53256-11-4

Upstream product

• 55606-94-5 1,4-bis(4'-fluorophenyl)-buta-1,3-diyne 
• 405-99-2 para-fluorostyrene 
• 460748-43-0 (E)-2-(4-fluorophenyl)vinylboronic acid 

Relevant academic research and scientific papers

Catalytic Dehydrogenative C-C Coupling by a Pincer-Ligated Iridium Complex

The pincer-iridium fragment (iPrPCP)Ir (RPCP = ?3-2,6-C6H3(CH2PR2)2) has been found to catalyze the dehydrogenative coupling of vinyl arenes to afford predominantly (E,E)-1,4-diaryl-1,3-butadienes. The eliminated hydrogen can undergo addition to another molecule of vinyl arene, resulting in an overall disproportionation reaction with 1 equiv of ethyl arene formed for each equivalent of diarylbutadiene produced. Alternatively, sacrificial hydrogen acceptors (e.g., tert-butylethylene) can be added to the solution for this purpose. Diarylbutadienes are isolated in moderate to good yields, up to ca. 90% based on the disproportionation reaction. The results of DFT calculations and experiments with substituted styrenes indicate that the coupling proceeds via double C-H addition of a styrene molecule, at β-vinyl and ortho-aryl positions, to give an iridium(III) metalloindene intermediate; this intermediate then adds a β-vinyl C-H bond of a second styrene molecule before reductively eliminating product. Several metalloindene complexes have been isolated and crystallographically characterized. In accord with the proposed mechanism, substitution at the ortho-aryl positions of the styrene precludes dehydrogenative homocoupling. In the case of 2,4,6-trimethylstyrene, dehydrogenative coupling of β-vinyl and ortho-methyl C-H bonds affords dimethylindene, demonstrating that the dehydrogenative coupling is not limited to C(sp2)-H bonds.

Ligand-Free Iron-Catalyzed Carbon (sp2)-Carbon (sp2) Oxidative Homo-Coupling of Alkenyllithiums

A new strategy was developed for the efficient synthesis of di-, tetra-, and hexa-substituted 1,3-butadienes. This one-pot procedure involves lithium-iodine exchange to generate the corresponding vinyllithium intermediates. A subsequent iron-catalyzed ligand-free oxidative homo-coupling eventually led to the formation of 1,3-butadienes in acceptable to excellent isolated yields.

Pd-catalyzed oxidative homo-coupling of acrylates and aromatic alkenes for the conjugated diene synthesis

We developed a bidentate monoanionic nitrogen ligand that was effective in the Pd-catalyzed oxidative homo-coupling reaction of acrylates and aromatic alkenes. In the presence of Pd(OAc)2/ligand several conjugated dienes were obtained in good yields with high stereoselectivities.

Copper(I)-catalyzed stereoselective hydrogenation of 1,3-diynes and enynes

A stereoselective hydrogenation of 1,3-diynes with an air-stable copper(I)/N-heterocyclic carbene complex, [IPrCuOH], has been developed. The corresponding products, 1,3-dienes, are obtained in a stereoselective manner depending on their substitution pattern: Diaryl-diynes yield E,E-1,3-dienes, whereas dialkyl-diynes are converted to the corresponding Z,Z-1,3-dienes. Hydrogenation and deuteration experiments with enynes indicate that these are competent reaction intermediates in the hydrogenation of diynes.

Synthesis of Buta-1,3-dienes through Palladium-Catalyzed Homocoupling of Aromatic Alkenes

A series of buta-1,3-dienes have been directly synthesized via a convenient palladium-catalyzed homodehydrogenation coupling reaction of aromatic alkenes under mild conditions. The homocoupling reaction enables a rapid synthesis of multisubstituted butadiene which shows typical aggregation-induced emission enhancement (AIEE) characteristics because it is practically not emissive in solution but emits blue fluorescence in aggregates.

Oxidative dimerization: Pd(II) catalysis in the presence of oxygen using aqueous media

Reported herein is a method for the formation of symmetric biaryls and dienes via oxidative dimerization of aryl and alkenyl boronic acids. These conditions utilized Pd(II) catalysts under an oxygen atmosphere with water as the solvent. The use of phase transfer catalysts promoted efficient and mild syntheses of a wide range of materials.