Umlagerungen organischer Anionen, VI. Kinetik und Mechanismus der Umlagerung von N‐Benzyl‐N‐methyl‐anilinoxiden zu O‐Benzyl‐N‐phenyl‐N‐methyl‐hydroxylaminen

Abstract

Die Umlagerungsgeschwindigkeit der N-Benzyl-N-methyl-anilinoxide 4 hangt nur wenig vom Substituenten im Benzyl-Kern ab, sehr aber vom Solvatationsvermogen des Losungsmittels.

A new version of the reverse-Cope elimination initiated by the nucleophilic addition of allylamines to nitrones: a synthesis of vicinal diamines

“…The accepted mechanism for this usually high-temperature process, which is also largely limited to the migration of allyl or benzyl groups, involves radical intermediates, to judge from the extensive studies carried out by the Schöllkopf group. 28 However, the present process represents a rather special case and clearly does not necessitate the evocation of radicals. Indeed, there is literature precedent for relatively simple Meisenheimer rearrangements involving α-aminoamine N-oxides.…”

“…CC (EtOAc-hexane-Et 3 N, 1 : 4 : 0.01) of the residue separated (i) the (3R,5R)-isoxazolidine 7a (99 mg, 13%), R f 0.58 (EtOAc-hexane-Et 3 N, 1 : 2 : 0.1), as a colourless oil, [α] D 20 ϩ1.7 (c 0.36, CHCl 3 ); ν max /cm Ϫ1 3360 and 1705; δ H (250) 1.37 (3H, s), 1.43 (3H, s), 1.44 (9H, s, Bu t ), 1.45 (3H, s), 1.48 (3H, s), 2.10 (1H, ddd, J 12.7, 10. (19), 115 (13), 98 (15), 84 (9), 68 (9), 59 (28) and 57 (25) , s), 1.43 (6H, s, 2 × Me), 1.44 (9H, s, Bu t ), 1.51 (3H, s), 2.12 (1H, ddd, J 12.5, 9.5 and 9.5, 4-H a ), 2.59 (1H, ddd, J 12.5, 5.9 and 2.6, 4-H b ), 2.80 (3H, s, NMe), 3.18 (1H, dd, J 9.5 and 2.6, 3-H), 3.25 (1H, m, CH a NH), 3.45 (1H, m, CH b NH), 4.05-4.08 (3H, m), 4.07 (1H, d, J 2.0), 4.27 (1H, d, J 1.9), 4.38 (1H, s) and 4.85 (1H, t, J 5.0, NH); m/z 388 (M ϩ ϩ H Ϫ Bu t , 9%), 159 (100), 141 (17), 115 (15), 98 (11), 84 (7), 68 (10), 59 (18) and 57 (22) (Found: M ϩ ϩ H Ϫ Bu t , 388.1842).…”

“…The nitrone 8 (82 mg, 0.61 mmol) and (E)-N-methylhex-2enamine 42 45b (69 mg, 0.61 mmol) were refluxed together in toluene (2 ml) for 21 h. Evaporation of the cooled solution and CC (EtOAc-LP, 1 : 4) gave the 3-butyloxadiazinane 46b (68 mg, 45%) as a pale yellow oil; ν max /cm Ϫ1 936; δ H (400) 0.92 (3H, t, J 7.0, 4Ј-Me), 1.25-1.40 (6H, m, 1Ј-, 2Ј-and 3Ј-CH 2 ), 2.00 (3H, s, 5-Me), 2.40 (1H, dd, J 12.8 and 11.3, 4-H ax ), 2.69 (3H, s, 2-Me), 2.84 (1H, m, 3-H), 3.09 (1H, dd, J 11.3 and 2.6, 4-H eq ), 4.76 (1H, s, 6-H), 7.32-7.36 (3H, m, Ph) and 7.44-7.47 (2H, m, Ph); δ C (100) 13.9 (4Ј-Me), 23.0, 27.4, 30.1 (all CH 2 ), 39.3 (5-Me), 43.5 (2-Me), 59.4 (4-CH 2 ), 64.4 (3-CH), 97.6 (6-CH), 128.0, 128.2, 128.4 (Ph CH) and 137.5 (Ph C); m/z 248 (M ϩ , 82%), 120 (21), 119 (47), 118 (100), 105 (19), 91 (29), 77 (28) and 72 (14) (Found: M ϩ , 248.1877. C 15 H 24 N 2 O requires M, 248.1889).…”

Electrochemical Synthesis of N,O‐Dialkylarylhydroxylamines and N,O‐Diacylarylhydroxylamines

“…l (ii) electrolytes with a continuous nonlinear variation of log(e) vs. (1/T), which can be fitted to a free-volume model (VTF) e = AT -1/~ exp -E~ [2] (iii) electrolytes with a mixed dependence, whose log(~) vs. (l/T) variation can be described by Eq. [2], for higher temperatures. [2], for higher temperatures.…”

“…Several reports describe 1,3 sigmatropic shifts of activated groups, such as allyl and benzyl, from nitrogen to oxygen of amine oxides (2)(3)(4)(5)(6)(7)(8)(9). Several reports describe 1,3 sigmatropic shifts of activated groups, such as allyl and benzyl, from nitrogen to oxygen of amine oxides (2)(3)(4)(5)(6)(7)(8)(9).…”