Alkylation Reactions with Alkylsulfonium Salts

Synthesis ◽  
2021 ◽  
Author(s):  
Ze-Yu Tian ◽  
Yu Ma ◽  
Cheng-Pan Zhang
Keyword(s):  
Organic Molecules ◽  
High Efficiency ◽  
Building Blocks ◽  
Organometallic Reagents ◽  
The Past ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Alkylation Reactions

Application of alkylsulfonium salts as alkyl transfer reagents in organic synthesis has reemerged over the past years. Numerous heteroatom- and carbon-centered nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others were readily alkylated by alkylsulfonium salts under mild conditions. The reactions feature convenience, high efficiency, readily accessible and structurally diversified alkylation reagents, good functional group tolerance, and a wide range of substrate types, allowing for facile synthesis of various useful organic molecules from the commercially available building blocks. This review summarizes the alkylation reactions using either isolated or in situ formed alkylsulfonium salts via nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox processes.

scholarly journals Arenophile-Mediated Photochemical Dearomatization of Nonactivated Arenes

2020 ◽  
Vol 74 (7) ◽  
pp. 577-583 ◽  
Author(s):  
Mikiko Okumura ◽  
David Sarlah
Keyword(s):  
Natural Products ◽  
Transition Metal ◽  
Visible Light ◽  
Bioactive Compounds ◽  
Aromatic Compounds ◽  
Ring Opening ◽  
Organic Molecules ◽  
Building Blocks ◽  
Metal Catalyzed

Aromatic compounds are one of the most abundant classes of organic molecules and find utility as precursors for alicyclic hydrocarbon building blocks. While many established dearomatization reactions are exceptionally powerful, dearomatization with concurrent introduction of functionality, i.e. dearomative functionalization, is still a largely underdeveloped field. This review aims to provide an overview of our recent efforts and progress in the development of dearomative functionalization of simple and nonactivated arenes using arenophile-arene cycloaddition platform. These cycloadducts, formed via a visible-light-mediated [4+2]-photocycloaddition, can be elaborated in situ through olefin chemistry or transition-metal-catalyzed ring-opening with carbon-, nitrogen-, and oxygen-based nucleophiles, providing access to diverse structures with functional and stereochemical complexity. Moreover, the dearomatized products are amenable to further elaborations, which effectively install other functionalities onto the resulting alicyclic carbocycles. The utility of the arenophile-mediated dearomatization methods are also highlighted by the facile syntheses of natural products and bioactive compounds through novel disconnections.

scholarly journals Transition Metal Catalyzed Azidation Reactions

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1173
Author(s):  
Roberto Sala ◽  
Camilla Loro ◽  
Francesca Foschi ◽  
Gianluigi Broggini
Keyword(s):  
Transition Metal ◽  
Materials Science ◽  
Building Blocks ◽  
Organic Azides ◽  
Wide Range ◽  
Carbon Carbon Bonds ◽  
Transition Metal Catalyzed ◽  
Vinyl Azides ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

A wide range of methodologies for the preparation of organic azides has been reported in the literature for many decades, due to their interest as building blocks for different transformations and their applications in biology as well as in materials science. More recently, with the spread of the use of transition metal-catalyzed reactions, new perspectives have also materialized in azidation processes, especially concerning the azidation of C–H bonds and direct difunctionalization of multiple carbon-carbon bonds. In this review, special emphasis will be placed on reactions involving substrates bearing a leaving group, hydroazidation reactions and azidation reactions that proceed with the formation of more than one bond. Further reactions for the preparation of allyl and vinyl azides as well as for azidations involving the opening of a ring complete the classification of the material.

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

scholarly journals Not Just Transporters: Alternative Functions of ABC Transporters in Bacillus subtilis and Listeria monocytogenes

2021 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Jeanine Rismondo ◽  
Lisa Maria Schulz
Keyword(s):  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Abc Transporters ◽  
Organic Molecules ◽  
Atp Hydrolysis ◽  
The Past ◽  
Wide Range ◽  
Regulatory Functions ◽  
Complex Organic ◽  
Detoxification Mechanisms

ATP-binding cassette (ABC) transporters are usually involved in the translocation of their cognate substrates, which is driven by ATP hydrolysis. Typically, these transporters are required for the import or export of a wide range of substrates such as sugars, ions and complex organic molecules. ABC exporters can also be involved in the export of toxic compounds such as antibiotics. However, recent studies revealed alternative detoxification mechanisms of ABC transporters. For instance, the ABC transporter BceAB of Bacillus subtilis seems to confer resistance to bacitracin via target protection. In addition, several transporters with functions other than substrate export or import have been identified in the past. Here, we provide an overview of recent findings on ABC transporters of the Gram-positive organisms B. subtilis and Listeria monocytogenes with transport or regulatory functions affecting antibiotic resistance, cell wall biosynthesis, cell division and sporulation.

