Synthesis Of Styrenes Research Articles

Stereoselective Synthesis of Axially Chiral Allenes and Styrenes via Chiral Phosphoric Acid Catalysis: An Overview.

Chiral allenes and styrenes are essential components in fields like medicinal chemistry, materials science, and organic synthesis. They serve a crucial role as chiral ligands and catalysts in asymmetric synthesis. Over the past decade, there has been a significant advancement in the development of practical methods utilizing organocatalytic strategies for the synthesis of chiral allenes and styrenes. It is noteworthy that despite extensive studies on the formation of allenes and styrenes, existing reviews on their construction confined to a specific organocatalysis, called chiral phosphoric acid catalysis, are less documented. This review aims to explore different conceptual approaches based on the electrophilic species involved in the reaction to produce stereoselective chiral allenes and styrenes, providing insights into recent advancements in the field. Emphasis is placed on works published since 2017, with detailed discussions on reaction mechanisms and examples from recent literature.

Synthesis of Styrenes and E‐Stilbenes by Palladium‐Catalyzed Vinylation of Aryl Iodides with 1,2‐Dibromoethane

AbstractThe Pd‐catalyzed vinylation reactions of aryl iodides using 1,2‐dibromoethane is developed for the synthesis of styrenes and stilbenes. In these reactions, vinyl bromide is generated from 1,2‐dibromoethane and then undergoes reductive cross‐coupling with aryl iodides, affording styrene products. Under slightly modified reaction conditions, styrenes can continue reacting with vinyl bromide to form E‐stilbenes, which provides a one‐pot synthetic method for stilbenes. Alcohols, including iso‐propanol and methanol, are employed as the reductant in these reductive cross‐coupling reactions.

Controlled Synthesis of α-CF2H or α-CF2Cl Styrenes from the Same Precursors: Dehydrazinative Hydrogenation or Chlorination of 3,3-Difluoroallyl Hydrazines.

By carefully choosing the reaction conditions, we have developed the controllable FeCl3- or CuCl2-mediated dehydrazinative hydrogenation or chlorination of 3,3-difluoroallyl hydrazines to access α-CF2H or α-CF2Cl styrenes. The current reaction provides for the first time a facile method for the direct and selective synthesis of α-CF2H and α-CF2Cl styrenes starting from the same precursors, which is easy to scale up and displays a broad substrate scope and good functional group tolerance. Moreover, product derivatization experiments demonstrated that the resulting α-CF2Cl styrenes are practical and versatile building blocks for the diversified synthesis of fluorinated molecules.

Pd-Catalyzed Dynamic Kinetic Asymmetric Cross-Coupling of Heterobiaryl Bromides with N-Tosylhydrazones.

A dynamic kinetic asymmetric Pd-catalyzed cross-coupling reaction of heterobiaryl bromides with ketone N-tosylhydrazones for the synthesis of heterobiaryl styrenes is described. The combination of Pd(dba)2 as a precatalyst with a TADDOL-derived phosphoramidite ligand provides the corresponding coupling products in good yields and high enantioselectivities under mild conditions. Racemization-free N-oxidation and N-alkylation of the products allowed us to obtain appealing functionalized axially chiral heterobiaryl derivatives.

Toolbox for the structure-guided evolution of ferulic acid decarboxylase (FDC)

