Reactions of atomic carbon with acyl chlorides

Reactions of arc-generated carbon atoms with acyl chlorides proceed by two distinct mechanistic pathways depending on the nature of the alkyl group in the substrate. Acetyl chloride affords vinyl chloride from the putative chloromethylcarbene produced by deoxygenation, whereas pivaloyl chloride gives t-butyl chloride as the predominant product via a chain reaction from the initially generated pivaloyl radical. When the alkyl group is isopropyl, both pathways are implicated.     

Reactions of acyl anions generated from acid chlorides and diiodosamarium

Acid chlorides react with SmI₂ to give α-diketones. Various experiments show that the initially formed acyl radical is rapidly transformed into an acyl anion which is thus generated by quite an unusual route.This species acylates acid chlorides, aldehydes and ketones in situ to give α-diketones and α-ketols. There are some limitations to this acyl anion chemistry but the reactions are realized with a good efficiency at room temperature in THF solution.     

Palladium-phosphinous acid-catalyzed cross-coupling of aliphatic and aromatic acyl chlorides with boronic acids

The cross-coupling of aromatic and aliphatic acyl chlorides with arylboronic acids in the presence of 2.5 mol % of (t-Bu₂POH)₂PdCl₂ (POPd) provides rapid access to ketones that are obtained in up to 93% yield. This palladium-phosphinous acid-catalyzed reaction is completed within 10 min when microwave irradiation is used, and it overcomes typical drawbacks of Friedel-Crafts acylation procedures such as harsh reaction conditions, untunable regiocontrol, and low substrate scope.     

Palladacycle-catalyzed cross-coupling reactions of arylboronic acids with carboxylic anhydrides or acyl chlorides

The triphenylphosphine–cyclopalladated ferrocenylimine (Cat. 2) exhibited highly catalytic activity for the both of arylboronic acids with carboxylic anhydrides and acyl chlorides with low catalyst loading (0.5 mol %). The reactions were unaffected by the presence of electron-releasing and electron-withdrawing substituents in both the arylboronic acids and carboxylic derivatives. Up to 98% yield was obtained for 32 examples. However, they were limited for arylboronic acid with strong electron-withdrawing groups. It is noting that catalyst 2 can be reused for eight times without losing its catalytic activity.     

Reactions of a carbamoylstannane with acid chlorides: highly efficient synthesis of alpha-oxo amides

Treatment of acid chlorides with a carbamoylstannane under mild conditions (mostly rt for a few hours) affords alpha-oxo amides in high yields. Vicinal polycarbonyl compounds are also obtained, although spontaneous decarbonylation occasionally occurs.     

Phosphine-free cross-coupling reaction of arylboronic acids with carboxylic anhydrides or acyl chlorides in aqueous media

The palladium acetate-catalyzed coupling reaction of aryl boronic acid with carboxylic anhydride or acyl chloride was carried out smoothly in water in the presence of poly(ethylene glycol) (PEG) or 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) to give high yields of ketones without the use of phosphine ligands. The Pd(OAc)2-H2O-[bmim][PF6] catalytic system can be recovered and reused eight times with high efficiency for both carboxylic anhydride and acyl chloride.     

Reactions of 2,2-dimethyl-3-phenylazirine with chlorides of unsaturated and amino-substituted acids

The reaction of 2,2-dimethyl-3-phenylazirine with N-phthalylglycine acid chloride gives initially N-acyl-3-chloroaziridine, which undergoes isomerization to a substituted 2-oxazoline and the corresponding keto amide. The reaction of 2,2-di-methyl-3-phenylazirine with the chlorides of crotonic, - (2-furyl) acrylic, cinnamic, and phenylpropiolic acids in benzene at 20 °C leads to 2,2-dimethylindoxyl and the corresponding unsaturated acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 643–645, May, 1981.     

Coupling of ortho-substituted aryl chlorides with bulky amides

Voluminous amides were coupled with deactivated, sterically hindered aryl chlorides in excellent yields providing products, which have not been efficiently accessible by transition metal catalysis so far. Application of an unsymmetric bisphosphine ligand was critical for the high catalytic activity.     

Semimicrodetermination of carboxylic acids in the presence of large amounts of acyl chlorides

A procedure for the semimicrodetermination of carboxylic acids in the presence of a large excess of acyl chloride is described. Acyl chloride is first reacted with m-chloroaniline. The m-chloroaniline hydrochloride and carboxylic acid are then determined sequentially by potentiometric titration with sodium hydroxide. Titrations are performed in 80–90% p-dioxane to enhance the potentiometric breaks. With 0.05 N sodium hydroxide, as little as 0.01 mM of carboxylic acid can be determined.     

Reactions of organocobaloximes with aryldisulfonyl chlorides

Photochemical reactions of benzyl, heteroaromaticmethyl and allylcobaloximes with aryldisulfonyl chlorides yield symmetrical disulfones. Allyl cobaloximes yield allyldisulfones as the major product whereas bibenzyl is the major product in benzylcobaloximes. A time dependent ¹H NMR studies show that bibenzyl is formed from O-benzyldimethylglyoxime - a predominant product in the initial stage of the reaction.     

Reactions of polyfluoroalkylsulfenyl chlorides with phenols

Polyfluoroalkylsulfenyl chlorides thiolate phenol and its ortho- and meta-substituted derivatives regiospecifically at the para-position in the absence of a catalyst and of a hydrogen chloride acceptor. Ortho thiolation occurs with significantly greater difficulty in the para-substituted phenols, and is only possible with the strong electron-donor properties of the substituent. Polyfluoroalkylthiolation of phenols is rendered more difficult with the increase in the steric impediments at the sulfur atom of the sulfenyl chloride and the volume of the substituents by the OH group of the phenol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1619–1625, July, 1991.