Palladium-Catalyzed Sonogashira Reaction for the Synthesis of Arylalkynecarboxylic Acids from Aryl Bromides at Low Temperature

Gold(I)-Catalyzed Intramolecular Hydrothiophenylation of N-Thiophen-3-yl Alkynylamides for Accessing Thieno[3,2-b]pyridine-5(4H)-ones: Development of F-Actin Specific Fluorescent Probes

Herein, we describe an original synthetic method for a series of fluorescent thieno[3,2-b]pyridine-5(4H)-one derivatives prepared via the gold(I)-catalyzed 6-endo-dig intramolecular hydrothiophenylation process involving N-thiophen-3-yl alkynylamides. The brightness was improved; emission could be tuned, and larger Stokes shifts were recorded. We also designed and synthesized the phalloidin-based fluorescent chemical probes KF-P1 and KF-P2 to realize fluorescent F-actin imaging.

Cu(i)- and Pd(ii)-catalyzed decarboxylative cross-couplings of alkynyl carboxylic acids with N-tosylhydrazones: access to trisubstituted allenes and conjugated enynes

This paper reports the copper- and palladium-catalyzed decarboxylative cross-coupling reactions of alkynyl carboxylic acids and N-tosylhydrazones, affording trisubstituted allenes and conjugated enynes, respectively.

Vinyl sulfone synthesis via copper-catalyzed three-component decarboxylative addition

The synthesis of vinyl sulfone derivatives via the reaction of arylpropiolic acids, K₂S₂O₅, and aryl boronic acids is reported. The CuBr₂/1,10-phenanthroline catalytic system in the presence of acetic acid provides the desired vinyl sulfones in moderate to good yield. Furthermore, the methodology features excellent functional group tolerance.

Total Synthesis of Leiodermatolide A via Transfer Hydrogenative Allylation, Crotylation, and Propargylation: Polyketide Construction beyond Discrete Allyl- or Allenylmetal Reagents

The total synthesis of leiodermatolide A was accomplished in 13 steps (LLS). Transfer hydrogenative variants of three carbonyl additions that traditionally rely on premetalated reagents (allylation, crotylation, and propargylation) are deployed together in one total synthesis.

Gold-catalyzed homo- and cross-annulation of alkynyl carboxylic acids: a facile access to substituted 4-hydroxy 2H-pyrones and total synthesis of pseudopyronine A

A Au(i)-catalyzed homo- and cross-annulation reaction of alkynyl carboxylic acids offering 3,6-disubstituted 4-hydroxy 2H-pyrones has been demonstrated. The reaction tolerates various substituted alkynyl carboxylic acids and moderate to good yields of α-pyrone scaffolds have been observed. Later, a gram-scale reaction of the acid and the total synthesis of the natural product pseudopyronine A have been carried out successfully.

Palladium-catalyzed decarboxylative gem-selective addition of alkynoic acids to terminal alkynes

Alkynoic acids added to terminal alkynes to give gem-1,3-enynes with high selectivity and good yields. In addition, the reaction of alkynoic acids with propiolic acid provided the corresponding gem-1,3-enynes via double decarboxylation.

Ni/Cu-Catalyzed Decarboxylative Addition of Alkynoic Acids to Terminal Alkynes for the Synthesis of gem-1,3-Enynes

The synthesis of gem-1,3-enynes via Ni/Cu-catalyzed decarboxylative addition of alkynoic acids to terminal alkynes has been developed. It was found that the decarboxylation of an alkynoic acid led predominantly to gem-1,3-enynes instead of 1,3-diynes, which have been known to be formed through the coupling of terminal alkynes. A variety of gem-1,3-enynes were obtained in good yields. This catalytic system exhibited excellent regioselectivity and high functional group tolerance.

Biomimetic Enantioselective Total Synthesis of (-)-Robustanoids A and B and Analogues

We report a step-economical, enantioselective total synthesis of (-)-robustanoid B and (-)-robustanoid A and four novel natural product-like compounds. Our strategy relied on our biosynthetic hypothesis and on a novel complexity generation methodology, namely, the one-pot hydroxylative double cyclization reaction. The latter consists of a modified 3,3-dimethyldioxirane-triggered epoxidation-epoxide-ring-opening cyclization reaction cascade and Trost's regioselectivity umpolung methodology ("anti-Michael addition").