The interest towards ferulic acid decarboxylase (FDC), piqued by the enzyme’s unique 1,3-dipolar cycloaddition mechanism and its atypic prFMN cofactor, provided several applications of the FDC mediated decarboxylations, such as the synthesis of styrenes, or its diverse derivatives, including 1,3-butadiene and the enzymatic activation of C-H bonds through the reverse carboligation reactions. While rational design-based protein engineering was successfully employed for tailoring FDC towards diverse substrates of interest, the lack of high-throughput FDC-activity assay hinders its directed evolution-based protein engineering. Herein we report a toolbox, useful for the directed evolution based and/or structure-guided protein engineering of FDC, which was validated representatively on the well described FDC, originary from Saccharomyces cerevisiae (ScFDC). Accordingly, the developed fluorescent plate-assay allows in premiere the FDC-activity screens of a mutant library in a high-throughput manner. Moreover, using the plate-assay for the activity screens of a rationally designed 23-membered ScFDC variant library against a substrate panel comprising of 16, diversely substituted cinnamic acids, revealed several variants of improved activity. The superior catalytic properties of the hits revealed by the plate-assay, were also supported by the conversion values from their analytical scale biotransformations. The computational results further endorsed the experimental findings, showing inactive binding poses of several non-transformed substrate analogues within the active site of the wild-type ScFDC, but favorable ones within the catalytic site of the variants of improved activity. The results highlight several ‘hot-spot’ residues involved in substrate specificity modulation of FDC, such as I189, I330, F397, I398 or Q192, of which mutations to sterically less demanding residues increased the volume of the active site, thus facilitated proper binding and increased conversions of diverse non-natural substrates. Upon revealing which mutations improve the FDC activity towards specific substrate analogues, we also provide key for the rational substrate-tailoring of FDC.

A potassium magnesiate complex: Synthesis, structure and catalytic intermolecular hydroamination of styrenes

A new heterobimetallic potassium magnesiate complex KMg[N(SiMe3)2]2Bn (Bn = PhCH2-) was synthesized by simply mixing magnesium amide and potassium benzyl in toluene. The TMEDA-ligated potassium magnesiate complex was also prepared and its solid structure was characterized by X-ray crystal diffraction, which revealed interactions between potassium and magnesium atoms via amide and benzyl group. The potassium magnesiate complex showed dramatic bimetallic synergistic effect in the catalytic intermolecular hydroamination of styrenes.

Gram-Scale Synthesis of β-Sulfonyl Styrenes

A simple and gram-scale synthesis of β-sulfonyl styrenes has been developed starting from one-pot PPA (polyphosphoric acid)-catalyzed 1,1-diacetoxylation of arylacetaldehydes (ArCH2CHO) with acetic anhydride (Ac2O) followed by deacetoxylative sulfonylation of the resulting 1,1-diacetate intermediate with sodium sulfinates (RSO2Na) in good yields under solvent-free conditions.

Pd]‐Catalyzed Intermolecular Coupling and Acid Mediated Intramolecular Cyclodehydration: One‐Pot Synthesis of Indenes

An efficient one‐pot synthesis of indenes from simple starting materials is presented. This process involves a dual C–C bond formation through an intermolecular Heck coupling reaction followed by acid‐mediated intramolecular cyclodehydration. The strategy is amenable to various substituted aromatics to give indenes. In addition, the regioselective synthesis of benzyl styrenes in a single column purification technique through in‐situ reduction of Heck products (ketones) followed by acid mediated dehydration of crude reaction mixture is presented.

Ultra-fast Suzuki and Heck reactions for the synthesis of styrenes and stilbenes using arenediazonium salts as super-electrophiles

The reliable and convenient procedure for the ultrafast conversion of potassium vinyltrifluoroborate to stilbenes and styrenes with impressive TOFs is proposed.

Synthesis of γ-sulfonyl δ-lactones and β-sulfonyl styrenes

A facile route to the synthesis of γ-sulfonyl lactones 5 and β-sulfonyl styrenes 6 has been developed, achieving moderate to good yields via the (1) NaH mediated Michael addition of β-ketosulfones 3 and methyl acrylate in refluxing THF and (2) NaBH4 mediated stereoselective reduction/lactonization of δ-ketoesters 4 in boiling MeOH, or (3) boron trifluoride etherate mediated ring-opening of lactones 5 in MeOH at reflux.

MIDA-vinylsilanes: selective cross-couplings and applications to the synthesis of functionalized stilbenes.

A rapid and stereodefined synthesis of MIDA-boryl vinylsilanes has been achieved through the hydrosilylation of an alkynylboronic ester. The E products which contain a silyl and boryl group can be selectively cross-coupled in a two-step bidirectional sequence to provide a rapid and high-yielding synthesis of complex styrenes.

