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Готові списки джерел за темами / Radical rearrangement

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Добірка наукової літератури з теми "Radical rearrangement"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "Radical rearrangement"

1

Greaney, Michael F., and David M. Whalley. "Recent Advances in the Smiles Rearrangement: New Opportunities for Arylation." Synthesis 54, no. 08 (December 1, 2021): 1908–18. http://dx.doi.org/10.1055/a-1710-6289.

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AbstractThe Smiles rearrangement has undergone a renaissance in recent years providing new avenues for non-canonical arylation techniques in both the radical and polar regimes. This short review will discuss recent applications of the reaction (from 2017 to late 2021), including its relevance to areas such as heterocycle synthesis and the functionalization of alkenes and alkynes as well as glimpses at new directions for the field.1 Introduction2 Polar Smiles Rearrangements3 Radical Smiles: Alkene and Alkyne Functionalization4 Radical Smiles: Rearrangements via C–X Bond Cleavage5 Radical Smiles: Miscellaneous Rearrangements6 Conclusions

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2

Kolodziejczak, Krystian, Alexander J. Stewart, Tell Tuttle, and John A. Murphy. "Radical and Ionic Mechanisms in Rearrangements of o-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et3SiH/KOtBu." Molecules 26, no. 22 (November 15, 2021): 6879. http://dx.doi.org/10.3390/molecules26226879.

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Rearrangements of o-tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et3SiH + KOtBu) were recently announced, in which the ethers were converted to o-hydroxydiarylmethanes, while the (o-tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce–Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of o-tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et3SiH/KOtBu system.

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3

Flintoft, Louisa. "A radical rearrangement." Nature Reviews Genetics 9, no. 1 (January 2008): 5. http://dx.doi.org/10.1038/nrg2292.

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4

Merkley, Nadine, Paul C. Venneri, and John Warkentin. "Cyclopropanation of benzylidenemalononitrile with dialkoxycarbenes and free radical rearrangement of the cyclopropanes." Canadian Journal of Chemistry 79, no. 3 (March 1, 2001): 312–18. http://dx.doi.org/10.1139/v01-017.

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Thermolysis of 2-cinnamyloxy-2-methoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazoline (1a) and the analogous 2-benzyloxy-2-methoxy compound (1b) at 110°C, in benzene containing benzylidenemalononitrile, afforded products of apparent regiospecific addition of methoxycarbonyl and cinnamyl (or benzyl) radicals to the double bond. When the thermolysis of 1a was run with added TEMPO, methoxycarbonyl and cinnamyl radicals were captured. Thermolysis of the 2,2-dibenzyloxy analogue (1c) in the presence of benzylidenemalononitrile gave an adduct that is formally the product of addition of benzyloxycarbonyl and benzyl radicals to the double bond. In this case, a radical addition mechanism could be ruled out, because the rate constant for decarboxylation of benzyloxycarbonyl radicals is very large. A mechanism that fits all of the results is predominant cyclopropanation of benzylidenemalononitrile by the dialkoxycarbenes derived from the oxadiazolines, in competition with fragmentation of the carbenes to radical pairs. The cyclopropanes so formed then undergo homolytic ring-opening to the appropriate diradicals. Subsequent β-scission of the diradicals to afford radical pairs, and coupling of those pairs, gives the final products. Thus, both carbene and radical chemistry are involved in the overall processes.Key words: cyclopropane, dialkoxycarbene, β-scission, oxadiazoline, radical.

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5

Davies, M. J., S. Fu, and R. T. Dean. "Protein hydroperoxides can give rise to reactive free radicals." Biochemical Journal 305, no. 2 (January 15, 1995): 643–49. http://dx.doi.org/10.1042/bj3050643.

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Proteins damaged by free-radical-generating systems in the presence of oxygen yield relatively long-lived protein hydroperoxides. These hydroperoxides have been shown by e.p.r. spectroscopy to be readily degraded to reactive free radicals on reaction with iron(II) complexes. Comparison of the observed spectra with those obtained with free amino acid hydroperoxides had allowed identification of some of the protein-derived radical species (including a number of carbon-centred radicals, alkoxyl radicals and a species believed to be the CO2 radical anion) and the elucidation of novel fragmentation and rearrangement processes involving amino acid side chains. In particular, degradation of hydroperoxide functions on the side chain of glutamic acid is shown to result in decarboxylation at the side-chain carboxy group via the formation of the CO2 radical anion; the generation of an identical radical from hydroperoxide groups on proteins suggests that a similar process occurs with these molecules. In a number of cases these fragmentation and rearrangement reactions give rise to further reactive free radicals (R., O2-./HO2., CO2-.) which may act as chain-carrying species in protein oxidations. These studies suggest that protein hydroperoxides are capable of initiating further radical chain reactions both intra- and inter-molecularly, and provide information on some of the fundamental mechanisms of protein alteration and side-chain fragmentation.

