1,168 research outputs found
Mono And Double Polar [4 + 2+] Diels-alder Cycloaddition Of Acylium Ions With O-heterodienes
No full textGas-phase reactions of acylium ions with α, β-unsaturated carbonyl compounds were investigated using pentaquadrupole multiple-stage mass spectrometry. With acrolein and metacrolein, CH3-C+=O, CH2=CH-C+=O, C6H5-C+=O, and (CH3)2N-C+=O react to variable extents by mono and double polar [4 + 2+] Diels-Alder cycloaddition. With ethyl vinyl ketone, CH3-C+=O reacts exclusively by proton transfer and C6H5-C+=O forms only the mono cycloadduct whereas CH2=CH-C+=O and (CH3)2N-C+=O reacts to great extents by mono and double cycloaddition. The positively charged acylium ions are activated O-heterodienophiles, and mono cycloaddition occurs readily across their C+=O bonds to form resonance-stabilized 1,3-dioxinylium ions which, upon collisional activation, dissociate predominantly by retro-addition. The mono cycloadducts are also dienophiles activated by resonance-stabilized and chemically inert 1,3-dioxonium ion groups, hence they undergo a second cycloaddition across their polarized C=C ring double bonds. 18O labeling and characteristic dissociations displayed by the double cycloadducts indicate the site and regioselectivity of double cycloaddition, which are corroborated by Becke3LYP/6-311++G(d,p) calculations. Most double cycloadducts dissociate by the loss of a RCO2COR1 molecule and by a pathway that reforms the acylium ion directly. The double cycloadduct of the thioacylium ion (CH3)2N-C+=S with acrolein dissociates to (CH3)2N-C+=O in a sulfur-by-oxygen replacement process intermediated by the cyclic monoadduct. The double by cycloaddition can be viewed as a charge-remote type of polar [4 + 2+] Diels-Alder cycloaddition reaction. Copyright © 2001 John Wiley & Sons, Ltd.372146154Olah, G.A., Gramain, A., White, A.M., (1976) Carbonium Ions, 5, p. 2084. , Olah GA, Schleyer PvR (eds.). Wiley-Interscience: New York, chapt. 35Olah, G.A., Laali, K.K., Wang, Q., Prakash, G.K.S., (1998) Onium Ions, , Wiley: New YorkChatfield, D.A., Bursey, M.M., (1976) J. Am. Chem. Soc., 98, p. 6492Staley, R.H., Wieting, R.D., Beauchamp, J.L., (1977) J. Am. Chem. Soc., 99, p. 5964Sparapani, C., Speranza, M., (1980) J. Am. Chem. Soc., 102, p. 3120Attinà, M., Cacace, F., (1983) J. Am. Chem. Soc., 105, p. 1122Caserio, M.C., Kim, J.K., (1983) J. Am. Chem. Soc., 105, p. 6896Rahman, N.A., Fisher, C.L., Caserio, M.C., (1988) Org. Mass Spectrom., 23, p. 517Kotiaho, T., Shay, B.J., Cooks, R.G., Eberlin, M.N., (1993) J. Am. Chem. Soc., 115, p. 1004Creaser, C.S., Wiliamson, B.L., (1996) J. Chem. Soc., Perkin Trans., 2, p. 427Al-Talib, M., Tashtoush, H., (1990) Org. Prep. Proced. Int., 22, p. 1Moraes, L.A.B., Pimpim, R.S., Eberlin, M.N., (1996) J. Org. Chem., 61, p. 8726Moares, L.A.B., Eberlin, M.N., (2001) J. Am. Soc. Mass Spectrom., 12, p. 150Eberlin, M.N., Cooks, R.G., (1993) Org. Mass Spectrom., 28, p. 679Moraes, L.A.B., Gozzo, F.C., Eberlin, M.N., Vainiotalo, P., (1997) J. Org. Chem., 62, p. 5096Carvalho, M.C., Juliano, V.F., Kascheres, C., Eberlin, M.N., (1997) J. Chem. Soc., Perkin Trans., 2, p. 2347Moraes, L.A.B., Eberlin, M.N., (1998) J. Am. Chem. Soc., 120, p. 11136Sparrapan, R., Mendes, M.A., Eberlin, M.N., (2000) J. Mass