Reinventing the De Mayo reaction: synthesis of 1,5-diketones or 1,5-ketoesters via visible light [2+2] cycloaddition of beta-diketones or beta-ketoesters with styrenes

[EN] A visible light mediated De Mayo reaction between 1,3-diketones and styrenes following a [2+2] cycloaddition pathway via a photosensitization mechanism gives access to 1,5-diketones. The reaction has been applied to substituted styrenes and aryl- and alkyl-substituted ketones. Moreover, the method converts -ketoesters, -amido esters, and -cyano ketones. Seven membered rings, a frequent structural motif of natural products, are also accessible using this methodology.This work was supported by the Deutsche Forschungsgemein-schaft DFG (GRK 1626, Chemical Photocatalysis). L. M. thanks the Alexander von Humboldt foundation for a postdoctoral fellowship. R. M.-H. thanks the DAAD for a short-term research grant. We thank Ms Regina Hoheisel (University of Regensburg) for her assistance in cyclic voltammetry measurements.Martínez-Haya, R.; Marzo, L.; König, B. (2018). Reinventing the De Mayo reaction: synthesis of 1,5-diketones or 1,5-ketoesters via visible light [2+2] cycloaddition of beta-diketones or beta-ketoesters with styrenes. Chemical Communications. 54(82):11602-11605. https://doi.org/10.1039/c8cc07044jS11602116055482Mayo, P. D., & Takeshita, H. (1963). PHOTOCHEMICAL SYNTHESES: 6. THE FORMATION OF HEPTANDIONES FROM ACETYLACETONE AND ALKENES. Canadian Journal of Chemistry, 41(2), 440-449. doi:10.1139/v63-061Begley, M. J., Mellor, M., & Pattenden, G. (1983). New synthetic approaches to fused-ring carbocycles based on intramolecular photocycloadditions of 1,3-dione enol esters. Journal of the Chemical Society, Perkin Transactions 1, 1905. doi:10.1039/p19830001905Oppolzer, W. (1982). The intramolecular [2 + 2] photoaddition/cyclobutane-fragmentation sequence in organic synthesis. Accounts of Chemical Research, 15(5), 135-141. doi:10.1021/ar00077a002Crimmins, M. T. (1988). Synthetic applications of intramolecular enone-olefin photocycloadditions. Chemical Reviews, 88(8), 1453-1473. doi:10.1021/cr00090a002Kärkäs, M. D., Porco, J. A., & Stephenson, C. R. J. (2016). Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis. Chemical Reviews, 116(17), 9683-9747. doi:10.1021/acs.chemrev.5b00760Winkler, J. D., Rouse, M. B., Greaney, M. F., Harrison, S. J., & Jeon, Y. T. (2002). The First Total Synthesis of (±)-Ingenol. Journal of the American Chemical Society, 124(33), 9726-9728. doi:10.1021/ja026600aWinkler, J. D., Muller, C. L., & Scott, R. D. (1988). A new method for the formation of nitrogen-containing ring systems via the intramolecular photocycloaddition of vinylogous amides. A synthesis of mesembrine. Journal of the American Chemical Society, 110(14), 4831-4832. doi:10.1021/ja00222a053Winkler, J. D., Scott, R. D., & Williard, P. G. (1990). Asymmetric induction in the vinylogous amide photocycloaddition reaction. A formal synthesis of vindorosine. Journal of the American Chemical Society, 112(24), 8971-8975. doi:10.1021/ja00180a049Winkler, J. D., Bowen, C. M., & Liotta, F. (1995). [2 + 2] Photocycloaddition/Fragmentation Strategies for the Synthesis of Natural and Unnatural Products. Chemical Reviews, 95(6), 2003-2020. doi:10.1021/cr00038a010Y.-J. Wu , in Name Reactions for Carbocyclic Ring Formations , ed. J. J. Li , John Wiley & Sons, Inc. , Hoboken, New Jersey , 2010 , ch. 5, pp. 451–488A. C. Weedon , in CRC Handbook of Organic Photochemistry and Photobiology , ed. W. M. Horspool and P.-S. Song , CRC Press , Boca Raton , 1995 , pp. 670–684Ravelli, D., Protti, S., & Fagnoni, M. (2016). Carbon–Carbon Bond Forming Reactions via Photogenerated Intermediates. Chemical Reviews, 116(17), 9850-9913. doi:10.1021/acs.chemrev.5b00662Skubi, K. L., Blum, T. R., & Yoon, T. P. (2016). Dual Catalysis Strategies in Photochemical Synthesis. Chemical Reviews, 116(17), 10035-10074. doi:10.1021/acs.chemrev.6b00018Goddard, J.