25118-60-9Relevant academic research and scientific papers
Rhodium-Catalyzed Annulation of Phenacyl Ammonium Salts with Propargylic Alcohols via a Sequential Dual C-H and a C-C Bond Activation: Modular Entry to Diverse Isochromenones
Nanubolu, Jagadeesh Babu,Reddy Singam, Maneesh Kumar,Sridhar Reddy, Maddi,Suresh, Vavilapalli,Suri Babu, Undamatla
supporting information, p. 7888 - 7893 (2021/10/25)
Given their omnipresence in natural products and pharmaceuticals, isochromenone congeners are one of the most privileged scaffolds to synthetic chemists. Disclosed herein is a dual (ortho/meta) C-H and C-C activation of phenacyl ammonium salts (acylammonium as traceless directing group) toward annulation with propargylic alcohols to accomplish rapid access for novel isochromenones by means of rhodium catalysis from readily available starting materials. This operationally simple protocol features broad substrate scope and wide functional group tolerance. Importantly, the protocol circumvents the need of any stoichiometric metal oxidants and proceeds under aerobic conditions.
Acid catalysed rearrangement of isobenzofurans to angularly fused phthalides
Chinta, Bhavani Shankar,Gandhi, Soniya,Baire, Beeraiah
supporting information, p. 4715 - 4719 (2019/05/24)
An acid catalysed, cascade process for the construction of angularly fused polycyclic phthalides from isobenzofurans under transition metal free conditions has been reported. This process is very general for diverse gem-disubstituted isobenzofuran substrates. Control experiments supported the mechanism as the nucleophilic attack of the carboxylate onto the acid activated furan ring for the simultaneous ring closing-ring opening cascade followed by dehydration. This method serves as a greener alternative for the synthesis of angularly fused polycyclic phthalides.
Catalytic Enantioselective α-Ketol Rearrangement
Wu, Hua,Andres, Rémi,Wang, Qian,Zhu, Jieping
supporting information, p. 499 - 503 (2018/12/13)
A highly enantioselective α-ketol rearrangement has been developed. In the presence of a chiral Cu-bisoxazoline complex, achiral β-hydroxy-α-dicarbonyls were isomerized to chiral α-hydroxy-β-dicarbonyls and their bicyclic derivatives in excellent yields and enantioselectivities. Enantioenriched 2-acyl-2-hydroxy cyclohexan-1-ones, dihydroxyhexahydrobenzofuranones, and dihydroxyhexahydro-cycloheptafuranones, with up to three stereocenters, were readily prepared from achiral starting materials in one operation. The reaction is applicable to the desymmetrization of meso substrates and kinetic resolution of racemic alcohols.
Dual Directing-Groups-Assisted Redox-Neutral Annulation and Ring Opening of N-Aryloxyacetamides with 1-Alkynylcyclobutanols via Rhodium(III)-Catalyzed C-H/C-C Activations
Pan, Jin-Long,Liu, Chang,Chen, Chao,Liu, Tuan-Qing,Wang, Man,Sun, Zhenliang,Zhang, Shu-Yu
supporting information, p. 2823 - 2827 (2019/04/30)
A cascade [3 + 2] annulation and ring opening of N-aryloxyacetamides with 1-alkynylcyclobutanols via Rh(III)-catalyzed redox-neutral C-H/C-C activations using internal oxidative O-NHAc and -OH as the dual directing groups has been achieved. This reaction provided an efficient and regioselective approach to benzofuran derivatives with good functional group compatibility and high yields.
Synthesis of 4-Oxoisoxazoline N-Oxides via Pd-Catalyzed Cyclization of Propargylic Alcohols with tert-Butyl Nitrite
Feng, Kai-Wen,Ban, Yong-Liang,Yuan, Pan-Feng,Lei, Wen-Long,Liu, Qiang,Fang, Ran
supporting information, p. 3131 - 3135 (2019/05/10)
A cyclization of propargylic alcohols with tert-butyl nitrite at room temperature in air was achieved using Pd(OAc)2 as catalyst. The first reported 4-oxoisoxazoline N-oxides could be directly accessed from a range of multisubstituted propargylic alcohols in moderate to excellent yields under mild conditions. Density functional theory calculations indicated that the reaction proceeds through a palladium-catalyzed NO2 addition that efficiently generates a ketoxime radical, which eventually produces 4-oxoisoxazoline N-oxide.
