Comparison of gas phase and condensed phase SNi reactions. The competitive four- and five-centre cyclisations of the 3,4-epoxybutoxide anion. A joint experimental and theoretical study
摘要:
MP2-Fc/6-31+G(d)水平的 Ab initio 计算表明,3,4-环氧丁氧阴离子应经过竞争性 SNi 循环(通过四元和五元过渡态),分别生成氧杂环丁烷-2-基甲醇和四氢呋喃-3-醇的 (M - H)- 离子。在每个过程中,进入过渡态的障碍相当(约 70 kJ mol-1),在所示理论水平上,四氢呋喃-3-醇更稳定,为 82 kJ mol-1。对通过碰撞活化激发的 3,4-环氧丁氧阴离子进行的气相研究符合这一设想,此外还表明,去质子化的 2-氧杂环丁烷甲醇可以转化为起始物质。在两种不同的溶剂系统[10% 氢氧化钠水溶液和氢化钠-四氢呋喃(均在回流条件下)]中对 2-(环氧乙烷-2-基)乙醇(3,4-环氧丁烷-1-醇)进行碱处理,可以得到与气相研究中观察到的相同的两种产物。不过,在这两种溶剂体系中,去质子化的四氢呋喃-3-醇都是动力学产物。
Metal promoted cyclization. 18. Novel cyclialkylation reactions of (.omega.-halo-1-alkenyl)metal derivatives. Synthetic scope and mechanism
作者:Eiichi. Negishi、Larry D. Boardman、Hiroyuki. Sawada、Vahid. Bagheri、A. Timothy. Stoll、James M. Tour、Cynthia L. Rand
DOI:10.1021/ja00224a025
日期:1988.8
Cyclisation d'(ω-halogenoalcene-1yl) M et d'([ω-halogeno trimethylsilyl-1] alcene-1yl) M en cyclenes (M=aluminium, zinc, zirconium, ou silicium)
环化 d'(ω-halogenoalcene-1yl) M et d'([ω-halogeno trimethylsilyl-1] alcene-1yl) M 环烯(M = 铝、锌、锆、硅)
Rapid Access to Azabicyclo[3.3.1]nonanes by a Tandem Diverted Tsuji–Trost Process
作者:Hannah G. Steeds、Jonathan P. Knowles、Wai L. Yu、Jeffery Richardson、Katie G. Cooper、Kevin I. Booker‐Milburn
DOI:10.1002/chem.202003762
日期:2020.11.11
system from simple pyrroles, employing a combined photochemical/palladium‐catalysed approach is reported. Substrate scope is broad, allowing the incorporation of a wide range of functionality relevant to medicinal chemistry. Mechanistic studies demonstrate that the process occurs by acid‐assisted C−N bond cleavage followed by β‐hydride elimination to form a reactive diene, demonstrating that efficient
A novel Pd-catalyzed intermolecular cascade oxidative amination of homoallylic alcohols to yield β-amino ketones has been developed by using TBHP as the terminal oxidant. The synthetic utility of the reaction can be performed by installing the carbonyl and amino groups along an alkyl chain in one step, offering several advantages such as simple starting materials and easy operation. The resultant β-amino
Synthesis of Secondary Amines by Titanium-Mediated Transfer of Alkenyl Groups from Alcohols
作者:Balasubramanian Ramanathan、Aaron L. Odom
DOI:10.1021/ja0628811
日期:2006.7.1
Reaction of Ti(NMe2)4 with allyl alcohols and primary amines leads to the selective formation of secondary allylic amines. The allyl transferfrom the alcohol to the amine occurs with selective allylic transposition. Due to substituent effects in the reactions, we postulate that the reaction occurs through a [2 + 2]/retro-[2 + 2]-cycloaddition mechanism. It was also found that a similar reaction could
Unusually Facile Thermal Homodienyl-[1,5]-Hydrogen Shift Reactions in Photochemically Generated Vinyl Aziridines
作者:Jonathan P. Knowles、Kevin I. Booker-Milburn
DOI:10.1002/chem.201600479
日期:2016.8.1
general and surprisingly low temperature ring opening through a [1,5]‐hydrogen shift reaction. The rate of the process was found to be highly dependent on the structure and substitution around the azirdine ring and the alkene terminus, with some substrates being observed to undergo ring opening at temperatures as low as 25 °C. The rigid nature of these polycyclic systems precludes a conformational explanation