-P., Ollivier, C., & Fensterbank, L. (2016). Photoredox Catalysis for the Generation of Carbon Centered Radicals. Accounts of Chemical Research, 49(9), 1924-1936. doi:10.1021/acs.accounts.6b00288Yoon, T. P. (2016). Photochemical Stereocontrol Using Tandem Photoredox–Chiral Lewis Acid Catalysis. Accounts of Chemical Research, 49(10), 2307-2315. doi:10.1021/acs.accounts.6b00280Margrey, K. A., & Nicewicz, D. A. (2016). A General Approach to Catalytic Alkene Anti-Markovnikov Hydrofunctionalization Reactions via Acridinium Photoredox Catalysis. Accounts of Chemical Research, 49(9), 1997-2006. doi:10.1021/acs.accounts.6b00304Staveness, D., Bosque, I., & Stephenson, C. R. J. (2016). Free Radical Chemistry Enabled by Visible Light-Induced Electron Transfer. Accounts of Chemical Research, 49(10), 2295-2306. doi:10.1021/acs.accounts.6b00270Ghosh, I., Marzo, L., Das, A., Shaikh, R., & König, B. (2016). Visible Light Mediated Photoredox Catalytic Arylation Reactions. Accounts of Chemical Research, 49(8), 1566-1577. doi:10.1021/acs.accounts.6b00229Meggers, E. (2015). Asymmetric catalysis activated by visible light. Chemical Communications, 51(16), 3290-3301. doi:10.1039/c4cc09268fGuo, L.-N., Wang, H., & Duan, X.-H. (2016). Recent advances in catalytic decarboxylative acylation reactions via a radical process. Organic & Biomolecular Chemistry, 14(31), 7380-7391. doi:10.1039/c6ob01113fMarzo, L., Pagire, S. K., Reiser, O., & König, B. (2018). Visible-Light Photocatalysis: Does It Make a Difference in Organic Synthesis? Angewandte Chemie International Edition, 57(32), 10034-10072. doi:10.1002/anie.201709766Lu, Z., & Yoon, T. P. (2012). Visible Light Photocatalysis of [2+2] Styrene Cycloadditions by Energy Transfer. Angewandte Chemie International Edition, 51(41), 10329-10332. doi:10.1002/anie.201204835Mojr, V., Svobodová, E., Straková, K., Neveselý, T., Chudoba, J., Dvořáková, H., & Cibulka, R. (2015). Tailoring flavins for visible light photocatalysis: organocatalytic [2+2] cycloadditions mediated by a flavin derivative and visible light. Chemical Communications, 51(60), 12036-12039. doi:10.1039/c5cc01344ePagire, S. K., Hossain, A., Traub, L., Kerres, S., & Reiser, O. (2017). Photosensitised regioselective [2+2]-cycloaddition of cinnamates and related alkenes. Chemical Communications, 53(89), 12072-12075. doi:10.1039/c7cc06710kZhao, J., Brosmer, J. L., Tang, Q., Yang, Z., Houk, K. N., Diaconescu, P. L., & Kwon, O. (2017). Intramolecular Crossed [2+2] Photocycloaddition through Visible Light-Induced Energy Transfer. Journal of the American Chemical Society, 139(29), 9807-9810. doi:10.1021/jacs.7b05277Hörmann, F. M., Chung, T. S., Rodriguez, E., Jakob, M., & Bach, T. (2018). Evidence for Triplet Sensitization in the Visible‐Light‐Induced [2+2] Photocycloaddition of Eniminium Ions. Angewandte Chemie International Edition, 57(3), 827-831. doi:10.1002/anie.201710441Alonso, R., & Bach, T. (2014). A Chiral Thioxanthone as an Organocatalyst for Enantioselective [2+2] Photocycloaddition Reactions Induced by Visible Light. Angewandte Chemie International Edition, 53(17), 4368-4371. doi:10.1002/anie.201310997Blum, T. R., Miller, Z. D., Bates, D. M., Guzei, I. A., & Yoon, T. P. (2016). Enantioselective photochemistry through Lewis acid–catalyzed triplet energy transfer. Science, 354(6318), 1391-1395. doi:10.1126/science.aai8228Miller, Z. D., Lee, B. J., & Yoon, T. P. (2017). Enantioselective Crossed Photocycloadditions of Styrenic Olefins by Lewis Acid Catalyzed Triplet Sensitization. Angewandte Chemie International Edition, 56(39), 11891-11895. doi:10.1002/anie.201706975Hanss, D., Freys, J. C., Bernardinelli, G., & Wenger, O. S. (2009). Cyclometalated Iridium(III) Complexes as Photosensitizers for Long-Range Electron Transfer: Occurrence of a Coulomb Barrier. European Journal of Inorganic Chemistry, 2009(32), 4850-4859. doi:10.1002/ejic.200900673Prier, C. K., Rankic, D. A., & MacMillan, D. W. C. (2013). Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis. Chemical Reviews, 113(7), 5322-5363. doi:10.1021/cr300503rTeegardin, K., Day, J. I., Chan, J., & Weaver, J. (2016). Advances in Photocatalysis: A Microreview of Visible Light Mediated Ruthenium and Iridium Catalyzed Organic Transformations. Organic Process Research & Development, 20(7), 1156-1163. doi:10.1021/acs.oprd.6b00101Flamigni, L., Barbieri, A., Sabatini, C., Ventura, B., & Barigelletti, F. (s. f.). Photochemistry and Photophysics of Coordination Compounds: Iridium. Topics in Current Chemistry, 143-203. doi:10.1007/128_2007_131Luo, J., & Zhang, J. (2016). Donor–Acceptor Fluorophores for Visible-Light-Promoted Organic Synthesis: Photoredox/Ni Dual Catalytic C(sp3)–C(sp2) Cross-Coupling. ACS Catalysis, 6(2), 873-877. doi:10.1021/acscatal.5b02204Fukuzumi, S., & Ohkubo, K. (2014). Organic synthetic transformations using organic dyes as photoredox catalysts. Org. Biomol. Chem., 12(32), 6059-6071. doi:10.1039/c4ob00843jRomero, N. A., & Nicewicz, D. A. (2016). Organic Photoredox Catalysis. Chemical Reviews, 116(17), 10075-10166. doi:10.1021/acs.chemrev.6b00057Ni, T., Caldwell, R. A., & Melton, L. A. (1989). The relaxed and spectroscopic energies of olefin triplets. Journal of the American Chemical Society, 111(2), 457-464. doi:10.1021/ja00184a008Xie, Z.