65284-00-6Relevant academic research and scientific papers
A synthesis of cephalostatin 1
Shi, Yong,Xiao, Qing,Lan, Quan,Wang, Da-Hai,Jia, Lan-Qi,Tang, Xiao-Hu,Zhou, Tao,Li, Min,Tian, Wei-Sheng
, p. 1722 - 1738 (2019)
A synthesis of cephalostatin 1 from hecogenin is described in detail. The gram-scale synthesis of south part features a Baeyer–Villiger oxidation of hecogenin to 16,20-diol, a selective oxidation of C16–OH with Dess–Martin periodinane, a Rh(I)-catalyzed C15–C16 double bond shift to C14–C15 position, and a Hg(OAc)2-mediated spiroketal formation from cyclic enol ethers with alkenyl side chain at 2-position. Key transformations in the synthesis of north part, also on gram scale, include an abnormal Baeyer–Villiger oxidation of hecogenin to the corresponding dinorcholanic lactone, where a catalytic amount of iodine acts as a traceless and catalytic switch, an umpolung of steroidal 22-aldehyde to forge C22–C23 bond with good stereochemical control, a cascade spiroketal-forming process to establish DEF rings in one operation, and a selective oxidation of C3–OH. There are also other noteworthy transformations that, although not used in our final route, are valuable and could be applied to other syntheses, including: intra- or intermolecular SN2′ processes of C14-heteroatom-substituted C15–C16 alkenes, an unprecedented rearrangement of β-adduct of D-ring dienes and singlet oxygen, a chelation-controlled methylallylation of C23 aldehyde, and so on.
A CONTRATHERMODYNAMIC EPIMERIZATION OF A 2,3-TRANS-DISUBSTITUTED BUTYROLACTONE: INTERMEDIATES FOR CHIRAL POLYPROPIONATE UNITS.
Ziegler, Frederick E.,Kneisley, Alyssa
, p. 263 - 266 (1985)
A method is described which produces the less thermodynamically stable cis-2,3-disubstituted lactone 8 from its more stable epimer 6.These substances are complementary to aldol and crotyl organometallics in the constrution of chiral polypropionate residues.
Synthesis and olfactory evaluation of optically active β-alkyl substituted γ-lactones and whiskey lactone analogues
Kato, Daiki,Kawasaki, Masashi,Morita, Yuko,Okada, Takuya,Tanaka, Yasuo,Toyooka, Naoki
, (2020/02/22)
Optically active β-alkyl substituted γ-lactones and whiskey lactone analogues were synthesized, and the odor properties were evaluated. During the preparation of the chiral intermediates, we found good reaction conditions for the highly enantioselective esterification of 3-arylmethyl-2-methyl-1-propanols to kinetically resolve them. The results of the olfactory evaluations of the synthesized lactones revealed that the alkyl groups on the γ-lactone rings played an important role for the odor profiles.
Regioselective Hydrogenation of Itaconic Acid to Γ-Isovalerolactone by Transition-Metal Nanoparticle Catalysts
Gowda, Ravikumar R.,Chen, Eugene Y.-X.
, p. 973 - 977 (2019/02/06)
Current methods for hydrogenation of bio-derived itaconic acid (IA) lead to a mixture of isomeric lactone products. Transition-metal nanoparticles (TM-NPs), in situ-generated through thermolysis of TM(0) (Ru, Fe, W, Cr) carbonyls, in particular Ru-NPs, were found to catalyze regioselective hydrogenation of IA by syngas (2 H2/CO) into γ-isovalerolactone (GiVL) in approximately 70 % isolated yield. Key sustainability features of this new route include: a one-pot direct transformation of bio-renewable IA into value-added GiVL selectively, use of inexpensive and renewable syngas in aqueous solution, and development of a supported recyclable NP catalyst system, Al2O3-Ru-NPs.
METHOD FOR REDUCTION OF ORGANIC MOLECULES
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Paragraph 0050; 0052; 0053; 0054; 0055, (2018/02/06)
A method for the reduction organic molecules comprising a Ruthenium-Triphosphine complex with aromatic ligands at the phosphors which are ortho or meta substituted.
