Β-trifluoromethylated Ketones Research Articles

Electrochemical Oxidative Aryl(alkyl)trifluoromethylation of Allyl Alcohols via 1,2-Migration.

An electrochemical oxidative difunctionalization of allyl alcohols for the synthesis of β-trifluoromethyl ketones is achieved through a 1,2-migration process. A series of β-trifluoromethyl ketones can be facilely obtained utilizing CF3SO2Na as a radical source, eliminating the use of metals and sacrificial chemical oxidants. Importantly, this protocol not only realizes aryl migration but also offers alkyl-migration products. Additionally, an electrochemically catalyzed ring expansion and gram-scale reaction demonstrated the synthetic usefulness of this protocol.

Two-step conversion of carboxylic esters into distally fluorinated ketones via ring cleavage of cyclopropanol intermediates: application of sulfinate salts as fluoroalkylating reagents.

Tertiary cyclopropanols easily available from carboxylic esters have been used in the synthesis of distally fluorinated ketones. Cyclopropane ring cleavage reactions in methanol with aqueous tert-butyl hydroperoxide in the presence of a copper(ii) acetate catalyst and sodium triflinate (Langlois reagent) afford β-trifluoromethyl ketones in 16-74% isolated yields. Sodium triflinate serves as a precursor of reactive trifluoromethyl copper species, enabling ring-opening trifluoromethylation, as evidenced by mechanistic studies. We also demonstrate here that other sulfinate salts, such as sodium 1,1-difluoroethanesulfinate, sodium 2-(4-bromophenyl)-1,1-difluoroethanesulfinate and sodium 1-(trifluoromethyl)cyclopropanesulfinate, can be used as fluoroalkylation reagents, resulting in the corresponding fluorinated ketones.

ChemInform Abstract: Copper‐Catalyzed Ring‐Opening Trifluoromethylation of Cyclopropanols.

AbstractStarting from aryl, hetaryl, alkyl, or alkenyl substituted cyclopropanols a diverse range of synthetically useful β‐trifluoromethyl ketones are prepared, including a drug derivative [cf.

Visible-Light-Induced Photocatalysis of 1,1,1-Trifluoro-2-iodoethane with Alkylalkenes and Silyl Enol Ethers

Reactions of 1,1,1-trifluoro-2-iodoethane with alkylalkenes and silyl enol ethers were performed in the presence of a catalytic amount of fac-Ir(ppy)3 and an excessive amount of Hunig’s base in acetonitrile irradiated by a 24 W fluorescent lamp under nitrogen atmosphere for 48 hours. The visible-light-induced photoredox reactions introduce simultaneously a 2,2,2-trifluoroethyl group and an iodine atom to both sides of the double bond of ordinary alkenes via an atom-transfer radical addition (ATRA). The same reaction with silyl enol ethers generates β-trifluoromethyl ketones, which are typically a challenge to synthesize. The reactions proved to be tolerant of a variety of functionalities.

Copper-catalysed ring-opening trifluoromethylation of cyclopropanols.

A copper-catalysed ring-opening trifluoromethylation reaction of cyclopropanols has been developed. Various β-trifluoromethyl ketones are obtained in good to excellent yields under mild reaction conditions. The present method also exhibits good functional-group compatibility. The mechanism of this new ring-opening trifluoromethylation reaction was investigated by radical trapping reactions.

Simple access to β-trifluoromethyl-substituted ketones via copper-catalyzed ring-opening trifluoromethylation of substituted cyclopropanols.

Tertiary cyclopropanols react rapidly with Togni reagent in methanol at room temperature in the presence of catalytic amounts (3 mol%) of CuCl affording β-trifluoromethyl ketones in 65-73% isolated yields. Ring opening in 1,2-dialkylsubstituted cyclopropanols gives a mixture of isomeric β-trifluoromethyl ketones in about 50% combined yield.

Boron-trihalide-promoted regioselective ring-opening reactions of gem-difluorocyclopropyl ketones

Boron trihalide-promoted ring-opening reactions of gem-difluorocyclopropyl ketones to give the corresponding β-trifluoromethyl ketones and β-halodifluoromethyl ketones were described. It was found that boron trihalides act as both Lewis acids and nucleophiles and the proximal bond prefers to cleave in this transformation.

ChemInform Abstract: Synthesis of β‐CF3 Ketones from Trifluoromethylated Allylic Alcohols by Ruthenium Catalyzed Isomerization.

This work describes the optimization process for the synthesis of β-trifluoromethylated ketones from trifluoromethylated allylic alcohols. This transformation proceeds through a ruthenium catalyzed isomerization under mild conditions with high atom economy. The effect of the CF3 group was analyzed and it provides fundamental insights into the isomerization reaction.

Regioselective 1,4-trifluoromethylation of α,β-unsaturated ketones via a S-(trifluoromethyl)diphenylsulfonium salts/copper system

Regioselective conjugate 1,4-trifluoromethylation of α,β-unsaturated ketones by the use of shelf-stable electrophilic trifluoromethylating reagents, S-(trifluoromethyl)diphenylsulfonium salts and copper under mild conditions is described. A wide range of acyclic aryl–aryl–enones and aryl–alkyl–enones were converted into β-trifluoromethylated ketones in low to moderate yields.

Iron(II) complexes are suitable catalysts for the isomerization of trifluoromethylated allylic alcohols. Synthesis of trifluoromethylated dihydrochalcones

We demonstrated that iron(II) complexes can substitute platinum metals as well as iron(0) carbonyls for the isomerization of γ-trifluoromethylated allylic alcohols into β-trifluoromethylated ketones. In particular, iron(II)-tetra(isonitrile) complexes were employed for the synthesis of a series of trifluoromethylated dihydrochalcones variously decorated on each aromatic ring.

Synthesis of β-CF3 ketones from trifluoromethylated allylic alcohols by ruthenium catalyzed isomerization

This work describes the optimization process for the synthesis of β-trifluoromethylated ketones from trifluoromethylated allylic alcohols. This transformation proceeds through a ruthenium catalyzed isomerization under mild conditions with high atom economy. The effect of the CF3 group was analyzed and it provides fundamental insights into the isomerization reaction.

Copper(I)‐Catalyzed Addition of Trifluoromethylated Benzyl Radicals Derived from Aryltrifluoroethyl Bromides to Terminal Olefins.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Copper(I)-catalyzed addition of trifluoromethylated benzyl radicals derived from aryltrifluoroethyl bromides to terminal olefins

Relatively unreactive aryltrifluoroethyl bromides were reacted with 1-octene in the presence of CuCl and 2,2′-bipyridyl at high temperatures. Trifluoromethylated benzyl radical was generated, and a diastereomer mixture of radical adducts was obtained with a (60–70):(40–30) diastereomer ratio. Ph3SnH reduction of the adducts gave the corresponding hydrocarbons with an isolated trifluoromethyl group. The reactions with styrene or aromatic and aliphatic silyl enol ethers led to the formation of trifluorodiphenylbutene and β-trifluoromethylated ketones, respectively.