联苯类化合物的合成

联苯类化合物是一类极为重要的有机合成中间体,在有机合成中往往通过有机金属偶联反应构建此类化合物.以反应底物分类综述了近年来通过偶联反应合成此类化合物的方法,详细介绍了以卤代芳烃与芳基金属化合物为底物的反应.     

Artificial,molecular-based light-harvesting antenna systems made of metal dendrimers and multibodipy species

Artificial photosynthesis is expected to include the development of light-harvesting antenna systems, similarly to what Natural Photosynthesis does. Here some basic requirements for designing synthetic light-harvesting antennae are presented, together with the results obtained by our team in the last few decades on light-harvesting antennae based on metal dendrimers or made of multibodipy species.     

Convenient synthesis of photochromic symmetrical or unsymmetrical bis(heteroaryl)maleimides via the Suzuki-Miyaura cross-coupling reaction

A general method for the synthesis of symmetrical or unsymmetrical bis(heteroaryl)maleimides by a one-pot procedure involving Suzuki-Miyaura cross-coupling sequence was developed on the basis of the reaction of 3,4-diiodo-1-benzyl-1H-pyrrole-2,5-dione with cyclic boronate esters using PdCl₂(dppf) as the catalyst. Photochromic properties of the products were examined.     

Functionally layered dendrimers: a new building block and its application to the synthesis of multichromophoric light-harvesting systems

[reaction: see text] A divergent synthesis of internally functionalized dendrimers based on a modular functional monomer has been developed. This strategy was applied to the construction of a light-harvesting dendrimer containing one set of naphthopyranone dyes located at the interior and another set of coumarin chromophores located in the adjacent outer layer surrounding a porphyrin acceptor. Quantitative energy transfer from both donor pigments is observed, giving rise to exclusive emission from the porphyrin core over all excitation wavelengths.     

Synthesis of formyl-thienylpyrroles: versatile building blocks for NLO materials

Several formyl-substituted 1-alkyl(aryl)-2-(2′-thienyl)pyrroles 3-7 were synthesized by functionalization of the pyrrole or thiophene ring of thienylpyrroles 2 using different methods: Vilsmeier formylation or metalation followed by reaction with DMF.     

An alternative convergent synthesis of dendrimers with 2,5-diarylsilole at the core

Dendrimers with 2,5-diarylsilole at the core are readily synthesized by the Ni-catalyzed reaction of 1,1,2,2-tetramethyldisilane and 1,6-diynes having poly(benzyl ether)-dendron units. The dendrimers display, upon excitation of the silole ring, an emission at about 500 nm. The fluorescence quantum yield of the dendrimers increases with increasing the generation of the dendron units. In addition, upon excitation of dendron units in the periphery, the dendrimers also display an emission from the silole ring at the core through the energy transfer from the dendron units to the silole core within the dendrimers.     

Synthesis of enantiomeric-pure cyclohexenyl nucleoside building blocks for oligonucleotide synthesis

Lipases were used for the resolution of (±) (4aR, 7R, 8aS)-2-phenyl-4a,7,8,8a-tetrahydro-4H-1,3-benzodioxine. This separation was carried out on preparative scale and used for the synthesis of eight phosphoramidites of cyclohexenyl nucleosides (d- and l-series).     

Synthesis of new 6-substituted purinyl-5′-nor-1′-homocarbanucleosides based on indanol

A series of new 6-substituted purinyl-5′-nor-1′-homocarbanucleosides based on indanol were synthesized from (±)-cis-3-hydroxymethyl-1-indanol, an appropriately functionalized derivative of which was reacted with 6-chloropurine in the presence of NaH and 18-crown-6 ether to prepare a key intermediate that gave access to the target molecules, purinylcarbanucleosides in which position 6 is occupied by a chloro, hydroxy, methoxy, amino or substituted phenyl group.     

Enantiomerically enriched cyclopropene derivatives: versatile building blocks in asymmetric synthesis

Enantiomerically enriched cyclopropene derivatives, the smallest possible unsaturated carbocycles, are of great synthetic interest since they serve as versatile reactive building blocks. Their reactivity results from the relief of the ring strain in the small molecule. They can be transformed into a wide variety of complex chiral structures and a special emphasis will be directed towards the preparation of enantiomerically enriched methylene- and alkylidenecyclopropane derivatives. The ready availability of a wide range of these chiral entities now provides an excellent opportunity to discover new and unique transformations that can further enrich mainstream synthetic methodology.     

Synthesis of unnatural cyclitols via a combined enzymatic-palladium catalysis approach

The Suzuki-Miyaura cross-coupling reaction of a hydroxylated vinyl bromide obtained by a chemoenzymatic approach with a diverse range of potassium organotrifluoroborates has been accomplished catalyzed by Pd(PPh₃)₄ in satisfactory yields. A variety of functional groups are tolerated in the nucleophilic partner.     

