Cyclization Reactions Of Acylium And Thioacylium Ions With Isocyanates And Isothiocyanates: Gas Phase Synthesis Of 3,4-dihydro-2,4-dioxo-2h-1,3,5- Oxadiazinium Ions

Gas-phase reactions of several acylium and thioacylium ions, that is H 2C=N-C+=O, H2C=N-C+=S, O=C=N-C +=O, S=C=N-C+=O, H3C-C+=O, and (CH3)2N-C+=O, with both a model isocyanate and isothiocyanate, that is, C2H5-N=C=O and C 2H5-N=C=S, were investigated using tandem-in-space pentaquadrupole mass spectrometry. In these reactions, the formation of mono- and double-addition products is observed concurrently with proton transfer products. The double-addition products are far more favored in reactions with ethyl isocyanate, whereas the reactions with ethyl isothiocyanate form, preferentially, either the mono-addition product or proton transfer products, or both. Retro-addition dominates the low-energy collision-induced dissociation of the mono- and double-addition products with reformation of the corresponding reactant ions. Ab initio calculations at Becke3LYP//6-311 + G(d,p) level indicate that cyclization is favored for the double-addition products and that products equivalent to those synthesized in solution, that is, of 3,4-dihydro-2,4-dioxo-2H-1,3,5-oxadiazinium ions and sulfur analogs, are formed. © 2005 American Society for Mass Spectrometry.161016021607McLafferty, F.W., Tandem Mass Spectrometry - From Infancy to Maturity in 25 Years (1993) Org. Mass Spectrom, 28, pp. 1403-1406Futrell, J.H., Development of Tandem Mass Spectrometry: One Perspective (2000) Int. J. Mass Spectrom, 200, pp. 495-508Shukla, A.K., Futrell, J.H., Tandem Mass Spectrometry: Dissociation of Ions by Collisional Activation (2000) J. Mass Spectrom, 35, pp. 1069-1090Stirk, K.M., Kiminkinen, L.K.M., Kenttamaa, H.I., Ion Molecule Reactions of Distonic Radical Cations (1992) Chem. Rev., 92, pp. 1649-1665Brodbelt, J.S., Analytical Applications of Ion-Molecule Reactions (1997) Mass Spectrom. Rev., 16, pp. 91-110Green, M.K., Lebrilla, C.B., Ion-Molecule Reactions as Probes of Gas-Phase Structures of Peptides and Proteins (1997) Mass Spectrom. Rev., 16, pp. 53-71Eberlin, M.N., Triple-Stage Pentaquadrupole (QqQqQ) Mass Spectrometry and Ion-Molecule Reactions (1997) Mass Spectrom. Rev., 16, pp. 113-144Takashima, K., Riveros, J.M., Gas-Phase Solvated Negative Ions (1998) Mass Spectrom. Rev., 17, pp. 409-430Filippi, A., Giardini, A., Piccirillo, S., Speranza, M., Gas-Phase Enantioselectivity (2000) Int. J. Mass Spectrom, 198, pp. 137-163Eberlin, M.N., Gas-Phase Polar Cycloadditions (2004) Int. J. Mass Spectrom, 235, pp. 263-278Ramirez-Arizmendi, L.E., Yu, Y.Q., Kenttamaa, H.I., Reactivity of Cl-P+-Cl Toward Cyclic Organic Ethers (1999) J. Am. Soc. Mass Spectrom, 10, pp. 379-385Wang, F., Tao, W.A., Gozzo, F.C., Eberlin, M.N., Cooks, R.G., Synthesis of B- and P-Heterocycles by Reaction of Cyclic Acetals and Ketals with Borinium and Phosphonium Ions (1999) J. Org. Chem., 64, pp. 3213-3223Kretzschmar, I., Schroder, D., Schwarz, H., Rue, C., Armentrout, P.B., Thermochemistry and Reactivity of Cationic Scandium and Titanium Sulfide in the Gas Phase (2000) J. Phys. Chem. a, 104, pp. 5046-5058O'Hair, R.A.J., Androutsopoulos, N.K., Can Transacylation Reactions Occur via S(N)2 Pathways in the Gas Phase? Insights via Ion-Molecule Reactions of N-Acylpyridinium Ions and ab Initio Calculations (2000) Org. Lett., 2, pp. 2567-2570Gevrey, S., Luna, A., Taphanel, M.H., Tortajada, J., Morizur, J.P., Experimental and Theoretical Studies of the Gas-Phase Reactivity of the (HO)2P=O+ Phosphonium Ions Towards Methanol (2000) Int. J. Mass Spectrom, 196, pp. 545-563De Moraes, P.R.P., Linnert, H.V., Aschi, M., Riveros, J.M., Experimental and Theoretical Characterization of Long-Lived Triplet State CH3CH2S+ Cations (2000) J. Am. Chem. Soc., 122, pp. 10133-10142D'Oca, M.G.M., Moraes, L.A.B., Pilli, R.A., Eberlin, M.N., Intrinsic Gas-Phase Electrophilic Reactivity of Cyclic N-Alkyl