Bioencapsulation in Sol-Gel Glasses

1998 ◽  
Vol 519 ◽  
Author(s):  
L. Bergogne ◽  
S. Fennouh ◽  
J. Livage ◽  
C. Roux
Keyword(s):  
Sol Gel ◽  
Porous Silica ◽  
Silica Matrix ◽  
Whole Cells ◽  
The Past ◽  
Wide Range ◽  
Activity Of Enzymes ◽  
Gel Glasses ◽  
Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

scholarly journals In situ X-ray Diffraction Investigation of the Crystallisation of Perfluorinated Ce(IV)-based Metal-Organic Frameworks with UiO-66 and MIL-140 architectures

2020 ◽  
Author(s):  
Stephen Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rate Determining Step ◽  
Wide Range ◽  
Metal Organic

We report on the results of a thorough <i>in situ</i> synchrotron powder X-ray diffraction study of the crystallisation in aqueous medium of two recently discovered perfluorinated Ce(IV)-based metal-organic frameworks (MOFs), analogues of the already well investigated Zr(IV)-based UiO-66 and MIL-140A, namely, F4_UiO-66(Ce) and F4_MIL-140A(Ce). The two MOFs were originally obtained in pure form in similar conditions, using ammonium cerium nitrate and tetrafluoroterephthalic acid as building blocks, and small variations of the reaction parameters were found to yield mixed phases. Here, we investigate the crystallisation of these compounds <i>in situ</i> in a wide range of conditions, varying parameters such as temperature, amount of the protonation modulator nitric acid (HNO<sub>3</sub>) and amount of the coordination modulator acetic acid (AcOH). When only HNO<sub>3</sub> is present in the reaction environment, F4_MIL-140A(Ce) is obtained as a pure phase. Heating preferentially accelerates nucleation, which becomes rate determining below 57 °C, whereas the modulator influences nucleation and crystal growth to a similar extent. Upon addition of AcOH to the system, alongside HNO<sub>3</sub>, mixed-phased products, consisting of F4_MIL-140A(Ce) and F4_UiO-66(Ce), are obtained. In these conditions, F4_UiO-66(Ce) is always formed faster and no interconversion between the two phases occurs. In the case of F4_UiO-66(Ce), crystal growth is always the rate determining step. An increase in the amount of HNO<sub>3</sub> slows down both nucleation and growth rates for F4_MIL-140A(Ce), whereas nucleation is mainly affected for F4_UiO-66(Ce). In addition, a higher amount HNO<sub>3</sub> favours the formation of F4_MIL-140A(Ce). Similarly, increasing the amount of AcOH leads to slowing down of the nucleation and growth rate, but favours the formation of F4_UiO-66(Ce). The pure F4_UiO-66(Ce) phase could also be obtained when using larger amounts of AcOH in the presence of minimal HNO<sub>3</sub>. Based on these <i>in situ</i> results, a new optimised route to achieving a pure, high quality F4_MIL-140A(Ce) phase in mild conditions (60 °C, 1 h) is also identified.

Stereoselective Synthesis of (Z)-Allyl Alcohols through Coinage-Metal-Catalyzed Nucleophilic Addition of Benzo[d]isoxazoles with Unactivated Propargyl Alcohols

Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1339-1345
Author(s):  
Zhiyuan Chen ◽  
Wenjin Wu ◽  
Tiantian Zheng ◽  
Jie Tan ◽  
Shouzhi Pu
Keyword(s):  
Stereoselective Synthesis ◽  
Silver Salt ◽  
Gold Catalyst ◽  
Building Blocks ◽  
Coinage Metal ◽  
Stereoselective Addition ◽  
Allyl Alcohols ◽  
Metal Catalyzed ◽  
Propargyl Alcohols

The Au/Ag-cocatalyzed stereoselective addition reaction of cyanophenol anion species generated in situ with unactivated propargyl alcohols to produce functionalized (Z)-allyl alcohols in mostly good yields is reported. Benzo[d]isoxazoles were found to be excellent building blocks for the production of highly reactive cyanophenol anions from Kemp elimination reactions, thus serving as a masked benzonitrile source for the preparation of organonitrile derivatives. Silver salt combined with gold catalyst were found to be necessary for the success of this transformation.

