Expeditious synthesis of 3,4-dihydroisocoumarins and phthalides using the Heck-Matsuda reaction

Several 3,4-dihydroisocoumarins and phthalides were synthesized by an effective Heck-Matsuda reaction involving an ortho carboxybenzenediazonium salt with a series of styrenes bearing electron donating and electron withdrawing groups, methylvinyl ketone, and methyl acrylate. The reaction was carried out in an open-flask with 1% mol of palladium acetate in aqueous ethanol at ∼80 °C, giving the correspondent 3-aryl-3,4-dihydroisocoumarins and phthalides with good overall yields. The electronic nature of the group attached to the olefin is a key feature for the regioselectivity of the cyclization step.     

Facile synthesis of symmetrical 3,3-diarylacrylates by a Heck-Matsuda reaction: an expedient route to biologically active indanones

A simple and straightforward synthesis of symmetrical 3,3-diarylacrylates based on a Heck-Matsuda reaction of arenediazonium salts bearing electron-donating groups with methylacrylates is described. The reaction employs Pd(OAc)₂ as catalyst and goes to completion within 1 h affording the corresponding unsaturated diaryl esters in good to high yields. This method permitted the expeditious and efficient synthesis of the anticancer 3-arylindanone 5 in two operative steps in 43% overall yield.     

Visible-light-mediated Gomberg-Bachmann reaction: An efficient photocatalytic approach to 2-aminobiphenyls

An efficient, metal-free and highly selective protocol for the synthesis of 2-aminobiphenyls via visible-light-mediated arylation of anilines using aryl diazonium salts (Gomberg-Bachmann reaction) has been reported. The reaction is an example of photoredox catalysed direct C(sp²)–H arylation of anilines using eosin Y as an organophotoredox catalyst. The presented visible-light-mediated environmentally sustainable approach has the potential to earn a decent position among the classical and contemporary methods for the synthesis of aminobiaryls.     

Visible-light-induced photoredox-catalyzed synthesis of benzimidazo[2,1-a]iso-quinoline-6(5H)-ones

A simple and efficient visible-light-induced photoredox-catalyzed diarylation of N-methacryloyl-2-arylbenzoimidazoles with aryl diazonium salts was developed. The reaction provides a convenient access to a variety of benzimidazoisoquinolinones through the construction of two CC bonds in one step under mild reaction conditions.     

Recent results in insect pheromone chemistry

Pheromones are substances which are secreted to the outside by an animal, especially an insect, and received by a second individual of the same species, in which they release a specific reaction, for example, a definite behavior or developmental process. The name is derived from the Greek pherein (to bear, transmit) and hormon (impel, excite). Pheromones include, inter alia, sex attractants, warning substances, and “aggregation pheromones”. Many of these substances are effective at very low concentration. The insect pheromones are predominantly derivatives of long-chain, slightly branched hydrocarbons.     

Aryl Diazonium Salt‐Triggered Cyclization and Cycloaddition Reactions: Past,Present, and Future

Aryl diazonium salts occupy a privileged role in synthetic chemistry owing to their ready availability and versatile reactivity. While their applications in accessing diversely functionalized arene derivatives via denitrogenation‐coupling and reduction/addition reactions have been well recognized by practitioners in both academia and industry, recent renaissance in chemical transformations of retaining the key N₂‐unit has emerged as a powerful technique to construct various N‐heterocycles. This review covers the history and latest advances in cyclization and cycloaddition reactions using aryl diazonium salts as N₂‐annulation synthons. The scope, applications, and opportunities in exploring new chemical space by this sustainable strategy are summarized and discussed.     

