- Cascade Ring-Opening Dual Halogenation of Cyclopropenones with Saturated Oxygen Heterocycles
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Represented is a CuX2- or I2-promoted ring-opening dual halogenation of cyclopropenones with saturated oxygen heterocycles, providing an efficient method for the synthesis of 3-haloacrylates. The ring-opening reaction enables the construction of two C–X (X = Cl, Br, or I) bonds and a C–O bond as well as the cleavage of two C–O bonds and a C–C bond in a single step. This protocol is highly atom economical, has an excellent substrate scope, and exhibits the ability for gram-scale reaction.
- Gao, Wen-Xia,Huang, Xiao-Bo,Liu, Miao-Chang,Miao, Wei-Hang,Wu, Hua-Yue,Zhou, Yun-Bing
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supporting information
p. 9425 - 9430
(2021/12/14)
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- Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
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An unprecedented C═C double bond cleavage of cyclopropenone and dioxygen activation by multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fully substituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
- Yao, Liangliang,Hu, Qiong,Bao, Li,Zhu, Wenjing,Hu, Yimin
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supporting information
p. 4971 - 4975
(2021/06/30)
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- A Palladium-Catalyzed Cascade C-C Activation of Cyclopropenone and Carbonylative Amination: Easy Access to Highly Functionalized Maleimide Derivatives
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We describe herein the first report on palladium-catalyzed C-C bond activation of cyclopropenone and concomitant carbonylative amination to produce maleimides. The interesting aspect of this reaction is that the sacrificial elimination of carbon monoxide from the substrate is efficiently recaptured by one of the intermediates in the catalytic cycle for the formation of maleimides. 18O isotopic studies confirmed that the source of carbon monoxide is from cyclopropenone.
- Nanda, Tanmayee,Ravikumar, P. C.
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supporting information
(2020/02/15)
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- Organocatalytic Regiodivergent C?C Bond Cleavage of Cyclopropenones: A Highly Efficient Cascade Approach to Enantiopure Heterocyclic Frameworks
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Here a highly efficient cascade approach is reported that combines a cycloaddition reaction with a regioselective strain-release process to afford diverse heterocyclic frameworks through bifunctional catalysis. The cooperation of hydrogen-bonding network activation and a regiodivergent strain-assisted effect is the key to promoting this complex chemical transformation, leading to the generation of two different ring systems in high yields with excellent stereoselectivities. The reaction proceeded by a mechanism involving a “spring-loaded” intermediate with switchable C?C bond cleavages achieved by controllable ring-strain release. This reaction was also amenable to gram scale synthesis with only 0.1 mol % catalyst loading.
- Cao, Jian,Fang, Ran,Liu, Jin-Yu,Lu, Hong,Luo, Yong-Chun,Xu, Peng-Fei
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p. 18863 - 18867
(2018/11/23)
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- Cyclopropenones for Metabolic Targeting and Sequential Bioorthogonal Labeling
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Cyclopropenones are attractive motifs for bioorthogonal chemistry, owing to their small size and unique modes of reactivity. Unfortunately, the fastest-reacting cyclopropenones are insufficiently stable for routine intracellular use. Here we report cyclop
- Row, R. David,Shih, Hui-Wen,Alexander, Austin T.,Mehl, Ryan A.,Prescher, Jennifer A.
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supporting information
p. 7370 - 7375
(2017/06/05)
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- Cyclopentadienone synthesis by rhodium(I)-catalyzed [3 + 2] cycloaddition reactions of cyclopropenones and alkynes
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The Rh(I)-catalyzed [3 + 2] cycloaddition of cyclopropenones and alkynes is found to provide a highly efficient and regiocontrolled route to cyclopentadienones (CPDs), building blocks of widespread use in the synthesis of natural and non-natural products, therapeutic leads, polymers, dendrimers, devices, and antigen presenting scaffolds. The versatility of the method is explored with 23 examples representing a wide range of alkyne variations (arylalkyl-, dialkyl-, heteroarylalkyl-) and diaryl- as well as arylalkylcyclopropenones. The reactions often proceed in high yield using minimal catalyst loadings and in all cases examined proceed with high or complete regioselectivity. The reaction is readily scalable to produce gram quantities of cycloadduct and provides a unique and versatile route to CPDs that would be otherwise difficult to obtain. Copyright
- Wender, Paul A.,Paxton, Thomas J.,Williams, Travis J.
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p. 14814 - 14815
(2008/02/08)
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- Preparation of methylenedifluorocyclopropanes via cyclopropyl anion promoted β-elimination
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Preparation of methylenedifluorocyclopropanes 2 through the β- elimination reaction promoted by difluorocyclopropyl anion formed by cleavage of C-Si bond with TBAF is described. Base-catalyzed isomerization of 2 to difluorocyclopropene 11 shows the latter structure thermodynamically more stable in contrast to non-fluorinated cases. Application of this method to the synthesis of methylenedifluorocyclopropylglycine (F2MCPG) derivative 17 is also presented.
- Shibuya, Akira,Okada, Midori,Nakamura, Yuko,Kibashi, Mie,Horikawa, Hiroaki,Taguchi, Takeo
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p. 10325 - 10340
(2007/10/03)
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- Regioselectivity in α-Cleavage Reactions: Arylalkylcyclopropenethiones
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Photoreactions of several arylalkylcyclopropenethiones (1b-e) have been investigated.The products formed have been rationalized on the basis of α-cleavage as the primary photoprocess.The photochemical α-cleavage is presumed to originate from the lowest ex
- Singh, Sharat,Ramamurthy, Vaidyanathan
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p. 3732 - 3738
(2007/10/02)
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