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6

Allart-Simon, Ingrid, Stéphane Gérard, and Janos Sapi. "Radical Smiles Rearrangement: An Update." Molecules 21, no. 7 (July 6, 2016): 878. http://dx.doi.org/10.3390/molecules21070878.

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7

Quiclet-Sire, Béatrice, and Samir Z. Zard. "A radical thia-Brook rearrangement." Chemical Communications 50, no. 45 (2014): 5990. http://dx.doi.org/10.1039/c4cc01683a.

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8

Bacqué, Eric, Myriem El Qacemi, and Samir Z. Zard. "An Unusual Radical Smiles Rearrangement." Organic Letters 7, no. 17 (August 2005): 3817–20. http://dx.doi.org/10.1021/ol051568l.

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9

Reynolds, Dan W., Bijan Harirchian, Huh-Sun Chiou, B. Kaye Marsh, and Nathan L. Bauld. "The cation radical vinylcyclobutane rearrangement." Journal of Physical Organic Chemistry 2, no. 1 (January 1989): 57–88. http://dx.doi.org/10.1002/poc.610020108.

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10

Tappin, Nicholas D. C., and Philippe Renaud. "Radical Reactions of Boron-Ate Complexes Promoting a 1,2-Metallate Rearrangement." CHIMIA International Journal for Chemistry 74, no. 1 (February 26, 2020): 33–38. http://dx.doi.org/10.2533/chimia.2020.33.

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Recently there has been an explosion of interest in the synthetic community for the addition of radicals into unsaturated organoboron-ate complexes. This review will give a concise outline for radical processes involving boron-ate complexes which trigger a subsequent anionotropic rearrangement.

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Більше джерел

Дисертації з теми "Radical rearrangement"

1

Topiwala, Upendra P. "Biomimetic radical spirocyclisation and rearrangement chemistry." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338494.

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2

Harling, John David. "Preparative radical rearrangement reactions for organic synthesis." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47464.

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3

Norberg, Daniel. "Quantum Chemical Studies of Radical Cation Rearrangement, Radical Carbonylation, and Homolytic Substitution Reactions." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8178.

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4

Ndu, Lauretta N. "Preliminary study of possible rearrangement of epoxidyl free radical." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1994. http://digitalcommons.auctr.edu/dissertations/3768.

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Анотація:

Evidence presented shows that bibenzyl was produced through pyrolysis and photolysis of styrene oxide. This supports McBay's^ postulate that decomposition of styrene oxide results in the production of the alpha styrene epoxidyl free radical, which rearranges to form the phenacyl free radical. Further successive rearrangement and decarbonylation of this radical ultimately results in the formation of bibenzyl. However, photobromination of styrene oxide did not generate the phenacyl free radical requried to produce bibenzyl, rather, polymeric styrene was produced. Also reported is the rearrangements of epoxidyl free radical generated through pyrolysis and photolysis of 2,3 epoxy butane. Pyrolysis at 450°C indicated that the resulting epoxidyl radical eventually forms 3,4 dimethyl 2,5 hexane-di-one. The reported results obtained from efforts on the aliphatic epoxidyl radical are thus far inconclusive. The technique for pyrolysis of these epoxides may well be optimized, and these investigations are ongoing. The photolysis of 2,3 epoxy butane under conditions which are effective for the aryl-substituted epoxides was ineffective with this aliphatic epoxide.

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5

Krishnamurthy, Venkatanarayanan. "The oxiranyl carbinyl radical rearrangement synthetic applications and kinetic studies /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487864485228417.

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6

Hutchison, Helen Susan. "Gas phase cyclisation and rearrangement reactions of aromatic free radicals." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/15081.

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7

Hachisu, Shuji. "Radical rearrangement of bicyclo [2.2.1] systems and application in kainoid synthesis." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414142.