Spectrom., 35, p. 189Moraes, L.A.B., Mendes, M.A., Sparrapan, R., Eberlin, M.N., (2001) J. Am. Soc. Mass Spectrom., 12, p. 14Moares, L.A.B., Kotiaho, T., Eberlin, M.N., (1999) J. Mass Spectrom., 34, p. 670Meurer, E.C., Moares, L.A.B., Eberlin, M.N., (2001) Int. J. Mass Spectrom., 212, p. 445Moraes, L.A.B., Eberlin, M.N., (2000) Chem. Eur. J., 6, p. 897Grandinetti, F., Pepi, F., Ricci, A., (1996) Chem. Eur. J., 2, p. 495Rocha, L.L., Sparrapan, R., Eberlin, M.N., J. Mass Spectrom., , in pressReid, G.E., Tichy, S.E., Pérez, J., O'Hair, R.A.J., Simpson, R.J., Kenttämaa, H.I., (2001) J. Am. Chem. Soc., 123, p. 1184Bruins, A.P., Nibbering, N.M.M., (1975) Tetrahedron Lett., p. 4491Williamson, B.L., Creaser, C.S., (1998) Eur. Mass Spectrom., 4, p. 103Moraes, L.A.B., Eberlin, M.N., J. Mass Spectrom., , in pressBoger, D.L., Weinreb, S.N., (1987) Hetero Diels-Alder Methodology in Organic Synthesis, , Wasserman HH (ed.). Academic Press: New YorkCarruthers, W., (1990) Cycloaddition Reactions in Organic Synthesis, , Pergamon Press: OxfordTietze, L.F., Kettschau, G., (1997) Top. Curr. Chem., 189, p. 1Fleming, I., (1998) Pericyclic Reactions, , Oxford University Press: OxfordSchmidt, R.R., Machat, R., (1970) Angew. Chem., Int. Ed Engl., 9, p. 311Bowers, M.T., Elleman, D.D., O'Malley, R.M., Jennings, K.R., (1970) J. Phys. Chem., 74, p. 2583Wilkins, C.L., Gross, M.L., (1971) J. Am. Chem. Soc., 93, p. 895van Doorn, R., Nibbering, N.M.M., Ferrer-Correa, A.J.V., Jennings, K.R., (1978) Org. Mass Spectrom., 13, p. 729van Tilborg, M.W.E.M., van Doorn, R., Nibbering, N.M.M., (1980) Org. Mass Spectrom., 15, p. 152Castle, L.W., Gross, M.L., (1989) Org. Mass Spectrom., 24, p. 637. , 24Berruyer, F., Bouchoux, G., (1990) Rapid Commun. Mass Spectrom., 4, p. 476Dass, C., (1990) Mass Spectrom. Rev., 9, p. 1Shay, B.J., Eberlin, M.N., Cooks, R.G., Wesdemiotis, C., (1992) J. Am. Soc. Mass Spectrom., 3, p. 518Bouchoux, G., Salpin, J.Y., (1994) Rapid Commun. Mass Spectrom., 8, p. 325Mourgues, P., Audier, H.E., Hammerum, S., (1994) Rapid Commun. Mass Spectrom., 8, p. 53. , 1Wiegel, K.N., Holman, R.W., Gross, M.L., (1995) Int. J. Mass. Spectrom, 146, p. 239Bakhtiar, R., Drader, J.J., Arneson, R.K., Jacobson, D.B., (1996) Rapid Commun Mass Spectrom, 10, p. 1405Eberlin, M.N., Sorrilha, A.E.P.M., Gozzo, F.C., Pimpim, R.S., (1997) J. Am. Chem. Soc., 119, p. 3550Gevrey, S., Taphanel, M.H., Morizur, J.P., (1998) J. Mass Spectrom., 33, p. 399Chen, Q., Sioma, C., Kan, S.Z., Freiser, B.S., (1998) Int. J. Mass. Spectrom., 180, p. 231Van Pelt, C.K., Carpenter, B.K., Brenna, J.T., (1999) J. Am. Soc. Mass Spectrom., 10, p. 1253Bouchoux, G., Nguyen, M.T., Salpin, J.Y., (2000) J. Phys. Chem., 104, p. 5778Holman, R.W., Rozeboom, M.D., Gross, M.L., (1986) Tetrahedron, 42, p. 6235Heinrich, N., Koch, W., Morrow, J.C., Schwarz, H., (1988) J. Am. Chem. Soc., 110, p. 6332Colorado, A., Barket, D.J., Hurst, J.M., Shepson, P.B., (1998) Anal. Chem., 70, p. 5129Sharifi, M., Einhorn, J., (1999) Int. J. Mass. Spectrom., 191, p. 253Sparrapan, R., Mendes, M.A., Carvalho, M., Eberlin, M.N., (2000) Chem. Eur. J., 6, p. 321Meurer, E.C., Eberlin, M.N., (2001) Int. J. Mass Spectrom., 210-211, p. 469Eberlin, M.N., Majumdar, T.K., Cooks, R.G., (1992) J. Am. Chem. Soc., 