Methyl vinyl ketone

About: Methyl vinyl ketone is a research topic. Over the lifetime, 1510 publications have been published within this topic receiving 26839 citations. The topic is also known as: 3-buten-2-one & gamma-oxo-alpha-butylene.

Organocatalytic Sequential One-Pot Double Cascade Asymmetric Synthesis of Wieland−Miescher Ketone Analogues from a Knoevenagel/Hydrogenation/Robinson Annulation Sequence: Scope and Applications of Organocatalytic Biomimetic Reductions

Abstract: A practical and novel organocatalytic chemo- and enantioselective process for the cascade synthesis of highly substituted 2-alkyl-cyclohexane-1,3-diones and Wieland−Miescher (W−M) ketone analogs is presented via reductive alkylation as a key step. First time, we developed the one-step alkylation of dimedone and 1,3-cyclohexanedione with aldehydes and Hantzsch ester through an organocatalytic reductive alkylation strategy. Direct combination of l-proline-catalyzed cascade Knoevenagel/hydrogenation and cascade Robinson annulation of CH acids (dimedone and 1,3-cyclohexanedione), aldehydes, Hantzsch ester, and methyl vinyl ketone furnished the highly functionalized W−M ketone analogues in good to high yields and with excellent enantioselectivities. Many of the reductive alkylation products show a direct application in pharmaceutical chemistry.

QM/MM Simulations for Diels−Alder Reactions in Water: Contribution of Enhanced Hydrogen Bonding at the Transition State to the Solvent Effect†

Abstract: Free energy profiles for Diels−Alder reactions of cyclopentadiene with acrylonitrile, methyl vinyl ketone, and 1,4-naphthoquinone have been computed in the gas phase and in aqueous solution using Monte Carlo simulations in a fully automated, mixed quantum and molecular mechanics (QM/MM) approach. The QM/MM calculations in water featured AM1 treatment for the solute in the presence of 500 TIP4P water molecules, and computation of solute−water interactions using scaled CM1A charges for the solute. Free energy perturbation calculations yielded the profiles along a reaction coordinate with all other degrees of freedom sampled. The free energies of activation are reduced on going from the gas phase to water by 1.5, 2.8, and 4.4 kcal/mol for the reactions with acrylonitrile, methyl vinyl ketone, and naphthoquinone, respectively. These values are in good agreement with the corresponding experimental results for transfer from hydrocarbon solvents to water (2.1, 3.8, and 5.0 kcal/mol). The cycloadducts are stabili...

Chiral Calcium VAPOL Phosphate Mediated Asymmetric Chlorination and Michael Reactions of 3-Substituted Oxindoles

Abstract: We disclose a novel high yielding and highly enantioselective chiral calcium VAPOL phosphate-catalyzed chlorination of 3-substituted oxindoles with N-chlorosuccinimide (NCS) The reaction conditions are also shown to be effective for the catalytic enantioselective Michael addition of 3-aryloxindoles to methyl vinyl ketone

Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

Abstract: A series of experiments have been performed to study the ozone-isoprene reaction in a smog chamber by adding externally produced O_3 to the hydrocarbon in the dark. A chemical tracer, methyl cyclohexane, was added to probe the OH formation in the system. O(^3P) formation was also examined using the known distribution of products that are unique to the O(^3P)-isoprene reaction (part I). The results provide clear evidence that both OH and O(^3P) are produced by the O_3-isoprene reaction directly in large quantities; about 0.68 ± 0.15 and 0.45 ± 0.20 per O_3-isoprene reaction, respectively. These additional radicals severely complicate the analysis of the O_3 reaction, hence, computer kinetic modeling was necessary to ascertain the products of the O_3 reaction itself, corrected for OH and O(^3P) reactions. The product distribution, which differs dramatically from that published previously, is: 67 ± 9% methacrolein, 26 ± 6% methyl vinyl ketone, and 7 ± 3% propene, accounting for 100 ± 10% of the reacted isoprene. Applicability of these results to the gas-phase O_3 reaction with other unsaturated hydrocarbons is briefly discussed.