DBU-promoted carbonylative synthesis of 1,3-oxathiolan-2-ones from propargylic alcohols with TFBen as the CO source
Ying, Jun,Zhou, Chao,Wu, Xiao-Feng
supporting information, p. 1065 - 1067 (2018/02/22)
A DBU-promoted carbonylative cyclization of propargylic alcohols with sulfur was developed. Various 1,3-oxathiolan-2-ones were produced in 61-98% yields under mild conditions in the absence of metal catalysts. TFBen (benzene-1,3,5-triyl triformate) as an efficient and solid CO surrogate and S8 as an ideal sulfur source were employed and incorporated.
Cyclic eneyne compound and synthesis method thereof
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Paragraph 0038-0040, (2017/10/05)
The invention relates to a cyclic eneyne compound and a preparation method thereof. The chemical formula is described in the description, wherein substituent R is any one of phenyl or p-methylphenyl or isohexyl or n-heptyl, ring is a five-membered ring or
Asymmetric Intermolecular Heck Reaction of Propargylic Acetates and Cycloalkenes to Access Fused Cyclobutenes
Jiao, Zhiwei,Shi, Qi,Zhou, Jianrong Steve
supporting information, p. 14567 - 14571 (2017/10/23)
An asymmetric Heck annulation of propargylic acetates with several types of cyclic olefins affords highly strained cyclobutenes in high enantioselectivity.
Unprecedented Intramolecular [4 + 2]-Cycloaddition between a 1,3-Diene and a Diazo Ester
Qiu, Huang,Srinivas, Harathi D.,Zavalij, Peter Y.,Doyle, Michael P.
supporting information, p. 1808 - 1811 (2016/03/01)
Diazo compounds that are well-known to undergo [3 + 2]-cycloaddition provide the first examples of the previously unknown [4 + 2]-cycloaddition with dienes that occur thermally under mild conditions and in high yields. Reactions are initiated from reactants prepared from propargyl aryldiazoacetates that undergo gold(I)-catalyzed rearrangement to activated 1,3-dienyl aryldiazoacetates. These reactions proceed to mixtures of both [4 + 2]-cycloaddition and the 1,3-dienyl aryldiazoacetate after long reaction times. At short reaction times, however, both E- and Z-1,3-dienyl aryldiazoacetates are formed and, after isolation, thermal reactions with the E-isomers form the products from [4 + 2]-cycloaddition with δH?298 = 15.6 kcal/mol and δS?298 = -27.3 cal/(mol·°C). The Z-isomer is inert to [4 + 2]-cycloaddition under these conditions. The Hammett relationships from aryl-substituted diazo esters (p = +0.89) and aryl-substituted dienes (p = -1.65) are consistent with the dipolar nature of this transformation.
Microwave-Assisted Organocatalyzed Rearrangement of Propargyl Vinyl Ethers to Salicylaldehyde Derivatives: An Experimental and Theoretical Study
Tejedor, David,Cotos, Leandro,Márquez-Arce, Daniel,Odriozola-Gimeno, Mikel,Torrent-Sucarrat, Miquel,Cossío, Fernando P.,García-Tellado, Fernando
supporting information, p. 18280 - 18289 (2015/12/24)
The microwave-assisted imidazole-catalyzed transformation of propargyl vinyl ethers (PVEs) into multisubstituted salicylaldehydes is described. The reaction is instrumentally simple, scalable, and tolerates a diverse degree of substitution at the propargylic position of the starting PVE. The generated salicylaldehyde motifs incorporate a broad range of topologies, spanning from simple aromatic monocycles to complex fused polycyclic systems. The reaction is highly regioselective and takes place under symmetry-breaking conditions. The preparative power of this reaction was demonstrated in the first total synthesis of morintrifolin B, a benzophenone metabolite isolated from the small tree Morinda citrifolia L. A DFT study of the reaction was performed with full agreement between calculated values and experimental results. The theoretically calculated values support a domino mechanism comprising a propargyl Claisen rearrangement, a [1,3]-H shift, a [1,7]-H shift (enolization), a 6π electrocyclization, and an aromatization reaction.
