Iridium-catalyzed addition of aroyl chlorides and aliphatic acid chlorides to terminal alkynes

Iridium complexes show high catalytic activity in intermolecular additions of acid chlorides to terminal alkynes to afford valuable (Z)-β-chloro-α,β-unsaturated ketones. Ligands in the catalytic system play a crucial role in this reaction. An N-heterocyclic carbene (NHC) is an efficient ligand for the addition of aroyl chlorides, while dicyclohexyl(2-methylphenyl)phosphine (PCy(2)(o-Tol)) is indispensable for the reaction of aliphatic acid chlorides. The addition reactions proceed regio- and stereoselectively with suppression of decarbonylation and β-hydrogen elimination, which have been two major intrinsic problems in transition-metal-catalyzed reactions. Stoichiometric reactions of active iridium catalysts with aroyl chlorides and aliphatic acid chlorides are carried out to gain insights into the reaction mechanisms.     

An Efficient Synthesis of Polymethylene-bis-aroyl Thiourea Derivatives under the Condition of Phase Transfer Catalysis

A number of 1,3-disubstituted derivatives are associated with various types of biological activity [1]. Some thioureas are useful as herbicides, insecticides and plant-growth regulators. Treatment of acylisothiocyanates, prepared from aroyl chlorides (0.0431mol) and potassium thiocyanate (33ml ofa 33% KSCN solution) using tetrabutylammonium bromides as a catalyst, were treated with aniline to yield the corresponding thioureas. However, probable hydrolysis of the aroyl chlorides led to decreased yields. The reaction of acid chlorides with different phenylthioureas or N1-acetyl-N3-arylthioureas requires high temperature and long reaction times. None of the other reported methods proved satisfactory. As a continuation of our earlier work on the biological activity of these compounds, [2-5] we now report acid chlorides are quantitatively converted to the acylisothiocyanates under solid-liquid phase-transfer conditions using PEG-400 as the catalyst. Treatment of these isothiocyanates with polymethylenediamines provides compounds 3 in high yields (scheme 1). The results were summarized in table 1.     

Intramolecular electrophilic cyclization of functional derivatives of unsaturated Compounds: I. Synthesis of 5-arylsulfanyl-6-phenylpiperidin-2-ones from cinnamylacetamides and arylsulfenyl chlorides

Sterically nonhindered N-alkyl(aryl)amides of cinnamylacetic acid in the reaction with phenyl(4-tolyl)sulfenyl chlorides in acetic acid in the presence of lithium perchlorate undergo a selective cyclization into 5-arylsulfanyl-6-phenylpiperidin-2-ones. Under similar conditions the reaction with arylsulfenyl chlorides of amides containing bulky substituents at the nitrogen atom resulted in 5-arylsulfanyl-6-phenyltetrahydropyran-2-iminium perchlorates, which by treatment with aqueous ethanol were converted into the corresponding derivatives of pyran-2-ones.     

LC diketones: synthesis, transformations and mesomorphic properties

The synthesis and chemical transformations of various diketones into liquid crystalline compounds are discussed. The diketones were prepared by the interaction of cyclohexene with acid chlorides and benzene in the presence of aluminium chloride (Nenitzescu method) or by Friedel Crafts reaction of trans-4-alkanoyl-1-phenylcyclohexanes or trans-2-alkyl-5-phenylcyclohexanones with acid chlorides, or by the condensation of corresponding Mannich salts with 2-substituted acetoacetates or acetylacetone.     

LC diketones: synthesis,transformations and mesomorphic properties

The synthesis and chemical transformations of various diketones into liquid crystalline compounds are discussed. The diketones were prepared by the interaction of cyclohexene with acid chlorides and benzene in the presence of aluminium chloride (Nenitzescu method) or by Friedel Crafts reaction of trans-4-alkanoyl-1-phenylcyclohexanes or trans-2-alkyl-5-phenylcyclohexanones with acid chlorides, or by the condensation of corresponding Mannich salts with 2-substituted acetoacetates or acetylacetone.     

