Ruthenium-Catalyzed Rearrangement of Aldoximes to Primary Amides in Water
作者:Rocío García-Álvarez、Alba E. Díaz-Álvarez、Javier Borge、Pascale Crochet、Victorio Cadierno
DOI:10.1021/om3006917
日期:2012.9.10
The rearrangement of aldoximes to primaryamides has been studied using the readily available arene-ruthenium(II) complex [RuCl2(η6-C6Me6)P(NMe2)3}] (5 mol %) as catalyst. Reactions proceeded cleanly in pure water at 100 °C without the assistance of any cocatalyst, affording the desired amides in high yields (70–90%) after short reaction times (1–7 h). The process was operative with both aromatic
from substituted aldoximes (mixture of E and Z) and alkynes, using alkyl nitrites under conventional heating conditions. The key nitrile oxide intermediates that are required for the synthesis of isoxazoles are formed by treatment of substituted aldoxime with either tert-butyl nitrite or isoamyl nitrite. The generated nitrile oxides underwent in situ [3+2] dipolar cycloaddition to the substituted alkynes
Catalyst Control in Positional-Selective C–H Alkenylation of Isoxazoles and a Ruthenium-Mediated Assembly of Trisubstituted Pyrroles
作者:Pravin Kumar、Manmohan Kapur
DOI:10.1021/acs.orglett.9b00446
日期:2019.4.5
determining the positional selectivity in C–H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C–H alkenylation product via ruthenium and copper co-catalysis
We have developed a chiral bisguanidinium salt catalyzed dynamic kinetic resolution of azlactones with oximes. A variety of chiral N-acyl amino acid oxime esters were generated with up to 97% ee and 99% yield. The products are useful in peptidesynthesis.