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.

Synthesis of functionalized alkyl substituted benzoquinones by Rh-catalyzed additions of boronic acids

Abstract: A general synthetic route to γ-oxo alkyl or α-hydroxy benzyl 2-substituted benzoquinones has been developed through a one-pot Rh-catalyzed C–C bond formation/oxidative demethylation sequence from 2,5-dimethoxy aryl boronic acids and several electron deficient alkenes or aldehydes. The process allows rapid access to functionalized benzoquinones under very mild conditions and good yields. We disclose the first example of a Rh-catalyzed 1,4-addition reaction of benzoquinonyl boronic acid to methyl vinyl ketone and other conjugate acceptors, which allows the direct synthesis of 2-(γ-functionalized alkyl) substituted benzoquinones.

The Mizoroki-Heck reaction in organic and aqueous solvents promoted by a polymer-supported Kaiser oxime-derived palladacycle

Abstract: A polystyrene-supported palladacycle derived from Kaiser oxime resin 3 is examined in organic and aqueous media used for the Mizoroki-Heck reactions. The couplings are efficiently performed in the presence of polymeric palladacycles in DMF, aqueous DMA, or water at relatively moderate temperature (110-130 oC) similarly to that in the presence of dimeric 4- hydroxyacetophenone 6 and 4-nitrobenzophenone oxime 2 palladacycles. Different acrylic, crotonic, and cinnamic acid derivatives as well as styrenes are arylated with aryl iodides, bromides, and chlorides with high efficiency. Enone precursors of 4-(p-hydroxyphenyl) and 4- (p-methoxy)phenylbutan-2-one, which are natural odorous products extracted from Aloe wood with raspberry scent, have been prepared by arylation of methyl vinyl ketone. Methylated resveratrol and the anti-cancer agent DMU-212 ((E)-3,4,5,4'-tetramethoxystilbene) have been prepared in high yields. Related Mizoroki-Heck reactions of o-halobenzaldehydes and o- iodoaniline with tolane afforded indenone and indol derivatives, respectively. XPS analysis of the starting and recycled polymer indicated that contains exclusively Pd(II). In addition, poisoning studies with Hg(0) of the reaction mixture stop the process indicating that the palladacycle acts as source of Pd(0) species. Recycling experiments are performed in organic and aqueous solvents with relatively low palladium leaching from the polymer (0.4-5% in DMF and 2-2.7% in H2O). ICP-OES analyses also indicate very low levels of Pd in the isolated crude products (2.9-37.2 ppm).

Nitropyrazoles 16. The use of methoxymethyl group as a protecting group for the synthesis of 4-methyl-3-nitro-5-R-pyrazoles

Abstract: 4-Methyl-3,5-dinitropyrazole prepared by nitration of 1,4-dimethylpyrazole readily reacts with methoxymethyl chloride and methyl vinyl ketone in acetonitrile in the presence of a base giving 1-methoxymethyl-4-methyl-3,5-dinitropyrazole and 4-methyl-3,5-dinitro-1-(3-oxobutyl)pyrazole, respectively. The action of the thioglycolanilide anion on 4-methyl-3,5-dinitro-1-(3-oxobutyl)pyrazole results only in the removal of 1-protecting group and the formation of 2-[(3-oxobutyl)thio]acetanilide, while the action of anionic S-nucleophiles on 1-methoxymethyl-4-methyl-3,5-dinitropyrazole leads to the substitution products of the 5-NO2 group in which the methoxymethyl group can be removed by acid hydrolysis.

3-Aryl-5-vinyl-2-isoxazolines and 3-Aryl-5-vinylisoxazoles from Aryl Nitrile Oxides and Methyl Vinyl Ketone Lithium Enolate: Reaction Limits and Synthetic Utility Exploitation

Abstract: 3-Aryl-5-hydroxy-5-vinyl-2-isoxazolines were synthesized by reacting aryl nitrile oxides with the lithium enolate of methyl vinyl ketone (MVK) at –78 °C. Fair to good yields are obtained in the case of aryl nitrile oxides bearing electron-withdrawing groups on the aryl moiety or less bulky groups. Conversely, lower yields or no reaction was observed in the presence of hindered aryl nitrile oxides. Such a behavior was confirmed by ab initio calculations of the activation energies for three reactions. A number of 3-aryl-5-vinylisoxazoles were quantitatively obtained by dehydration/aromatization of the corresponding 5-hydroxy-2-isoxazolines under acidic conditions. The side-chain elaboration is reported as a synthetic utility of some vinylisoxazoles and vinylisoxazo­lines.