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.
A consecutive 2-step synthesis of N-unprotected polysubstituted indoles bearing an electron-withdrawing group at the C-3 position from readily available nitroarenes is reported. The protocol is based on the [3,3]-sigmatropic rearrangement of N-oxyenamines generated by the DABCO-catalyzed reaction of N-arylhydroxylamines and conjugated terminal alkynes, and delivers indoles endowed with a wide array
Proximity effects in diaryl derivatives. Part 7. Mechanism of base-catalysed rearrangement of 2-(hydroxyamino)aryl phenyl sulphones to 2-hydroxy-2′-(phenylsulphonyl)azoxybenzenes
作者:Robert J. Cummings、Michael F. Grundon、Anthony C. Knipe、Adil S. Wasfi
DOI:10.1039/p29830000105
日期:——
Base-catalysedrearrangement of a 2-(hydroxyamino)arylphenylsulphone (1b) to the 2-hydroxy-2′-(phenylsulphonyl)azoxybenzene (4b) was shown by isolation and kinetic studies to be a rapid reaction requiring oxygen; in the absence of oxygen the sulphur-free azoxybenzene (3; R = Cl) was the only product isolated from the reaction of (1c). A mechanism for the formation of 2-hydroxyazoxybenzenes (4) is
分离和动力学研究表明,碱催化的2-(羟基氨基)芳基苯基砜(1b)重排至2-羟基-2'-(苯基磺酰基)氮杂苯(4b)是需要氧气的快速反应。在没有氧气的情况下,无硫的z氧基苯(3; R = Cl)是唯一从(1c)反应中分离的产物。提出了形成2-羟基乙氧基苯(4)的机理(方案2),涉及亚硝基芳基自由基阴离子(9)二聚为NN的二价阴离子。-二醇(10),以及通过氧从氮原子的分子内转移来取代苯磺酰基。对2-(羟氨基)芳基苯硫醚(12)在氧气存在下的碱催化反应的类似研究表明,离去基团较弱时,会形成双(苯硫基)氮氧基苯(11; R = SPh)。描述了一种由硝基苯制备N-芳基羟胺的改进方法。
Rapid catalytic transfer reduction of aromatic nitro compounds to hydroxylamines
作者:Ian D. Entwistle、Terry Gilkerson、Robert A.W. Johnstone、Robert P. Telford
DOI:10.1016/s0040-4020(01)93607-5
日期:1978.1
A general method has been developed for the rapid, metal-catalysed transfer reduction of nitrocompounds to N-substituted hydroxylamines.
Skeletal Rearrangement in the Zn<sup>II</sup>-Catalyzed [4+2]-Annulation of Disubstituted<i>N</i>-Hydroxy Allenylamines with Nitrosoarenes to Yield Substituted 1,2-Oxazinan-3-one Derivatives
作者:Pankaj Sharma、Rai-Shung Liu
DOI:10.1002/chem.201602579
日期:2016.10.24
reports zinc‐catalyzed [4+2]‐annulation reactions of disubstituted N‐hydroxy allenylamines with nitrosoarenes to afford substituted 1,2‐oxazinan‐3‐ones with a skeletal rearrangement. This annulation is applicable to a reasonable scope of allenylamines and nitrosoarenes. Our control experiments indicate that nitrosobenzene can also implement this annulation through a radical annulation path, but with