Synthons In Organic Chemistry Research Articles

Novel Technological Paradigm of the Application of Carbon Dioxide as a C1 Synthon in Organic Chemistry: I. Synthesis of Hydroxybenzoic Acids, Methanol, and Formic Acid

Novel Technological Paradigm of the Application of Carbon Dioxide as a C1 Synthon in Organic Chemistry: I. Synthesis of Hydroxybenzoic Acids, Methanol, and Formic Acid

Recent Advances in the Use of Dimethyl Sulfoxide as a Synthon in Organic Chemistry.

Dimethyl sulfoxide (DMSO), as extremely important aprotic polar solvent and reaction medium, has attracted widespread attention from chemists in recent years due to its wide range of uses and the multiple functions it displays in various chemical processes. Especially in the past decade, dimethyl sulfoxide has become increasingly favored as a synthon in organic chemistry, resulting in great progress in this research field. In this context, this review provides a comprehensive summary of the literature on the recent progress in organic synthesis using dimethyl sulfoxide as a synthon, covering all the reports from 1 January 2016 to 11 May 2022. This type of reaction is mainly performed by transferring one or more units of dimethyl sulfoxide, such as oxygen (-O-, =O), methyl (-CH3), methylene (-CH2-), methylidene (=CH2), methine (=CH-), donor of formylation (-CHO), sulfur (-S-), methylthio (-SMe), methyl sulfoxide (-SOMe), donor of methyl thiomethylation (-CH2SMe), or donor of methyl sulfoxide methylation (-CH2SOMe), to the target molecules. At the same time, we hope that this review will stimulate future studies and promote developments in this area.

Heteroarene‐tethered Functionalized Alkyne Metamorphosis

Heteroarene-tethered functionalized alkynes are multipotent synthons in organic chemistry. This detailed Review described herein offers a thorough discussion of the metamorphosis of heteroarene-tethered functionalized alkynes, an area which has earned much attention over the past decade in the straightforward synthesis of architecturally complex heterocyclic scaffolds in atom and step economic manner. Depending upon the variety of functionalized alkynes, this Review is divided into multiple sections. Amongst the vast array of synthetic transformations covered, dearomatizing spirocyclizations and cascade spirocyclization/rearrangement are of great interest. Synthetic transformations involving the heteroarene-tethered functionalized alkynes with scope, challenges, limitations, mechanism, their application in the total synthesis of natural products and future perceptions are surveyed.

Asymmetric Cross [10+2] Cycloadditions of 2-Alkylidene-1-indanones and Activated Alkenes under Phase-Transfer Catalysis.

Isobenzofulvene species are versatile synthons in organic chemistry, which have been employed in diverse challenging higher-order cycloaddition reactions. Here, the first chemoselective and asymmetric cross [10+2] cycloaddition reaction between activated 2-alkylidene-1-indanones and a variety of electron-deficient alkenes has been developed, relying on the in situ generation of dearomative 1-hydroxyl isobenzofulvene anion intermediates under the catalysis of a newly designed bulky cinchona-derived phase-transfer compound. An array of fused frameworks with multifunctionalities were generally furnished in excellent diastereo- and enantioselectivity, even at 1 mol % catalyst loadings.

Strategy for identification of cis-dihydrodiendiol-degrading dehydrogenases in E. coli BW25113

cis-Dihydrodiendiols are valuable compounds, finding multiple application as chiral synthons in organic chemistry. The biotechnological route for the generation of cis-dihydrodiendiols involves the dihydroxylation of aromatic compounds, catalyzed by Rieske non-heme iron dioxygenases. To date, numerous examples of recombinant E. coli, harboring such dioxygenases, can be found in the literature. Nevertheless, there is only a minor number of publications, addressing the E. coli catalyzed degradation of cis-dihydrodiendiols into catechols via dehydrogenases. Identification and elimination of such dehydrogenase catalyzed degradation is key for the establishment of enhanced recombinant E. coli platforms pursuing the production of cis-dihydrodiendiols. Here, we provide a fast and easy strategy for the identification of promiscuous alcohol dehydrogenases in E. coli BW25113, catalyzing the degradation of cis-dihydrodiendiols into catechols. This approach is based on the screening of dehydrogenase deficient KEIO strains, regarding their incapability of degrading a cis-dihydrodiendiol of choice.•Novel screening strategy for E. coli BW25113 dehydrogenase knock-outs, incapable of degrading cis-dihydrodiendiols was validated for cis-1,2-dihydrocatechol as substrate•Corresponding knock-outs can be used for recombinant production of cis-dihydrodiendiols•Simple analysis based on liquid chromatography with diode array detector (HPLC-DAD)

Green & sustainable nanocatalysed synthetic route for an exploration of knoevenagel condensation

Indole-3-carbaldehyde has a wide variety of applications, as a versatile synthon in organic chemistry, also found to be remarkably active as 12- & 15- lipoxygenase inhibitors, anti-tumour, antimicrobial and anti-inflammatory agents. In this work, we report the synthesis of targeted knoevenagel condensed products of indole-3-carbaledehydes (1a–e) and active methylene containing moieties 3-methyl-1-phenyl-5-pyrazolone (A) in the presence of ZnO nanoparticles by using solvent free grindstone method and compared with traditional refluxing method. Grindstone method for preparation of libraries of these knoevenagel condensed products lead to many advantages in terms of excellent yields, short reaction time, high reaction rate and also attracts the attention from the environment point of view as well as economic perspective. All the synthesized compounds have been characterized by their IR, 1H NMR, and Q-TOF mass spectral data and elemental analyses.