114, p. 2884Eberlin, M.N., Cooks, R.G., (1993) J. Am. Chem. Soc., 115, p. 9226Lemos, A.B., Eberlin, M.N., J. Mass Spectrom., , in pressEberlin, M.N., Morgon, N.H., Yang, S.S., Shay, B.J., Cooks, R.G., (1995) J. Am. Soc. Mass. Spectrom., 6, p. 1Lu, L., Yang, S.S., Wang, Z., Cooks, R.G., (1995) J. Mass Spectrom., 30, p. 581Cheng, C.F., Gross, M.L., (2000) Mass Spectrom. Rev., 19, p. 398Juliano, V.F., Kascheres, C., Gozzo, F.C., Eberlin, M.N., Lago, C.L., (1996) Anal. Chem., 68, p. 1328Tiernan, T.O., Futrell, J.H., (1968) J. Phys. Chem., 72, p. 3080Eberlin, M.N., (1997) Mass Spectrom. Rev., 16, p. 113Schwartz, J.C., Wade, A.P., Enke, C.G., Cooks, R.G., (1990) Anal. Chem., 62, p. 1809Becke, A.D., (1993) J. Chem. Phys., 98, p. 5648Stephens, P.J., Devlin, F.J., Chabalowski, C.F., Frisch, M.J., (1994) J. Phys. Chem., 98, p. 11623Lee, C., Yang, W., Parr, R.G., (1988) Phys. Rev. B, 37, p. 785Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998), Gaussian 98, Revision A.6. Gaussian: Pittsburgh, PAMoraes, L.A.B., Eberlin, M.N., (1997) J. Chem. Soc., Perkin Trans., 2, p.
Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013)
No full textThis document contains recommendations for terminology in mass spectrometry. Development of standard terms dates back to 1974 when the IUPAC Commission on Analytical Nomenclature issued recommendations on mass spectrometry terms and definitions. In 1978, the IUPAC Commission on Molecular Structure and Spectroscopy updated and extended the recommendations and made further recommendations regarding symbols, acronyms, and abbreviations. The IUPAC Physical Chemistry Division Commission on Molecular Structure and Spectroscopy’s Subcommittee on Mass Spectroscopy revised the recommended terms in 1991 and appended terms relating to vacuum technology. Some additional terms related to tandem mass spectrometry were added in 1993 and accelerator mass spectrometry in 1994. Owing to the rapid expansion of the field in the intervening years, particularly in mass spectrometry of biomolecules, a further revision of the recommendations has become necessary. This document contains a comprehensive revision of mass spectrometry terminology that represents the current consensus of the mass spectrometry community
Gas-phase Polar [4+ + 2] Cycloaddition With Ethyl Vinyl Ether: A Structurally Diagnostic Ion-molecule Reaction For 2-azabutadienyl Cations
No full textThe intrinsic reactivity of eight gaseous, mass-selected 2-azabutadienyl cations toward polar [4+ + 2] cycloaddition with ethyl vinyl ether has been investigated by pentaquadrupole mass spectrometric experiments. Cycloaddition occurs readily for all the ions and, with the only exception of those from the N-acyl 2-azabutadienyl cations (N-acyliminium ions), the cycloadducts are found to dissociate readily upon collision activation (CID) both by retro-Diels-Alder reaction and by a characteristic loss of an ethanol (46u) neutral molecule. Ethanol loss from the intact polar [4+ + 2] cycloadduct functions therefore as a structurally diagnostic test: 72 u neutral gain followed by 46 u neutral loss, i.e., as a combined ion-molecule reaction plus CID 'signature' for N-H, N-alkyl and N-aryl 2-azabutadienyl cations. The two N-acyliminium