Effect of amides on the bromination of methyl alkyl ketones

Conclusions The bromination of methyl alkyl ketones in methanol medium in the presence of urea, methylurea or carboxamides gives a mixture of the 1-bromo- and 3-bromo-2-alkanones in a 70–8030–20 ratio.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 454–456, February, 1984.     

Catalyst-free synthesis of amines from cyclic ketones and formamides in superheated water

A novel and environmentally benign protocol for the synthesis of amines from cyclic ketones and formamides is demonstrated. The reaction proceeds under catalyst-free and superheated water conditions and yields range from poor to excellent.     

Catalytic reaction of methyl formate with amines to formamides

A feasible procedure of using methyl formate as cheap reagent for the conversion of aliphatic and aromatic amines into formamides with high yields is reported. The improved amine formylation method proceeds mainly at room temperature and in presence of bicyclic guanidines as catalysts. A verifiable key intermediate of outstanding formylating activity is generated from methyl formate and the catalyst in the reaction mixture.     

Organocatalytic asymmetric direct aldol reactions of trifluoroacetaldehyde ethyl hemiacetal with aromatic methyl ketones

The organocatalytic asymmetric direct aldol reaction of trifluoroacetaldehyde ethyl hemiacetal with aromatic methyl ketones in the presence of a catalytic amount of (S)-5-(pyrrolidin-2-yl)-1H-tetrazole in dichloroethane at 40 °C proceeds smoothly to produce (R)-4,4,4-trifluoro-1-aryl-3-hydroxy-1-butanones in high yields with up to 90% ee.     

Convergent integration of three self-sorting domino sequences: three-component direct synthesis of 3-methylthio-4-aryl-maleimides from methyl ketones with acetonitrile and DMSO

An I₂-promoted three-component coupling reaction was described for the construction of 3-(methylthio)-4-aryl-1H-pyrrole-2,5-diones from methyl ketones with acetonitrile and DMSO. This transformation involved the in situ generation and application of α-ketoimides. Furthermore, DMSO was converted to DMS in situ, which subsequently served as a methylthiolation reagent in the reaction. To the best of our knowledge, this protocol provided the first known example of convergent integration of three self-sorting domino sequences.     

POCl3 promoted metal-free synthesis of tertiary amides by coupling of carboxylic acids and N,N-disubstituted formamides

Herein we report a robust and synthetically useful catalyst-free amination methodology by the coupling of carboxylic acids and N-substituted formamides using POCl₃ as a promoter. Versatile amides with a wide array of substituent groups were prepared within only 1?h in good to excellent yields. And even multi-substituted aromatic carboxylic acids could give the desired products with satisfactory results.     

New, general, and practical preparation of methyl ketones via the direct coupling of amides with CH2Cl2 promoted by TiCl4/Mg

The direct coupling of a variety of amides with CH2 Cl2 or CD2 Cl2 promoted by TiCl 4/Mg/THF provides an extremely simple, practical, selective, and efficient approach for the construction of methyl ketones. The efficiency and practicability of this chemistry is illustrated by the very simple synthesis of deuterated methyl ketones.     

Facile synthesis of 1-naphthols through a copper-catalyzed arylation of methyl ketones with o-bromoacetophenones

The coupling reactions of simple methyl ketones with o-bromoacetophenones and subsquential cyclization reactions were realized to produce a range of 1-naphthols. These cascade reactions were initiated by a rare Cu-catalyzed arylation reaction of methyl ketones with aromatic bromides.     

Highly efficient synthesis of aryl ketones by PEPPSI-palladium catalyzed acylative Suzuki coupling of amides with diarylborinic acids

An improved acylative cross-coupling of various N-methyl-N-tosyl amides with diarylborinic acids for synthesis of aryl ketones is developed. In most cases, aryl ketones could be obtained in excellent yields by using 1?mol% 2,6-diisopropylphenylimidazolylidene and 3-chloropyridine co-supported palladium chloride as catalyst in the presence of 3 equiv. K₂CO₃ as base in refluxing THF. The readily prepared and cost-effective substrates, N-methyl-N-tosylamides and diarylborinic acids, and the commercially available catalyst system promise a practical and efficient access to aryl ketones.     

Reaction of diazomethane with selenoesters : Preparation of α-(alkyl- or arylseleno)methyl ketones and methyl ketones

The reaction of diazomethane with a series of selenoesters 1 in the presence of CuI, CuSePh or Cu powder produced α-(alkyl- or arylseleno)methyl ketones 2 in yields of 41–65%. Methyl ketones 3 and bis(arylseleno)methanes 9 or 14 were formed as by-products. The direct conversion of selenoesters to methyl ketones was accomplished in high yield by the usual reaction with diazomethane, followed by workup with HBr solution. The simultaneous copper-catalyzed reactions of selenoesters 1c and 1i with diazomethane resulted in crossover, with the formation of all four possible α-seleno ketones 2b, 2c, 2h and 2i. A non-concerted mechanism involving attack by the diazo compound upon the acyl carbon atom of an activated selenoester with the formation of a tetrahedral intermediate 11 has been suggested. The reaction of the selenothiocarbamate 4 with diazomethane resulted in 1,3-dipolar cycloaddition to afford 5 instead of insertion into the acyl-selenium bond.     

Rhodium-catalyzed direct aldol condensation of ketones: a facile synthesis of fused aromatic compounds

Cationic rhodium complex [Cp^∗Rh(η⁶-C₆H₆)](BF₄)₂ (1) acts as an efficient catalyst for direct aldol condensation of ketones. The method can be applied to one-pot synthesis of fused aromatic compounds from cyclic ketones via sequential C-C bond formations.     

Mild and direct conversion of esters to morpholine amides using diisobutyl(morpholino)aluminum: application to efficient one-pot synthesis of ketones and aldehydes from esters

Morpholine amide intermediates, which are easily prepared by aminolysis of various esters with diisobutyl(morpholino)aluminum, react with organolithium and reducing agents (DIBALH or LDBMA) without isolation of the aminolysis intermediates to give ketones in 83–95% yields and aldehydes quantitatively.     

Microwave-assisted direct transformation of amines to ketones using water as an oxygen source

Retro-reductive aminations, direct transformations of amines to ketones, were catalyzed by Pd/C in water under microwave irradiation.     

A practical synthesis of alpha-aryl methyl ketones via a transition-metal-free Meerwein arylation

We report herein a simple, scalable, transition-metal-free approach to the synthesis of alpha-aryl methyl ketones from diazonium tetrafluoroborate salts under mild conditions. This methodology uses easily accessible and nontoxic starting material and was applied to the multi-kilogram-scale preparation of 1-(3-bromo-4-methylphenyl)propan-2-one.