A Stille biaryl-coupling approach to dityrosines. Formal total synthesis of Hazimycin

The Stille cross-coupling reaction between 3-tributylstannyltyrosine derivatives (15-23, 40), and 3-iodotyrosines (6-14, 39) afforded the corresponding dityrosines (24-37, 41). Additionally, this method provided a short and improved access to Hazimycin (3) a naturally occurring anti-fungal agent.     

Carbon-carbon bond forming reactions via Pd-catalyzed detellurative homocoupling of diorganyl tellurides

A simple and highly efficient method for the constructions of Csp-Csp, Csp²-Csp² and Csp³-Csp³ bonds is reported. The symmetrical diaryl tellurides undergo detellurative homocouplings to afford symmetrical biaryl products. The reactions are carried out at ambient temperature using PdCl₂ as a catalyst in the presence of Ag₂O and Na₂CO₃. Similarly, the detellurative homocouplings of dibenzyl telluride and bis(phenylethynyl)telluride give bibenzyl and the conjugated diyne, respectively.     

Synthesis of functionalized 3-arylpyridazines via Pd-catalyzed decarboxylative cross-coupling of pyridazine-3-carboxylic acids

An efficient and general protocol for the decarboxylative cross-coupling of pyridazine-3-carboxylic acids with aryl-bromides has been described. This method provides a new avenue for the synthesis of 3-arylpyridazines via decarboxylative cross-coupling strategy by employing the dual-catalyst system of Pd(PPh₃)₄/Cu₂O in the presence of Li₂CO₃ at 160 °C in DMA.     

Pd-catalyzed decarboxylative cross-coupling of sodium pyrimidinecarboxylates with (hetero)aryl bromides

A straightforward method for the synthesis of functionalized 4- or 5-(hetero)arylpyrimidines via decarboxylative cross-coupling reaction from readily available pyrimidine-4- and pyrimidine-5-carboxylates was described. In the presence of dual-catalyst system of Pd(PPh₃)₄/Cu₂O, the reaction proceeds smoothly, tolerates a variety of functional groups, and provides easy access to the synthesis of different (hetero)arylpyrimidines compounds.     

Synthesis of chiral vinylic sulfoxides by Pd-catalyzed asymmetric sulfinylzincation

Novel asymmetric sulfinylzincation of alkynoates has been accomplished via a Pd-catalyzed sulfinylzincation using 1-alkynyl sulfoxides bearing chiral auxiliaries as a sulfinylating reagent. The reaction proceeded in a highly syn-selective fashion, giving the (E)-β-sulfinyl α,β-unsaturated ester exclusively. Among the chiral sulfinylating reagents tested, an isoborneol-type compound (Rs)-4 showed the best results in terms of both yield and diastereoselectivity. As a result of optimization of the reaction, the selectivity was improved up to 92:8 dr, and stereochemistry of the newly formed sulfur stereogenic center was revealed as (Ss)-configuration.     

Functional polypyridine ligands from copper-mediated room temperature coupling of 4-chloro-2-trimethylsilylpyridine

A range of functional polypyridine ligands (bipyridines and terpyridine) has been synthesized by copper-mediated oxidative homocoupling of 4-chloro-2-trimethylsilylpyridine or cross-coupling with functional bromopyridines. The reaction proceeded smoothly at room temperature.     

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.     

Synthesis of new tetracyclic azaheteroaromatic cores via auto-tandem Pd-catalyzed and one-pot Pd- and Cu-catalyzed double C-N bond formation

Inter- and intramolecular transition metal-catalyzed amination of 2-chloro-3-iodopyridine and 2,3-dibromopyridine, respectively, with benzodiazinamines yielded six hitherto unknown tetracyclic azaheteroaromatic cores. C-N bond formation was achieved via auto-tandem (Pd-catalyst) as well as one-pot (sequential use of a Pd- and Cu-catalyst) catalysis.     

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.     

Pd-catalyzed cross-coupling reactions of arenediazonium salts with arylsilanes and aryltrifluoroborates in water

Pd-catalyzed cross-coupling reactions of various arenediazonium salts with ArSi(OR)₃ and KArBF₃ have been achieved in good to excellent yields under simple aerobic conditions in water at room temperature. The functional group tolerance makes these transformations as attractive alternatives to the traditional cross-coupling approaches. Furthermore, the sequence can also be performed in a one-pot domino process, omitting the isolation of the intermediate arenediazonium salt.     

Stille coupling approaches for the synthesis of 8-aryl guanines

The reaction of 8-bromoguanines with aryl and hetaryl stannanes in the presence of a palladium catalyst leads to the formation of the corresponding 8-aryl(hetaryl)guanines. It was found that the addition of triphenylarsine or triphenylbismuth strongly reduces the reaction time and increases product yields.     

