fused tetrahydronaphthalene synthesis. Numerous manganese(III) acetate initiated carbon–phosphorus bond formation reactions were also devised during recent years, involving both phosphonyl and phosphinoyl radicals, and are a key part of this review. Manganese(III) acetate promotes functionalization of significant organic compounds, thereby guiding the synthesis of important and complex molecules, such as the formation of propellanes, quinolinones, 1,2-dioxalanes; oxidation of indoles; lactonization of fullerene [C60], malonyl cyclopentanes, glycols; and hydroperoxidation of heterocycles. The review will also envelop several recent milestones that have been achieved in the chemistry of natural products precising the vital role of manganese(III) acetate in the key synthetic steps.
124 citations
TL;DR: An efficient methodology for the oxidative addition reaction of various aldehydes with 5,5-dimethylcyclohexane-1, 3-dione and 1,3-indandione to selectively afford spiro dihydrofuran and cyclopropane derivatives under mechanical milling conditions has been demonstrated.
82 citations
TL;DR: The triphenylphosphine-catalyzed formal [3 + 2] cycloaddition of allenoates and trifluoromethylketones was realized to give the corresponding dihydrofurans in good yields with excellent γ-regioselectivities.
Abstract: The triphenylphosphine-catalyzed formal [3 + 2] cycloaddition of allenoates and trifluoromethylketones was realized to give the corresponding dihydrofurans in good yields with excellent γ-regioselectivities. Hydrogenation of the dihydrofurans gave 2,4,4-trisubstituted tetrahydrofurans in good yields with exclusive cis-selectivities.
54 citations
TL;DR: It was proposed that the process for the formation of 2 must include the 1,2-aryl radical rearrangement followed by oxidative decarboxylation.
Abstract: The oxidation of monoalkyl 2-(9H-xanthenyl)malonates 1 with Mn(OAc)3 gave the 9- or 10-dibenz[b,f]oxepincarboxylates 2 in good yields. The reaction proceeds with high regioselectivity except for the case of (1-methoxyxanthenyl)malonate 1 (R1 = Me, R2 = 1-MeO), which gave two regioisomers. It was proposed that the process for the formation of 2 must include the 1,2-aryl radical rearrangement followed by oxidative decarboxylation.
45 citations
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622 citations
TL;DR: Manganese-III mediated reactions of unsaturated systems with carbonyl compounds are discussed in this paper which focuses mainly on publications of the last decade, and the process on the whole is highly selective both at the initiation and functionalization steps.
Abstract: Manganese(III) mediated reactions of unsaturated systems with carbonyl compounds are discussed in this review which focuses mainly on publications of the last decade. The process on the whole is highly selective both at the initiation and functionalization steps. Manganese(III) acetate generates α-oxo- and α,α-dioxoalkyl radicals by regioselective oxidation of carbonyl compounds, such as, aldehydes, ketones, acids, diketones, keto esters, and diesters. The functionalization step, which consists of the introduction of α-oxo- and α,α-dioxoalkyl moieties into multiple bond containing substrates, occurs in most cases with high regio-, chemo- and stereoselectivities
138 citations
TL;DR: In this paper, the role of l'anhydride acetique in the synthesis of cycliques and cycliques has been investigated, and the stereoselectivite de l'addition a divers alcanes acycliques et cycliques is discussed.
Abstract: L'annelation d'un cycle γ-lactone sur un alcene par oxydation par l'acetate de manganese(III) de l'acide acetique est etudiee. La regioselectivite de l'addition a des alcenes substitues de facon non symetrique ainsi que la stereoselectivite de l'addition a divers alcanes acycliques et cycliques sont rapportees. Le role de l'anhydride acetique dans ces reactions est etudie
126 citations
TL;DR: In this paper, the cyclisation par l'acetate de manganese III de cetoacides ou d'alcoxycarbonylacides en γ-lactones is described.
Abstract: Etude de la cyclisation par l'acetate de manganese III de cetoacides ou d'alcoxycarbonylacides en γ-lactones: par exemple cyclisation de l'acide cyclohexene-2 acetylacetique en perhydro cyclopenta [cd] benzofurannone-2; application au malonate de cyclohexene-2yle a l'acide methyl-7 oxo-3 octene-6oique, a l'acide β-oxo cyclohexene-3 propionique et a l'acide cyclopentene-2 acetylacetique (obtention de perhydro furo [4,3,2-cd] benzofurannedione, d'oxatricyclododecanedione, de perhydro cyclopenta [c] furannedione-1,6, de perhydro indeno [1,6-bc] furannedione-2,3 et de perhydro indeno [2,1-b:6,1-b'-c'] difurannedione
118 citations