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
Synthesis of isoxazoles by hypervalent iodine-induced cycloaddition of nitrile oxides to alkynes
作者:Anup M. Jawalekar、Erik Reubsaet、Floris P. J. T. Rutjes、Floris L. van Delft
DOI:10.1039/c0cc04646a
日期:——
Treatment of oximes with hypervalent iodine leads to substituted isoxazoles via rapid formation of nitrile oxides. Reaction with terminal alkynes led to a series of 3,5-disubstituted isoxazoles with complete regioselectivity and high yield, in a procedure mild enough to prepare a range of nucleoside and peptide conjugates. Exceptionally high reactionrates were found for the formation of 3,4,5-trisubstituted
Copper(0) Nanoparticles in Click Chemistry: Synthesis of 3,5-Disubstituted Isoxazoles
作者:T. M. Vishwanatha、Vommina V. Sureshbabu
DOI:10.1002/jhet.2065
日期:2015.11
An efficient procedure for the synthesis of 3,5‐disubstituted isoxazoles via [3 + 2] cycloaddition reaction of in situ generated nitrileoxides with acetylenes employing readily preparable copper(0) nanoparticles is described. A variety of in situ generated nitrileoxide and acetylenic substrates were engaged in the study and found to undergo cyclization in short duration affording respective isoxazoles
Ruthenium-catalyzed oxidative coupling of vinylene carbonate with isoxazoles: access to fused anthranils
作者:Pravin Kumar、Manmohan Kapur
DOI:10.1039/d2cc01048h
日期:——
A ruthenium-catalyzedoxidative coupling of vinylene carbonate with isoxazoles has been developed to achieve the direct C–H formylmethylation of a diverse array of arylisoxazoles utilizing the isoxazole ring as the directing group. A simple manipulation of the established reaction conditions leads to the formation of fused-anthranils. Importantly, the vinylene carbonate functions as both a formylmethyl