Synthesis of Benzisoxazolines by the Coupling of Arynes with Nitrones
摘要:
A variety of substituted benzisoxazolines have been synthesized by the [3 + 2] cycloaddition of nitrones and arynes. The reaction scope is broad, the reaction conditions are mild, and the process tolerates a variety of functional groups.
selective and efficient reagent for the oxidation of hydroxylamines. The developed reaction conditions were shown to be compatible with the in situ trapping of the produced nitrones by a strained alkyne, via a [3 + 2] cycloaddition reaction.
A Metal-Free General Procedure for Oxidation of Secondary Amines to Nitrones
作者:Carolina Gella、Èric Ferrer、Ramon Alibés、Félíx Busqué、Pedro de March、Marta Figueredo、Josep Font
DOI:10.1021/jo901108u
日期:2009.8.21
An efficient and metal-free protocol for direct oxidation of secondaryamines to nitrones has been developed, using Oxone in a biphasic basic medium as the sole oxidant. The method is general and tolerant with other functional groups or existing stereogenic centers, providing rapid access to enantiomerically pure compounds in good yields.
<i>C</i><sub>3</sub>-Symmetric Titanium(IV) Triphenolate Amino Complexes for a Fast and Effective Oxidation of Secondary Amines to Nitrones with Hydrogen Peroxide
The efficient catalytic oxidation of secondary amines to nitrones usinghydrogen peroxide as primary oxidant is described. The titanium(IV) complex 2 bearing a C3-symmetrical triphenolate amino ligand has proved to be an air- and water-tolerant complex that efficiently catalyzes secondary amineoxidations at 60 °C without previous activation [catalyst loading as low as 0.01%, yields up to 99%, turnover
描述了使用过氧化氢作为伯氧化剂将仲胺有效催化氧化为硝酮的方法。带有C 3对称三酚盐氨基配体的钛(IV)配合物2已被证明是一种耐空气和水的配合物,可在60°C的温度下有效催化仲胺氧化,而无需事先活化[催化剂负载量低至0.01%,产量高达99%,周转率(TONs)高达8000,周转率(TOFs)高达11000 h -1)。
Effective Oxidation of Secondary Amines to Nitrones with Alkyl Hydroperoxides Catalysed by (Trialkanolaminato)titanium(IV) Complexes
作者:Massimiliano Forcato、Miriam Mba、William A. Nugent、Giulia Licini
DOI:10.1002/ejoc.200900867
日期:2010.2
The effective catalytic oxidation of secondaryamines to nitrones with alkyl hydroperoxides as the primary oxidants is described. The titanium alkoxide catalysts are protected from the water co-product by the combined use of a tightly binding trialkanolamine ligand and molecular sieves. Nitrones can be obtained in high yields (up to 98 %) under homogeneous, anhydrous conditions and even in the absence
Comprehensive study of the addition of nitroalkanes to nitrones was conducted. The reaction proved efficient with TMAF or TBD as bases, in the presence of a large excess of R–NO2. Phase‐transfer catalysis gave also acceptable yields. Nitroethane or nitropropane afforded mixtures of isomerisable diastereomers. The reaction was applied to the synthesis of biologically relevant compounds.