Pd-catalyzed sequential reaction for the synthesis of fused tricyclic compounds containing a dihydrofuran or isobenzofuranone unit

A novel Pd-catalyzed sequential reaction for the synthesis of fused tricyclic compounds with a dihydrofuran or isobenzofuranone unit was developed.

Synthesis of novel chiral phosphine-triazine ligand derived fromα-phenylethylamine for Pd-catalyzed asymmetric allylic alkylation

A novel chiral phosphine-triazine ligand was synthesized from chiral α-phenylethylamine through a three-step procedure. In a model reaction of Pd-catalyzed allylic alkylation of rac-1,3-diphenylprop-2-en-1-y1 pivalate with dimethyl malonate, good enantioselectivity （90% e.e.） was obtained by using this ligand.

Recent Advances in Pd-Catalyzed Reactions Involving the “On-Water” Mechanism

As the chemical industry grapples with the need for more eco-friendly practices,the use of water as a reaction medium is gaining attraction in organic transformations.This mini-review delves into Pd-catalyzed reactions that utilize the "on-water" mechanism,spanning from 2019 to late 2023.These reactions are neatly categorized into several types: (A) Catalytic C—H activations,(B) Mizoroki- Heck-type reactions,(C) Suzuki-Miyaura reactions,and (D) Cyclization reactions.By showcasing the potential of water as a sustainable reaction medium for organic transformations,these reactions leave no doubt about the importance of embracing eco-friendly practices in the chemical industry.Key Scientists In 1980,a seminal work by Breslow et al.showed an acceleration of reaction rate in the Diels-Alder reaction.Sharpless and co-workers noted a significant increase in the rate of the [2σ+2σ+2π] cycloaddition of quadricyclane and dimethyl azodicarboxylate (DMAD) when the reaction was conducted in water,as opposed to when it was carried out in organic solvents.The term "on-water" was then coined to describe this phenomenon.This strategy was further expanded to transition-metal catalyzed transformations by Ackermann in 2011.Later,Varma and Leazer disclosed a Pd-catalyzed Mizoroki-Heck type arylation of alkenes with diaryliodonium salts “on-water”.The enantioselective version of "on-water" process was not realized until 2014 by the Zhou group.Later on,the Schaub group described a Pd-catalyzed Suzuki–Miyaura coupling reaction of electron-poor aryl chlorides with water,using only 50 ppm of catalyst loading.Very recently,Liu and Lin extended the "on-water" strategy to Pd-catalyzed double Mizoroki-Heck reactions.This mini-review has focused on Pd-catalyzed reactions involving the “on-water” mechanism.

Pd-Catalyzed Ortho-Directed C-H Glycosylation of Arenes Using N-linked Bidentate Auxiliaries

Main observation and conclusion A set of Pd-catalyzed ortho-directed C-H glycosylation reactions with glycosyl chloride donors using various N-linked bidentate auxil-iaries has been developed for synthesis of C-aryglycosides.A broad range of pyranose and furanose moieties can be installed on the ortho position of arylamine,carbazole,indole and benzylamine type substrates in high yield and with high regio-and diastereoselec-tivity.These auxiliaries can be readily installed and removed under relatively mild conditions.

The Pd-catalyzed synthesis of difluoroethyl and difluorovinyl compounds with a chlorodifluoroethyl iodonium salt(CDFI)

Herein, we report a simple and efficient method for the direct installation of chlorodifluoroethyl group onto aromatic molecules of various aromatic amides with a new 2-chloro,2,2-difluoroethyl(mesityl)iodonium salt(CDFI). Moreover, the chlorodifluoroethyl compounds could be smoothly converted into difluorovinyl compounds in a one-pot or discrete procedure and regarded as a steady source of difluorovinyl compounds with “HCl-mask”.

Synthesis of 1,3,5-Trisubstituted [4-tert-Butyl 2-（5,5-difluoro- 2,2-dimethyl-6-vinyl-l,3-dioxan-4-yl）acetate]pyrazoles via a Pd-Catalyzed C--H Activation

The gem-difluoromethylenated acetonide 2 was efficiently synthesized as new precursor of HMG-CoA reduc- tase inhibitor. Straightforward olefination via Pd-catalyzed C4-H activation of 1,3,5-trisubstituted pyrazoles 1 was proceeded smoothly in the presence of Pd（OAc）2 and AgCO3. This protocol has merits in terms of the improved atomic economy and prevention from the generation of by-products.