METHODS OF FORMING DIOL COMPOUNDS
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Paragraph 0115, (2017/11/06)
Methods of forming a C4 to C7 diol compound, the methods including a first step of reacting a C4 to C7 dicarboxylic acid with hydrogen (H2) gas on a first heterogeneous catalyst at a first temperature and a first pressure to form a C4 to C7 lactone; and a subsequent step of reacting the lactone with hydrogen (H2) gas on a second heterogeneous catalyst at a second temperature and a second pressure, wherein the second temperature is lower than the first temperature. Also disclosed are methods of forming a solvent, the methods including reacting a C4 to C7 dicarboxylic acid with hydrogen (H2) gas on a first heterogeneous catalyst at a first temperature and a first pressure to form a solvent. Further disclosed herein are methods that include reacting mevalonolactone with hydrogen (H2) gas on a second heterogeneous catalyst at a second temperature and a second pressure to form a diol compound.
First chemo-enzymatic synthesis of the (R)-Taniguchi lactone and substrate profiles of CAMO and OTEMO, two new Baeyer–Villiger monooxygenases
Rudroff, Florian,Fink, Michael J.,Pydi, Ramana,Bornscheuer, Uwe T.,Mihovilovic, Marko D.
, p. 157 - 165 (2017/01/17)
Abstract: This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer–Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobutanones and cyclohexanones, regiodivergent oxidation of terpenones and bicyclic ketones, as well as kinetic resolution of racemic cycloketones. We demonstrated the applicability of the title enzymes in the enantioselective synthesis of (R)-(?)-Taniguchi lactone, a building block for the preparation of various natural product analogs such as ent-quinine. Graphical abstract: [Figure not available: see fulltext.]
Direct hydrogenation of biobased carboxylic acids mediated by a nitrogen-centered tridentate phosphine ligand
Deng, Li,Kang, Bin,Englert, Ulli,Klankermayer, Jürgen,Palkovits, Regina
, p. 177 - 180 (2016/02/05)
A novel nitrogen-centered tridentate ligand was identified from a series of multidentate ligands and applied for the direct hydrogenation of 9 biogenic acids into alcohols, lactones and esters with high yields. Comparison of substrates and ruthenium precursors suggested that the RuII hydride cationic species was more active to transform acids than the corresponding lactone or esters.
Branched Diol Monomers from the Sequential Hydrogenation of Renewable Carboxylic Acids
Spanjers, Charles S.,Schneiderman, Deborah K.,Wang, Jay Z.,Wang, Jingyu,Hillmyer, Marc A.,Zhang, Kechun,Dauenhauer, Paul J.
, p. 3031 - 3035 (2016/10/11)
A prominent challenge in replacing petrochemical polymers with bioderived alternatives is the efficient transformation of biomass into useful monomers. In this work, we demonstrate a practical process for the synthesis of multifunctional alcohols from five- and six-carbon acids using heterogeneous catalysts in aqueous media. Design of this process was guided by thermodynamic calculations, which indicate the need for two sequential high-pressure hydrogenations: one, reduction of the acid to a lactone at high temperature; two, further reduction of the lactone to the corresponding diol or triol at low temperature. For example, the conversion of mesaconic acid into (α or β)-methyl-γ-butyrolactone was achieved with 95 % selectivity at a turnover frequency of 1.2 min?1 over Pd/C at 240 °C. Subsequent conversion of (α or β)-methyl-γ-butyrolactone into 2-methyl-1,4-butanediol was achieved with a yield of 80 % with Ru/C at 100 °C. This process is an efficient method for the production of lactones, diols, and triols, all valuable monomers for the synthesis of bioderived branched polyesters.
A sustainable process for the production of 2-methyl-1,4-butanediol by hydrogenation of biomass-derived itaconic acid
Liu, Xiaoran,Wang, Xicheng,Liu, Qiang,Xu, Guoqiang,Li, Xuemin,Mu, Xindong
, p. 88 - 93 (2016/07/06)
Pd-ReOx/C catalysts with different Re contents were prepared and employed to catalyze the aqueous hydrogenation of itaconic acid in this study. The Pd-ReOx/C catalysts were characterized by XRD, TEM, BET, NH3-TPD and H2-TPR. Results showed that the addition of ReOx species in supported Pd catalysts promoted the direct conversion of itaconic acid to 2-methyl-1,4-butanediol. The promoting effect was ascribed to the interaction between Pd and ReOx species, as has been proved by the characterizations. A 2-methyl-1,4-butanediol yield of above 80% could be obtained over Pd-3ReOx/C under the reaction condition of 180 °C, 4 MPa H2.
