72036-37-4Relevant academic research and scientific papers
Metal-free annulative hydrosulfonation of propiolate esters: synthesis of 4-sulfonates of coumarins and butenolides
Fernandes, Rodney A.,Gangani, Ashvin J.,Kunkalkar, Rupesh A.
, p. 3970 - 3984 (2020/03/19)
An efficient metal-free and cost-effective method for the synthesis of coumarin and butenolide 4-sulfonates (46 examples) has been developed. The reaction involves addition of sulfonic acids to ethyl propiolates followed by lactonization, resulting in direct formation of coumarin and butenolide 4-sulfonates. This methodology has been elaborated to Sonogashira and Suzuki coupling including the synthesis of rac-tolterodine.
Synthesis of trisubstituted allenamides utilizing 1,2-rearrangement of dialkoxyphosphoryl moiety under Br?nsted base catalysis
Kondoh, Azusa,Ozawa, Ryosuke,Terada, Masahiro
supporting information, p. 1164 - 1167 (2019/09/07)
A new method for the synthesis of trisubstituted allenamides was developed by utilizing the 1,2-rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen under Br?nsted base catalysis. The reaction would involve the catalytic generation of an α-amino propargyl anion through the key rearrangement, the addition to an electrophile at the α-position of the anionic intermediate, and the unprecedented rearrangement of a phosphoramidate moiety of the adduct, providing trisubstituted allenamides that are difficult to synthesize by using conventional methods.
Reactions of alkyl 4-hydroxybut-2-ynoates with arenes under superelectrophilic activation with triflic acid or HUSY zeolite: Alternative propargylation or allenylation of arenes, and synthesis of furan-2-ones
Devleshova, Natalia A.,Lozovskiy, Stanislav V.,Vasilyev, Aleksander V.
, (2019/08/27)
Reactions of alkyl 4-aryl(or 4,4-diaryl)-4-hydroxybut-2-ynoates [Ar(H or Ar')(OH)C4–C3≡C2–CO2Alk] with arenes under the action of triflic acid TfOH or HUSY zeolite result in the formation of two main compounds, aryl substituted furan-2-ones or products of propargylation of electron rich arenes. Key reactive intermediates in these transformations are the corresponding O,O-diprotonated forms of starting butynoates, Ar(H or Ar')(+OH2)C4–C3≡C2– C(=O+H)(OAlk), dehydration of which gives rise to mesomeric propargyl-allenyl cations Ar(H or Ar')(OH)4C+–C3≡C2–C(=O+H)(OAlk) ? Ar(H or Ar')(OH)4C = C3 = 2C+–C(=O+H)(OAlk), having two electrophilic centers on the carbons C4 and C2 respectively. Reactions of these species with arenes at C4 lead to products of arene propargylation, alternatively, reactions at C2 result in allenylation of arenes, followed by further transformation into furan-2-ones. Using quantum chemical calculations by the DFT method, it has been shown that the reactivity of such propargyl-allenyl cations is mainly explained by orbital factors. Plausible reaction mechanism is discussed.
: NBu4NPF6 promoted regioselective cascade synthesis of functionally embellished naphthofurans under acid, metal & solvent free conditions
Pareek, Abhishek,Dada, Ravikrishna,Rana, Monika,Sharma, Anuj K.,Yaragorla, Srinivasarao
, p. 89732 - 89743 (2016/10/03)
nBu4NPF6 mediated highly regioselective synthesis of functionally embellished naphthofurans has been achieved from easily available naphthols and propargyl alcohols through a cascade benzylation, oxacyclisation (5-exo dig) and isomerization under solvent free conditions. The reaction works in a short time through dibenzyl ether formation followed by the decomposition to the carbocation to furnish the high yielding products with large substrate scope. The synthetic utility of the products is demonstrated through C(sp3)-H functionalization. In addition, we investigated selected naphthofurans for their anti-amyloidogenic properties. Preliminary studies suggest that these are excellent inhibitors for amyloid formation, a hallmark for several neurodegenerative diseases.
Synthesis of γ-acetoxy β-keto esters through regioselective hydration of γ-acetoxy-α,β-alkynoates
Pradhan, Tapas R.,Mendhekar, Kishor L.,Mohapatra, Debendra K.
, p. 5517 - 5531 (2015/06/16)
The Au(I)-catalyzed regioselective hydration of γ-acetoxy-α,β-acetylinic ester by the assistance of a neighboring carbonyl group has been developed. Varieties of simple primary, secondary, and tertiary γ-acetoxy-α,β-acetylinic esters, even those bearing sensitive functional group in the remote reaction sites, are selectively hydrated to the corresponding β-keto esters. The reaction tolerates a wide variety of other carboxylates, such as benzoates, propionates, acrylates, and pivalates, including chiral carboxylates with retention of the configuration. The broad substrate scope, including the derivatization of complex natural products and neutral and open air conditions, makes this atom economical approach very practical. 18O labeling experiments disclose that the oxygen transposition occurs from the carboxylate group to the triple bond, not from water.
