6053-54-9Relevant articles and documents
Ruthenium-catalyzed hydrohydroxyalkylation of acrylates with diols and α-hydroxycarbonyl compounds to form spiro- and α-methylene-γ- butyrolactones
McInturff, Emma L.,Mowat, Jeffrey,Waldeck, Andrew R.,Krische, Michael J.
supporting information, p. 17230 - 17235 (2013/12/04)
Under the conditions of ruthenium(0)-catalyzed hydrohydroxyalkylation, vicinal diols 1a-1l and methyl acrylate 2a are converted to the corresponding lactones 3a-3l in good to excellent yield. The reactions of methyl acrylate 2a with hydrobenzoin 1f, benzoin didehydro-1f, and benzil tetradehydro-1f form the same lactone 3f product, demonstrating that this process may be deployed in a redox level-independent manner. A variety of substituted acrylic esters 2a-2h participate in spirolactone formation, as illustrated in the conversion of N-benzyl-3-hydroxyoxindole 1o to cycloadducts 4a-4h. Hydrohydroxyalkylation of hydroxyl-substituted methacrylate 2i with diols 1b, 1f, 1j, and 1l forms α-exo-methylene-γ-butyrolactones 5b, 5f, 5j, and 5l in moderate to good yield. A catalytic cycle involving 1,2-dicarbonyl-acrylate oxidative coupling to form oxaruthenacyclic intermediates is postulated. A catalytically competent mononuclear ruthenium(II) complex was characterized by single-crystal X-ray diffraction. The influence of electronic effects on regioselectivity in reactions of nonsymmetric diols was probed using para-substituted 1-phenyl-1,2-propanediols 1g, 1m, and 1n and density functional theory calculations.
Studies toward the Syntheses of Functionally Substituted γ-Butyrolactones and Spiro-γ-butyrolactones and Their Reaction with Strong Acids: A Novel Route to α-Pyrones
Mandal, A.K.,Jawalkar, D.G.
, p. 2364 - 2369 (2007/10/02)
A general strategy for the conversion of 5-keto carboxylic acids, 6 (via their enol-lactones 7), to a variety of γ-lactones, 8a-c, and spiro-γ-lactones, 8d-g, is described.Lactones 8b and 8d,e may be further converted into the corresponding α-pyrones, 17b and 17d,e, respectively, in the presence of strong acids.
