Reaction Of Propargylic Alcohols Research Articles

Insight into the role of [C2C1mim][OAc] and AgNO3 in the reaction of propargylic alcohols, CO2, and 2-aminoethanols

The chemical fixation of CO2 has attracted elevated attentions since it is a promising pathway to solve the serious environmental pollution and fuel shortage. The three-component reaction of CO2, propargyl alcohols, and 2-aminoethanols is one of the most attractive candidates due to the wide applications and extreme importance of products. However, the reaction mechanism is desired to explore due to the complicated catalytic components and substrates. In addition, contribution of each catalytic component and actual catalytic component are still not clear. The mechanism of title reaction catalyzed by AgNO3/[C2C1mim][OAc] is elucidated by the density functional theory (DFT). In addition, the catalytic routes of AgNO3/[C4C1mim][OAc], AgNO3/[DBUH][OAc], AgNO3/[C2C1mim][NO3], and AgNO3/[C2C1mim][ClO4] are also considered to unfold the contribution of cation and anion. The atoms in molecule (AIM) and noncovalent interactions (NCI) are calculated for some important configurations to deeply understand the difference among various catalysts. To elucidate these issues is favorable to explore the more robust catalysts for this reaction.

Rhodium(III)-Catalyzed [4 + 2] Annulation of N-Arylbenzamidines with Propargyl Alcohols: Highly Regioselective Synthesis of 1-Aminoisoquinolines Controlled by Noncovalent Interaction

A highly regioselective synthesis of 1-aminoisoquinolines has been explored via rhodium(III)-catalyzed C-H bond activation/annulation reactions of propargyl alcohols with N-arylbenzamidines. The imidamide was used as the directing group and the nitrogen source of the heterocycle and for regulating the regioselective migratory insertion of propargyl alcohol through a hydrogen bond. In this transformation, a specific isomer was obtained that would provide a new strategy for the synthesis of 1-aminoisoquinolines with biological activity.

Insight into the Interactions between Azole-Anion-Based Ionic Liquids and Propargylic Alcohol: Influence on the Carboxylative Cyclization of Propargylic Alcohol with Carbon Dioxide

To reveal the interactions between azole-anion-based ionic liquids (AILs) and propargyl alcohol (PA) and their effect on the carboxylative cyclization reaction of PA with CO₂, three AILs, namely, [P₆₆₆₁₄][Im], [P₆₆₆₁₄][4-MeIm], and [P₆₆₆₁₄][4-BrIm], were synthesized and characterized. The interactions between the AILs with 2-methyl-3-butyn-2-ol (MBY) were investigated through IR and ¹H NMR spectra and DFT calculations. The results indicate that azole-based anions can form H-bonds with the hydroxyl (O–H) and the alkynyl hydrogen atoms (C≡C–H) of MBY simultaneously, with the former much stronger than the latter, which is supported by the interaction energy and the distance of the H-bond from DFT calculations. Interestingly, the strength of the former always increases with the mole fraction of AIL (xAIL), while that of the latter first decreases and then increases, reaching a minimum at xAIL ≈ 0.4. Furthermore, the order of the strength of the two H-bonds is as follows: [P₆₆₆₁₄][Im] > [P₆₆₆₁₄][4-MeIm] > [P₆₆₆₁₄][4-BrIm], which is in good agreement with their basicity. According to the interactions between the AILs with MBY and combined with the reaction mechanism of MBY with CO₂ promoted by AILs, it is evident that the increase in the basicity of the AILs enhances the H-bond between the AILs with O–H, thereby enhancing the activation of MBY and the subsequent CO₂ conversion. However, this will also increase the interaction between AILs and C≡C–H, resulting in the deprotonation of C≡C–H and hindering the activation of MBY. Therefore, choosing a suitable basic AIL and controlling its ratio are the keys to the reaction of PA and CO₂.

Catalyst-free synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones.

An unambiguous and precise method for the synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones by the reaction of propargylic alcohols and salicylic/thiosalicylic acids under a catalyst-free and open-air atmosphere is described. This strategy is found to be quite general using various 2-mercapto and 2-hydroxybenzoic acids providing benzoxathiinones/benzodioxinones in good yields.

Click chemistry: In vitro evaluation of glycosyl hybrid phosphorylated/thiophosphorylated 1,2,3-triazole derivatives as irreversible acetyl cholinesterase (AChE) inhibitors

A novel series of phosphorylated/ thiophosphorylated glucosyl-1,2,3-triazole derivatives have been synthesized in three step process. The synthetic approach was progressed from the reaction of propargyl alcohol with dialkoxychlorophosphate/thiophosphate derivatives to give propargylphosphate/thiophosphate derivatives. Then, the reaction of above synthesized compounds with acetylated glucosyl azides through azide-alkyne [2 + 3]-cycloaddition reaction (click reaction) led to the formation of the title phosphorylated/thiophosphorylated glucosyl-1,2,3-triazole derivatives in good yields. The synthesized compounds are subjected to biological evaluation as acetyl cholinesterase (AChE) inhibitors and the results are compared with reported compounds.