-F., Suemune, H., & Sakai, K. (1989). A Facile Ring Enlargement. Synthetic Communications, 19(5-6), 987-992. doi:10.1080/00397918908051019Li, C.-J., Chen, D.-L., Lu, Y.-Q., Haberman, J. X., & Mague, J. T. (1998). Metal-mediated two-atom carbocycle enlargement in aqueous medium. Tetrahedron, 54(11), 2347-2364. doi:10.1016/s0040-4020(98)00004-0Hong, B.-C., Chen, S.-H., Kumar, E. S., Lee, G.-H., & Lin, K.-J. (2003). Intramolecular [2+2] Photocycloaddition-Fragmentation: Facile Entry to a Novel Tricyclic 5-6-7 Ring System. Journal of the Chinese Chemical Society, 50(4), 917-926. doi:10.1002/jccs.200300129Roscini, C., Davies, D. M. E., Berry, M., Orr-Ewing, A. J., & Booker-Milburn, K. I. (2008). Product Selection through Photon Flux: Laser-Specific Lactone Synthesis. Angewandte Chemie International Edition, 47(12), 2283-2286. doi:10.1002/anie.200704816Tobita, S., Ohba, J., Nakagawa, K., & Shizuka, H. (1995). Recovery mechanism of the reaction intermediate produced by photoinduced cleavage of the intramolecular hydrogen bond of dibenzoylmethane. Journal of Photochemistry and Photobiology A: Chemistry, 92(1-2), 61-67. doi:10.1016/1010-6030(95)04158-xMoriyasu, M., Kato, A., & Hashimoto, Y. (1986). Kinetic studies of fast equilibrium by means of high-performance liquid chromatography. Part 11. Keto–enol tautomerism of some β-dicarbonyl compounds. J. Chem. Soc., Perkin Trans. 2, (4), 515-520. doi:10.1039/p29860000515Casey, B. M., Eakin, C. A., Jiao, J., Sadasivam, D. V., & Flowers, R. A. (2009). Solvent-dependent oxidative coupling of 1-aryl-1,3-dicarbonyls and styrene. Tetrahedron, 65(52), 10762-10768. doi:10.1016/j.tet.2009.06.118Ko, T. Y., & Youn, S. W. (2016). Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3-Dicarbonyls and Styrenes: Construction of Five-Membered Heterocycles. Advanced Synthesis & Catalysis, 358(12), 1934-1941. doi:10.1002/adsc.201600280Casals, P.-F., Ferard, J., & Ropert, R. (1976). Photoaddition de dicetones-1,3 aromatiques sur divers carbures styreniques : orientation et stereospecificite de l’addition. Tetrahedron Letters, 17(35), 3077-3080. doi:10.1016/0040-4039(76)80074-3Kikuchi, A., Oguchi, N., & Yagi, M. (2009). Optical and Electron Paramagnetic Resonance Studies of the Excited States of 4-tert-Butyl-4′-Methoxydibenzoylmethane and 4-tert-Butyl-4′-Methoxydibenzoylpropane. The Journal of Physical Chemistry A, 113(48), 13492-13497. doi:10.1021/jp905236mTurro, N. J. (1966). Triplet-triplet excitation transfer in fluid solution: Applications to organic photochemistry. Journal of Chemical Education, 43(1), 13. doi:10.1021/ed043p13Dilling, W. L. (1969). Photochemical cycloaddition reactions of nonaromatic conjugated hydrocarbon dienes and polyenes. Chemical Reviews, 69(6), 845-877. doi:10.1021/cr60262a005N. J. Turro , in Modern Molecular Photochemistry , Benjamin/Cummings , California , 1978 , ch. 9, pp. 296–359Albini, A. (1981). Photosensitization in Organic Synthesis. Synthesis, 1981(04), 249-264. doi:10.1055/s-1981-29405Kalyanasundaram, K. (1982). Photophysics, photochemistry and solar energy conversion with tris(bipyridyl)ruthenium(II) and its analogues. Coordination Chemistry Reviews, 46, 159-244. doi:10.1016/0010-8545(82)85003-0Juris, A., Balzani, V., Barigelletti, F., Campagna, S., Belser, P., & von Zelewsky, A. (1988). Ru(II) polypyridine complexes: photophysics, photochemistry, eletrochemistry, and chemiluminescence. Coordination Chemistry Reviews, 84, 85-277. doi:10.1016/0010-8545(88)80032-8Cismesia, M. A., & Yoon, T. P. (2015). Characterizing chain processes in visible light photoredox catalysis. Chemical Science, 6(10), 5426-5434. doi:10.1039/c5sc02185