Pauson-Khand反应的研究进展

综述了过渡金属络合物参与或催化的Pauson-Khand反应，不对称Pauson- Khand反应的最新进展。     

氮杂Wittig反应的最近进展

综述了最近几年氮杂Wittig反应的研究进展,包括分子间氮杂Wittig反应、分子内氮杂wittig反应及串联的氮杂Wittig反应。讨论了氮杂Wittig反应在一些含氮杂环、稠杂环及天然产物合成中的应用。     

Palladium-catalyzed C-N bond formation via direct C-H bond functionalization. Recent developments in heterocyclic synthesis

The formation of carbon-nitrogen bonds by reaction between a nitrogen atom and an unactivated carbon-hydrogen bond is a highly atom-economical process that attracted the attention of the chemists in the last two decades. The widely useful amination and hydroamination reactions, which furnish acyclic or cyclic products, give access to various nitrogen-containing basic and fine chemicals. This review highlights recent progress in the development of palladium-catalyzed reactions that occur by direct functionalization of simple carbon-hydrogen bonds to give heterocyclic products. Pd(0)- and Pd(II)-catalyzed reactions are described separately, emphasizing the different behavior of the metal in these two oxidation states.     

Recent developments in the synthesis of heterocyclic derivatives by PdI2-catalyzed oxidative carbonylation reactions

A simple catalytic system, consisting of PdI₂ in conjunction with an excess of KI, has proven to be very valuable for the direct one-step synthesis of a variety of heterocyclic derivatives by oxidative carbonylation of suitably functionalized alkynes. The same catalyst also promoted the oxidative carbonylation of β-amino alcohols to oxazolidin-2-ones with unprecedented catalytic efficiencies for this kind of reaction.     

Revisiting the Hirao cross-coupling: improved synthesis of aryl and heteroaryl phosphonates

The palladium-catalyzed cross-coupling of dialkylphosphite with aromatic electrophiles (Hirao coupling) was re-investigated. Some limitations in terms of palladium loadings and substrate reactivity are alleviated with the use of Pd(OAc)₂ complexed to 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand. Various aryl and heteroaryl halides are employed to deliver both known and novel substituted phosphonates. The first examples of aryl chloride couplings are also reported.     

Exploration of the interrupted Fischer indolization reaction

A convergent method to access the fused indoline ring system present in a multitude of bioactive molecules has been developed. The strategy involves the condensation of hydrazines with latent aldehydes to ultimately deliver indoline-containing products by way of an interrupted Fischer indolization sequence. The method is convergent, mild, operationally simple, broad in scope, and can be used to access enantioenriched products. In addition, our approach is amenable to the synthesis of furoindoline and pyrrolidinoindoline natural products as demonstrated by the concise formal total syntheses of physovenine and debromoflustramine B. The strategy will likely enable the synthesis of more complex targets such as the communesin alkaloids.     

Palladium catalyzed alkynylation of aryl halides (Sonogashira reaction) in water

The palladium catalyzed alkynylation of aryl halides (Sonogashira reaction) has been achieved in pure water without any additives or phase transfer catalysts. The reaction, which requires only 0.5 mol % of Pd(PPh₃)₄ catalyst, is remarkably fast (30 min at 70 °C) producing high yields of the aryl alkyne products.     

Synthesis and catalytic applications of sulfonate β-ketoimine and β-diimine in the Suzuki reaction in aqueous phase

A series of sulfonated β-ketoimine and β-diimine compounds were synthesized and characterized. As supporting ligands they were used in the Suzuki cross-coupling reaction in aqueous phase with PdCl₂ as catalyst. The new catalytic system can tolerate a wide range of substrates.     

Palladium-catalyzed highly regioselective Heck reaction of aryl nonaflates with electron-rich olefins

Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.     

Recent advances in indoline synthesis

Indoline is an important structural motif present in several biologically active compounds from both natural and synthetic origins. The occurrence of this heterocyclic unity in these compounds is closely related to the biological activities they exhibit. This fact stimulated efforts that have been made worldwide to develop new synthetic approaches to prepare indolines. In this paper we reviewed critically the methods for indoline synthesis developed in the last years (from 2010 to 2018).     

Recent advances in energy chemistry of precious-metal-free catalysts for oxygen electrocatalysis

The rational design and effective construction of precious-metal-free materials for OER and ORR, respectively, are reviewed in the respects of electronic structure regulation, nanostructure tailor, and freestanding electrode fabrication. This affords fresh concepts for oxygen electrocatalysis and is also enlightening for other energy catalysis with targeted optimization.