Metal‐Free Synthesis of (E)‐Vinyl Sulfones via An Insertion of Sulfur Dioxide/1,5‐Hydrogen Atom Transfer Sequence

AbstractA metal‐free three‐component reaction of propargyl alcohols, sodium metabisulfite, and aryldiazonium tetrafluoroborates under mild conditions is described. The reaction proceeds efficiently at room temperature without the need of any catalysts, affording the corresponding (E)‐vinyl sulfones in moderate to good yields with excellent functional group tolerance. Preliminary mechanistic studies show that a vinyl radical‐induced 1,5‐hydrogen atom transfer process and functional group migration are involved, resulting in the cleavage of inert C−H and C−C bonds in sequence.magnified image

Rh‐Catalyzed Reaction of Propargylic Alcohols with Aryl Boronic Acids–Switch from β‐OH Elimination to Protodemetalation

Summary of main observation and conclusionIt is known that Rh‐catalyzed reaction of propargylic alcohols with aryl metallic reagents undergoes SN2’‐type reaction affording allenes via a sequential arylmetalation and β‐OH elimination process. Here we report a Rh/Ag‐cocatalyzed reaction of propargylic alcohols with organoboronic acids affording stereo‐defined (E)‐3‐arylallylic alcohols via arylmetalation and protodemetalation with a high regio‐ and stereoselectivity under very mild conditions. The reaction exhibits a good substrate scope and the compatibility with synthetically useful functional groups with no racemization for optically active propargylic alcohols. Such a reaction may also be extended to homopropargylic alcohols with a remarkable regioselectivity and exclusive E‐stereoselectivity.

Transition-Metal-Free, Brønsted Acid-Mediated Cascade Sequence in the Reaction of Propargyl Alcohols with Sulfonamido-indoles/-indolines: Highly Substituted δ- and α-Carbolines.

Brønsted acid-mediated, transition-metal-free reaction of propargyl alcohols with sulfonamido-indoles/-indolines under mild conditions affords highly substituted δ- or α-carbolines in good to excellent yields. This protocol involves cascade reaction sequences of Friedel-Crafts alkylation/ [1,5]-hydrogen shift/electrocyclization/elimination/ [1,2]-aryl migration followed by aromatization. An unexpected regioselective tosyl group migration from indole 2- to 6-position and arene elimination leading to α-carbolines has also been discovered.

Solvent-free Zn(OTf)2-catalyzed dehydrative cross coupling of propargyl alcohols with diarylphosphine oxides to afford allenylphosphine oxides

A less expensive and more environmentally friendly Zn(OTf)2-catalyzed dehydrative coupling reaction of propargyl alcohols with diarylphosphine oxides is reported. The reaction takes place under mild and solvent free conditions, and features a high regioselectivity to provide an effective method for the synthesis of some diarylphosphinyl allenes in moderate to high yields.

Ag(I)/(C2H5)4NCl Cooperation Catalysis for Fixing CO2 or Its Derivatives into β‐Oxopropylcarbamates

AbstractIt remains a great challenge to convert CO2 into high value‐added products under ambient pressure. Herein, an efficient dual‐component catalytic system, i. e., Ag(I)/(C2H5)4NCl was developed for the synthesis of various β‐oxopropylcarbamates via one‐pot three‐component coupling of CO2, secondary amines and propargylic alcohols under atmospheric pressure. Besides, the strategy avoided the use of any additional ligand and basic species, and excellent selectivity was achieved with a yield of up to 98%. Additionally, 13Ccarbonyl‐labeled and control experiments were carefully performed to demonstrate the mechanism. Notably, this new method was also applied efficiently in quantitative chemical fixation of CO2, i. e., the two‐component reaction of propargylic alcohols and ammonium carbamates.

Cadmium(II) Chloride‐Catalyzed Dehydrative C−P Coupling of Propargyl Alcohols with Diarylphosphine Oxides to Afford Allenylphosphine Oxides

AbstractThe cadmium(II) chloride‐catalyzed dehydrative C−P cross‐coupling reaction of propargyl alcohols with diarylphosphine oxides is reported. Several propargyl alcohols including those bearing the sterically demanding tert‐butyl group at the triple bond terminus can be used as good substrates in the reaction to produce the corresponding allenylphosphine oxides in good to high yields in acetonitrile at 100 °C. The reaction can also be easily scaled up to a gram‐scale synthesis. A mechanism study indicates that the reaction may proceed through a process of propargylic substitution to generate phosphonite intermediates followed by [2,3] sigmatropic rearrangement to produce the allenyl products, rather than through a common allenylative substitution resulting from P‐nucleophilicity.magnified image

Reduced graphene oxide composites with water soluble copolymers having tailored lower critical solution temperatures and unique tube-like structure

Nanohybrids of graphene with water soluble polymer were synthesized using ‘grafting from’ method. GO, prepared by modified Hummers’ method, was first reacted with sodium azide. Alkyne-terminated RAFT-CTA was synthesized by reaction of propargyl alcohol and S-1-dodecyl-S’-(α,α‘-dimethyl-α”-acetic acid) trithiocarbonate. RAFT-CTA was grafted onto the GO sheets by facile click-reaction and subsequently, N-isopropylacrylamide (NIPAM) and N-ethyleacrylamide (NEAM) were polymerized on graphene sheets via RAFT polymerization method. The respective copolymers with different ratios were also prepared. The nanohybrids were characterized by FTIR, XRD, TGA, Raman, SEM, and AFM. Both SEM and AFM clearly showed rod-like structures for rGO-PNEAM. XRD showed a small peak at 2θ = 19.21°, corresponding to d-spacing ≈ 4.6 Å. In addition, the nanohybrids showed a very broad temperature range for the LCST in water between ca. 30 and 70 °C.