Recent Progress in Chemistry of β-Lactams

The β-lactams constitute a well-known class of compounds having tremendous biological significance. Besides being a motif of biological interest, they serve as versatile synthons in organic chemistry. In fact, their easy accessibility in the laboratory by several methods combined with inherent reactivity of the β -lactam ring due to ring-strain places it among the most sought for substrate in the arsenal of synthetic organic chemists. Several chemical reagents, heat, and light promote its ring-opening, ring-expansions and rearrangement reactions yielding a wide variety of biologically relevant nitrogen-containing acyclic and heterocyclic compounds. In recent years, the reactivity of differently functionalized β-lactam rings towards diverse kinds of reagents has been investigated. These investigations exploit selective bond cleavage of the β-lactam nucleus via N1-C2, C3- C4, C2-C3 or N1-C4 bond cleavage using simple reagents. The reduction of amide carbonyl group, thionation, and pyrolysis/photolysis have also been explored. These investigations have led to the discovery of many easy synthetic methods for biologically important classes of compounds such as β-amino acids, β-amino esters, amino sugars, amino alcohols, peptides, azetidines, and other heterocyclic compounds. This article discusses the advances made in the studies on the reactivity of β- lactam ring during the last ten years.

Unsaturated Derivatives of Trifluoromethanesulfonamide

Unsaturated derivatives of trifluoromethanesulfonamide (CF3SO2NH2, triflamide, TfNH2) of general formula TfNRR′ where R and/or R′ contain C=C or C≡C bonds, are of particular interest in triflate chemistry because they open the way for further functionalization and provide access to new adducts and cycloadducts. Two approaches to these compounds have been developed in our group. One is treatment of triflic anhydride (or fluoride) with unsaturated amines, or alkylation of triflamide with unsaturated alkyl halides. The second approach consists of oxidative triflamidation of dienes, with one C=C bond remaining intact. Another class of unsaturated triflamide derivatives is that of N‐alkylidenetriflamides (TfN=R). At the time our comprehensive review on triflamides and related compounds covering the literature up to 2012 was published, very little information on unsaturated triflamides was available. Since then, research in this area has expanded. In this review we demonstrate new examples of unusual reactivity of unsaturated triflamides, such as unprecedented splitting of α,ω‐bis(triflamidomethyl)diacetylene, diverse courses of oxidative triflamidation and arenesulfonamidation of dienes, different routes of cycloaddition of fluorinated and non‐fluorinated N‐sulfinylsulfonamides to carbodiimides, isomerization, etc. The high NH‐acidity, the strong electron‐acceptor ability and good nucleofugality of the triflyl and triflamido groups, and the presence of multiple bonds in the unsaturated triflamides all make them both interesting objects for investigations of hydrogen bonding and self‐organization processes, as well as valuable synthons in organic chemistry.

Alkynes From Furans: A General Fragmentation Method Applied to the Synthesis of the Proposed Structure of Aglatomin B

AbstractFurans are versatile synthons in organic chemistry. Described is a general method for transforming furans into alkynes by dual C−C double‐bond cleavage. The reaction is proposed to proceed by sequential [4+2] cycloaddition between furan and singlet oxygen and a formal retro‐(3+2) fragmentation of the endoperoxide intermediate. A wide array of furans, including those derived from sapogenins, are amenable to this reaction, thus providing the corresponding alkynoic acids in up to 88 % yields. The synthetic utility was demonstrated by a seven‐step synthesis of the proposed structure of a pregnane natural product, aglatomin B, from a known intermediate.

Alkynes From Furans: A General Fragmentation Method Applied to the Synthesis of the Proposed Structure of Aglatomin B.

Furans are versatile synthons in organic chemistry. Described is a general method for transforming furans into alkynes by dual C-C double-bond cleavage. The reaction is proposed to proceed by sequential [4+2] cycloaddition between furan and singlet oxygen and a formal retro-(3+2) fragmentation of the endoperoxide intermediate. A wide array of furans, including those derived from sapogenins, are amenable to this reaction, thus providing the corresponding alkynoic acids in up to 88 % yields. The synthetic utility was demonstrated by a seven-step synthesis of the proposed structure of a pregnane natural product, aglatomin B, from a known intermediate.

Oxidation of Vicinal Diols to α-Hydroxy Ketones with H2O2 and a Simple Manganese Catalyst.

