Showing papers on "Methyl vinyl ketone published in 2019"

Dual Benzophenone/Copper-Photocatalyzed Giese-Type Alkylation of C(sp3 )-H Bonds.

Abstract: Photocatalyzed Giese-type alkylations of C(sp3 )-H bonds are very attractive reactions in the context of atom-economy in C-C bond formation. The main limitation of such reactions is that when using highly polymerizable olefin acceptors, such as unsubstituted acrylates, acrylonitrile, or methyl vinyl ketone, radical polymerization often becomes the dominant or exclusive reaction pathway. Herein, we report that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone (BP) with a catalytic amount of Cu(OAc)2 . Under mild and operationally simple conditions, the Giese adducts resulting from the C(sp3 )-H functionalization of amines, alcohols, ethers, and cycloalkanes could be synthesized. Preliminary mechanistic studies have revealed that the reaction does not proceed through a radical chain, but through a dual BP/Cu photocatalytic process, in which both CuII and low-valent CuI/0 species, generated in situ by reduction by the BP ketyl radical, may react with α-keto or α-cyano intermediate radicals, thus preventing polymerization.

Formation of Organosulfur Compounds from Aqueous Phase Reactions of S(IV) with Methacrolein and Methyl Vinyl Ketone in the Presence of Transition Metal Ions

Abstract: The catalytic oxidation of S(IV) species by transition metal ions (TMIs) is a significant pathway for aqueous sulfate formation. Sulfoxy radicals, such as SO3–, SO4–, and SO5– radicals, are major i...

Computational Insights into Endo/Exo Selectivity of the Diels-Alder Reaction in Explicit Solvent at Ab Initio Quantum Mechanical/Molecular Mechanical Level.

Abstract: The microscopic insight into the endo/exo stereoselectivity of the Diels–Alder (DA) reaction between cyclopentadiene and methyl vinyl ketone (MVK) has posed a challenge to the computational chemist...

Synthesis of Propargylamines via Michael Addition Using Methyl Vinyl Ketone Derivatives, 1-Alkynes, and Secondary Amines Catalyzed by Copper (I) Halides.

Abstract: Propargylamines are synthesized from methyl vinyl ketone derivatives, 1-alkynes, and secondary amines catalyzed by Cu salts involving the Michael addition of amine followed by an unusual C–C bond c...

trans-2-Pentenal, an Active Compound in Cigarette Smoke, Identified via Its Ability to Form Adducts with Glutathione

Abstract: α,β-Unsaturated carbonyl compounds readily form adducts with SH or NH2 residues, which are nucleophilic agents, by Michael addition. Glutathione (GSH) is a tripeptide that contains an SH residue and functions as an antioxidant. We demonstrated previously that acrolein (ACR), crotonaldehyde (CA), and methyl vinyl ketone (MVK) are present in nicotine- and tar-removed cigarette smoke extract (CSE) and reacted with GSH in B16-BL6 mouse melanoma cells to form GSH-ACR, GSH-CA, and GSH-MVK adducts, suggesting a possible mechanism for CSE-induced cytotoxicity. In this study, we searched for novel α,β-unsaturated carbonyl compounds other than ACR, CA, and MVK. We selected candidate compounds in CSE based on accurate mass values generated using LC/MS analysis of products formed between CSE and GSH, and identified these using GC/MS analysis and library screening. As a result, we isolated trans-2-methyl-2-butenal, 2-methyl-2-cyclopenten-1-one, 3-methyl-2-cyclopenten-1-one, and furfural, which were poorly reactive with GSH and only very weakly inhibited growth of Colon-26 mouse carcinoma cells and BALB/3T3 clone A31 mouse normal cells. We also isolated 2-cyclopenten-1-one, trans-2-pentenal, 3-methyl-2-butenal and ethyl vinyl ketone, which were highly reactive with GSH and significantly inhibited the growth of both cell lines. Our data suggest that the reactivity of compounds in CSE with GSH may be positively correlated with the effect on inhibiting cell growth. Notably, trans-2-pentenal showed marked inhibition of carcinoma cells growth, whereas this compound exhibited little inhibitory effect on normal cells. trans-2-Pentenal may be a potent candidate or seed for antitumor agents.

How to Start a Total Synthesis from the Wieland-Miescher Ketone?

Abstract: Background The Wieland-Miescher ketone consists of a couple of enantiomers of 9-methyl- Δ5(10)-octalin-1,6-dione, in which the configuration at 9-position is S- or R-type. The Robinson annulation of 2-methyl-1,3-cyclohexanedione with methyl vinyl ketone is able to afford the Wieland-Miescher ketone. As widely used in the total synthesis, the Wieland-Miescher ketone is treated at the beginning of total synthesis, and protocols for treating the Wieland-Miescher ketone are worthy to be addressed. Objective The presented review provides the progress of the usage of Wieland-Miescher ketone for the total synthesis, while treatments on C=C and C=O in the Wieland-Miescher ketone at the beginning of total synthesis are exemplified herein. Conclusion Modifications of the Wieland-Miescher ketone are composed of oxidation, reduction, and electrophilic or nucleophilic addition. In addition, protection of non-conjugated C=O with glycol or protection of conjugated C=O with ethanedithiol, and the introduction of substituents into α-position of C=C can also be used to modify the structure of the Wieland-Miescher ketone. It is reasonably believed that many novel strategies will be found to treat the Wieland-Miescher ketone in the future total synthesis.