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8

Mahy, William. "Catalytic synthesis and modification of heterocycles." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687323.

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Анотація:

The following thesis outlines work carried out during the past three years for the discovery and investigation of catalytic methodologies towards the synthesis and modification of heterocycles, namely cyclic carbamates, carbonates and their sulfur analogues. Chapter 1 summarises the current catalytic methods reported in the literature towards the synthesis and modification of functionalized 2-oxazolidinones. This introduction highlights the diverse range of methods and catalysts that have been developed and their scope and limitations. In addition the review highlights the importance of these structural motifs and suggests areas in which the following research fulfills unmet needs. Chapter 2 reports the discovery and development of a one-pot two-step copper-catalysed methodology towards the synthesis of N-aryl oxazolidinones from amino alcohol carbamates. The scope of both the N-aryl substituent as well as oxazolidinone functionalization is presented in addition to preliminary investigations into the mechanisms of both reactions. Chapter 3 presents the application of the previously reported one-pot process towards the synthesis of a number of medicinally active molecules and blockbuster pharmaceuticals. The one-pot two-step copper-catalysed reaction was utilized to synthesise a common intermediate in the synthesis of a number of oxazolidinone-based pharmaceuticals. The complete syntheses of Toloxatone, Linezolid, Tedizolid and Rivaroxaban are reported. Chapter 4 reports the modification of N-aryl oxazolidinones towards a diverse library of N-aryl oxazolidinethiones. The reactivity of these structures, in addition to N-alkyl oxazolidinethiones, towards transition metal catalysis was investigated and revealed a ruthenium catalysed O- to S-alkyl migration to afford structurally diverse thiazolidinones. Investigations into the substrate scope and mechanism were also carried out, suggesting a pseudo-reversible radical pathway drawing mechanistic parallels to the classic Barton-McCombie reaction. Chapter 5 details further development of the pseudo-reversible radical pathway for the regioselective rearrangement of dioxolane-2-thiones using Pd(PPh3)4 as a catalyst. The scope of the reaction is reported for the formation of highly selective, highly substituted sulfur-rearrangement products.

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9

De, Lijser Hubrecht Johan Peter. "Studies on the interconversion and rearrangement of C¦4H¦6 and C¦8H¦1¦2 radical cations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24751.pdf.

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10

Fadelalla, Ali Mohamad Mohamad. "Manganese(iii)acetate-based Free-radical Additions Of -dicarbonyl Compounds To Bicyclic Systems." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608402/index.pdf.

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Additions of carbon-centered radicals to alkenes are useful method for cyclic compounds formation. Manganese(III)-based oxidative free-radical cyclizations, where the radicals are generated and terminated oxidatively, are established as efficient methods for the construction of cyclic molecule. Treatment of a mixture of dimedone, Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid with homobenzonorbornadiene (80) (4h at 50 &
#61616
C) gave furan derivative (107), dihydrofuran adduct (108), in addition to rearranged product (109) as a major product. The reaction run under the same reaction conditions without using Cu(II)acetate for 8h afforded dihydrofuran adduct (108) along with dihydrofuran (110), where no rearranged products could be formed. On the other hand, reflux of alkene 80 with a mixture of acetylacetone, Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid (3h at 50 &
#61616
C) gave oxidative product (131) and rearranged product (132) (major). The reaction run under the same reaction conditions without using Cu(II)acetate for 7h produced, in addition to the oxidative product 131, a dihydrofuran derivative (133). In a second system, we examined the oxidation of benzobarrelene 82 with Mn(OAc)3, and Cu(OAc)2 in glacial acetic acid (1h at 50 &
#61616
C) in presence of dimedone resulted in the formation of five different products rearranged products (148, 149) and a dihydrofuran (109), besides, a mixture containing two major rearranged isomers (150/151). The same reaction was carried out under the same conditions in absence of Cu(II) for 9h and gave the isomeric mixture 150/151 exclusively, and the yield was reduced. The oxidative cyclization of acetylacetone with alkene 82 for 3h at 50 &
#61616
C, afforded in addition to the dihydrofuran (132), two rearranged products (169, 170) and a mixture consisting of two isomers (171/ 172). The isomeric mixture was converted to one product by treatment with methanolic ammonia providing hydroxyl derivative which was oxidized by MnO2 to afford product 174 in a good yield. Additionally, we investigated the behavior of nitrogen bridge in the bicyclic system on the course of the reaction. Oxidation of N-carbethoxy-7-aza-2,3-benzonorbornadiene 83 with dimedone in the presence of Cu(OAc)2 as well as in its absence in glacial acetic acid (2h at 50 &
#61616
C), rearranged product (189) was obtained as the sole product. Regarding the reaction of aza-derivative 83 with acetylacetone in the presence of Cu(OAc)2 (18 h at 50 &
#61616
C), rearranged product 195 was resulted as sole product. The reaction of 83 was also run with out Cu(OAc)2 for 22h and gave the rearranged product 195.

