Highly regioselective nitrile oxide dipolar cycloadditions with ortho-nitrophenyl alkynes

Abstract

The dipolar cycloadditions of ortho-nitrophenyl alkynes with aryl nitrile oxides has been demonstrated. A range of substituents are tolerated on the alkyne. These reactions proceed with excellent levels of regioselectivity. Subsequent functionalization of the isoxazole scaffold has been demonstrated.

β‐Cyclodextrin–Glycerol Dimers: Synthesis and NMR Conformational Analysis

“…In 2012, Carter demonstrated that ortho ‐nitrophenylalkynes undergo facile and regioselective dipolar cycloaddition with nitrile oxides to give trisubstituted isoxazoles in good yields (Scheme ) 30. The presence of the nitro substituent is required to achieve efficient cycloaddition.…”

“… Regioselective synthesis of 3,5‐disubstituted and trisubstituted isoxazoles using ortho ‐nitrophenyl alkynes in [3+2] cycloaddition by Carter 30…”

Synthesis of Isoxazole and 1,2,3-Triazole Isoindole Derivatives via Silver- and Copper-Catalyzed 1,3-Dipolar Cycloaddition Reaction

“…Dihydroisoindolin-1-one derivatives have been extensively studied, but to the best of our knowledge there are no reports on dihydroisoindolin-1-ones incorporating an isoxazole or triazole moiety. A classical route for the preparation of isoxazole or triazole is the reaction of alkynes with nitrile oxides and aryl azides, respectively [35][36][37]. In this context and in connection with our current research interest in the preparation of biologically relevant nitrogenated and oxygenated compounds by 1,3-dipolar cycloaddition on unsaturated systems with several 1,3-dipoles [38,39] we wish to describe in this paper an efficient synthesis of a series of novel 3,5-disubstituted isoxazoles and 1,4-disubstituted 1,2,3-triazoles by regioselective reaction of arylnitrile oxides 1a-d and azides 2a-d with the dihydroisoindolin-1-one-derived terminal alkyne 3.…”

Synthesis of New Spirooxindole‐Fused Isoxazoline/Triazole and Isoxazoline/Isoxazole Derivatives from Three‐Component 1,3‐Dipolar Cycloaddition

“…The cycloaddition reaction of alkynes/alkenes with nitrile oxides and arylazides, respectively, constitutes a classical route for isoxazole, isoxazoline, or triazole formation . In this context and in connection with our current research dealing on the preparation of biologically relevant compounds via 1,3‐dipolar cycloaddition across unsaturated systems with several 1,3‐dipoles , we herein describe initially an efficient synthesis of a series of novel spirooxindole/isoxazoline/1,4‐disubstituted triazoles.…”