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Research has been conducted on the oxime-derived chloro-bridged palladacycles. The effect of bases, additives and solvents on the containing phenylboronic acids aryl bromide and chloride Suzuki couplings with oxime-derived palladacycles as catalysts has been investigated and the details are reported.

Research points out that simple amino acids can be used as ligands in the ruthenium(II)-catalyzed transfer hydrogenation of aryl alkyl ketones. The bicyclic beta-amino alcohols are obtained by simple aza-Diels-Alder adduct formation between cyclopentadiene and iminium ion and adduct's subsequent reduction.

Hybrid density functional methods were used to study the mechanism of the Ru(arene)(amino alcohol)-catalyzed transfer hydrogenation of ketones using isopropyl alcohol as the hydrogen source. An evaluation of three mechanistic alternatives revealed that the reaction took place by means of a six-membered transition state, where a metal-bound hydride and a proton of a coordinated amine were transferred simultaneously to the ketone. Computational results were supported by experimental studies of both rate and enantioselectivity.

A study was conducted to analyze the effects of reaction conditions on the catalytic hydrogenation of 2-aza-bicyclo hept-5-ene and oct-5-ene derivatives. The use of reaction routes was characterized by the selective preparation of four categories of optically active alpha-amino acid derivatives. Results indicated the possibility of extending the allylic vs benzylic C-N hydrogenolysis by varying H2 pressure and the acidity of the reaction medium.

A study was conducted to analyze the deprotection of the chiral N-sulfonyl aziridines under various desulfonylation environments. A chiral column was utilized to perform high performance liquid chromatography. Experimental results indicated that chiral N-sulfonyl aziridines can be deprotected by magnesium in ultrasonic environments or lithium during the presence of a catalytic amount of di-tert-butyl biphenyl.

The organolithium intermediate compounds, obtained from tosyl substituted N-benzylmethallylamine, act as 1,4-dinucleophiles in the synthesis of five to eight membered nitrogen containing heterocycles. The synthesis is regioselective and stereospecific in nature. Proton-NMR and X-rays are used to analyze the conformation and configuration of these sulphone containing heterocycles. These heterocycles have a wide application in the synthesis of hexahydroazepines and heptahydroazocines.

A study was conducted to characterize the use of 2-azanorbornyl derivatives as ligands in asymmetric catalysis. The ruthenium complex dimer was weighted into a flash wherein moisture was removed through the evaporation of benzene. The solution was then refluxed under argon before being cooled and transferred to a ketone solution. Results indicated that ruthenium complexes could be effective catalysts for the enantioselective transfer hydrogenation of aromatic ketones.

The chiral trans-cyclohexanediamine-benzimidazole organocatalysts were used to promote the conjugate addition of a wide variety of 1,3-dicarbonyl compounds such as malonates, ketoesters, and 1,3-diketones to nitroolefins in the presence of TFA as cocatalyst in toluene as solvent at rt or 0 degree [Celsius]. The DFT calculations indicated that the protonated tertiary amine from the cyclhexanediamine backbond activated the nitroolefin, while the benzimidazole unit activates the 1,3-dicarbonyl nucleophile.

3,5-bis(trifluoromethyl)phenyl (BTFP) sulfones are employed in the Julia-Kocienski olefination reaction with carbonyl compounds. Mechanistic studies of the olefination reaction between benzyl BTFP sulfone and aromatic aldehydes performed by KOH-induced Smiles rearrangement of stereodefined syn-and anti-Beta-hydroxyalkyl BTFP sulfones indicate that the stereocontrol of the reaction is determined in the elimination step.

The palladium-catalyzed acylation of terminal alkynes with carboxylic acid chlorides can be performed under mild copper- and phosphane-free conditions, employing either oxime-derieved palladacycle or Pd(OAc)2 as catalyst in toluene as solvent and TEA as base. It is shown that palladacycle performs better than Pd(OAc)2 under low catalyst loading conditions at 110 degree Celsius.