ions tested are exceptional as they form intact cycloadducts with ethyl vinyl ether which dissociate exclusively by the retro-Diels-Alder pathway. Copyright © 2003 John Wiley & Sons, Ltd.381010751080Schoffstall, A.M., Padwa, A., (1990) Advances in Cycloaddition, 2, p. 1. , Curran DP (ed). JAI Press: GreenwichBoger, D.L., Weinreb, S.N., (1987) Hetero Diels-Alder Methodology in Organic Synthesis, , Wasserman HH (ed). Academic Press: New YorkBowers, M.T., Elleman, D.D., O'Malley, R.M., Jennings, K.R., (1970) J. Phys. Chem., 74, p. 2583Wilkins, C.L., Gross, M.L., (1971) J. Am. Chem. Soc., 93, p. 895van Doorn, R., Nibbering, N.M.M., Ferrer-Correa, A.J.V., Jennings, K., (1978) Org. Mass Spectrom., 13, p. 729Dass, C., (1990) Mass Spectrom. Rev., 9, p. 1Shay, B.J., Eberlin, M.N., Cooks, R.G., Wesdemiotis, C., (1992) J. Am. Soc. Mass Spectrom., 3, p. 518Bouchoux, G., Salpin, J.Y., (1994) Rapid Commun. Mass Spectrom., 8, p. 325Mouregues, P., Audier, H.E., Hammerum, S., (1994) Rapid Commun. Mass Spectrom., 8, p. 53Eberlin, M.N., Morgon, N.H., Yang, S.S., Shay, B.J., Cooks, R.G., (1995) J. Am. Soc. Mass. Spectrom., 6, p. 1Wiegel, K.N., Holman, R.W., Gross, M.L., (1995) Int. J. Mass. Spectrom., 146, p. 239Eberlin, M.N., Sorrilha, A.E.P.M., Gozzo, F.C., Pimpim, R.S., (1997) J. Am. Chem. Soc., 119, p. 3550Gevrey, S., Taphanel, M.H., Morizur, J.P., (1998) J. Mass. Spectrom., 33, p. 399Bouchoux, G., Nguyen, M.T., Salpin, J.Y., (2000) J. Phys. Chem. A, 104, p. 5778Eberlin, M.N., Majumdar, T.K., Cooks, R.G., A few cycloaddition reactions have been proposed or used as class-selective ion-molecule reactions (1992) J. Am. Chem. Soc., 114, p. 2884. , see, for instanceColorado, A., Barket, D.J., Hurst, J.M., Shepson, P.B., (1998) Anal. Chem., 70, p. 5129Sharifi, M., Einhorn, J., (1999) Int. J. Mass. Spectrom., 191, p. 253Sparrapan, R., Mendes, M.A., Carvalho, M., Eberlin, M.N., (2000) Chem. Eur. J., 6, p. 321Schmidt, R.R., (1973) Angew. Chem., Int. Ed. Engl., 12, p. 212Gassman, P.G., Singleton, D.A., Wilwerding, J.J., Chavan, S.P., (1987) J. Am. Chem. Soc., 109, p. 2182Barluenga, J., Aznar, F., Fustero, S., Tomas, M., (1990) Pure Appl. Chem., 62, p. 1957Knoelker, H.J., Baum, G., Gonser, P., (1995) Tetrahedron Lett., 36, p. 8194Beifuss, U., Ledderhose, S., (1995) J. Chem. Soc. Chem. Commun., p. 2137Augusti, R., Gozzo, F.C., Moraes, L.A.B., Sparrapan, R., Eberlin, M.N., (1998) J. Org. Chem., 63, p. 4889Meurer, E.C., Eberlin, M.N., (2001) Int. J. Mass Spectrom., 210, p. 469Juliano, V.F., Gozzo, F.C., Eberlin, M.N., Kascheres, C., Lago, C.L., (1996) Anal. Chem., 68, p. 1328Eberlin, M.N., (1997) Mass Spectrom. Rev., 16, p. 113Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998), Gaussian 98, Revision A. 6, Gaussian, Inc, Pittsburgh. PABarluenga, J., Sordo, T.L., Sordo, J.A., Fustero, S., Gonzalez, J., (1994) J. Mol. Struct. (THEOCHEM), 315, p. 63Venturini, A., Joglar, J., Fustero, S., Gonzalez, J., (1997) J. Org. Chem., 62, p. 3919Pinho e Melo, T.M.V.D., Fausto, R., Rocha Gonsalves, A.M.D., Gilchrist, T.L., (1998) J. Org. Chem., 63, p. 5350Domingo, L.R., Zaragoza, R.J., Williams, R.M., (2003) J. Org. Chem., 68, p. 2895Pachuta, R.R., Kenttämaa, H.I., Cooks, R.G., Zennie, T.M., Ping, C., Chang, C.J., Cassady, J.M., (1988) Org. Mass