Utilisation de complexes de Rh(I) du type [Rh(diphosphine) (diene)]ClO 4 et [Rh(diphosphine)(S) 4 ]ClO 4 (diphosphine: diphosphine tertiaire chelatant-cis; diene=cyclooctadiene ou norbornadiene; S=solvant). Ces composes sont des catalyseurs actifs de la migration d'hydrogene dans les allylamines secondaires et tertiaires pour donner les (E)-enamines et imines correspondants
[Rh(diphosphine) (diene)]ClO 4 et [Rh(diphosphine)(S) 4 ]ClO 4 (diphosphine: diphosphine tertiaire chelatant-cis; diene=cyclooctadiene ou norbornadiene; S =溶剂)。Ces 组成sont des catalyseurs actifs de la migration d'hydrogene dans les allylamines secondaires et tertiaires pour donner les (E)-enamines et 亚胺通讯员
Synthesis of 5-aminoisoxazolines from N-allyl compounds and nitrile oxides via tandem isomerization-1,3-dipolar cycloaddition
5-aminoisoxazolines via tandem catalytic isomerization (of N-allyl systems to N-(1-propenyl) systems)—1,3-dipolar cycloaddition (of a stable nitrileoxide to N-(1-propenyl) systems) is presented. Rhodium and ruthenium complexes, Verkade’s superbase, and 18-crown-6/KOH system were used for the syntheses of the N-(1-propenyl) systems. 4-P-substituted isoxazoline was also synthesized via cycloaddition of
The synthesis of a new class of stable coloured azomethineylides 3 derived from 3,4-diazanorcaradienes is reported, which under acid catalysis are transformed to again coloured stable azomethineylides 4 containing a five-membered 1-aza-1,3-cyclopentadiene skeleton. Azomethineylides 3 in boiling methanol rearrange to 3,5-diazahomotropilidenes 8 in good yields.
Nonstereospecific 1,3-dipolar cycloadditions of azomethine ylides and enamines
作者:Thomas Böhm、Andreas Weber、Jürgen Sauer
DOI:10.1016/s0040-4020(99)00517-7
日期:1999.7
The combination of electron-poor azomethine ylides 3 (AMY-I) or 4 (AMY-II) with electron-rich enamines 5 results in nonstereospecific 1,3-dipolar cycloadditions, which are LUMOdipole-HOMOdipolarophile controlled reactions. This phenomenon can be explained only by a two-step mechanism via zwitterionic intermediates.