Mechanism of Methoxide Ion Substitution in the <i>Z</i> and <i>E</i> Isomers of <i>O</i>-Methylbenzohydroximoyl Halides
作者:James E. Johnson、Debra D. Dolliver、Lonchun Yu、Diana C. Canseco、Michael A. McAllister、Jeffrey E. Rowe
DOI:10.1021/jo030299e
日期:2004.4.1
isomers of O-methylbenzohydroximoyl halides [1Z and 1E, ArC(X)NOCH3] with sodium methoxide in 9:1 DMSO−methanol. The reactions of methoxide ion with hydroximoyl fluorides (X = F) are stereospecific. The reaction with 1Z (X = F) gives only the Z substitution product (1Z, X OCH3). The reaction of methoxide ion with 1E (X = F) is less selective, giving ca. 85% E substitution product. The Hammett ρ-values for
在9:1 DMSO-甲醇中,对O-甲基苯并氧肟基卤化物的Z和E异构体[ 1Z和1E,ArC(X)NOCH 3 ]与甲醇钠的反应进行了动力学和立体化学研究。甲醇离子与羟肟基氟化物(X = F)的反应是立体定向的。与1Z(X = F)的反应仅给出Z取代产物(1Z,X OCH 3)。甲醇离子与1E(X = F)的反应选择性较低,大约为。E替代品占85%。的哈米特ρ值Z和E异构体(X = F)分别为+2.94和+3.30。1Z(Ar = C 6 H 5)的元素效应为2.21(X = Br):1.00(X = Cl):79.7(X = F)。所述1E元件效果(AR = C 6 H ^ 5)1.00(X = Cl)的:18.3(X = F)和(AR = 4-CH 3 OC 6 H ^ 4)1.97(X = Br的):1.00(X = Cl):12.1(X = F)。激活用于这些反应的熵是否定的(例如,Δ小号⧧
Determination of configurations of N-methoxyimidoyl halides via catalytic hydrogenation. Synthesis of pure (E)-aldoximes
作者:Takeshi Sakamoto、Kimio Okamoto、Yasuo Kikugawa
DOI:10.1021/jo00037a053
日期:1992.5
A New Synthesis of Nitriles from<i>N</i>-Methoxy Imidoyl Bromides by Photolysis
作者:Yasuo Kikugawa、Liang Hua Fu、Takeshi Sakamoto
DOI:10.1080/00397919308018582
日期:1993.4
Abstract N-Methoxy imidoyl bromides are synthesized in one-pot from the carboxylic acids with methoxyamine and triphenylphosphine-tetrabromomethane. Photolysis of them leads to formation of the corresponding nitriles in high yield without affecting functional groups sensitive to ordinary dehydrating and halogenating reagents.