65717-27-3Relevant articles and documents
Synthesis of bicyclic γ-butyrolactone derivatives by rhodium catalyzed intramolecular C-H insertion of α-dizao α-phosphoryl cycloalkyl esters
Shie, Jr-Yun,Zhu, Jia-Liang
, p. 1590 - 1601 (2016)
Under the catalysis of Rh2(OAc)4, several readily prepared cycloalkyl α-diazo α-phosphoryl esters undergo a intramolecular C-H insertion reaction to afford the fused bicyclic α-phosphoryl-γ-butyrolactones in varying yields (10%-80%) and dr ratios (69:14:17 to >99:1). The experimental results reveal that the reactivity of the precursors and the diastereoselectivity of the cyclization are both influenced by the ring sizes of the cycloalkyl moieties. Moreover, most of the resulting products can be further elaborated into α,α-dialkyl γ-butyrolactones via a two-step alkylation/reductive alkylation sequence with the controlled installation of two alkyl groups to the lactones. In addition, application of Horner-Wadsworth-Emmons (HWE) olefination reaction to the insertion products allows an access to bicyclic α-alkylidene-γ-butyrolactone ring systems that occur ubiquitously in biologically active natural products and synthetic molecules.
Convenient general asymmetric synthesis of roche ester derivatives through catalytic asymmetric hydrogenation: Steric and electronic effects of ligands
Pautigny, Cyrielle,Jeulin, Severine,Ayad, Tahar,Zhang, Zhaoguo,Genet, Jean-Pierre,Ratovelomanana-Vidal, Virginie
supporting information; experimental part, p. 2525 - 2532 (2009/09/07)
An efficient and concise asymmetric hydrogenation of acrylate esters promoted by the cationic ruthenium monohydride complex [Ru(H) (hη6-cot)SYNPHOS]+BF44- is reported. A full investigation of the effects of catalyst precursors, solvents, temperature, hydrogen pressure, substrates as well as steric and electronic properties of ligands was carried out. The corresponding valuable Roche ester derivatives were obtained in good to excellent isolated yields and high enantioselectivities under mild conditions. The robustness and practicability of this highly enantioselective hydrogenation was demonstrated by the synthesis of the 3-hydroxy-2-methylpropanoic acid tert-butyl ester on a multigram scale, resulting in excellent yield and ee up to 94%.