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Частини книг з теми "Radical rearrangement"

1

Creary, Xavier. "Substituent Effects on the Methylenecyclopropane Rearrangement. A Probe for Free Radical Effects." In Substituent Effects in Radical Chemistry, 245–62. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4758-0_18.

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2

Dowd, Paul, Guiyong Choi, Boguslawa Wilk, Soo-Chang Choi, Songshen Zhang, and Rex E. Shepherd. "On the Mechanism of Action of Vitamin B12: A Non-Free Radical Model for the Methylmalonyl-CoA — Succinyl-CoA Rearrangement." In Chemical Aspects of Enzyme Biotechnology, 235–44. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4757-9637-7_19.

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3

Beckwith, A. L. J., A. G. Davies, and I. G. E. Davison. "The Mechanisms of the Rearrangements of Allylic Hydroperoxides." In Organic Free Radicals, 37–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73963-7_19.

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4

Porter, Ned A., and Patrick H. Dussault. "Rearrangements of Optically Pure Hydroperoxides." In Free Radicals in Synthesis and Biology, 407–21. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-0897-0_30.

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5

Greenberg, Arthur, and Joel F. Liebman. "Resonance and 1,2-Rearrangement Enthalpies in Radicals: from Alkyl Radicals to Alkylcobalamins." In Energetics of Organic Free Radicals, 196–223. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0099-8_7.

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6

"Radical Rearrangement." In Encyclopedia of Metalloproteins, 1833. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-1533-6_101036.

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7

Motherwell, William B., and David Crich. "Preparative Free Radical Rearrangement Reactions." In Free Radical Chain Reactions in Organic Synthesis, 147–77. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-08-092495-3.50012-x.

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8

Zhang, J., D. Liu, and Y. Chen. "1.9 Oxygen-Centered Radicals." In Free Radicals: Fundamentals and Applications in Organic Synthesis 1. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-234-00177.

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AbstractOxygen-centered radicals (R1O•) are reactive intermediates in organic synthesis, with versatile synthetic utilities in processes such as hydrogen-atom transfer (HAT), β-fragmentation, radical addition to unsaturated carbon–carbon bonds, and rearrangement reactions. In this review, we focus on recent advances in the generation and transformation of oxygen-centered radicals, including (alkyl-, α-oxo-, aryl-) carboxyl, alkoxyl, aminoxyl, phenoxyl, and vinyloxyl radicals, and compare the reactivity of oxygen-centered radicals under traditional reaction conditions with their reactivity under visible-light-induced reaction conditions.

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9

Zipse, H. "Charge distribution and charge separation in radical rearrangement reactions." In Advances in Physical Organic Chemistry, 111–30. Elsevier, 2003. http://dx.doi.org/10.1016/s0065-3160(03)38003-7.

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10

Taber, Douglass. "The Castle Synthesis of (-)-Acutumine." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0104.