Ester-functionalized phthalonitriles and zinc phthalocyanines via palladium-catalyzed cyanation of 4,5-dichlorophthalates

Dicyanophthalates 3 were synthesized via Pd-catalyzed two-fold cyanation of the corresponding 4,5-dichlorophthalates with Zn(CN)₂. Appropriate modification of reaction conditions allowed one-pot synthesis of the corresponding zinc phthalocyanines 7 bearing eight peripheral alkyl ester groups. Powder X-ray diffraction study of a mesogenic zinc phthalocyanine bearing branched alkyl substituents revealed a rare case of a transition between two columnar rectangular liquid crystalline mesophases with different symmetry.     

Synthesis of indolequinones via a Sonogashira coupling/cyclization cascade reaction

A mild strategy for constructing indolequinone motifs is described on the basis of the Sonogashira reaction and a copper-catalyzed intramolecular cyclization cascade reaction. The first step involves the palladium- and copper-catalyzed reaction between halogenated naphthoquinone and terminal acetylene to generate a coupling product, which then reacts in a copper-catalyzed intramolecular cyclization with the nitrogen functional group adjacent to the carbon-carbon triple bond.     

芳基锡烷的合成研究进展

芳基锡烷化合物是参与构筑功能分子中芳基碳碳键和碳杂原子键的一类重要合成中间体. 其在药物化学、材料科学以及有机合成中都具有重要应用, 因此发展其高效新颖的合成方法具有重要的意义. 根据反应机理的类型, 综述了近些年来合成芳基锡烷的方法, 包括(1)芳香亲核试剂的锡化反应; (2)芳香亲电试剂的锡化反应; (3)过渡金属催化的锡化偶联反应; (4)芳基自由基中间体介导的锡化反应; (5)炔烃的环化和串联的锡化反应. 最后, 进一步分析了未来合成芳基锡烷的研究趋势.     

Synthesis of a novel bridged 2-(cyclopentadienyl)-indene system using Pd-catalyzed Negishi-type cross coupling

The palladium-catalyzed Negishi-type C-C-coupling of the nonaromatic systems 2-indenyl and cyclopentadienyl were investigated. The employed catalyst played a decisive role in product formation. Instead of Pd(PPh₃)₄, the more bulky Pd(dppf)Cl₂·CH₂Cl₂ led to the desired system in distinguished yields.     

Microwave-promoted Suzuki-Miyaura coupling of arylboronic acids with 1-bromo-2-naphthol, o-bromophenol, and o-chlorophenol

In this letter we report a simple and efficient way for the direct Suzuki-Miyaura cross-coupling of unprotected 2-hydroxyaryl bromides and of 2-chlorophenol with arylboronic acids using suitable phosphine/Pd(OAc)₂ catalysts systems with moist K₃PO₄/toluene or moist CsF/dioxane and microwave heating (20 min 105 °C to 3 h 100-120 °C) with an internal temperature control providing 2-hydroxybiaryls in yields up to 98%.     

Synthesis of enantiopure B-nor-steroids by multiple Pd-catalyzed transformations

The synthesis of the novel enantiopure B-nor-steroid 9 is described employing a combination of a Suzuki- and a Heck-reaction. As substrates the 2-bromobenzylchloride (11) and the boronic ester 16 were used; the latter was prepared from the Hajos-Wiechert ketone derivative 17 in five steps. Noteworthy, the Heck-reaction was performed under microwave irradiation, which was much superior compared to the normal thermal reaction. The purpose of the described work is the design of novel estrogens, which bind to the β-unit of the maxi K⁺-channel located on the surface of the endothelium without showing the hormonal activity of estradiol 6.     

Pd-catalyzed Negishi coupling of pyrazole triflates with alkyl zinc halides

A mild, functional group tolerant palladium-catalyzed Negishi coupling of pyrazole triflates and nonaflates with alkyl, benzyl, and aryl zinc halides has been developed. It allows quick access to 3-substituted pyrazole analogs at late stage via common synthetic intermediates.     

固相有机合成中钯催化的交叉偶联反应研究进展

过渡金属钯催化交叉偶联反应是形成碳一碳键的一种十分有效的方法,因此钯催化的C—C偶联反应引起了更多人们的广泛关注,并发展了多种不同的C—C偶联反应,包括Heck反应、Negishi反应、Suzuki偶联和Stille偶联等。固相有机合成具有反应条件温和、可使多种活性官能团兼容、受空间位阻影响小、具有高度的化学选择性、毒...     

The Synthesis of Tetra‐α‐Phenoxyphthalocyanines and Research of their Physical and Chemical Properties

A series of phthalocyanines (Pcs) substituted by phenoxy groups were synthesized through the route whose intermediates are selected to be phthalonitriles with different structures. These phthalocyanines and their intermediates are characterized by elemental analysis, IR and MS. The thermogravimetric loss and the aggregation behavior data of phthalocyanines are determined with the purpose to better understand the possible recording mechanism and to improve the dye's practical applications in the optoelectronic field.