Enamine‐Mediated Azide‐Ketone [3 + 2] Cycloaddition of Azidoperfluoroalkanes

Abstract

An effective synthesis of highly functionalized N‐perfluoroalkyl‐1,2,3‐triazoles from azidoperfluoroalkanes has been achieved. In situ generated enamines readily participate in the azide‐carbonyl [3+2] cycloaddition, providing a facile way to fully substituted triazole frameworks in good to excellent yields. The synthetic value of these triazoles was shown in the synthesis of perfluorinated 1,5‐disubstituted triazoles by hydrolysis and decarboxylation.

Synthesis, Stability and Reactivity of α‐Fluorinated Azidoalkanes

“…Another pathway to fully substituted triazoles with N ‐fluoroalkyl groups is the [3+2] cycloaddition of azides with carbonyl compounds catalyzed by pyrrolidine or other bases, such as 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU, Scheme ) . When pyrrolidine is used as a catalyst, the reaction proceeds via enamines, as verified by a control experiment in which an isolated enamine afforded with CF 3 N 3 the same triazole product (R 1 =CO 2 Et, R 2 =Me).…”

CoFe2O4/Cu(OH)2 magnetic nanocomposite: an efficient and reusable heterogeneous catalyst for one-pot synthesis of β-hydroxy-1,4-disubstituted-1,2,3-triazoles from epoxides

“…38 Ramachary-Bressy-Wang cycloaddition of enolate intermediates and organic azides is the other basic method for one-pot preparation of 1,4-disubstituted-1,2,3-triazoles. [39][40][41][42][43] The reduction of work-up procedures and purication steps, high purity of desired products, short reaction times, high to excellent yields are among the signicant benets of multicomponent one-pot reactions. 44,45 Furthermore, the reaction involving ring opening of epoxides with organic azides in water solvent occurs with perfect regioselectivity and takes advantage of green and benign conditions.…”

Green Protocols in Heterocycle Syntheses via 1,3-Dipolar Cycloadditions

“…Alternative synthetic pathways for 1,2,3-triazoles have also been developed and 1,2,3 triazoles have freely been obtained from a combination of azides with a range of reaction partners: e.g., cycloadditions of either β-keto esters or nitriles to azides catalyzed by secondary amines (Costa et al, 2017), cycloaddition of a triple domino sequence of reactions between azide, amine, and 5-bromo-2-furylcarbinol (Yang et al, 2015), the reaction of enols and enamines with azides (Blastik et al, 2018), nitro methylene-based three-component synthesis (Thomas et al, 2014), and others. However, these methods entail the use of organic azides or sodium azides, which are difficult to handle and toxic, particularly on a large scale.…”