Die Acylierung von Acetylenen mit β, γ-ungesättigten Säurechloriden. Eine neue Synthese von 5-Cyclopentenonen

The Acylation of Acetylenes with β,γ-Unsaturated Acid Chlorides, A New Synthesis of 5-Substituted 2-Cyclopentenones The acylation of acetylenes with α,α-disubstituted, β,γ-unsaturated acid chlorides under Friedel-Crafts-type conditions leads to 5-substituted 2-cyclopentenones. Phenols are formed with β,γ-unsaturated acid chlorides bearing at least one α-H-atom. These transformations are explained by the intramolecular cyclization of the initially formed vinyl cation, which, in the cases of α,α-disubstituted acid chlorides, is followed by ring contraction. The reaction leading to 2-cyclopentenones is applied to the synthesis of some spiro[4.4]nona- and spiro[4.5]deca-2,6-dienones.     

Synthesis of diamides from 1,4-benzodioxane-2- and isochroman-1-carboxylic acids

1,4-Benzodioxane-2-carboxylic acid and isochroman-1-carboxylic acid were treated with thionyl chloride, and the resulting acid chlorides reacted with p-aminobenzoic acid in dioxane in the presence of pyridine to produce the corresponding amido acids. The latter were converted into acid chlorides which were brought into reaction with various amines to obtain a number of new diamides.     

An atom-efficient palladium-catalyzed cross-coupling reaction of triarylbismuths with acid chlorides: synthesis of diaryl and alkyl aryl ketones

The cross-coupling reaction of triarylbismuths with acid chlorides using a catalytic amount of PdCl₂/PPh₃ afforded the corresponding ketones in high yields. The reactions of aromatic and aliphatic acid chlorides occurred with atom efficiency, as 3 equiv of acid chlorides coupled effectively with 1 equiv of triarylbismuths to yield 3 equiv of the corresponding diaryl and alkyl aryl ketones.     

Synthesis of functionalized dialkyl ketones from carboxylic acid derivatives and alkyl halides

Unsymmetrical dialkyl ketones can be directly prepared by the nickel-catalyzed reductive coupling of carboxylic acid chlorides or (2-pyridyl)thioesters with alkyl iodides or benzylic chlorides. A wide variety of functional groups are tolerated by this process, including common nitrogen protecting groups and C-B bonds. Even hindered ketones flanked by tertiary and secondary centers can be formed. The mechanism is proposed to involve the reaction of a (L)Ni(alkyl)(2) intermediate with the carboxylic acid derivative.     

New method for the synthesis of macrocyclic compounds

The intramolecular acylation of acid chlorides of ω-thienylalkanoic acids of various structures in the presence and absence of silica gel was investigated. The reaction of aluminum chloride etherate and the indicated acid chlorides with the surface groups of silica gel was studied by IR spectroscopy, and the role of the compounds formed on the surface in the reaction under consideration was discussed. A sequence of processes and a mechanism involving participation of the solid phase in the intramolecular acylation of acid chlorides of ω-thienylalkanoic acids are formulated.     

N-Acyl andN-sulfonyl derivatives of thiazolidines

The major reaction center in the reaction of 4,4-dialkyl-5-methylene-2-phenyliminothiazolidines with acid chlorides or anhydrides and with arenesulfonyl chlorides is the nitrogen atom at position 3 of the ring.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2968–2970, December, 1996.     

Reaction of 2-amino-5-aryl-1,3,4-oxadiazoles with compounds with activated double bonds

The reaction of 2-amino-5-aryl-1,3,4-oxadiazoles with unsaturated acids and their chlorides was studied. It was shown by IR spectroscopy and mass spectrometry that acylation with acrylic, methacrylic, and cinnamic acid chlorides takes place at the nitrogen atom of the exocyclic amino group. Depending on the solvent, two reaction pathways are realized with unsaturated acids: acylation of the starting 2-amino-5-aryl-1,3,4-oxadiazole occurs in bromobenzene, while nucleophilic addition to the unsaturated acid molecule is realized in DMF in the presence of potassium hydroxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–829, June, 1990.     

Palladium‐Catalyzed Catellani ortho‐Acylation Reaction: An Efficient and Regiospecific Synthesis of Diaryl Ketones

A palladium‐catalyzed, norbornene‐mediated Catellani ortho‐acylation reaction was developed by the use of either acyl chlorides or acid anhydrides as acylation reagents. The addition of more than a stoichiometric amount of H₂O is crucial for this transformation when acid chlorides are used, and kinetic studies indicate that the active acylation reagent is possibly an acid anhydride.     

Synthesis of 1,3,5-tricarbonyl derivatives by condensation of 1,3-bis(silyl enol ethers) with acid chlorides

A variety of 1,3,5-tricarbonyl derivatives were prepared by reaction of 1,3-bis(silyl enol ethers) with acid chlorides under mild conditions. This includes reactions of both aromatic and aliphatic acid chlorides and bis(acid chlorides). The yields vary depending on the type of acid chloride employed.     