Ruthenium-catalyzed [2 + 2] cycloadditions between norbornene and propargylic alcohols or their derivatives
Tsui, Gavin C.,Villeneuve, Karine,Carlson, Emily,Tam, William
, p. 3847 - 3856 (2014/08/18)
Diastereoselective ruthenium-catalyzed [2 + 2] cycloadditions of norbornene and propargylic alcohols or their derivatives were investigated. The cycloadditions were found to be highly stereoselective, giving exo cycloadducts in moderate to excellent yields with diastereoselectivities up to 92:8. When a chiral propargylic alcohol was used in the cycloaddition, up to 80% ee of the [2 + 2] cycloadducts was observed after oxidation of the alcohol.
Robust eco-friendly protocol for the preparation of γ-hydroxy- α,β-acetylenic esters by sequential one-pot elimination-addition of 2-bromoacrylates to aldehydes promoted by LTMP in 2-MeTHF
Pace, Vittorio,Castoldi, Laura,Alcantara, Andres R.,Holzer, Wolfgang
, p. 1859 - 1863 (2012/08/14)
An efficient and widely applicable preparation of γ-hydroxy-α, β-acetylenic esters is described by means of a one-pot dehydrobromination of a 2-bromoacrylate ester with LTMP followed by the electrophilic addition of the transient propiolate to different aldehydes in the eco-friendly solvent 2-MeTHF. The Royal Society of Chemistry 2012.
Gold(I)-catalyzed tandem alkoxylation/lactonization of γ-hydroxy- α,β-acetylenic esters
Ramon, Ruben S.,Pottier, Christophe,Gomez-Suarez, Adrian,Nolan, Steven P.
supporting information; experimental part, p. 1575 - 1583 (2011/08/04)
The formation of 4-alkoxy-2(5H)-furanones was achieved via tandem alkoxylation/lactonization of γ-hydroxy-α,β-acetylenic esters catalyzed by 2 mol% of [2,6-bis(diisopropylphenyl)imidazol-2-ylidine]gold bis(trifluoromethanesulfonyl)imidate [Au(IPr)(NTf2)]. The economic and simple procedure was applied to a series of various secondary propargylic alcohols allowing for yields of desired product of up to 95%. In addition, tertiary propargylic alcohols bearing mostly cyclic substituents were converted into the corresponding spiro derivatives. Both primary and secondary alcohols reacted with propargylic alcohols at moderate temperatures (65-80 °C) in either neat reactions or using 1,2-dichloroethane as a reaction medium allowing for yields of 23-95%. In contrast to [Au(IPr)(NTf2)], reactions with cationic complexes such as [2,6-bis(diisopropylphenyl)imidazol-2-ylidine] (acetonitrile)gold tetrafluoroborate [Au(IPr)(CH3CN)][BF4] or (μ-hydroxy)bis{[2,6-bis(diisopropylphenyl)imidazol-2-ylidine]gold} tetrafluoroborate or bis(trifluoromethanesulfonyl)imidate - [{Au(IPr)} 2(μ-OH)][X] (X=BF4, NTf2) - mostly stop after the alkoxylation. Analysis of the intermediate proved the exclusive formation of the E-isomer which allows for the subsequent lactonization. Copyright
3,3′-anisyl-substituted BINOL, H4BINOL, and H 8BINOL ligands: Asymmetric synthesis of diverse propargylic alcohols and their ring-closing metathesis to chiral cycloalkenes
Yue, Yang,Turlington, Mark,Yu, Xiao-Qi,Pu, Lin
supporting information; experimental part, p. 8681 - 8689 (2009/12/30)
(Chemical Equation Presented) A series of optically active BINOL, H 4BINOL, and H8BINOL derivatives were prepared. These compounds in combination with ZnEt2 and Ti(OiPr) 4 were used to catalyze the asymmetric reaction of alkynes with aldehydes to generate chiral propargylic alcohols at room temperature. Through this comparative study, a 3,3′-bisanisyl-substituted H8BINOL (S)-7 was found to be a generally enantioselective catalyst for the reaction of structurally diverse terminal alkynes with a variety of aldehydes. It catalyzed the reactions of alkyl propiolates with 88-99% ee; the reactions of phenylacetylene with 81-87% ee; the reactions of 4-phenyl-1-butyne, an alkyl alkyne, with 77-89% ee; and the reactions of trimethylsilylacetylene with 92-97% ee. The optically active propargylic alcohols generated from this catalytic asymmetric alkyne addition were observed to undergo efficient ring-closing-metathesis (RCM) reaction in the presence of the Grubbs II catalyst to produce chiral cycloalkenes. It was further found that some of the chiral propargylic alcohols underwent a highly chemoselective tandem RCM hydrogenation reaction with retention of the enantiomeric purity. 2009 American Chemical Society.
