20913-05-7Relevant academic research and scientific papers
Silica gel-promoted synthesis of multisubstituted spiroindolenines from tryptamines and γ-chloro-α,β-unsaturated ketones
Liu, Qiang-Qiang,Zheng, Chao,You, Shu-Li
, (2021)
Here we report a one-pot synthesis of multisubstituted spiroindolenines from a series of tryptamine derivatives with γ-chloro-α,β-unsaturated ketones. The reaction sequence consists of base-induced condensation and silica gel-promoted intramolecular Michael addition. The target molecules are afforded in up to 90% yield with up to >20:1 diastereoselectivity.
An efficient keim-type catalyst based on an electron-poor P,O-chelate; tuning the selectivity of ethylene oligomerisation towards short α-olefins
Kuhn, Pierre,Semeril, David,Jeunesse, Catherine,Matt, Dominique,Lutz, Pierre,Welter, Richard
, p. 1477 - 1481 (2005)
The tertiary phosphane Ph2P-pzONa, in which the phosphorus atom is substituted by an electron-withdrawing pyrazolonato unit, reacts with trans-[NiPhCl(PPh3)2] to afford quantitatively trans-P,P′-[NiPh(Ph2P-pzO)(
Formation of epoxychromeno[4,3-c]isoquinolines through diastereoselective one-pot IMDA reaction of 4-chloro-3-[(1E)-3-oxo-3-phenyl-1-propen-1-yl]-2H-chromen-2-one and furfurylamine
Alizadeh, Abdolali,Amir Ashjei Asalemi, Kaveh,Farajpour, Behnaz,Halvagar, Mohammad Reza
, p. 3393 - 3399 (2020)
Abstract: An intramolecular Diels–Alder mediated reaction of (2E)-3-(4-chloro-2-methylene-2H-chromen-3-yl)-1-phenyl-2-propen-1-one, which was obtained in situ from the reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehyde and Wittig reagent, with furfuryl
Benzoylmethylenetriphenylphosphorane, C26H21OP
Kalyanasundari, M.,Panchanatheswaran, K.,Parthasarathi, V.,Robinson, Ward T.,Wen, Huo
, p. 1738 - 1741 (1994)
The air-stable phosphorane (2-oxo-2-phenyltriphenylphosphoniumethylide) is shown to be a resonance hybrid of an ylene, ylidic and enolate canonical assembly.The geometry around the P atom is nearly tetrahedral.The O atom is oriented cis to the P atom.The phenyl ring of the benzoyl group is twisted with respect to the plane containing the carbonyl group.
The Influence of Substitution on Thiol-Induced Oxanorbornadiene Fragmentation
De Pascalis, Lucrezia,Yau, Mei-Kwan,Svatunek, Dennis,Tan, Zhuoting,Tekkam, Srinivas,Houk,Finn
supporting information, p. 3751 - 3754 (2021/05/10)
Oxanorbornadienes (ONDs) undergo facile Michael addition with thiols and then fragment by a retro-Diels-Alder (rDA) reaction, a unique two-step sequence among electrophilic cleavable linkages. The rDA reaction rate was explored as a function of the furan
Stereoselective Visible-Light Catalyzed Cyclization of Bis(enones): A Viable Approach to the Synthesis of Enantiomerically Enriched Cyclopentane Rings
Medici, Fabrizio,Resta, Simonetta,Presenti, Piero,Caruso, Lucia,Puglisi, Alessandra,Raimondi, Laura,Rossi, Sergio,Benaglia, Maurizio
, p. 4521 - 4524 (2021/06/12)
Photoredox catalytic cyclization of aryl enones in the presence of visible light, promoted either by metals or organic dyes, represent a valuable strategy for the synthesis of cycloalkanes. The development of a stereoselective version of such transformation, in the presence of the metal-free catalyst Eosin Y was studied, with the aim to realize an efficient protocol for the in-flow synthesis of enantiomerically enriched functionalized cyclopentane rings, taking advantage of the flow reactors technology. The use of a chiral auxiliary on the bisenone to be cyclized offers a straightforward and convenient option to exert a stereocontrol on the light-driven cyclization. By exploiting Evans’ oxazolidinones, the stereoselective light-driven cyclization affords, after the removal of the chiral auxiliary, a functionalized 1,2-trans cyclopentane ring in up to 83/17 enantiomeric ratio. When the reaction was performed in continuo, in a homemade coil photoreactor, high yields were observed. The cyclization was also successfully realized in a 3D-printed mesoreactor, without any change in the diastereoseletctivity of the process.
Ground-State Electron Transfer as an Initiation Mechanism for Biocatalytic C-C Bond Forming Reactions
Fu, Haigen,Lam, Heather,Emmanuel, Megan A.,Kim, Ji Hye,Sandoval, Braddock A.,Hyster, Todd K.
supporting information, p. 9622 - 9629 (2021/07/01)
The development of non-natural reaction mechanisms is an attractive strategy for expanding the synthetic capabilities of substrate promiscuous enzymes. Here, we report an "ene"-reductase catalyzed asymmetric hydroalkylation of olefins using α-bromoketones as radical precursors. Radical initiation occurs via ground-state electron transfer from the flavin cofactor located within the enzyme active site, an underrepresented mechanism in flavin biocatalysis. Four rounds of site saturation mutagenesis were used to access a variant of the "ene"-reductase nicotinamide-dependent cyclohexanone reductase (NCR) from Zymomonas mobiles capable of catalyzing a cyclization to furnish β-chiral cyclopentanones with high levels of enantioselectivity. Additionally, wild-type NCR can catalyze intermolecular couplings with precise stereochemical control over the radical termination step. This report highlights the utility for ground-state electron transfers to enable non-natural biocatalytic C-C bond forming reactions.
Nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane
Chen, Xue,Jin, Hongwei,Liu, Yunkui,Wang, Zhen,Zhou, Bingwei,Zhou, Jinyong
supporting information, p. 8021 - 8024 (2021/10/04)
Herein we describe a nickel-catalyzed remote hydrosilylation of unconjugated enones with bulky triphenylsilane. A range ofZ-silyl enol ethers are obtained as major isomers due to the process of nickel triggered alkene isomerization. Notably, some specific
Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
supporting information, p. 20501 - 20512 (2021/12/03)
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
Rh(iii)-catalyzed diastereoselective cascade annulation of enone-tethered cyclohexadienonesviaC(sp2)-H bond activation
Chegondi, Rambabu,Jadhav, Sandip B.,Maurya, Sundaram,Navaneetha, N.
, p. 13598 - 13601 (2021/12/23)
Herein, we report highly diastereoselective arylative cyclization of enone-tethered cyclohexadienonesviaRh(iii)-catalyzed C-H activation ofN-methoxybenzamides. This reaction proceeds through the formation of a five-membered rhodacycle followed by bis-Michael cascade annulation to access functionalized bicyclic scaffolds with four contiguous stereocenters with a broad substrate scope. These products have excellent functional handles, allowing further synthetic transformation to increase the structural complexity. Furthermore, mechanistic studies of arylative cyclization and a gram-scale experiment are also presented.