Acyl chlorides of 2,2,5,5-tetramethyl-3-imidazolin-1-oxyl-4-0-acylhydroximic acids

Acylation of nitroenamine derivatives of imidazolidin-1-oxyl with carboxylic acid chlorides leads to 0-acylhydroximic acid chloride derivatives of 3-imidazolin-1-oxyl. The reaction proceeds apparently through a nitrile oxide. It was shown for the 0-benzoyl derivative that reaction of the obtained acyl chlorides with nucleophilic reagents usually gives products of chlorine atom substitution with simultaneous cleavage of the acyl group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 444–450, February, 1991.     

First reaction of a bare silicon surface with acid chlorides and a one-step preparation of acid chloride terminated monolayers on scribed silicon

Methyl-terminated and acyl chloride terminated monolayers are produced when silicon is scribed under mono- and diacid chlorides, respectively. To the best of our knowledge, this is the first report of the reaction between a bare silicon surface and acid chlorides. This reaction takes place by wetting the silicon surface in the air with the acid chloride and scribing. Scribing activates the silicon surface by removing its passivation layer. We propose that scribed silicon abstracts chlorine from an acid chloride to form an Si-Cl bond and that the resulting acyl radical diffuses back to the surface to condense with the surface and form an alkyl monolayer. X-ray photoelectron spectroscopy (XPS) confirms the presence of chlorine and shows a steady increase in the amount of carbon with increasing alkyl chain lengths of the acid chlorides. Time-of-flight secondary ion mass spectrometry shows SiCl(+) species and a steady increase in representative hydrocarbon fragments with increasing alkyl chain lengths of the acid chlorides. XPS indicates that diacid chlorides react primarily at one of their ends to create acyl chloride terminated surfaces in a single step. The resulting surfaces are shown to react with various amines (piperazine, morpholine, and octylamine) and a protein. Calculations at Hartree-Fock and density functional theory levels are consistent with the proposed mechanism.     

The use of 2-0xazolidinone as a latent aziridine equivalent. I. A facile method for the preparation of 2-substituted oxazolines

Ring-opening reaction of 2-oxazolidinone with acid chlorides followed by treatment with aqueous sodium hydroxide yields 2-substituted oxazolines.     

Reactions of some 2-oxo-1,3,2-oxathiaphospholanes and 2-oxo-1,3,2-phosphorinanes with phosphorus pentachloride

2-Phenoxy- and 2-dialkylamino-2-oxa-1,3,2-oxathiaphospholanes react with PCl₅ with ring opening and formation of the corresponding acid chlorides of thiophosphoric acid. Under analogous conditions, 2-phenoxy-2-oxo-1,3,2-oxathiaphosphorinanes do not react with PCl₅, while acid chlorides of thiophosphoric acid are formed in low yield along with other products in the reaction of 2-dialkylamino-2-oxo-1,3,2-oxthiaphosphorinanes with PCl₅.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2676–2678, November, 1992.     

Heterocyclic Syntheses on the Basis of Arylation Products of Unsaturated Compounds: X. 3-Aryl-2-chloropropanals as Reagents for the Synthesis of 2-Amino-1,3-thiazole Derivatives

Meerwein reaction of arenediazonium chlorides with acrolein gave 3-aryl-2-chloropropanals which were brought into cyclocondensation with thiourea. The resulting 2-amino-5-benzyl-1,3-thiazoles were acylated with carboxylic acid chlorides and phthalic anhydride to afford, respectively, 2-acylamino-5-benzyl-1,3-thiazoles and N-(5-benzyl-1,3-thiazol-2-yl)phthalimides.     

Horner-Wadsworth-Emmons reagents as azomethine ylide analogues: pyrrole synthesis via (3 + 2) cycloaddition

Amido-substituted Horner-Wadsworth-Emmons reagents can serve as precursors to 1,3-dipoles for use in cycloaddition. These compounds are assembled in one pot via the TMSOTf-catalyzed Arbuzov reaction of imines, acid chlorides, and phosphites. The coupling of this synthesis with alkyne cycloaddition provides a three-component synthesis of pyrroles. The dipoles can be prepared with a diverse range of imines and acid chlorides, and (3 + 2) cycloaddition with unsymmetrical alkynes is highly regiospecific, providing a modular approach to form substituted pyrroles.