Selective assembly of N1- and N2-alkylated 1,2,3-triazoles via copper-catalyzed decarboxylative cycloaddition of alkynyl carboxylic acids with ethers and azidotrimethylsilane

An efficient and regiocontrolled method for the synthesis of various N1- and N2 alkylated 1,2,3-triazoles via copper-catalyzed decarboxylative cycloaddition of alkynyl carboxylic acids with ethers and azidotrimethylsilane.

A Parallel Approach to 7-(Hetero)arylpyrazolo[1,5- a]pyrimidin-5-ones

A modular, two-pot assembly of 7-arylpyrazolo[1,5- a]pyrimidones from aryl/heteroaryl halides and aminopyrazoles in library format was developed. Sonogashira coupling of aryl bromides with triethyl orthopropiolate, followed by in situ orthoester hydrolysis, provides access to β-aryl ynoates, which undergo regioselective cyclocondensation with aminopyrazoles. The ability to vary the C7 vector of 7-arylpyrazolo[1,5- a]pyrimidones in two steps using readily available (hetero)aryl halides significantly enhances synthetic access to this challenging vector.

Ruthenium-Catalyzed C-H Activation of Salicylaldehyde and Decarboxylative Coupling of Alkynoic Acids for the Selective Synthesis of Homoisoflavonoids and Flavones

Homoisoflavonoids were formed in DMSO exclusively, and flavones were formed in t-AmOH when salicylaldehyde and alkynoic acids reacted with [Ru(p-cymene)Cl₂]₂ and CsOAc. They were formed through C-H activation of salicylaldehyde and decarboxylative coupling of alkynoic acid. This reaction system showed good yields, broad substrate scope, and good functional group tolerance. It was found that chalcone was an intermediate in the formation of both homoisoflavonoid and flavone.

Palladium-Catalyzed Decarboxylative Coupling of Alkynyl Carboxylic Acids with Aryl Tosylates

Decarboxylative coupling reactions of alkynyl carboxylic acids with aryl tosylates were developed in the presence of a palladium catalyst. Among the commercially available phosphine ligands, only 1-dicyclohexylphosphino-2-(di-tert-butylphosphino-ethyl)ferrocene (CyPF-tBu) showed good reactivity. The reaction took place smoothly and gave the decarboxylative coupled products in moderate to good yields. This demonstrates the excellent functional group tolerance toward alkyl, alkoxy, fluoro, thiophenyl, ester, and ketone groups. In addition, alkyl-substituted propiolic acids, such as octynoic and hexynoic acids, were coupled with phenyl tosylate to provide the desired products. We found that the electronic properties of the substituents on the phenyl ring in arylpropiolic acids are an important factor. The order of reactivity was found to be aryl iodide > aryl bromide > aryl tosylate > aryl chloride. However, aryl chloride-bearing electron-withdrawing groups showed higher reactivity than those bearing aryl tosylates.

Sonogashira coupling in 3D-printed NMR cuvettes: synthesis and properties of arylnaphthylalkynes

A set of push–pull substituted arylnaphthylalkynes has been synthesized under inert gas conditions in 3D-printed cuvettes out of NMR-transparent polyamide and their optical properties were investigated.

Supported palladium nanoparticles-catalyzed decarboxylative coupling approaches to aryl alkynes, indoles and pyrrolines synthesis

The polystyrene supported palladium (Pd@PS) nanoparticles catalyzed decarboxylative coupling of arylhalides and alkynyl carboxylic acids was developed for the synthesis of diaryl alkynes, indoles and pyrrolines.

Ag-mediated cascade decarboxylative coupling and annulation: a convenient route to 2-phosphinobenzo[b]phosphole oxides

Structurally sophisticated 2-phosphinobenzo[b]phosphole oxide frameworks have been conveniently constructed by cascade decarboxylative coupling and annulation reactions.

Copper-catalyzed direct decarboxylative hydrosulfonylation of aryl propiolic acids with sulfonylhydrazides leading to vinylsulfones

A simple and facile protocol for (E)-vinylsulfones was developed using inexpensive propiolic acids or terminal alkynes as new alkene sources.

Rapid access to unsymmetrical 1,3-diynes and 2,5-disubstituted thiophenes under ligand and Pd/Ni-free Cu-catalysis

A Pd/Ni-free copper-catalysed tandem synthesis was realized for rapid access to unsymmetrical 1,3-diynes from 1,1-dibromoalkenes and terminal alkynes.