A practical synthetic method for vinyl chlorides and vinyl bromides from ketones via the corresponding vinyl phosphate intermediates

A new synthetic method for the preparation of vinyl chlorides and vinyl bromides from acyclic and cyclic ketones is described. Vinyl halides are practically obtained from the corresponding vinyl phosphate intermediates with triphenylphosphine dihalide.     

Chemistry of difluorocarbene adducts: Stereospecific synthesis of conjugated fluoroolefins and 1,3-azabutadienes from gem-difluorocyclopropenyl ketones

Treatment of gem-difluorocyclopropenyl ketones with malonate anion, amine gave stereospecifically conjugated fluoroolefins and azabutadienes, respectively.     

A novel synthesis of alkyl vinyl ketones and divinyl ketones from carbonyl compounds by three-carbon homologation

Alkyl vinyl ketones and divinyl ketones are synthesized from carbonyl compounds and 1-chloro-3-phenylthiopropyl phenyl sulfoxide as a three-carbon homologating agent in good overall yields.     

Indium-mediated formation of propargyl ketones from aldehydes or acyl chlorides

Propargyl ketones were prepared from aldehydes via an indium-mediated alkynylation reaction followed by an indium-mediated Oppenauer oxidation. They were also obtained via an indium-mediated alkynylation of the relevant acyl chlorides.     

Chemoselective and stereoselective synthesis of gem-difluoro-β-aminoesters or gem-difluoro-β-lactams from ethylbromodifluoroacetate and imines during Reformatsky reaction

The chemoselective and stereoselective synthesis of gem-difluoro-β-aminoesters or gem-difluoro-β-lactams was investigated from ethylbromodifluoroacetate and imines during Reformatsky reaction. Influence of various reaction parameters, such as nature of the amine part, nature of the chiral auxiliary, was evaluated. High levels of stereoselectivity (up to 98%) were obtained for gem-difluoro-β-aminoesters and gem-difluoro-β-lactams using either (R)-phenylglycinol or (R)-methoxyphenylglycinol.     

Practical synthesis of gem-difluorides from cyclohexanone: Synthesis of gem-bistrifluoroacetates and their reactions with fluoride nucleophiles

Formation of ketone acylals bearing trihaloacetoxy groups and their nucleophilic geminal disubstitution by fluoride ions were investigated. Cyclohexanone reacted with trifluoroacetic anhydride without catalyst to give gem-bistrifluoroacetates via a concerted bimolecular reaction. Treatment with hydrogen fluoride under mild conditions efficiently yielded the corresponding gem-difluorides. In this reaction process, trifluoroacetic acid was recovered and converted to trifluoroacetic anhydride using P₂O₅. Since gem-difluorides were derived from ketones, HF and P₂O₅, this constitutes a practical synthesis of gem-difluorides.     

A simple and efficient synthesis of gem-dihydroperoxides from ketones using aqueous hydrogen peroxide and catalytic ceric ammonium nitrate

Ketones were efficiently converted into the corresponding gem-dihydroperoxides in high yields within a short period of time on treatment with aqueous H₂O₂ (50%) in the presence of a catalytic amount of CAN in acetonitrile at room temperature.     

Efficient synthesis of selenol esters from acid chlorides mediated by indium metal

This article describes an efficient and easy one-pot route for the synthesis of a wide range of selenol esters from acyl chloride with diselenides in the presence of indium metal. A variety of functional groups can be tolerated within the diorgano diselenide and the acyl chloride coupling partner.     

Electrochemical synthesis of ketones from acid chlorides and alkyl and aryl halides catalysed by nickel complexes

The nickel-catalysed electrochemical cross-coupling of acid chlorides and alkyl or aryl halides in acetonitrile affords unsymmetric ketones in good to high yields. The reaction can be performed under very simple and mild conditions in a diaphragmless cell. A zinc rod as the sacrificial anode has been found to be the most efficient.     

Synthesis of gem-dihaloenynes and butatrienes from gem-dihalovinyl derivatives

gem-Dihaloenynes were synthesized in high yields from 1,1,4,4-tetrahalo-1,3-butadienes through the Fritsch-Buttenberg-Wiechell (FBW) rearrangement mediated by an organolithium compound. Butatriene derivatives could be obtained efficiently via an organolithium-mediated reaction of o-halo-(2,2-dihalovinyl)benzenes.     

Transition metal free large-scale synthesis of aromatic vinyl chlorides from aromatic vinyl carboxylic acids using bleach

While continuing our research on Hunsdiecker reaction, we came across an interesting application of bleach, sodium hypochlorite (NaOCl) for decarboxylative chlorination reaction. The reaction is easily scaled up to 10?mmol. The reaction has good tolerance towards wide variety of functional groups. The reaction has mild conditions and gave relatively high chemical yield of the desired product.     

Acyl palladium species in synthesis: single-step synthesis of alpha,beta-unsaturated ketones from acid chlorides

Conditions are reported for the facile, one-pot synthesis of alpha,beta-unsaturated ketones via the palladium-catalysed cross-coupling of acyl chlorides with hydrozirconated acetylenes, and its use in the 2-step synthesis of D-5-O-benzyl deoxyxylulose.     

One-pot synthesis of benzimidazoles from gem-dibromomethylarenes using o-diaminoarenes

A one-pot synthesis of benzimidazoles from gem-dibromomethylarenes is described. The reaction shows the method to prepare a variety of benzimidazole analogues with excellent yield.     

Functional group selectivity in reactions of epoxides with tungsten hexachloride

The reactivity of several cyclohexene oxides bearing various functional groups toward the reagent tungsten hexachloride is reported. In general, the conversion of the epoxide to the trans dichloride occurs relatively rapidly. Several groups proved stable—esters, sulfides, sulfones, hindered silyl ethers—while others were unstable—alcohols, unhindered silyl ethers, ketones. The diaxial dichloride is usually formed although the diequatorial dichloride could also be prepared.     

Synthesis of acetylenic ketones from straight-chain acid chlorides

Conclusions A method for the catalytic condensation of acetylenes with the acid chlorides of unbranched aliphatic acids was found.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 687–688, March, 1984.     

1,3-diketones from acid chlorides and ketones: a rapid and general one-pot synthesis of pyrazoles

[reaction: see text] 1,3-Diketones were synthesized directly from ketones and acid chlorides and were then converted in situ into pyrazoles by the addition of hydrazine. This method is extremely fast, general, and chemoselective, allowing for the synthesis of previously inaccessible pyrazoles and synthetically demanding pyrazole-containing fused rings.     

Efficient and selective solid-phase synthesis of trans 3-alkyl β-lactams from nonactivated acid chlorides

An efficient and stereoselective procedure for a rapid access to diverse trans 3-alkyl β-lactams by solid-phase methodology is described.