Freezing of hard spheres confined in narrow cylindrical pores

Monte Carlo simulations for the equation of state and phase behavior of hard spheres confined inside very narrow hard tubes are presented. For pores whose radii are greater than 1.1 hard sphere diameters, a sudden change in the density and the microscopic structure of the fluid is neatly observed, indicating the onset of freezing. In the high-density structure the particles rearrange in such a way that groups of three particles fit in sections across the por

Computer simulation study of the nematic–vapour interface in the Gay–Berne model

We present computer simulations of the vapour–nematic interface of the Gay–Berne model. We considered situations which correspond to either prolate or oblate molecules. We determine the anchoring of the nematic phase and correlate it with the intermolecular potential parameters. On the other hand, we evaluate the surface tension associated to this interface. We find a corresponding states law for the surface tension dependence on the temperature, valid for both prolate and oblate molecules.Fundación Portuguesa para la Ciencia y la Tecnología EXCL / FIS-NAN / 0083/2012Ministerio de Economía y Competitividad FIS2012-32455Junta de Andalucía P09-FQM-493

18-crown-6-sodium cholate complex: thermochemistry, structure and stability

18-crown-6, one of the most relevant crown ethers, and sodium cholate, steroidal surfactant classified as natural bile salt, are components of novel, synthesized coordination complex ; 18-crown-6-sodium cholate (18C6•NaCh). Like crown ethers, bile salts act as building blocks in supramolecular chemistry in order to design new functionalized materials with a desired structure and properties. In order to obtain thermal behavior of this 1:1 coordination complex, thermogravimetry and differential thermal analysis were used, as well as microscopic observations and differential scanning calorimetry. Temperature dependent infrared spectroscopy (IR) gave a detailed view into phase transitions. The structures during thermal treatment were observed with powder X-ray diffraction, and molecular models of the phases are made. Hard, glassy, colorless compound 18C6•NaCh goes through crystalline – crystalline polymorphic phase transitions at higher temperatures. The room temperature phase is indexed to a triclinic lattice, while in the high temperature phases molecules take randomly one of the two different configurations in the unit cell, resulting in the 2-fold symmetry. The formation of cholesteric liquid crystalline phase occurs simultaneously with partial decomposition, followed by the isotropisation with simultaneous and complete decomposition at much higher temperature, as obtained by IR. The results provide valuable information about the relationship between molecular structure, thermal properties, and stability of the complex, indicating the importance of an appropriate choice of cation, amphiphilic, and crown ether unit in order to synthesize compounds with desired behavior

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Quantum mechanical and quasiclassical trajectory study of state-to-state differential cross sections for the F+D2→DF+D reaction in the center-of-mass and laboratory frames

International audienc