α‐Hydroxy ketones are valuable synthons in organic chemistry. Here we show that oxidation of vic‐diols to α‐hydroxy ketones with H2O2 can be achieved with an in situ prepared catalyst based on manganese salts and pyridine‐2‐carboxylic acid. Furthermore the same catalyst is effective in alkene epoxidation, and it is shown that alkene oxidation with the MnII catalyst and H2O2 followed by Lewis acid ring opening of the epoxide and subsequent oxidation of the alkene to α‐hydroxy ketones can be achieved under mild (ambient) conditions.

β-Lactam rearrangements into five-membered heterocycles

β-Lactams are compounds of great importance in both medicinal chemistry and as building blocks for the synthesis of different types of biologically relevant compounds. Among other transformations, β-lactams can easily be rearranged into five-membered heterocycles. The rearrangement occurs by cleavage of any of four β-lactam bonds. The type of final five-membered ring mainly depends on the side chain groups of starting β-lactam, as well as reaction conditions. Furthermore, rearrangement reactions are often stereoselective, with product rings retaining the stereochemistry of β-lactams. The ability of β-lactams to form a variety of diversely decorated five-membered heterocycles, often in stereoselective fashion, makes this class of compounds attractive synthons in organic chemistry. This review covers the progress in the field within last ten years.

ChemInform Abstract: Dimethyl Sulfoxide as a Synthon in Organic Chemistry

AbstractReview: [84 refs.

Dimethyl Sulfoxide as a Synthon in Organic Chemistry

Dimethyl sulfoxide is generally characterized as a solvent and oxidant rather than as a substrate, building block, or synthon in organic chemistry. However, an abundance of reports have recently appeared that demonstrate dimethyl sulfoxide acting in these roles. This review article offers a comprehensive summary of the literature on this topic until the end of 2015. Synthetic transformations that have utilized the ‘C–S–C’, ‘C’, and ‘C–S’ fragments of dimethyl sulfoxide as building blocks are systematically summarized. 1 Introduction 2 History and Recent Highlights of DMSO-Based Oxidations 3 DMSO-Based Methylthiomethylation (–CH2SMe) 4 DMSO as a One-Carbon Synthon 4.1 DMSO-Based Methylation (–Me) 4.2 DMSO-Based Methylenation (–CH2–) 4.3 DMSO-Based Annulation/Aromatization (=CH–) 4.4 DMSO-Based Formylation (–CHO) 4.5 DMSO-Based Cyanation (–CN) 5 DMSO as Synthon for ‘S–C’ Functionalities 5.1 DMSO-Based Thiomethylation (–SMe) 5.2 DMSO-Based Methylsulfonylation (–SO2Me) 6 Summary and Conclusions

Toward a Green Atom Economy: Development of a Sustainable Multicomponent Reaction

The recently discovered photoinduced three-component reaction of diazo ketones, carboxylic acids, and isocyanides can be efficiently performed under continuous-flow conditions with consequential advantages in terms of selectivity and productivity. The investigation of the flow process and the determination of its sustainability are discussed in detail. This multicomponent reaction affords stereodefined captodative olefins, useful as synthons in organic chemistry.

On the acceptor properties of a Al-Nacnac carbene analogue, a density functional investigation

The Al-Nacnac compound is isolobal to the imidazol-2-ylidene (NHC) and forms donor complexes with phosphines and NHCs. These structural types were studied by density functional calculations. They reveal a strong biradical character, since donor addition to the Al-Nacnac reduces the singlet stability of the free carbene-analogue. This facilitates further biradical reactions, such as a subsequent hydrogen shift to the final corresponding tetravalent aluminium product. The latter is determined by maximum singlet stability, i.e. a large singlet-triplet energy separation. Relevance to the analogues Wittig ylids is drawn; these are constituted formally by addition of a phosphine to a carbene, and are well-known as stable synthons in organic chemistry.

ChemInform Abstract: Enantioselective Rhodium‐Catalyzed Synthesis of Branched Allylic Amines by Intermolecular Hydroamination of Terminal Allenes.

AbstractOptimized conditions allow the preparation of α‐chiral allylic amines as important synthons in organic chemistry.

ChemInform Abstract: Valorization of Glycerol 1,2‐Carbonate as a Precursor for the Development of New Synthons in Organic Chemistry.

AbstractActivated glycerol carbonate derivatives (halogen or pseudohalide derivatives) such as (I) and (IV) are prepared and subjected to reactions with olefins (II).

Enantioselective Rhodium‐Catalyzed Synthesis of Branched Allylic Amines by Intermolecular Hydroamination of Terminal Allenes

Optimized conditions allow the preparation of α-chiral allylic amines as important synthons in organic chemistry.

Valorization of glycerol 1,2-carbonate as a precursor for the development of new synthons in organic chemistry

Conjugate addition reactions are efficiently performed by a very simple electrochemical method using nickel complexes as catalysts. In this paper, we reported a new method for the valorization of glycerol 1,2-carbonate. Firstly, we prepared the activated glycerol 1,2-carbonate derivatives (halogen or pseudo-halide derivatives), and secondly applied these halogen derivatives in coupling reactions by electrochemical methods with organic compounds and environment-friendly solvent (propylene carbonate). To our knowledge, this is the first report of creation of carbon–carbon bonds on the glycerol 1,2-carbonate and of the synthesis of these compounds.