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3
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84943051489
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and references therein
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For employment of silyl nitronates in classical reactions of ANC. For modification of the Henry reaction, see: (a) Seebach, D.; Beck, A. K.; Lehr, F.; Webler, T.; Colwin, E. W. Angew. Chem., Int. Ed. Engl. 1981, 20 and references therein.
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Seebach, D.1
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4
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9344264406
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Russian translation, 1985, 2635
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For modification of the Mannich reaction, see: (b) Kalinin, A. V.; Apasov, E. T.; Ioffe, S. L.; Kozjukov, V. P.; Kozjukov, V. P. Bull. Acad. Sci. Div. Chem. Sci. 1985, 34, 2442 (Russian translation, 1985, 2635).
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Kalinin, A.V.1
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(d) Tartakovsky, V. A.; Ioffe, S. L.; Dilman, A. D.; Tishkov, A. A. Russ. Chem. Bull. 2001, 50, 1936.
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Tartakovsky, V.A.1
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Dilman, A.D.3
Tishkov, A.A.4
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8
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0001673687
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N,N-Bis(hydroxy)iminium cations are widely discussed as intermediates of the Nef reaction: Kornblum, N.; Brown, R. A. J. Am. Chem. Soc. 1965, 87, 1742.
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Kornblum, N.1
Brown, R.A.2
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9
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9344269754
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ref 2d
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For the suggested generation of 2 by silylation of silylnitronates, see: (a) ref 2d.
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-
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10
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0034670629
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For the suggested generation of 2 by interaction of N,N-bissiloxyenamines with certain electrophiles, see: (b) Dilman, A. D.; Lyapkalo, I. M.; Ioffe, S. L.; Strelenko, Yu. A.; Tartakovsky, V. A. J. Org. Chem. 2000, 65, 8826.
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Tartakovsky, V.A.5
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(c) Dilman, A. D.; Ioffe, S. L.; Mayr, H. J. Org. Chem. 2001, 66, 3196.
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0037568437
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(d) Ustinov, A. V.; Dilman, A. D.; Ioffe, S. L.; Strelenko, Yu. A.; Smit, W. A.; Tartakovsky, V. A. Mendeleev Commun. 2003, 74.
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Smit, W.A.5
Tartakovsky, V.A.6
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14
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0033516546
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For intramolecular trapping of N,N-bis(siloxy)iminium cations, see: (b) Tishkov, A. A.; Kozintsev, A. V.; Lyapkalo, I. M.; Ioffe, S. L.; Kachala, V. V.; Strelenko, Yu. A.; Tartakovsky, V. A. Tetrahedron Lett. 1999, 5075.
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Tishkov, A.A.1
Kozintsev, A.V.2
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Ioffe, S.L.4
Kachala, V.V.5
Strelenko, Yu.A.6
Tartakovsky, V.A.7
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15
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0034336227
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(c) Smirnov, V. O.; Tishkov, A. A.; Kozintsev, A. V.; Lyapkalo, I. M.; Ioffe, S. L.; Kachala, V. V.; Strelenko, Yu. A.; Tartakovsky, V. A. Russ. Chem. Bull. 2000, 49, 874.
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Smirnov, V.O.1
Tishkov, A.A.2
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Lyapkalo, I.M.4
Ioffe, S.L.5
Kachala, V.V.6
Strelenko, Yu.A.7
Tartakovsky, V.A.8
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16
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0001053365
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Compounds 1a-j were prepared from nitromethane or nitroethane using the modified procedures of the following: (a) Denmark, S. E.; Thorarensen, A. Chem. Rev. 1996, 96, 137.
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Denmark, S.E.1
Thorarensen, A.2
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18
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0034723164
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Similar changes in NMR spectra upon the silylation of nitrones have been attributed to the generation of N-siloxy-N-alkyliminium cations: Chalaye-Mauger, H.; Denis, J.-N.; Averbuch-Pouchot, M.-T.; Vallee, Y. Tetrahedron 2000, 56, 791.
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Tetrahedron
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Chalaye-Mauger, H.1
Denis, J.-N.2
Averbuch-Pouchot, M.-T.3
Vallee, Y.4
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19
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9344220294
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note
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The NMR investigation of the N,N-bis(oxy)iminium cations formed upon the interaction of TBDMSOTf with other nitronates will be published in due course.
