Pd-catalyzed Domino Research Articles

Pd-catalyzed domino reactions of nitroaromatics: A surrogate access towards the saturated N-heterocycles

Using Pd/HCOOCs as a surrogate reagents synthesis of saturated N-heterocycles was described from nitroaromatics as starting materials. The developed new reaction conditions exclude the generally used toxic reagents like carbon monoxide as deoxygenative agent. The developed protocol permits the synthesis privileged bioactive N-heterocyclic scaffolds in good yields and selectivity.

ChemInform Abstract: Diastereoselective Pd‐Catalyzed Domino Heck/Arylborylation Sequence Forming Borylated Chromans.

AbstractThe reaction can be scaled up.

Diastereoselective Pd-Catalyzed Domino Heck/Arylborylation Sequence Forming Borylated Chromans

A diastereoselective palladium-catalyzed domino Heck/arylborylation of aryl iodides yielding an alkylboronate containing a chroman is reported. The generated alkylpalladium(II) intermediate is intercepted with bis(pinacolato)diboron (B2pin2) in good yield as a single diastereomer.

ChemInform Abstract: Domino Heck/Borylation Sequence Towards Indolinone‐3‐methyl Boronic Esters: Trapping of the σ‐Alkylpalladium Intermediate with Boron.

Pd-catalyzed domino Heck/borylation of acrylamides with B2pin2 is reported to generate synthetically useful indolinone-3-methyl boronic esters, via capturing σ-alkyl palladium with boron. Further functionalization of the obtained boronic ester qualify it as a new starting point for the functionalization of specific C(sp(3))-H bond. Moreover, the application of an Ugi-adduct as starting material or B2nep2 as an alternative boron source works equally well, making this a broadly applicable and robust method for the formation of a C-C and C-B bond in a single operation.

ChemInform Abstract: Regio‐ and Chemoselective N‐1 Acylation of Indoles: Pd‐Catalyzed Domino Cyclization to Afford 1,2‐Fused Tricyclic Indole Scaffolds.

AbstractThe procedure allows access to various tricyclic N‐heterocycles which contain a diazepine unit.

Synthesis of indolo[1,2-f]phenanthridines by Pd-catalyzed domino C-N coupling/hydroamination/C-H arylation reactions.

A new and convenient method for the synthesis of indolo[1,2-f]phenanthridines via palladium-catalyzed domino C-N coupling/hydroamination/C-H arylation reactions was developed. The reactions allow for the synthesis of various phenanthridines in good yields from easily accessible starting materials using a single palladium catalyst.

Domino Heck/borylation sequence towards indolinone-3-methyl boronic esters: trapping of the σ-alkylpalladium intermediate with boron.

Pd-catalyzed domino Heck/borylation of acrylamides with B2pin2 is reported to generate synthetically useful indolinone-3-methyl boronic esters, via capturing σ-alkyl palladium with boron. Further functionalization of the obtained boronic ester qualify it as a new starting point for the functionalization of specific C(sp(3))-H bond. Moreover, the application of an Ugi-adduct as starting material or B2nep2 as an alternative boron source works equally well, making this a broadly applicable and robust method for the formation of a C-C and C-B bond in a single operation.

Synthesis of pyrrolocoumarins via Pd-catalyzed domino C–N coupling/hydroamination reactions

A series of chromeno[3,4-b]pyrrol-4(3H)-ones were synthesized by Pd-catalyzed domino C–N coupling/hydroamination reactions. This methodology provides a new and convenient approach to pyrrolocoumarins in only two steps from readily available starting materials.

A fast way to fluorescence: a fourfold domino reaction to condensed polycyclic compounds.

A fast and efficient palladium-catalyzed fourfold domino Sonogashira/double-carbopalladation/CH-activation reaction that converts simple aromatic systems into complex polycyclic hydrocarbons has been developed. A number of substituted products has thus been prepared in yields up to 89 %. The structural assignment has been confirmed by using single-crystal X-ray crystallography. The products show intriguing fluorescence activity and thus might serve as chemical sensors or fluorescent imaging dyes.

Domino synthesis of 1,3-diynes from 1,1-dibromoalkenes: a Pd-catalyzed copper-free coupling method

Pd-catalyzed domino synthesis of 1,3-diynes was accomplished using 1,1-dibomoalkenes under copper-free coupling conditions. This domino procedure involves base mediated in situ generation of 1-bromoalkyne and its subsequent coupling to give 1,3-diyne. The optimized copper-free coupling method afforded good to high yields of symmetrical 1,3-diynes in a one-pot operation.

Fe-catalyzed novel domino isomerization/cyclodehydration of substituted 2-[(indoline-3-ylidene)(methyl)]benzaldehyde derivatives: an efficient approach toward benzo[b]carbazole derivatives.

