- 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
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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.
- Nanubolu, Jagadeesh Babu,Reddy Singam, Maneesh Kumar,Sridhar Reddy, Maddi,Suresh, Vavilapalli,Suri Babu, Undamatla
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supporting information
p. 7888 - 7893
(2021/10/25)
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- Catalytic Enantioselective α-Ketol Rearrangement
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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.
- Wu, Hua,Andres, Rémi,Wang, Qian,Zhu, Jieping
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supporting information
p. 499 - 503
(2018/12/13)
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- 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
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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.
- Pan, Jin-Long,Liu, Chang,Chen, Chao,Liu, Tuan-Qing,Wang, Man,Sun, Zhenliang,Zhang, Shu-Yu
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supporting information
p. 2823 - 2827
(2019/04/30)
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- Synthesis of 4-Oxoisoxazoline N-Oxides via Pd-Catalyzed Cyclization of Propargylic Alcohols with tert-Butyl Nitrite
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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.
- Feng, Kai-Wen,Ban, Yong-Liang,Yuan, Pan-Feng,Lei, Wen-Long,Liu, Qiang,Fang, Ran
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supporting information
p. 3131 - 3135
(2019/05/10)
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- Acid catalysed rearrangement of isobenzofurans to angularly fused phthalides
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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.
- Chinta, Bhavani Shankar,Gandhi, Soniya,Baire, Beeraiah
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supporting information
p. 4715 - 4719
(2019/05/24)
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- DBU-promoted carbonylative synthesis of 1,3-oxathiolan-2-ones from propargylic alcohols with TFBen as the CO source
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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.
- Ying, Jun,Zhou, Chao,Wu, Xiao-Feng
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supporting information
p. 1065 - 1067
(2018/02/22)
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- Cyclic eneyne compound and synthesis method thereof
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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
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Paragraph 0038-0040
(2017/10/05)
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- Asymmetric Intermolecular Heck Reaction of Propargylic Acetates and Cycloalkenes to Access Fused Cyclobutenes
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An asymmetric Heck annulation of propargylic acetates with several types of cyclic olefins affords highly strained cyclobutenes in high enantioselectivity.
- Jiao, Zhiwei,Shi, Qi,Zhou, Jianrong Steve
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supporting information
p. 14567 - 14571
(2017/10/23)
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- Unprecedented Intramolecular [4 + 2]-Cycloaddition between a 1,3-Diene and a Diazo Ester
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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.
- Qiu, Huang,Srinivas, Harathi D.,Zavalij, Peter Y.,Doyle, Michael P.
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supporting information
p. 1808 - 1811
(2016/03/01)
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- Microwave-Assisted Organocatalyzed Rearrangement of Propargyl Vinyl Ethers to Salicylaldehyde Derivatives: An Experimental and Theoretical Study
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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.
- Tejedor, David,Cotos, Leandro,Márquez-Arce, Daniel,Odriozola-Gimeno, Mikel,Torrent-Sucarrat, Miquel,Cossío, Fernando P.,García-Tellado, Fernando
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supporting information
p. 18280 - 18289
(2015/12/24)
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- Regioselectivity switch: Gold(I)-catalyzed oxidative rearrangement of propargyl alcohols to 1,3-diketones
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The gold(I)-catalyzed oxidative rearrangement of propargyl alcohols provides an efficient and selective route to 1,3-diketones under mild conditions. Pyridine-N-oxides were used as external oxidants with, different from related substrates, no alkylidenecycloalkanones or oxetan-3-ones formed as side-products.
- Hashmi, A. Stephen K.,Wang, Tao,Shi, Shuai,Rudolph, Matthias
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p. 7761 - 7767
(2012/11/07)
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- Gold-catalyzed isomerization of unactivated allenes into 1,3-dienes under ambient conditions
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We have developed a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.
- Ting, Chun-Ming,Hsu, Yi-Ling,Liu, Rai-Shung
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supporting information; experimental part
p. 6577 - 6579
(2012/07/31)
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- Synthesis of 2,3-diiodoindenes and their applications in construction of 13H-indeno[1,2-l]phenanthrenes
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A series of 2,3-diiodoindene were synthesized at first, and 13H-indeno[1,2-l]phenanthrenes were then constructed via a Suzuki coupling reaction and subsequently a Scholl reaction. Structures of synthesized compounds were fully characterized by 1H NMR, 13C NMR, and HRMS. Their photophysical properties, such as UV-vis and FL spectra were investigated, and electronic properties were theoretically calculated by the software of Gaussian 03. The results suggested that these modified indene and indenophenanthrene compounds might have potential applications as light emitting materials.