and N-Acyliminium Ions (2001) J. Org. Chem., 66, pp. 3854-3864Tomazela, D.M., Moraes, L.A.B., Pilli, R.A., Eberlin, M.N., D'Oca, M.G.M., Mannich-Type Reactions in the Gas-Phase: The Addition of Enol Silanes to Cyclic N-Acyliminium Ions (2002) J. Org. Chem., 67, pp. 4652-4658Gronert, S., Mass Spectrometric Studies of Organic Ion-Molecule Reactions (2001) Chem. Rev., 101, pp. 329-360Sparrapan, R., Mendes, M.A., Carvalho, M., Eberlin, M.N., Formal Fusion of a Pyrrole Ring onto 2-Pyridyl and 2-Pyrimidyl Cations: One-Step Gas-Phase Synthesis of Indolizine and Its Derivatives (2000) Chem. Eur. J., 6, pp. 321-326Augusti, R., Gozzo, F.C., Moraes, L.A.B., Sparrapan, R., Eberlin, M.N., The Simplest Azabutadienes in their N-Protonated Forms. Generation, Stability, and Cycloaddition-Reactivity in the Gas Phase (1998) J. Org. Chem., 63, pp. 4889-4897Moraes, L.A.B., Eberlin, M.N., Laali, K.K., Gas-Phase Synthesis and Characterization of an Azaphosphirenium Ion: The First N,P-Analog of the Aromatic Cyclopropenyl Cation (2001) Organometallics, 20, pp. 4863-4868Takats, Z., Wiseman, J.M., Gologan, B., Cooks, R.G., Mass Spectrometry Sampling under Ambient Conditions with Desorption Electrospray Ionization (2004) Science, 306, pp. 471-473Eberlin, M.N., Cooks, R.G., Polar [4 + 2+] Diels-Alder Cycloadditions of Acylium Ions in the Gas-Phase (1993) J. Am. Chem. Soc., 115, pp. 9226-9233Moraes, L.A.B., Eberlin, M.N., Ketalization of Gaseous Acylium Ions (2001) J. Am. Soc. Mass Spectrom, 12, pp. 150-162Moraes, L.A.B., Eberlin, M.N., The Gas-Phase Meerwein Reaction (2000) Chem. Eur. J., (6), pp. 897-905Moraes, L.A.B., Eberlin, M.N., Structurally Diagnostic Ion-Molecule Reactions: Acylium Ions with α-, β-, and γ-Hydroxy Ketones (2002) J. Mass Spectrom, 37, pp. 162-168Lemos, A.B., Sparrapan, R., Eberlin, M.N., Reactions of Gaseous Acylium Ions with 1,3-Dienes: Further Evidence for Polar [4 + 2(+)] Diels-Alder Cycloaddition (2003) J. Mass Spectrom, 38, pp. 305-314Meurer, E.C., Eberlin, M.N., Mono and Double Polar [4 + 2+] Diels-Alder Cycloaddition of Acylium Ions with O-Heterodienes (2002) J. Mass Spectrom, 37, pp. 146-154Meurer, E.C., Moraes, L.A.B., Eberlin, M.N., Cyclization of Acylium Ions with Nitriles: Gas-Phase Synthesis and Characterization of 1,3,5-Oxadiazinium Ions (2001) Int. J. Mass Spectrom, 212, pp. 445-454Mahato, S.B., Advances in the Chemistry of Friedel - Crafts Acylation (2000) J. Indian Chem. Soc, 77, pp. 175-191Altalib, M., Tashtoush, H., Recent Advances in the Use of Acylium Salts in Organic Synthesis - A Brief Review (1990) Org. Prep. Proced. Int., 22, p. 1Hamed, A., Ismail, A., Hitzler, M.G., Jochims, J.C., On the Reaction of Acylium Salts with Isocyanates (1995) J. Prakt. Chem./Chem. Ztg., 337, pp. 385-390Juliano, V.F., Gozzo, F.C., Eberlin, M.N., Kascheres, C., Dolago, C.L., Fast Multidimensional (3D and 4D) MS2 and MS3 Scans in a High-Transmission Pentaquadrupole Mass Spectrometer (1996) Anal. Chem., 68, pp. 1328-1334Tiernan, T.O., Futrell, J.H., Ionic Reactions in Unsaturated Compounds. Ethylene (1968) J. Phys. Chem., 72, pp. 3080-3081Schwartz, J.C., Wade, A.P., Enke, C.G., Cooks, R.G., Systematic Delineation of Scan Modes in Multidimensional Mass Spectrometry (1990) Anal. Chem., 62, pp. 1809-1818Becke, A.D., Density-Functional Thermochemistry. the Role of Exact Exchange (1993) J. Chem. Phys., 98, pp. 5648-5652Lee, C., Parr, R.G., Exchange-Correlation Functional for Atoms and Molecules (1990) Phys. Rev. a, 42, pp. 193-200Stephens, P.J., Devlin, F.J., Chabalowski, C.F., Frisch, M.J., Ab-Initio Calculation of Vibrational Absorption and Circular-Dichroism Spectra Using Density-Functional Force Fields (1994) J. Phys. Chem., 98, pp. 11623-11627Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., Gaussian 98, , Gaussian, Inc.: Pittsburgh PA, Revision A6Hunter, E.P., Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update (1998) J. Phys. Chem. Ref. Data, 27, pp. 413-65