Spectrom., 23, p. 10Kenttämaa, H.I., Pachuta, R.R., Rothwell, A.P., Cooks, R.G., (1989) J. Am. Chem. Soc., 111, p. 1654Speckamp, W.N., Moolenaar, M.J., (2000) Tetrahedron, 56, p. 3817Hiemstra, H., Speckamp, W.N., (1991) Comprehensive Organic Chemistry (Synthesis), 2, p. 1047. , Trost BM, Fleming I (eds). Pergamon: OxfordPilli, R.A., Russowshy, D., (1997) Trends Org. Chem., 6, p. 101Tomazela, D.M., Moraes, L.A.B., D'Oca, M.G.M., Pilli, R.A., Eberfin, M.N., A gas-phase order of intrinsic reactivity toward nucleophilic addition for a series of gaseous N-acyliminium ions have been recently determined by similar mass spectrometric experiments (2002) J. Org. Chem., 67, p. 4652. , seeD'Oca, M.G.M., Moraes, L.A.B., Pilli, R.A., Eberlin, M.N., (2001) J. Org. Chem., 66, p. 3854Eberlin, M.N., Sabino, A.A., Pilli, R.A., (2003) J. Org. Chem., , submitte
Antimicrobial metabolites produced by an intertidal Acremonium furcatum
No full textIn a screening for antimicrobial metabolites, amides of d-allo- and l-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities. © 2006 Elsevier Ltd. All rights reserved.Fil: Gallardo, Gabriela Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Butler, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Gallo, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Rodriguez, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Eberlin, Marcos N.. Universidade Estadual de Campinas; BrasilFil: Cabrera, Gabriela Myriam. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentin
Characterisation of fungal lanostane-type triterpene acids by electrospray ionisation mass spectrometry
No full textLanostane-triterpene acids obtained from the culture of the fungus Coriolellus malicola were studied by electrospray mass spectrometry in the negative ion mode using quadrupole time-of-flight and quadrupole ion trap analysers. Despite the differences observed in the mass spectra recorded with these instruments, a set of fragment ions was found to be characteristic of the family, depending on the Δ79(11) or Δ8 skeleton and the particular functional group at C-3. Copyright © 2007 John Wiley & Sons, Ltd.Fil: Cabrera, Gabriela Myriam. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Vellasco, Adriana P.. Universidade Estadual de Campinas; BrasilFil: Levy, Laura M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Eberlin, Marcos N.. Universidade Estadual de Campinas; Brasi
Phosphine-free heck reaction: mechanistic insights and catalysis “on water” using a charge-tagged palladium complex
No full textA novel Pd-complex with a charge tag (imidazolium cation) was applied for online monitoring of the neutral Heck reaction by electrospray ionization (tandem) mass spectrometry-ESI-MS(/MS). The results shed light on the mechanism of the reaction, whereas the charge-tagged ligand also allowed the unprecedented MS monitoring of Pd2+ reduction to Pd0. Key reaction intermediates associated with Pd catalysis could also be detected and characterized due to the presence of the charge tag on the Pd-complex. DFT calculations supported the proposed mechanism. The new charge-tagged Pd-complex is also shown to function as an active catalyst "on water" with the advantage of using cheaper and less reactive aryl