Mechanistic insight into the synergistic Cu/Pd-catalyzed carbonylation of aryl iodides using alcohols and dioxygen as the carbonyl source

Pd-catalyzed carbonylation,as an efficient synthetic approach to the installation of carbonyl groups in organic compounds,has been one of the most important research fields in the past decade.Although elegant reactions that allow highly selective carbonylations have been developed,straightforward routes with improved reaction activity and broader substrate scope remain long-term challenges for new practical applications.Here,we show a new type of synergistic Cu/Pd-catalyzed carbonylation reaction using alcohols and dioxgen as the carbonyl sources.A broad range of aryl iodides and alcohols are compatible with this protocol.The reaction is concise and practical due to the ready availability of the starting materials and the scalability of the reaction.In addition,the reaction affords lactones and lactams in an intermolecular fashion.Moreover,DFT calculations have been performed to study the detailed mechanisms.

Synthesis and Potential Application of Novel C_(2)-Symmetrical Bis(ferrocenyl)P2N Ligand

A novel chiral bis(ferrocenyl) P2N ligand 1 with C2-symmetry was synthesized through a four-step procedure from (R)-N,N-dimethyl-1-ferrocenylethylamine. In a model reaction of Pd-catalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate 6 with dimethyl malonate, good enantioselectivity (86% e.e.) was obtained.

[3+2]Cycloaddition of Vinyl Cyclopropane and Hydroxylamines via Isocynate Intermediate toγ-Lactams

Comprehensive Summary A general and efficient strategy for the synthesis ofγ-lactams has been reported.The hydroxylamines form Lossen rearrangement products of electron-deficient group migration with base and then undergo[3+2]cycloaddition reaction with vinyl cyclopropane,which could be performed with broad substrate scope,excellent functional group tolerance and high efficiency to produce the desired products.It also allowed further modification to other derivatives of theseγ-lactams.

Palladium-Catalyzed[4+4]Cycloaddition of Homo-TMM All-Carbon 1,4-Dipole Precursors for Construction of Benzofuro[3,2-b]azocines and Furo[3,2-b]azocines

We developed a novel Pd-catalyzed[4+4]cycloaddition of(benzo)furan-derived azadienes with homo-TMM all-carbon 1,4-dipoles in situ generated fromα-allyl malonate derivatives,affording an array of benzofuro[3,2-b]azocines and furo[3,2-b]azocines with good to excellent yields(up to 96%)and exclusive regioselectivities.This methodology featured mild reaction conditions and good functional group tolerance.The synthetic utility was demonstrated by a gram-scale reaction.Furthermore,the catalytic asymmetric[4+4]cycloaddition version has also been explored.

Palladium-Catalyzed Addition of Carbon Monoxide and Carbon Tetrachloride to 1-Octene in Supercritical Carbon Dioxide

The Pd-catalyzed addition of carbon monoxide and carbon tetrachloride to 1-octene gave coadduct [alkyl 2-(2,2,2-trichloroethyl)octanoate] as the major product in supercritical carbon dioxide by using pyridine as the base. It was found that the selectivity and the yield of coadduct were greatly affected by the pressure of carbon dioxide,the reaction temperature and the amounts of alcohol and base used.

Asymmetric synthesis of ABC tricyclic systems in Daphniphyllum alkaloid

Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system.In addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.

Palladium-Catalyzed Oxidation of Dihydromyrcene to Citronellal in Supercritical Carbon Dioxide

Citronellal was the major product of catalytic oxidation of dihydromyrcene with oxygen using the catalyst comprised of (MeCN)2PdClNO2 and CuCl2 in a tertiary alcohol in supercritical carbon dioxide. It was found that the chemoselectivity of the reaction and the yield of citronellal were greatly affected by the pressure of carbon dioxide, the reaction temperature and the molar ratio of Pd/Cu.

Synthesis of Substituted Benzoxacycles via a Pd（ll）-Catalyzed Intramolecular Arylation Reaction of Allylic Alcohols

ein a Pd-catalyzed intramolecular allylation reaction of unprotected allylic alcohols was developed,and the reaction proceeded through a Pd（Ⅱ）-mediated allylic carbocation species formation,followed by a Friedel-Crafts type annulation to afford functionalized chromanes.

Palladium-catalyzed amination of chloro-substituted 5-nitropyrimidines with amines

A concise and efficient approach was developed for the synthesis of mono-substituted and di-substituted pyrimidines products via palladium-catalyzed amination of chloro-substituted 5-nitropyrimidines and amines. This synthetic methodology can produce various di-substituted pyrimidines in high yields with good functional group tolerance, and provide a complementary tool for the syntheses of important intermediates of nucleosides and purines with bioactivities.