52896-91-0Relevant articles and documents
Hydrodeoxygenation of the angelica lactone dimer, a cellulose-based feedstock: Simple, high-yield synthesis of branched C7-C10 gasoline-like hydrocarbons
Mascal, Mark,Dutta, Saikat,Gandarias, Inaki
, p. 1854 - 1857 (2014)
Dehydration of biomass-derived levulinic acid under solid acid catalysis and treatment of the resulting angelica lactone with catalytic K 2CO3 produces the angelica lactone dimer in excellent yield. This dimer serves as a novel feedstock for hydrodeoxygenation, which proceeds under relatively mild conditions with a combination of oxophilic metal and noble metal catalysts to yield branched C7-C10 hydrocarbons in the gasoline volatility range. Considering that levulinic acid is available in >80 % conversion from raw biomass, a field-to-tank yield of drop-in, cellulosic gasoline of >60 % is possible. Fuel for thought: Biomass-derived levulinic acid can be converted in three simple steps via the angelica lactone dimer into branched, gasoline-range hydrocarbons in high yield by using a combination of oxophilic metal and noble metal catalysts (see scheme). Copyright
Hydrogen Atoms as Convenient Synthetic Reagents: Mercury-Photosensitized Dimerization of Functionalized Organic Compounds in the Presence of H2
Muedas, Cesar A.,Ferguson, Richard R.,Brown, Stephen H.,Crabtree, Robert H.
, p. 2233 - 2242 (2007/10/02)
Hydrogen atoms are generated by mercury photosensitization in an unexceptional apparatus that makes them readily available for organic chemistry on a preparatively useful scale at 1 atm of pressure and temperatures from 0-150 °C. The H atoms add to CH2=CH-CH2X to give the intermediate radical CH3-(?CH)-CH2X, which dimerizes to give CH3CH(CH2X)-CH(CH2X)CH3. The saturated substrates CH3CH2CH2X undergo H abstraction to give CH3CH2(?CH)X as intermediates and CH3CH2CH(X)-CH(X)CH2CH3 as final products. The reaction shows a tolerance for different functional groups, X, which may be an alkyl or fluoroalkyl chain or contain vinyl, epoxy, ester, ketone, nitrile, and silyl groups. Radical disproportionation products are also formed but are easily separated. H atoms attack the weakest C-H bonds of the substrates with high selectivity. In our earliest direct mercury photosensitization, Hg* often failed to attack the substrate C-H bonds to give dimers; the presence of H2 strongly suppresses direct Hg* chemistry. H atoms are not sensitive to steric or polar effects Radical fragmentation is avoided by using "high" pressures (1 atm). Intramolecular radical additions to C=C bonds and methyl group 1,2-shift were also seen in some cases. Exceptional product ratios are observed for cross-reactions involving hydroxyalkyl radicals where H-bonding favors the homodimers in certain cases. Several bond strengths of C-H bonds α to CO were determined: EtCO2Me, 94.5; i-PrCO2Me, 92.7; cyclopentanone, 94.3; (i-Pr)2CO, 91.9 kcal/mol.
