Selective synthesis of 3-methyleneindolin-2-ones by one-pot multicatalytic processes

A General and Highly Versatile Heterogeneous Pd-Catalyzed Oxidative Aminocarbonylation of Alkynes with Aromatic and Aliphatic Amines

An efficient heterogeneous catalytic system for the oxidative aminocarbonylation of alkynes and amines in the presence of CO/O2 to afford substituted propiolamides has been developed. The active nanocatalyst, [Pd/Mg3Al-LDH]-300(D), is composed by Pd nanoaggregates (2-3 nm average particle size) stabilized over a partially dehydrated [Mg3Al-LDH] matrix. The methodology has resulted widely applicable, being the first catalytic system, either homogeneous or heterogeneous, able to activate not only aliphatic amines but also poorly-nucleophilic aromatic amines. In fact, >60 substituted propiolamides have been synthesized in good to excellent isolated yields through this methodology, being 27 novel compounds. An important characterization effort (XRD, 27Al MAS NMR, TGA, TPD-CO2, BET area, XPS, HAADF-HRSTEM and HRTEM) and optimization of the synthesis conditions of the optimal catalyst has been performed. This study, together with a series of kinetic and mechanistic essays, indicates that the optimal catalyst is composed by Pd(0) species stabilized in a partially dehydrated/dehydroxylated LDH material with a Mg/Al molar ratio of 3 and a small crystallite size. All the experimental data indicates that the in situ formation of [PdI2] active species in the material surface together with the presence of a matrix with the optimal acid/base properties are key aspects of this process.

Difluorocarbene-Enabled Synthesis of 3-Alkenyl-2-oxindoles from ortho-Aminophenylacetylenes

Herein, we report a transition-metal-free [4 + 1] cyclization pathway from difluorocarbene and ortho-amino aryl alkynone, rendering an effective and universal strategy for the construction of 3-alkenyl-2-oxindoles. Our strategy starts from cheap and accessible ortho-amino aryl alkynone instead of the direct indole skeleton; moreover, in situ generated difluorocarbene from commercially available halogenated difluoroalkylative reagents enables the cleavage of a C-N bond and formation of new C-N bonds and C-C bonds.

Transient Chelating Group-Controlled Stereoselective Rh(I)-Catalyzed Silylative Aminocarbonylation of 2-Alkynylanilines: Entry to (Z)-3-(Silylmethylene)indolin-2-ones

A new, mild acryl transient chelating group-controlled stereoselective Rh(I)-catalyzed silylative aminocarbonylation of 2-alkynylanilines with CO and silanes for producing (Z)-3-(silylmethylene)indolin-2-ones is presented. By using an acryl transient chelating group 2-alkynylanilines...

Domino carbometalation/coupling reactions of N-arylpropiolamides: a novel and promising synthetic strategy toward stereocontrolled preparation of highly substituted 3-methyleneindolinones

3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natural occurrence and pharmacological significance.

Synthesis of Functionalized 6-Hydroxy-2-oxindole Derivatives by Phenoxide Cyclization

An apparent intramolecular cross-dehydrogenative coupling of N-(3-hydroxy)monoanilide of maleic esters comprising base promoted phenoxide cyclization and subsequent base-mediated aerobic oxidation was developed to synthesize a variety of 2-(6-hydroxy-2-oxoindolin-3-ylidene)acetate derivatives. The isolation of intermediate cyclized products during the large scale reactions and their ready dehydrogenation with 1 equiv of base support this proposed two-step path.

Palladium-Catalyzed One-Pot Approach to 3-(Diarylmethylene)oxindoles from Propiolamidoaryl Triflate

3-(Diarylmethylene)oxindoles have been synthesized from propiolamidoaryl triflate utilizing a palladium-catalyzed one-pot reaction consisting of three successive reactions: Sonogashira, Heck, and Suzuki-Miyaura. This method allows for the production of a complex skeleton of 3-(diarylmethylene)oxindole from propiolamidoaryl triflate using a commercially available aryl iodide and arylboronic acid in a simple and efficient way with moderate yield and stereoselectivity.

Sequential one-pot approach for the synthesis of functionalized phthalans via Heck-reduction–cyclization (HRC) reactions

An efficient and practical method is described for the direct synthesis of 1,3-dihydroisobenzofurans, an important structural motif present in biologically active natural or synthetic compounds.

Catalytic thia-Sommelet-Hauser rearrangement: application to the synthesis of oxindoles

A series of 3-arylthio-1,3-disubstituted-oxindoles were prepared in good yields by the reaction of α-diazocarbonyl compounds and sulfenamides. The reaction involves a Rh-catalyzed thia-Sommelet-Hauser-type rearrangement.