Boronic acid-substituted metal complexes: versatile building blocks for the synthesis of multimetallic assemblies

Polypyridyl complexes of Ru(II) and Ir(III) incorporating a boronic acid substituent undergo cross-coupling with bromo-substituted complexes, and a sequential coupling-bromination-coupling strategy permits the controlled synthesis of a luminescent Y-shaped heterometallic assembly, in which efficient energy transfer to the terminus occurs.     

AB3 building blocks for the synthesis of polyester dendrimers

Syntheses of several examples of a new type of trivalent building blocks for the preparation of aliphatic polyester dendrimers are presented. Starting from the well-known mono-O-benzylidenepentaerythritol, AB₃ type acid dendrons can be obtained in high yield in only two steps. Other triprotected bis-2,2-(hydroxymethyl)-3-hydroxypropanoic acid derivatives with varying protecting groups were also synthesized readily. This type of dendron was used in combination with 2,2′-bis(hydroxymethyl) propanoic acid (bis-HMPA) divalent dendrons to produce low generation mixed polyester dendrimers with increased number of branching points.     

Versatility of the Biginelli reaction: Synthesis of new biphenyl dihydropyrimidin-2-thiones using different ketones as building blocks

A multi-component synthesis of biphenyl dihydropyrimidin-2-thiones from 1-phenylthiourea, aldehydes and ketones or di-ketones has been demonstrated. The reaction proceeded well for aldehydes with electron donor or acceptor substituents under mild conditions.     

Prospects and Applications of Palladium Nanoparticles in the Cross-coupling of (hetero)aryl Halides and Related Analogues

Discovering efficient methods for the formation of carbon-carbon bonds is a central ongoing theme in organic synthesis. Cross-coupling reactions catalysed by metal nanoparticles are attractive alternatives to the traditional use of metal counterparts due to the catalytic tunability, selectivity, recyclability and reusability of the nanoparticles. The ongoing search for sustainable processes demands that reusable and environmentally benign catalysts are used. While the advantages of nanoparticles catalysts over bulk catalysts cannot be overemphasised, the problem of sintering, agglomeration and leaching are drawbacks to their full industrial applications. Hence, efforts are being made towards advancing the efficiency of the catalytic nanoparticle systems over the years. This review presents the progress, the challenges and the prospects of palladium nanoparticle with focus on Heck, Suzuki, Hiyama and Sonogashira cross-coupling reactions involving (hetero) aryl halides and the analogues.     

Synthesis of new polyaza heterocycles. Part 42: Diazines

Using Pd-catalyzed Stille cross-coupling reactions, we report here the synthesis of various mono- or bis(tri-n-butylstannyl)diazines which were reacted with various halogenated diazines to access to various polyaza heterocyclic derivatives.     

Salen and half-salen palladium(II) complexes: synthesis, characteriztion and catalytic activity toward Suzuki-Miyaura reaction

Salen and half-salen palladium(II) complexes (salden)Pd (1, salden=N,N′-bis(3,5-di- tert-butylsalicylidene)-1,2-dimethylethylenediamine), (hsalph)PdCl (2, hsalph=3,5-di-tert- butylsalicylidene-1-iminophenylene-2-amine), and (salph)Pd (4, salph=N,N′-bis(3,5-di-tert- butylsalicylidene)-1,2-phenylenediamine) were prepared and structurally characterized by X-ray crystallography. Complex 2 proved to exhibit high catalytic activity toward Suzuki-Miyaura reaction. Polyaromatic C₃-symmetric derivatives and various fluorinated biphenyl derivatives were readily achieved in good yields using Suzuki-Miyaura reaction catalyzed by complex 2.     

Ethynyl MIDA boronate: a readily accessible and highly versatile building block for small molecule synthesis

Ethynyl N-methyliminodiacetic acid (MIDA) boronate is a very useful building block for small molecule synthesis. This compound can serve as both a bifunctional acetylene equivalent with the capacity for terminus-selective bis-functionalization and a versatile starting material for the preparation of a wide range of other MIDA boronate building blocks.     

含羟基手臂双咪唑鎓氯盐的合成及其Pd络合物对Suzuki-Miyaura交叉偶联反应的催化活性

合成了一种新型含羟基手臂的双咪唑鎓氯盐(L.2HCl)。N2保护下L.2HCl与Pd(OAc)2原位制备N-杂环卡宾-Pd络合物。以DMF-H2O为溶剂,K2CO3为碱,该络合物催化溴代芳烃和芳基硼酸的Suzuki-Miyaura交叉偶联反应合成取代联苯,收率75%～99%。     

Synthesis and cross-coupling reactions of imidomethyltrifluoroborates with aryl chlorides

Potassium imidomethyltrifluoroborate salts were efficiently synthesized. Potassium phthalimidomethyltrifluoroborate was successfully used in Suzuki-Miyaura-like cross-coupling reactions with a variety of aryl chlorides.