Correlation of rates of uncatalyzed and hydroxide-ion catalyzed ketene hydration. A mechanistic application and solvent isotope effects on the uncatalyzed reaction
An asymmetric pericyclic cascade approach to 3-alkyl-3-aryloxindoles: generality, applications and mechanistic investigations
作者:Edward Richmond、Kenneth B. Ling、Nicolas Duguet、Lois B. Manton、Nihan Çelebi-Ölçüm、Yu-Hong Lam、Sezen Alsancak、Alexandra M. Z. Slawin、K. N. Houk、Andrew D. Smith
DOI:10.1039/c4ob02526a
日期:——
The reaction of l-serine derived N-arylnitrones with alkylarylketenes generates 3-alkyl-3-aryloxindoles in good yields and excellent enantioselectivities.
Oxygen bridged Homobinuclear Mn(II) compounds with Anthranilic acid: Theoretical calculations, oxidation and catalase activity
作者:Esra Su、Alaettin Guven、Ibrahim Kani
DOI:10.1002/aoc.4105
日期:2018.2
mono‐ and bidentate carboxylate bridgedcompounds, Mn–Mn distances of 1 and 2 are 3,461 Å, and 4,639 Å, respectively. The energy of the compounds was determined with a DFT (Density Functional Theory) calculation on B3LYP/6‐31G(d,p) optimized geometry by using the B3LYP/6‐31G(d,p) basis set. These compounds acts as biomimetic catalyst and show catalase‐like activity for the hydrogen peroxide dismutation
Nitroxyl Radical Reactions with 4-Pentenyl- and Cyclopropylketenes: New Routes to 5-Hexenyl- and Cyclopropylmethyl Radicals
作者:Annette D. Allen、Michael F. Fenwick、Huda Henry-Riyad、Thomas T. Tidwell
DOI:10.1021/jo0102922
日期:2001.8.1
in hydrocarbon solvents. The reactions of these ketenes with the nitroxylradicals tetramethylpiperidinyloxyl (TEMPO, TO*) and tetramethylisoindoline-2-oxyl (TMIO, IO*) form carboxy substituted 5-hexenyl and cyclopropylmethyl radicals which are either trapped by a second nitroxylradical or undergo rearrangements followed by trapping. The rate constant of the reaction of 4a with TEMPO was similar to
4-戊烯基酮4a和9以及环丙基烯酮3a,13、14(RCH = C = O)是通过光化学Wolff重排生成的,并且在室温下在烃类溶剂中被IR观察为相对长寿的物种。这些烯酮与硝基氧基四甲基哌啶基氧基(TEMPO,TO *)和四甲基异吲哚啉-2-氧基(TMIO,IO *)的反应形成羧基取代的5-己烯基和环丙基甲基,它们被第二个硝基氧基所俘获或进行重排通过诱捕。4a与TEMPO的反应速率常数与n-BuCH = C = O(1b)相似,而3a的反应速率高4.3倍,表明初始自由基的环丙基稳定性。
Ketene Reactions with the Aminoxyl Radical TEMPO: Preparative, Kinetic, and Theoretical Studies
作者:Annette D. Allen、Bernice Cheng、Michael H. Fenwick、Babak Givehchi、Huda Henry-Riyad、Valerij A. Nikolaev、Elena Aleksadrovna Shikhova、Daryoush Tahmassebi、Thomas T. Tidwell、Silas Wang
DOI:10.1021/jo0011336
日期:2001.4.1
reactive ketenes were generated as rather long-lived species by photochemical Wolff rearrangement in isooctane solution, characterized by IR and UV, and used for kinetic studies. The rate constants of TEMPO addition to eight different ketenes have been measured and give a qualitative correlation of log k(2)(TEMPO) = 1.10 log k(H(2)O) -3.79 with the rate constants for hydration of the same ketenes. Calculations
四甲基哌啶基氧基(TEMPO,TO *)与通过Wolff重排或酰基氯的脱氯化氢反应生成的烯酮RR(1)C = C = O反应,得到的产物是将一个TEMPO自由基加到羰基碳上,再将第二个TEMPO自由基加成激进。苯基乙烯基乙烯酮4b和4f,苯基炔基乙烯酮4c和二烯基乙烯酮AcOCMe = CHCH = CHCMe = C = O的反应发生烯丙基或炔丙基重排。通过在异辛烷溶液中进行光化学Wolff重排,甚至以相当长的寿命生成了相当活泼的烯酮,其特征在于IR和UV,并用于动力学研究。已测量了TEMPO除八种不同烯酮外的速率常数,并给出了log k(2)(TEMPO)= 1.10 log k(H(2)O)-3.79与相同烯酮水合的速率常数的定性相关性。
Reactions of 2-Methyltetrahydropyran on Silica-Supported Nickel Phosphide in Comparison with 2-Methyltetrahydrofuran
作者:Phuong P. Bui、S. Ted Oyama、Atsushi Takagaki、Brad P. Carrow、Kyoko Nozaki
DOI:10.1021/acscatal.6b01033
日期:2016.7.1
The reactions of 2-methyltetrahydropyran (2-MTHP, C6H12O) on Ni2P/SiO2 provide insights on the interactions between a cyclic ether, an abundant component of biomass feedstock, with a transition-metal phosphide, an effective hydrotreating catalyst. At atmospheric pressure and a low contact time, conditions similar to those of a fast pyrolysis process, 70% of products formed from the reaction of 2-MTHP
2-甲基四氢吡喃(2-MTHP,C 6 H 12 O)在Ni 2 P / SiO 2上的反应提供了关于环醚(一种生物质原料的丰富成分)与一种有效的过渡金属磷化物之间的相互作用的见解。加氢处理催化剂。在大气压和短接触时间下,类似于快速热解过程的条件,70%的产物由2-MTHP在Ni 2 P / SiO 2上反应形成为脱氧产物2-己烯和2-戊烯,表明具有良好的除氧能力。主要的反应途径是去质子化,氢解,脱水和脱羰基。反应顺序从吸附2-MTHP开始,然后在甲基取代的一面(路径I)或未取代的一面(路径II)上开环,以生成吸附的醇盐。在路径I中,伯醇盐在α-碳处被氧化以产生醛,其随后被脱羰基化为2-戊烯。伯醇盐也可以被质子化以产生伯醇,伯醇可以解吸或形成最终产物2-己烯。在路径II中,仲醇盐被氧化生成酮,或被质子化为仲醇,然后脱水生成2-己烯。O-中间体很可能是Ni位点。