chloride substrates in a phosphine-free version of the Heck reaction. © the Partner Organisations 2014.A novel Pd-complex with a charge tag (imidazolium cation) was applied for online monitoring of the neutral Heck reaction by electrospray ionization (tandem) mass spectrometry – ESI-MS(/MS). The results shed light on the mechanism of the reaction, whereas38729582963CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFsem informaçãosem informaçãosem informaçãosem informaçãosem informaçãosem informaçãoKandukuri, S.R., Schiffner, J.A., Oestreich, M., (2012) Angew. Chem., Int. Ed., 51, pp. 1265-1269Faulkner, A., Bower, J.F., (2012) Angew. Chem., Int. Ed., 51, pp. 1675-1679Perez-Temprano, M.H., Casares, J.A., Espinet, P., (2012) Chem.-Eur. J., 18, pp. 1864-1884Cotugno, P., Monopoli, A., Ciminale, F., Cioffi, N., Nacci, A., (2012) Org. Biomol. Chem., 10, pp. 808-813Torborg, C., Beller, M., (2009) Adv. Synth. Catal., 351, pp. 3027-3043Budarin, V.L., Shuttleworth, P.S., Clark, J.H., Luque, R., (2010) Curr. Org. Synth., 7, pp. 614-627Blaser, H.U., Pugin, B., Spielvogel, D., (2011) Chim. Oggi, 29, pp. 62-65Cassol, C.C., Umpierre, A.P., Machado, G., Wolke, S.I., Dupont, J., (2005) J. Am. Chem. Soc., 127, pp. 3298-3299Consorti, C.S., Flores, F.R., Dupont, J., (2005) J. Am. Chem. Soc., 127, pp. 12054-12065Prediger, P., Genisson, Y., Correia, C.R.D., (2013) Curr. Org. Chem., 17, pp. 238-256Taylor, J.G., Moro, A.V., Correia, C.R.D., (2011) Eur. J. Org. Chem., pp. 1403-1428Coelho, F., Eberlin, M.N., (2011) Angew. Chem., Int. Ed., 50, pp. 5261-5263Santos, L.S., (2011) J. Braz. Chem. Soc., 22, pp. 1827-1840Amarante, G.W., Milagre, H.M.S., Vaz, B.G., Ferreira, B.R.V., Eberlin, M.N., Coelho, F., (2009) J. Org. Chem., 74, pp. 3031-3037Santos, L.S., (2008) Eur. J. Org. Chem., pp. 235-253Sabino, A.A., Machado, A.H.L., Correia, C.R.D., Eberlin, M.N., (2004) Angew. Chem., Int. Ed., 43, p. 4389Fernandes, T.D., Vaz, B.G., Eberlin, M.N., Da Silva, A.J.M., Costa, P.R.R., (2010) J. Org. Chem., 75, pp. 7085-7091Stefani, H.A., Pena, J.M., Gueogjian, K., Petragnani, N., Vaz, B.G., Eberlin, M.N., (2009) Tetrahedron Lett., 50, pp. 5589-5595Fiebig, L., Schmalz, H.G., Schafer, M., (2011) Int. J. Mass Spectrom., 308, pp. 307-310Smith, R.L., Kenttamaa, H.I., (1995) J. Am. Chem. Soc., 117, pp. 1393-1396Hinderling, C., Adlhart, C., Chen, P., (1998) Angew. Chem., Int. Ed., 37, pp. 2685-2689Bryce, D.J.F., Dyson, P.J., Nicholson, B.K., Parker, D.G., (1998) Polyhedron, 17, pp. 2899-2905Chisholm, D.M., McIndoe, J.S., (2008) Dalton Trans., pp. 3933-3945Yunker, L.P.E., Stoddard, R.L., McIndoe, J.S., (2014) J. Mass Spectrom., 49, pp. 1-8Schade, M.A., Feckenstem, J.E., Knochel, P., Koszinowski, K., (2010) J. Org. Chem., 75, pp. 6848-6857Vikse, K.L., Henderson, M.A., Oliver, A.G., McIndoe, J.S., (2010) Chem. Commun., 46, pp. 7412-7414Limberger, J., Leal, B.C., Back, D.F., Dupont, J., Monteiro, A.L., (2012) Adv. Synth. Catal., 354, pp. 1429-1436Oliveira, F.F.D., Dos Santos, M.R., Lalli, P.M., Schmidt, E.M., Bakuzis, P., Lapis, A.A.M., Monteiro, A.L., Neto, B.A.D., (2011) J. Org. Chem., 76, pp. 10140-10147Alvim, H.G.O., Fagg, E.L., De Oliveira, A.L., De Oliveira, H.C.B., Freitas, S.M., Xavier, M.