Ru-MACHO-Catalyzed Direct Inter/Intramolecular Macrocyclization of Alcohols and Ketones.

Herein we describe a new approach for end-to-end cyclization to construct macrocycles through the inter/intramolecular dehydrogenative coupling of alcohols and ketones in the presence of a Ru-MACHO catalyst. This method is highly atom economical and sustainable and can be used for many substrates. Additionally, this method results in the generation of only water as the byproduct.

Catalytic Acceptorless Dehydrogenation of Amino Alcohols and 2-Hydroxybenzyl Alcohols for Annulation Reaction under Neutral Conditions.

A base-free and acceptorless Ru-catalyzed dehydrogenative approach has been developed for the synthesis of -heterocycles by using 1,3-dicarbonyls and amino alcohols through a domino sequential enamine formation and intramolecular oxidative cyclization strategy. This unified approach is also applicable for the synthesis of O-heterocycles involving 2-hydroxybenzyl alcohol as a coupling reactant via consecutive C-alkylation and intramolecular cyclization steps. The present protocol is general for the synthesis of varieties of biologically important scaffolds, such as tetrahydro-4-indol-4-one, 3,4-dihydroacridin-1(2)-one, and tetrahydro-1-xanthen-1-ones derivatives using a single catalytic system, viz.

Proton-Coupled Electron Transfer in the Aqueous Nanochannels of Lyotropic Liquid Crystals: Interplay of H-Bonding and Polarity Effects.

A molecular-level description of the aqueous nanochannels in lyotropic liquid crystals (LLCs) is crucial for their widespread utilization in diverse fields. Herein, the polarity and hydrogen bonding effects of LLC water molecules have been simultaneously explored using a single probe, 4'-N,N-dimethylamino-3-hydroxyflavone (DMA3HF), by the unique multiparametric sensitivity of the excited state proton-coupled electron transfer (PCET) phenomenon. The decreased ESIPT efficiency and the significantly retarded ESIPT dynamics (>20 times) of DMA3HF in the LLC phases suggests the dominant influence of strong hydrogen-bonded solute-solvent complexes that leads to a high activation barrier for ESIPT in the mesophases.

Synthesis of Quaternary Spirooxindole 2H-Azirines under Batch and Continuous Flow Condition and Metal Assisted Umpolung Reactivity for the Ring-Opening Reaction.

An efficient and new approach for the synthesis of spirooxindole 2H-azirines via intramolecular oxidative cyclization of 3-(amino(phenyl)methylene)-indolin-2-one derivatives in the presence of I and Cs CO under batch/continuous flow is described. This method is mild and facile to synthesize a variety of spirooxindole 2H-azirines derivatives in gram-scale. Furthermore, we have synthesized spiroaziridine derivatives from spirooxindole 2H-azirines derivatives via addition of Grignard reagent.

Transition-Metal-Free Addition Reaction for the Synthesis of 3-(Aminobenzylidene/aminoalkylidene)indolin-2-ones and Its Synthetic Applications.

A novel and efficient transition-metal-free approach for the exclusive synthesis of -3-(aminobenzylidene/aminoalkylidene)indolin-2-ones in high yield from 2-oxindole and aryl/alkyl nitrile in the presence of LiOBu and 2,2'-bipyridine system is described. In addition, we disclosed a new approach towards the metal-free fluorination using selectfluor and the C═C bond cleavage using CuI and environmentally benign O.

Ru-Catalyzed dehydrogenative synthesis of antimalarial arylidene oxindoles.

Ru(ii)-NHC catalyzes α-olefination of 2-oxindoles using diaryl methanols in the absence of an acceptor. A wide array of symmetrical and unsymmetrical diaryl methanols undergoes dehydrogenative coupling with 2-oxindole selectively to generate various substituted 3-(diphenylmethylene)indolin-2-one derivatives in good yields and produces environmentally benign by-products, H2 and H2O. This methodology was successfully applied for the synthesis of a bioactive drug i.

Iron-Catalyzed Batch/Continuous Flow C-H Functionalization Module for the Synthesis of Anticancer Peroxides.

Iron-catalyzed dehydrogenative cross-coupling of carbonyl compounds with aliphatic peroxide was developed under mild conditions. A library of linear alkylated and arylated peroxides are synthesized in good to excellent yield. This method is highly selective and general for a range of biologically important derivatives of 2-oxindole, barbituric acid, and 4-hydroxy coumarin with a good functional group tolerance and without the cleavage of the peroxide bond.

Ru-NHC Catalyzed Domino Reaction of Carbonyl Compounds and Alcohols: A Short Synthesis of Donaxaridine.

Direct α-alkylation of amides and the synthesis of C3-alkylated 3-hydroxyindolin-2-one/2-substituted-2-hydroxy-3,4-dihydronaphthalen-1(2)-one derivatives from 2-oxindole/1-teralone were reported using primary alcohols in the presence of Ru-NHC catalyst in a one pot condition under the borrowing hydrogen method. In the case of inert conditions, 2-oxindole/1-teralone exclusively forms the C3-alkylated product. Whereas, allowing this reaction mixture to occur under an air atmosphere predominantly forms C3-alkylated 3-hydroxyindolin-2-one via domino C-H alkylation and aerobic C-H hydroxylation.

Ruthenium-catalyzed direct α-alkylation of amides using alcohols.

The highly efficient direct α-alkylation of unactivated amides has been accomplished using alcohols in the presence of the Ru-PNN catalyst (0.1 mol%) with a high turnover number. Using this approach, 2-oxindole was directly transformed into C3-alkylated 3-hydroxyindolin-2-one in one step without the use of any oxidant.