N-P二座配位のパラジウム(？U)触媒を用いたHeck反応に関する理論的研究

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Immobilization of Pd(0) nanoparticles on polyaza-ligand-functionalized polyacrylonitrile fiber as highly active catalyst for the Heck reaction

A gold-catalyzed Heck reaction of aryl and styryl iodides with styrenes was developed. The hemilabile P,N-ligand-assisted gold-catalyzed C(sp2)-C(sp2) cross-coupling can synthesize stilbenes and bistyryl complexes, with good functional-group tolerance and mild conditions. The elementary organometallic steps of migratory insertion and β-hydride elimination might be involved in this ligand-enabled Au(I)/Au(III)-catalyzed Heck reaction with styrenes.

1-(2-Iodophenyl)-1H-tetrazole as a ligand for Pd(II) catalyzed Heck reaction

As part of pharmacological-phytochemical in- tegrated studies of medicinal plants from Indian flora, costunolide (1) was isolated as a major compound from Saussurea lappa, plant traditionally used in different Asian traditional medicine systems. To improve the efficacy of this natural product lead, a series of analogues have been synthesized by the coupling of various aryl iodides using the standard Heck reaction conditions and evaluated for their cytotoxic activities against human cancer cell lines. The results indicated that several of the analogues were effective against the tested cell lines compared to the parent compound costunolide. Among the tested com- pounds, 2c and 2j demonstrated good activity against Hela cell line while compounds 2d showed potent activity against DU-145 and MCF-7 cell lines, respectively. Graphical Abstract A series of costunolide derivatives have been synthesized by Pd(II)-catalyzed Heck reaction and were studied for their cytotoxic properties against the panel of human cancer cell lines (B-16, DU-145, Hela, A549, MCF-7).

Pd 触媒を用いたHeck反応は、有機合成や有機金属化学において最も広く用いられている、重要な反応の一つである。触媒として用いられるPd 錯体の配位子は、反応性に影響するため、その探索は重要な研究課題の一つである。本研究では、密度汎関数理論（DFT）計算を用いて新たに合成された2-(2'-ピリジル)ベンゾアゾール, L を配位子に持つPd錯体を触媒としたHeck反応の反応機構の解析を行った。計算結果より、活性種は反応基質のエチレンとPh-Brから生成するPd(Ph)(Br)(L)であることがわかった。生成した活性種から始まる触媒サイクルは、(1)エチレン配位、(2)エチレン挿入反応、 (3) β-H引き抜き反応、(4)スチレンの脱離、 (5) Ph-Br配位、(6)H-Brの脱離反応、(7) Ph-Brの酸化的付加反応の7つの素反応過程から構成される。律速段階はPh-Brの酸化的付加反応であり、その活性化自由エネルギーは30 ～ 32 kcal/mol程度と計算された。これらの結果より、この触媒サイクルは、PdII/PdIV ではなく、Pd0/PdII で進むことが明らかとなった。

Predicting the catalytic efficiency by quantum-chemical descriptors: Theoretical study of pincer metallic complexes involved in the catalytic Heck reaction

Ligand-free indium(III)-catalyzed Heck reaction

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Palladium complexes containing an o-phenylene-derived amido diphosphine ligand efficiently catalyze the Heck olefination of a wide array of aryl halides, leading to extremely high turnover numbers of up to 4.5 × 107.

Preparation of the 5-substituted azepino[3,4-b]indole core structure can be realised through a catalytic Heck reaction. The scope and limitations of this methodology are reported. The reactivity of di-tert-butyl 5-ethoxycarbonylmethylene-1,3,4,5-tetrahydro-1-oxoazepino[3,4-b]indole-2,10-dicarboxylate (1) was investigated in order to prepare the indole analogue of hymenialdisine and derivatives.

Theoretical studies on the β-hydrogen elimination reactions of palladium and platinum alkoxide complexes containing bidentate ligands

Achieving high selectivity in the Heck reaction of electronically unbiased alkenes has been a longstanding challenge. Using a nickel‐catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for branched products (≥19:1 in all cases) over a wide range of aryl electrophiles and aliphatic olefins. A bidentate ligand with a suitable bite angle and steric profile was key to obtaining high branched/linear selectivity, whereas the appropriate base suppressed alkene isomerization of the product. Although aryl triflates are traditionally used to access the cationic Heck pathway, we have shown that, by using triethylsilyl trifluoromethanesulfonate, we can effect a counterion exchange of the catalytic nickel complex, such that cheaper and more stable aryl chlorides, mesylates, tosylates, and sulfamates can be used to yield the same branched products with high selectivity.

Facile synthesis of nanostructured Ni-Co/ZnO material: An efficient and inexpensive catalyst for Heck reactions under ligand-free conditions

Immobilization of Pd(0) nanoparticles on gemini quaternary ammonium functionalized polyacrylonitrile fibers as highly active catalysts for heck reactions and 4-nitrophenol reduction