-A.E., Soares, T.A., Neto, B.A.D., (2013) Org. Biomol. Chem., 11, pp. 4764-4777Ramos, L.M., Tobio, A., Dos Santos, M.R., De Oliveira, H.C.B., Gomes, A.F., Gozzo, F.C., De Oliveira, A.L., Neto, B.A.D., (2012) J. Org. Chem., 77, pp. 10184-10193Neto, B.A.D., Alves, M.B., Lapis, A.A.M., Nachtigall, F.M., Eberlin, M.N., Dupont, J., Suarez, P.A.Z., (2007) J. Catal., 249, pp. 154-161Machado, A.H.L., Milagre, H.M.S., Eberlin, L.S., Sabino, A.A., Correia, C.R.D., Eberlin, M.N., (2013) Org. Biomol. Chem., 11, pp. 3277-3281Ramos, L.M., Guido, B.C., Nobrega, C.C., Corrêa, J.R., Silva, R.G., De Oliveira, H.C.B., Gomes, A.F., Neto, B.A.D., (2013) Chem.-Eur. J., 19, pp. 4156-4168Medeiros, G.A., Da Silva, W.A., Bataglion, G.A., Ferreira, D.A.C., De Oliveira, H.C.B., Eberlin, M.N., Neto, B.A.D., (2014) Chem. Commun., 50, pp. 338-340Gozzo, F.C., Santos, L.S., Augusti, R., Consorti, C.S., Dupont, J., Eberlin, M.N., (2004) Chem.-Eur. J., 10, pp. 6187-6193Dos Santos, M.R., Diniz, J.R., Arouca, A.M., Gomes, A.F., Gozzo, F.C., Tamborim, S.M., Parize, A.L., Neto, B.A.D., (2012) ChemSusChem, 5, pp. 716-726Amatore, C., Jutand, A., (2000) Acc. Chem. Res., 33, pp. 314-321Kozuch, S., Shaik, S., Jutand, A., Amatore, C., (2004) Chem.-Eur. J., 10, pp. 3072-3080Kozuch, S., Amatore, C., Jutand, A., Shaik, S., (2005) Organometallics, 24, pp. 2319-2330Knowles, J.P., Whiting, A., (2007) Org. Biomol. Chem., 5, pp. 31-44Phan, N.T.S., Van Der Sluys, M., Jones, C.W., (2006) Adv. Synth. Catal., 348, pp. 609-679Dos Santos, M.R., Gomes, A.F., Gozzo, F.C., Suarez, P.A.Z., Neto, B.A.D., (2012) ChemSusChem, 5, pp. 2383-2389Corilo, Y.E., Nachtigall, F.M., Abdelnur, P.V., Ebeling, G., Dupont, J., Eberlin, M.N., (2011) RSC Adv., 1, pp. 73-78Mi, X.L., Luo, S.Z., Cheng, J.P., (2005) J. Org. Chem., 70, pp. 2338-2341Corma, A., Garcia, H., Leyva, A., (2004) Tetrahedron, 60, pp. 8553-8560Spickermann, C., Thar, J., Lehmann, S.B.C., Zahn, S., Hunger, J., Buchner, R., Hunt, P.A., Kirchner, B., (2008) J. Chem. Phys., 129, p. 10450
Synthesis of B- and P-heterocycles by reaction of cyclic acetals and ketals with borinium and phosphonium ions
No full textTricoordinated cyclic boron cations result from gas-phase ion/molecule reactions of dicoordinated borinium ions with neutral acetals and ketals and thiazolidine. The reaction, which proceeds via initial cationic binding to a heteroatom followed by a consecutive ring-opening and ring-reclosing process, resembles the Eberlin transacetalization of acylium ions (Eberlin, M. N.; Cooks, R. G. Org. Mass Spectrom. 1993, 28, 679). The cyclic structure of the tricoordinated boron cation is demonstrated by tandem mass spectrometry and further confirmed by comparison with authentic cyclic tricoordinated boron cations.; The five-membered cyclic boron cations dissociate by ethylene oxide loss to thus reform the reactant-dicoordinated borinium ion; the six-membered boron cations fragment instead by ethylene loss. Consistent with the proposed mechanism, the ion/molecule reaction efficiency falls in the order CH3OB+C2H5 > CH3OB+OCH3 much greater than CH3B+CH3; i.e., the higher the nucleophilicity of the borinium ion, the higher the reaction efficiency. A potential energy surface is calculated for the reaction of CH3OB+OCH3 with 2-methyl-1,3-dioxolane, and the reaction is found