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-
-
-
20
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0030923304
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The electrophilicity parameter (E) for N,N-dialkyliminium cations is ca. -5: Mayr, H.; Ofial, A. R. Tetrahedron Lett. 1997, 3503. It might be expected that the E parameter for cations 2 is higher.
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Tetrahedron Lett
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Mayr, H.1
Ofial, A.R.2
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21
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0037363116
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For catalytic activation of electrophilic reagents with silicon Lewis acids, see: Dilman, A. D.; Ioffe, S. L. Chem. Rev. 2003, 103, 733.
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Chem. Rev.
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Dilman, A.D.1
Ioffe, S.L.2
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22
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9344240240
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note
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1H NMR data of crude reaction mixtures did not reveal the presence of the diastereomers, except those shown in Table 2. (13) The N-attack of carbenium cations on enamines can be characterized by a rate higher than that of the C-attack (for the discussion, see ref 10 and references therein). Normally, N-vinylammonium cations are thermodynamically less stable than the isomeric iminium ions (i.e., the products resulted from C-attack). Therefore, N-alkylated enamine 9 could be formed as a kinetic product, which cannot rearrange to the iminium cation like 8 due to the fast irreversible loss of the silyl group.
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-
-
-
23
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9344229584
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Thieme, G., Ed.; Verlag: Berlin
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(a) Hesse, M.; Meier, H.; Zeeh, B. Spektroskopische Methoden in der organischen Chemie; Thieme, G., Ed.; Verlag: Berlin, 1995; p 108.
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Spektroskopische Methoden in der Organischen Chemie
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Hesse, M.1
Meier, H.2
Zeeh, B.3
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25
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9344224337
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CCDC 230273 (4d), CCDC 230274 (4c), CCDC 230275 (4f), CCDC 230276 (10), CCDC 230277 (4g″), and CCDC 230278 (4j) contain the supplementary crystallographic data for this paper. These data can be obtained online (http://www.ccdc.cam.ac.uk/cgi-bin/catreq.cgi) free of charge.
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-
-
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26
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0344391947
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For conformational analysis of some N-oxides, 5,6-dihydro-[4H]-oxazines, and tetrahydro-[4H]-oxazines, see ref 14b and the following: Tishkov, A. A.; Lesiv, A. V.; Khomutova, Yu. A.; Strelenko, Yu. A.; Nesterov, I. D.; Antipin, M. Yu.; Ioffe, S. L.; Denmark, S. E. J. Org. Chem. 2003, 68, 9477.
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Tishkov, A.A.1
Lesiv, A.V.2
Khomutova, Yu.A.3
Strelenko, Yu.A.4
Nesterov, I.D.5
Antipin, M.Yu.6
Ioffe, S.L.7
Denmark, S.E.8
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27
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0000639932
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For data on the hindered inversion of the nitrogen atom in the systems bearing the O-N-O fragment, see: Rudchenko, V. F. Chem. Rev. 1993, 93, 725.
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Chem. Rev.
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Rudchenko, V.F.1
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28
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9344246662
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note
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N processes in oxazine derivatives, see ref 14b.
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-
-
-
29
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0027945291
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For the discussion of stereochemistry of the reduction of 5,6-[4H]-dihydrooxazines, see: Zimmer, R.; Arnold, Th.; Homann, K.; Reissig, H.-U. Synthesis 1994, 1050.
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(1994)
Synthesis
, pp. 1050
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Zimmer, R.1
Arnold, Th.2
Homann, K.3
Reissig, H.-U.4
-
30
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9344228259
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-
note
-
Alternatively, the generation of 4e′-g′, along with 4e-g, could be explained as a result of the competition between syn and anti approaches of 3 relative to C-6 of the cationic intermediate 2 (cf. ref 19).
-
-
-
-
31
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9344239140
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note
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The prepared tetrahydrooxazine derivatives 4a-j, 6, 8, 10, and 13 could be considered structural analogues to the well-known N- trialkylsiloxyisoxazolidines. (For preparation of natural and biologically active compounds from N-trialkylsiloxyisoxazolidines, see ref 1b.)
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