Ionic Liquid Promoted Eco-friendly and Efficient Synthesis of Six-membered Npolyheterocycles

2018 ◽  
Vol 15 (8) ◽  
pp. 1124-1146 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Chemistry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Organic Solvents ◽  
Review Article ◽  
Environmentally Benign ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Reaction Media

Background: The synthesis of N-polyheterocycles by environmentally benign method is highly attractive but challenging proposition. New strategies have been developed for the preparation of polycyclic heterocycles in the last decades. In this review article, the synthesis of nitrogen containing six-membered polycyclic heterocyclic compounds is presented with the application of ionic liquids. This contribution focuses on the literature related to the total synthesis of six-membered N-polyheterocycles. Objective: Ionic liquids not only acted as environmentally benign reaction media but also as catalysts which afforded the very promising replacements of traditional molecular solvents in organic chemistry due to their stability, non-flammability, non-volatility and ease of recyclability. Ionic liquids are utilized in metal catalyzed reactions in place of organic solvents in the last years. It has attracted considerable attention in recent years. Ionic liquids acted as alternatives of organic solvents and these ILs are environment friendly. Conclusion: In the area of green chemistry ionic liquid assisted synthesis is a very promising technique which afforded a flexible platform for the formation of heterocycles. The influence of ILs on the development of efficient and new synthetic protocols over the last decade for the construction of N-polyheterocycles is featured in this review article. These synthetic strategies will continue to attract more attention and will find a wide range of applications in organic synthesis. In conclusion, ionic liquids assisted syntheses have become an efficient and powerful tool in organic chemistry quickly.

Working Tools Study for JiaoLong Manned Submersible

2019 ◽  
Vol 53 (2) ◽  
pp. 56-64
Author(s):  
Xianpeng Shi ◽  
Yugang Ren ◽  
Jialing Tang ◽  
Wentao Fu ◽  
Baohua Liu
Keyword(s):  
Deep Sea ◽  
High Efficiency ◽  
Deep Ocean ◽  
Basic Research ◽  
Extreme Environment ◽  
The Past ◽  
Wide Range ◽  
Manned Submersible ◽  
Observation Function ◽  
Scientific Questions

AbstractThe remarkable progress in deep submergence science with manned submersibles in the past 50 years has made it possible for us to directly explore the inaccessible underwater extreme environment. Basic research carried out at depths over 1,000 m in the deep ocean has provided dramatic and unique insights into some of the most compelling scientific questions ever posed. Deep research manned submersibles have been widely recognized as indispensable platforms for conducting deep-sea research. Whereas all deep-sea submersibles share the unique feature of direct observation function by scientists and pilots from the cabin, all manned submersibles are equipped with different tools to implement a wide range of jobs in different exploration purposes. These can directly affect productivity and each dive's outcomes, such that it would be meaningful to study the samplers, sensors, and other devices that have been installed on the different deep-sea research manned submersibles around the world. This article will also introduce the research and development status of the JiaoLong manned submersible's operational tools, which have been researched and tested during the sea trials and test operational phase over the past 9 years. Based on developed technologies, state-of-the-art tools are essential to achieve a high-efficiency use for each dive. The article brings forward discussion and suggestions for the development of JiaoLong's operational tools, followed by a conclusion from the perspective of JiaoLong's operation team.

From Propargylic Fluorinations to [1,3]-Rearrangements: Anion and Ligand Effects in Cu-Acetylide Chemistry

Synlett ◽  
2018 ◽  
Vol 29 (13) ◽  
pp. 1675-1682 ◽  
Author(s):  
Christopher Cordier ◽  
Li-Jie Cheng ◽  
Alexander Brown
Keyword(s):  
Reactive Intermediates ◽  
Copper Catalysis ◽  
Mechanistic Studies ◽  
Ligand Effects ◽  
The Past ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Nucleophilic Fluorination

Metal-catalyzed reactions of propargylic substrates have been widely studied. Of this reaction class, Cu-catalyzed methods have received much attention within the past decade, with Cu-allenylidenes being proposed as key reactive intermediates. This Synpacts article will outline our development of a nucleophilic fluorination protocol of propargylic electrophiles using copper catalysis. Following an analysis of the importance of anion and ligand effects, this study led us to the unexpected discovery of a formal [1,3]-rearrangement of O-propargylic alkoxypyridine derivatives that was later rendered enantioselective. By contrast to Cu-allenylidene proposals, our mechanistic findings have identified alternatives involving bimetallic intermediates.1 Introduction2 Propargylic Fluorination3 Anion Effects4 Propargylic Rearrangements5 Mechanistic Studies6 Conclusions

Sign in / Sign up

Export Citation Format

Share Document