Iodine mediated propargylic substitution/aza-Meyer–Schuster rearrangement: stereoselective synthesis of conjugated unsymmetrical azines

A facile synthesis of highly substituted as well as conjugated unsymmetrical azines via the reaction of propargyl alcohols and isatin hydrazones in the presence of iodine is demonstrated under open to air. A series of unsymmetrical azines have been synthesized with excellent yields from simple and readily available starting materials in a complete stereoselective manner.

ChemInform Abstract: Triazole—Gold Promoted Intermolecular Propargyl Alcohol Addition to Alkyne: The Reaction Cascade Toward Substituted Allenes.

AbstractAu‐catalyzed intermolecular addition of propargyl alcohols (I) to alkynes (II) affords intermediate vinyl ethers, which in turn undergo [3,3]‐sigmatropic rearrangement towards substituted allenes (III).

Piperazines by Palladium-Catalyzed Reactions of Propargylic Alcohols

Piperazines by Palladium-Catalyzed Reactions of Propargylic Alcohols

Catalysis by β‐Cyclodextrin Hydrate – Synthesis of 2,2‐Disubstituted 2H‐Chromenes in Aqueous Medium

AbstractA cost‐effective, operationally simple and eco‐compatible protocol for the one‐pot synthesis of photochromic pyrans by the reaction of propargyl alcohols as well as propargyl ethers with differently substituted phenols under ambient atmosphere in aqueous medium has been developed using β‐cyclodextrin hydrate as an efficient, recyclable and stable catalyst. This is the first report where β‐cyclodextrin hydrate acted as a catalyst for an organic transformation but β‐cyclodextrin alone failed.magnified image

Triazole-gold promoted intermolecular propargyl alcohol addition to alkyne: the reaction cascade toward substituted allenes.

Gold-catalyzed intermolecular propargyl alcohol addition to alkyne was achieved. The reaction of propargyl alcohol with a typical gold catalyst gave the hydration product almost exclusively. The triazole gold catalyst (TA-Au) successfully prevented the hydration, giving the vinyl ether followed by a 3,3-rearrangement. Synthetically useful substituted allenes were formed with high efficiency, substrate tolerability and chemoselectivity. Also, more than 95% chirality transfer from propargyl alcohol to allene was obtained.

Catalytic σ-activation of carbon-carbon triple bonds: reactions of propargylic alcohols and alkynes.

The majority reactions of alkynes in the literature are reported to proceed via either structural σ-activation or catalytic π-activation of C≡C bonds. We skillfully designed novel methods for the catalytic σ-activation of C≡C bonds of alkynyl compounds. For terminal alkynyl compounds, σ-activation was achieved by silver(i)-catalyzed C-H functionalization. Whereas σ-activation of internal alkynes was accomplished by the generation of propargylic cations from propargylic alcohols under Lewis-acid catalysis. These σ-activated species have been successfully used for new C-C and C-heteroatom bond formation reactions. Plausible reaction pathways were proposed based on typical control experiments to help the readers to gain insights into reactions and for further discovery of new reactions based on this concept of catalytic σ-activation of C≡C bonds.

ChemInform Abstract: AgSbF6‐Catalyzed Efficient Propargylation/Cycloisomerization Tandem Reaction for the Synthesis of Fully Substituted Furans and New Insights into the Reaction Mechanism.

A mild and efficient AgSbF6 mediated one-pot propargylation/cycloisomerization tandem process has been developed for the construction of fully substituted furans through the reaction of propargylic alcohols and 1,3-dicarbonyl compounds. The isolation of a key reaction intermediate provided new insights into the reaction mechanism.

Synthesis of Allenyl Sulfones via a TBHP/TBAI-Mediated Reaction of Propargyl Alcohols with Sulfonyl Hydrazides.

A new TBHP/TBAI-mediated reaction of propargyl alcohols with sulfonyl hydrazides in the presence of HOAc has been established, in which a wide variety of allenyl sulfones were obtained in moderate to excellent yields. Mechanistic studies indicate that this transformation involves HOAc-promoted sulfonohydrazide intermediate formation, sequential C-O, C-N, and N-S bond cleavage, and C-S bond formation. Significantly, this sulfonohylation proceeds in a radical process and shows highly functional group compatibility and excellent regioselectivity, with a short reaction time and inexpensive reagents.