Ultrasonic and Microwave-Assisted Synthesis of β-Nitro Styrenes and Nitro Phenols with Tertiary Butyl Nitrite under Acid-Free Conditions

Tertiary butyl nitrite (TBN) is an acid-free and safe nitrating agent that provides preferentially β-nitrostyrenes with cinnamic acids and corresponding nitro derivatives with phenols in good yields under classical conditions. However, ultrasonic and microwave-assisted reactions reduced the reaction times substantially and enhanced the yields from good to excellent. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

ChemInform Abstract: Stereoselective Synthesis of Hydroxy Stilbenoids and Styrenes by Atom‐Efficient Olefination with Thiophthalides.

AbstractThe preparation of the title compounds is accomplished with high (E)‐stereoselectivity where only elemental sulfur is lost.

ChemInform Abstract: The Continuous‐Flow Synthesis of Styrenes Using Ethylene in a Palladium‐Catalyzed Heck Cross‐Coupling Reaction.

AbstractA fast, safe and practical synthesis of styrenes by Pd‐catalyzed Heck reaction of aryl iodides with ethylene is described using a tube‐in‐tube gas‐liquid reactor under continuous flow conditions.

Stereoselective synthesis of hydroxy stilbenoids and styrenes by atom-efficient olefination with thiophthalides

The synthesis of stilbenoids and styryl carboxylic acids is accomplished with high E-stereoselectivity by olefination of aldehydes with thiophthalides under basic conditions. The olefination is highly atom-efficient as it only loses elemental sulfur during the reaction. This olefination, in conjunction with retro Kolbe-Schmitt reaction, allows facile synthesis of E-hydroxystilbenoids with minimal employment of protecting groups. This study also discloses two important findings: formation of i) 4-methylsulfanyl isocoumarins and ii) an 2-arylindenone.

The Continuous-Flow Synthesis of Styrenes Using Ethylene in a Palladium-Catalysed Heck Cross-Coupling Reaction

The Continuous-Flow Synthesis of Styrenes Using Ethylene in a Palladium-Catalysed Heck Cross-Coupling Reaction

Mechanistic Switch via Subtle Ligand Modulation: Palladium‐Catalyzed Synthesis of α,β‐Substituted Styrenes via CH Bond Functionalization

AbstractA new catalyst system able to efficiently perform the synthesis of styrenes via CH bond functionalization and a subtle ligand modification are described. The high level of activity achieved allows for the synthesis of highly functionalized α,β‐substituted styrenes, even the elusive E‐configured trisubstituted olefins, in a regio‐ and stereoselective manner. Mechanistic experiments allowed for the identification of the corresponding synthetic intermediates.

ChemInform Abstract: Synthesis of Styrenes by Palladium(II)‐Catalyzed Vinylation of Arylboronic Acids and Aryltrifluoroborates by Using Vinyl Acetate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Styrenes by Palladium(II)‐Catalyzed Vinylation of Arylboronic Acids and Aryltrifluoroborates by Using Vinyl Acetate

One Heck of a reaction: Treatment of arylboronic acids or aryltrifluoroborates with vinyl acetate by using a palladium(II) catalyst gives the corresponding styrenes (see scheme). No palladium reoxidant is needed and the vinylation is performed under non-inert conditionsReactions of aromatic and heteroaromatic boronic acids or aryltrifluoroborate salts with vinyl acetate in the presence of a palladium(II) catalyst give the corresponding styrenes in good yields. This Heck reaction proceeds with microwave heating in less than 30 min at 140 degrees C in the absence of base and tolerates a variety of substituents. No palladium reoxidant is needed and the vinylation is performed under non-inert conditions. Mass spectrometry (electrospray ionization mass spectrometry (ESIMS) and tandem mass spectrometry (MS/MS)) was used to identify cationic palladium-containing complexes in ongoing reactions. The key intermediates that have been detected, together with experiments that used deuterated vinyl acetate, support the existence of catalytically active palladium hydride species, and that it is the arylation of ethylene, not vinyl acetate, which generates the styrene product. The mechanism of the reaction is discussed in terms of the palladium(II) intermediates mentioned above.

ChemInform Abstract: Unique Versatility of Ionic Liquids as Clean Decarboxylation Catalyst Cum Solvent: A Metal‐ and Quinoline‐Free Paradigm Towards Synthesis of Indoles, Styrenes, Stilbenes and Arene Derivatives under Microwave Irradiation in Aqueous Conditions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.