title: Ruthenium-catalyzed hydrohydroxyalkylation of acrylates with diols and α-hydroxycarbonyl compounds to form spiro- and α-methylene-γ-butyrolactones.
abstract: 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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Emma L
authors.initials: EL
authors.lastname: McInturff
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Mowat
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Waldeck
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Krische
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D000179:Acrylates / Q000737:chemistry*; D000478:Alkylation; D002384:Catalysis; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D012428:Ruthenium / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000179:Acrylates; D013141:Spiro Compounds; C014096:alpha-methylene gamma-butyrolactone; D012428:Ruthenium; D015107:4-Butyrolactone; C035956:methyl acrylate