Chiral trans-cyclohexanediamine-benzimidazole organocatalysts promote the conjugate addition of a wide variety of 1,3-dicarbonyl compounds such as malonates, ketoesters, and 1,3-diketones to nitroolefins in the pretence of TFA as cocatalyst in toluene as solvent at rt or 0 °C. The Michael adducts are obtained in high yield and enantioselectivity, using the chiral 2-aminobenzimidazole 7b at hydrogen-bond-mediated chiral organocatalyst. This catalyst can be recovered by acid—base extractive workup in 94% yield. The proposed bifunctional Bronsted acid—base activation role of the catalyst and the origin of the stereoselectivity of the process is in agreement with DFT calculations. According to these calculations, the protonated tertiary amine from the cyclohexanediamine back- bond activates the nitroolefin, while the benzimidazole unit activates the 1,3-dicarbonyl nucleophile. [ABSTRACT FROM AUTHOR]

3,5-Bis(trifluoromethyl)phenyl (BTFP) sulfones 7 have been employed in the Julia-Kocienski olefination reaction with carbonyl compounds. Sulfones 7 are readily prepared in high yields (6497%) from commercially available 3,5-bis(trifluoromethyl)thiophenol through an alkylation/oxidation two-step sequence. The stability of metalated BTFP sulfones has been studied and compared with heteroaryl benzothiazol-2-yl (BT), 1-phenyl-1H-tetrazol-5-yl (PT), and 1-tert-butyl-1H-tetrazol-5-yl (TBT) sulfones 9-11 under different reaction conditions. The Julia-Kocienski olefination between alkyl BTFP sulfones 7 and a wide variety of aldehydes affords the corresponding 1,2-disubstituted alkenes and dienes in good yields and stereoselectivities. This one-pot protocol can be performed using KOH at room temperature or the phosphazene bases P2-Et and P4-t-Bu at -78 °C or rt and has been successfully used in a high-yielding and stereoselective synthesis of various methoxylated stilbenes such as trimethylated resveratrol. These new reaction conditions for the Julia-Kocienski olefination reaction have been also studied with BT, PT, and TBT sulfones, giving poorer results. Methylenation of aliphatic and aromatic aldehydes, ketones, and 1,2-dicarbonyl compounds is carried out through the modified Julia olefination using BTFP methyl sulfone 7d to give terminal alkenes and dienes. Mechanistic studies of the olefination reaction between benzyl BTFP sulfone 7a and aromatic aldehydes performed by KOH-induced Smiles rearrangement of stereodefined syn- and anti-β-hydroxyalkyl BTFP sulfones indicate that the stereocontrol of the reaction is determined in the elimination step. [ABSTRACT FROM AUTHOR]

Reports on the study of mono and dilithiation of benzylmethallylamine with n-butyllithium leading to the new allyl sulfone anions. Configuration and conformation of heterocycles by HNMR experiments and X-ray analysis; Confirmation by Molecular Mechanics calculations; Studies on base-induced reactions.

During the last years, the development of more sustainable and straightforward methodologies to minimize the generation of waste organic substances has acquired high importance within synthetic organic chemistry. Therefore, it is not surprising that many efforts are devoted to ameliorating already well-known successful methodologies, that is, the case of the asymmetric allylic allylation reaction of carbonyl compounds. The use of free alcohols as alkylating agents in this transformation represents a step forward in this sense since it minimizes waste production and the substrate manipulation. In this review, we aim to gather the most recent methodologies describing this strategy by paying special attention to the reaction mechanisms, as well as their synthetic applications., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The recyclable chiral 2-aminobenzimidazole-derived organocatalyst 1f efficiently promotes the room temperature asymmetric conjugate addition of 1,3-diketones, β-ketoesters, and malonates to maleimide and N-substituted maleimides, affording the corresponding Michael adducts in excellent yields and enantioselectivities even at gram scale.