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The complex tetracyclic alkaloid (-)-acutumine 3, isolated from the Asian vine Menispermum dauricum, shows selective T-cell toxicity. The two adjacent cyclic all-carbon quaternary centers of 3 offered a particular challenge. Steven L. Castle of Brigham Young University solved (J. Am. Chem. Soc. 2009, 131, 6674) this problem by effecting net enantioselective conjugate allylation of the enantiomerically pure substrate 1 to give 2 with high diastereocontrol. The starting coupling partners ( Organic Lett . 2006, 8, 3757; Organic Lett. 2007, 9, 4033) for the synthesis were the Weinreb amide 4, prepared over several steps from 2,3- dimethoxyphenol, and the diastereomerically- and enantiomerically-pure cyclopentenyl iodide 5, prepared by singlet oxygenation of cyclopentadiene followed by enzymatic hydrolysis. Transmetalation of 5 by the Knochel protocol, addition of the resulting organometallic to 4 and enantioselective (and therefore diastereoselective) reduction of the resulting ketone delivered the alcohol 6. Methods for installing cyclic halogenated stereogenic centers are not well developed. Exposure of the allylic alcohol to mesyl chloride gave the chloride 7 with inversion of absolute configuration. Remarkably, this chlorinated center was carried through the rest of the synthesis without being disturbed. A central step in the synthesis of 3 was the spirocyclization of 7 to 8. Initially, iodine atom abstraction generated the aryl radical. The diastereoselectivity of the radical addition to the cyclopentene was set by the adjacent silyloxy group. The α-keto radical so generated reacted with the Et3Al to give a species that was oxidized by the oxaziridine to the α-keto alcohol, again with remarkable diastereocontrol. Conjugate addition to the cyclohexenone 1 failed, so an alternative strategy was developed, diastereoselective 1,2-allylation of the ketone followed by oxy-Cope rearrangement. The stereogenic centers of 1 are remote from the cyclohexenone carbonyl, so could not be used to control the facial selectivity of the addition. Fortunately, the stoichiometric enantiomerically-pure Nakamura reagent delivered the allyl group preferentially to one face of the ketone 1, to give 9. The subsequent sigmatropic rearrangement to establish the very congested second quaternary center of 2 then proceeded with remarkable facility, at 0°C for one hour.

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Тези доповідей конференцій з теми "Radical rearrangement"

1

Ayyalasomayajula, Madhavi, Sydha Salihu, Vincent Kish, and Nilay Mukherjee. "Influence of Rearrangement of Actin Cytoskeleton on the Overall Material Properties of ATDC5 Cells During Chondrogenesis." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61286.

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ATDC5 cells, a prechondrocytic cell line, were cultured in 2% agarose gel-cell constructs. A major reorientation of actin structure (stress-fiber to punctate) was observed during the chondrogenesis of these cells. 2D finite element models of cell (considered as a composite with embedded actin fibers) in a 500μ3 gel were created for days 1 (prechondrocytes), 5, 8 & 12 (chondrocytes) of culture. The response of the cells to uniaxial compression of the gel-cell construct was studied. The model predicted that, as a result of rearrangement of actin, the cells became more compliant and less anisotropic. When the gel size was reduced to 20μ3, RUTL (Ratio of radial deformations of cell in the Transverse direction to Loaded direction) became significantly different between prechondrocytes and chondrocytes. The difference in force required to compress a 20μ3 gel-cell construct containing a prechondrocyte vs a chondrocyte to 15% deformation was 103nN (152.3 vs 48.8 nN). This information can be used to build MEMS based devices that can mechanically distinguish between the different cell types.

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2

Kullolli, Borana, Matthias Baeßler, Pablo Cuéllar, Shilton Rica, and Frank Rackwitz. "An Enhanced Interface Model for Friction Fatigue Problems of Axially Loaded Piles." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96078.

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Abstract The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile-soil interface is subject to cyclic shearing solicitations. Thereby, the soil may densify and lead to a decrease of confining stress around the pile due to micro-phenomena such as particle crushing, migration and rearrangement. This reduction of radial stress has a direct impact on the shaft capacity, potentially leading in extreme cases to pile failure. An adequate interface model is needed in order to model this behaviour numerically. Different authors have proposed models that take typical interface phenomena in account such as densification, grain breakage, normal pressure effect and roughness. However, as the models become more complex, a great number of material parameters need to be defined and calibrated. This paper proposes the adoption and transformation of an existing soil bulk model (Pastor-Zienkiewicz) into an interface model. To calibrate the new interface model, the results of an experimental campaign with the ring shear device under cyclic loading conditions are here presented. The constitutive model shows a good capability to reproduce typical features of sand behaviour such as cyclic compaction and dilatancy, which in saturated partially-drained conditions may lead to liquefaction and cyclic mobility phenomena.

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Звіти організацій з теми "Radical rearrangement"

1

Dibble, Theodore S. Dynamics of Peroxy and Alkenyl Radicals Undergoing Competing Rearrangements in Biodiesel Combustion. Office of Scientific and Technical Information (OSTI), March 2016. http://dx.doi.org/10.2172/1243092.

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