Controlling Selectivity by Controlling the Path of Trajectories
摘要:
Consideration of the role of dynamic trajectories in [1,2]- and [2,3]-sigmatropic rearrangements suggests a counterintuitive approach to controlling the selectivity. In our hypothesis, [2,3] selectivity can be promoted by reaction conditions that thermodynamically disfavor the [2,3] rearrangement step and thereby make the transition state later. The application of this idea has led to a successful prescription for dictating the selectivity in Stevens/Sommelet-Hauser rearrangements of ammonium ylides. A combination of kinetic isotope effects, crossover experiments, and computational dynamic trajectories support the idea that the selectivity is controlled through control of the path of trajectories.
Palladium(II)-Catalyzed Remote <i>meta</i>-C–H Functionalization of Aromatic Tertiary Amines
作者:Bo Wang、Yu Zhou、Niuniu Xu、Xiufang Xu、Xiaohua Xu、Zhong Jin
DOI:10.1021/acs.orglett.9b00499
日期:2019.3.15
Pd(II)-catalyzed remoteC–H olefination of aromatic tertiary amines was achieved with high meta selectivity. With the assistance of an elaborated template, C–Hfunctionalization of unreactive aryl tertiary amines, hindered by the p−π conjugation between the lone-pair electrons of the nitrogen atom and the phenyl ring, was realized with high meta regioselectivity via a quaternary ammonium salt assembly. The results
Nickel Photocatalyzed Reductive 1,4-Dicarbofunctionalization of 1,3-Enynes with <i>N</i>-Methylamines and Organohalides Enabled by Site-Selective C(sp<sup>3</sup>)–H Functionalization
作者:Chaozhihui Cheng、Gui-Fen Lv、Shuang Wu、Yang Li、Jin-Heng Li
DOI:10.1021/acs.orglett.3c01103
日期:2023.6.16
catalysis for 1,4-dicarbofunctionalization of 1,3-enynes with tertiary N-methylamines and organohalides to produce tetrasubstituted allenes is presented. This method enables the generation of the aminoalkyl C(sp3)-centered radicals by site selective cleavage of the N-methyl C(sp3)–H bonds in tertiary N-methylamines and is extended to alkyl bromides as the electrophilic terminating regents. Mechanistic
提出了一种用于 1,3-烯炔与叔N-甲胺和有机卤化物的 1,4-二碳官能化以产生四取代丙二烯的协同镍和光氧化还原还原催化。该方法能够通过对 N-甲基叔胺中的N-甲基C(sp 3 )–H 键进行位点选择性裂解,生成以 C (sp 3 ) 为中心的氨基烷基自由基,并将其扩展为烷基溴作为亲电子终止试剂。机理研究表明该反应涉及自由基过程和Ni 0 /Ni I /Ni III催化循环。
Novel Isomerization Reaction of <i>N</i>,<i>N</i>-Dimethyl-α-(methoxycarbonyl)-4-substituted- benzylammonium <i>N</i>-Methylides
作者:Chen Zhang、Hiroto Ito、Yasuhiro Maeda、Naohiro Shirai、Shin-ichi Ikeda、Yoshiro Sato
DOI:10.1021/jo981729h
日期:1999.1.1
Fluoride ion-induced desilylation of N,N-dimethyl-N-[(trimethylsilyl)methyl]-alpha-(methoxycarbonyl)- 4-substituted benzylammonium salts (7) gave two Stevens rearrangement products: methyl 3-(dimethylamino)-2-(4-substituted phenyl)propionates (13) from N-methylides 8, and methyl 3-(dimethylamino)-3-(4-substituted phenyl)propionates (15) from N-benzylides 10. Additional Stevens rearrangement products, methyl 2-(dimethylamino)-3-(4-substituted phenyl)propionates (16), were competitively formed from ylides 12 when the cesium fluoride used was not predried. The mechanism of the isomerization from methylides 8, which was initially generated, to 10 and 12 is discussed.
RAZINA, T. L.;OGANDZHANYAN, S. M.;KOCHARYAN, S. T.;BABAYAN, A. T., ARM. XIM. ZH., 1982, 35, N 10, 644-648
作者:RAZINA, T. L.、OGANDZHANYAN, S. M.、KOCHARYAN, S. T.、BABAYAN, A. T.
DOI:——
日期:——
BABAYAN A. T.; KOCHARYAN S. T.; OGANDZHANYAN S. M., AJKAKAN KIMIAKAN AMSAGIR., ARM. XIM. ZH. <AUKZ-AN>, 1976, 29, HO 5, 403-4+
作者:BABAYAN A. T.、 KOCHARYAN S. T.、 OGANDZHANYAN S. M.