- Zhou, Chao,Chen, Xiaopeng,Lu, Ping,Wang, Yanguang
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supporting information; experimental part
p. 2844 - 2850
(2012/05/05)
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- Generation of allenic/propargylic zirconium complexes and subsequent cross-coupling reactions: A facile synthesis of multisubstituted allenes
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(Chemical Equation Presented) The β-alkoxide elimination reaction of propargylic ether with Negishi reagent leads to allenes and/or alkynes after hydrolysis. The product distribution is highly dependent on the substitution pattern of starting propargylic
- Zhang, Hao,Fu, Xiaoping,Chen, Jingjin,Wang, Erjuan,Liu, Yuanhong,Li, Yuxue
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supporting information; experimental part
p. 9351 - 9358
(2010/03/04)
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- Synthesis of propargylic alcohols by base promoted alkynylation of ketones with ethynylbenzene using ionic liquid [(bmim) PF6]
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A mild and efficient addition of ethynylbenzene with ketones using KOH in ionic liquid 1-butyl-3-methylimidazolium hexaflurophosphate [(bmim) PF 6] gives propargylic alcohols in high yields.
- Jagtap, Sachin R.,Bhanage, Bhalchandra M.
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p. 370 - 372
(2008/09/16)
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- Unexpected reactivity of 3-(phenylethynyl)-1H-indenes towards nucleophiles: Noncatalytic addition to triple bond with or without double bond migration
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When studying the chemical properties of (3-phenylethynyl)-1H-indenes, a new reaction was discovered, namely, nucleophilic addition to conjugated enynes accompanied in some cases by migration. The reaction takes place under mild conditions and is not cata
- Ivchenko,Nifant'ev,Luzikov,Mkoyan
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p. 1038 - 1046
(2008/02/02)
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- Indium-mediated carbonyl alkynylation
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Indium mediates a Barbier-type reaction between alkynyl halides and aldehydes or ketones to give secondary or tertiary propargyl alcohols. Secondary alcohols can be oxidised in situ according an Oppenauer process.
- Augé, Jacques,Lubin-Germain, Nadège,Seghrouchni, Latifa
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p. 5255 - 5256
(2007/10/03)
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- Tertiary acetylenic alcohols and diols on the basis of phenylacetylene and 2-methyl-3-butyn-2-ol
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A procedure has been proposed for the synthesis of tertiary acetylenic alcohols and diols by treatment of phenylacetylene or 2-methyl-3-butyn-2-ol with butyllithium and subsequent reaction of lithium phenylacetylide or lithium 4-lithio-2-methyl-3-butyn-2-
- Potkin,Dikusar,Kozlov
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p. 1260 - 1265
(2007/10/03)
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- Solvent-free addition of ethynylbenzene to ketones
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The addition of ethynylbenzene to ketones proceeded efficiently in the absence of a solvent to give tertiary alkynols in good yields.
- Miyamoto,Yasaka,Tanaka
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p. 185 - 186
(2007/10/03)
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- THE-PALLADIUM-CATALYSED REDUCTIVE ADDITION OF ARYL IODIDES TO PROPARGYL ALCOHOLS: A ROUTE TO γ,γ-DIARYL ALLYLIC ALCOHOLS
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The reaction of aryl iodides with ethynyl and arylethynyl, dialkyl carbinols in the presence of the tri- or dialkylammonium formate-palladium reagent provides a convenient route to γ,γ-diarylallylic alcohols.In the presence of arylethynyl, alkylcarbinols a lack of regioselectivity was observed and mixtures of β,γ-, γ,γ-diarylallylic alcohols, and α,β-unsaturated ketones were obtained.
- Arcadi, A.,Cacchi, S.,Marinelli, F.
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p. 5121 - 5132
(2007/10/02)
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- Cycloaddition Reactions of Allenyl Cations with Cyclopentadiene
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Propargyl halides R1-C=-C-CR2R3X (14) and cyclopentadiene react with zinc halide catalysis in ether/dichloromethane solution to give 3-halogenobicycloocta-2,6-dienes 13 (R1 = alkyl) or 5-(α-halogenobenzylidene)norbornenes 15 (R1 = aryl).The reactions are interpreted by stepwise - and -cycloadditions of intermediate allenyl cations 1, proceeding via propargylcyclopentenyl cations 5 and bicyclic vinyl cations 9 or 12.If the reactions are initiated by equimolar amounts of silver trifluoroacetate, quenching products of all postulated intermediates are isolated.The relative energies of the intermediate carbenium ions are estimated on the basis of force field calculations and of gas phase stabilities of simple carbocations.Stereochemical studies indicate that the addition reactions proceed via the compact transition state 42 rather than 41.The zinc chloride catalysed reaction of propargyl chloride 14e with cyclopentadiene yields the 2:1 product 17 (structurally assigned by X ray analysis) in addition to the 1:1 product 15e.The formation of 17 is rationalised by a -cycloaddition of allenyl cation 1 with cyclopentadiene.
- Mayr, Herbert,Halberstadt-Kausch, Inge K.
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p. 3479 - 3515
(2007/10/02)
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