to be 43.3 kcal/mol exothermic due to initial formation of a strong B-O bond. The analogous reactivity displayed by phosphonium ions is also investigated by both experiment and ab initio calculations. In contrast to the borinium ions, the phosphonium ions exhibit higher regioselectivity for sulfur compared to nitrogen and oxygen. Finally, the present findings indicate that the reaction exothermicity and the regioselectivity are controlled by both the Lewis acidity of the reactant cations and the leaving ability of the released neutrals in the rate-limiting nucleophilic-induced recyclization step.6493213322
Reactions of gaseous acylium ions with 1,3-dienes: further evidence for polar [4+2(+)] Diels-Alder cycloaddition
No full textA novel reaction of acylium and thioacylium ions, polar [4 + 2(+)] Diels-Alder cycloaddition with 1,3-dienes and O-heterodienes, has been systematically investigated in the gas phase (Eberlin MN, Cooks RG. J. Am. Chem. Soc. 1993; 115: 9226). This polar cycloaddition, yet without precedent in solution, likely forms cyclic 2,5-dihydropyrylium ions. Here we,report the reactions of gaseous acylium ions [(CH3)(2)N-C+=O, Ph-C+=O, (CH3)(2)N-C+=S, CH3-(C+=O, CH3CH2-C+=O, and CH2=CH-C+=O] with several 1-oxy-substituted 1,3-dienes of the general formula RO-CH=CH-C(R-1)=CH2, which were performed to collect further evidence for cycloaddition. In reactions with 1-methoxy and 1-(trimethylsilyloxy)1,3-butadiene, adducts are formed to a great extent, but upon collision activation they mainly undergo structurally unspecific retro-addition dissociation. In reactions with Danishefsky's diene (trans-1-methoxy-3-(trimethylsilyloxy)-1,3-butadiene), adducts are also formed to great extents, but retro-addition is no longer their major dissociation; the ions dissociate instead mainly to a common fragment, the methoxyacryl cation of m/z 85. This fragment ion is most likely formed with the intermediacy of the acyclic adduct, which isomerizes prior to dissociation by a trimethylsilyl cation shift. Theoretical calculations predict that meta cycloadducts bearing 1-methoxy and 1-trimethylsilyloxy substituents are unstable, undergoing barrierless ring opening induced by the charge-stabilizing effect of the 1-oxy substituents. In contrast, for the reactions with 1-acetoxy-1,3-butadiene, both the experimental results and theoretical calculations point to the formation of intrinsically stable cycloadducts, but the intact cycloadducts are either not observed or observed in low abundances. Both the isomeric ortho and meta cycloadducts are likely formed, but the nascent ions dissociate to great extents owing to excess internal energy. The ortho cycloadducts dissociate by ketene loss; the meta cycloadducts undergo intramolecular proton transfer to the acetoxy group followed by dissociation by acetic acid loss to yield aromatic pyrylium ions. Either or both of these dissociations, ketene and/or acetic acid loss, dominate over the otherwise favored retro-Diels-Alder alternative. The pyrylium ion products therefore constitute: compelling evidence for polar [4 + 2] cycloaddition since their formation can only be rationalized with the intermediacy of cyclic adducts. Copyright (C) 2003 John Wiley Sons, Ltd.38330531
- …