A new and efficient protocol to synthesize substituted benzo[b]carbazole derivatives has been demonstrated involving iron-catalyzed domino isomerization/cyclodehydration sequences from substituted 2-[(indoline-3-ylidene)(methyl)]benzaldehyde derivatives. The substrates could be easily made via Pd-catalyzed domino Heck-Suzuki coupling from 2-bromo-N-propargylanilide derivatives in high yields. Notably, the generality and efficiency of this two-stage domino strategy was further exemplified by the synthesis of a polycyclic benzofuran derivative.

A Simple and Efficient Microwave-Assisted Synthesis of Substituted Isoindolinone Derivatives via Ligand-Free Pd-Catalyzed Domino C-C/C-N Coupling Reaction

We have reported a microwave-assisted, ligand-free Pd-catalyzed domino C–C/C–N coupling reaction to construct diverse isoindolinone derivatives using amides and isocyanides as coupling partners. This strategy provides isoindolinone derivatives in moderate to good yield and high stereoselectivity. A broad range of amides has been tolerated and there is no need for extra-dry conditions in this reaction protocol, which offered highly diverse products and easy handling of the reaction.

ChemInform Abstract: Palladium‐Catalyzed Cascade Process Consisting of Isocyanide Insertion and Benzylic C(sp3)—H Activation: Concise Synthesis of Indole Derivatives.

Synthesis of the indole skeleton was achieved using a Pd-catalyzed cascade process consisting of isocyanide insertion and benzylic C(sp3)–H activation. It was found that slow addition of isocyanide is effective for reducing the amount of catalyst needed and Ad2PnBu is a good ligand for C(sp3)–H activation. The construction of the tetracyclic carbazole skeleton was also achieved by a Pd-catalyzed domino reaction incorporating alkyne insertion.

Palladium-Catalyzed Domino Carbopalladation/C–H Activation for the Synthesis of Tetrasubstituted Alkenes Bearing Five- and Seven-Membered Rings

A Pd-catalyzed domino carbopalladation/C–H-activation reaction of phenoxyphenyl-substituted propargylic alcohols was used for the synthesis of tetrasubstituted alkenes bearing either a dihydroindene or benzo[7]annulene motif. These compounds are of interest for the construction of molecular switches and motors.

Palladium-Catalyzed Cascade Process Consisting of Isocyanide Insertion and Benzylic C(sp3)–H Activation: Concise Synthesis of Indole Derivatives

Synthesis of the indole skeleton was achieved using a Pd-catalyzed cascade process consisting of isocyanide insertion and benzylic C(sp(3))-H activation. It was found that slow addition of isocyanide is effective for reducing the amount of catalyst needed and Ad(2)P(n)Bu is a good ligand for C(sp(3))-H activation. The construction of the tetracyclic carbazole skeleton was also achieved by a Pd-catalyzed domino reaction incorporating alkyne insertion.

ChemInform Abstract: A Domino Palladium‐Catalyzed C—C and C—O Bonds Formation via Dual O—H Bond Activation: Synthesis of 6,6‐Dialkyl‐6H‐benzo[c]chromenes.

An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2-bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald–Hartwig cyclization. This domino process effectively involves breaking of five σ-bonds (2C–Br, 2O–H, and a C–C) and formation of two new σ-bonds (C–C and C–O). This mechanistic pathway is unprecedented and further illustrates the power of transition metal catalysis.

A Domino Palladium-Catalyzed C–C and C–O Bonds Formation via Dual O–H Bond Activation: Synthesis of 6,6-Dialkyl-6H-benzo[c]chromenes

An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2-bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald-Hartwig cyclization. This domino process effectively involves breaking of five σ-bonds (2C-Br, 2O-H, and a C-C) and formation of two new σ-bonds (C-C and C-O). This mechanistic pathway is unprecedented and further illustrates the power of transition metal catalysis.

Pd-catalyzed domino carbonylative–decarboxylative allylation: an easy and selective monoallylation of ketones

In the presence of an allyl alcohol, α-chloroacetophenones undergo an allyloxycarbonylation reaction followed by in situ decarboxylative allylation to selectively afford the corresponding monoallylated ketones via a Pd-catalyzed domino sequence. The scope of the reaction was extended to substituted α-chloroacetophenones as well as various allyl alcohols.

A Ridge Walk between Reaction Modes: An Unprecedented Pd-Catalyzed Domino Sequence of Diynyl-Substituted Bromoarenes

Diynyl-substituted bromoarenes underwent a novel Pd-catalyzed domino reaction to provide benzofurans, pyridinofurans, isochromenes, and indole derivatives. Slight changes of the substrate push the reaction in another direction resulting in benzene annulation.

Palladium-Catalyzed Aromatic Sulfonylation: A New Catalytic Domino Process Exploiting in situ Generated Sulfinate Anions

Allylic sulfones are excellent precursors of aryl sulfones via a new Pd-catalyzed domino sequence involving in situ generation of sulfinate anions and subsequent cross-coupling with aryl ­iodides or bromides.