Taming Chlorine Azide: Access to 1,2-Azidochlorides from Alkenes

Abstract

The in situ preparation and trapping of chlorine azide provided a versatile one-pot method for the azidochlorination of alkenes. Gaseous ClN3 generated from sodium azide, hypochlorite, and acetic acid can be explosive if isolation is attempted. Instead, we generated the reagent in biphasic media in the presence of olefinic compounds dissolved in the organic layer or evenly emulsified throughout the solution in the absence of organic solvent. Under these conditions, ClN3 is created slowly and trapped immediately at the aqueous-organic interface. The resulting safe and reliable procedure provided 1,2-azidochloride derivatives of a variety of substrates, with evidence for both polar and radical mechanisms. Minor impurities characterized in the product mixtures indicated the presence of alternative reaction pathways deriving primarily from radical intermediates.

Chemie mit Schönheit und Fantasie

“…The in situ generation of the complex trimethylsulfonium bis(azido)iodate(I) ( 3c ) from 3a using TMSN 3 or NaN 3 is an advantageous and promising alternative to the commonly used halogen azide methods. Moreover, this process could significantly overcome the “azidophobia”15a associated with the use of highly explosive and toxic X–N 3 or hydrazoic acid 15b…”

Unexpected Direct Synthesis of N‐Vinyl Amides through Vinyl Azide–Enolate [3+2] Cycloaddition

“…In conclusion, we have reported the remarkable and unexpected direct synthesis of a,b-unsaturated N-vinyl amides from esters and N-vinyl amides from aldehydes.T he reaction most likely proceeds through the in situ formation of an N-vinyl azide,which undergoes facile azide-enolate [3+ +2] cycloaddition, followed by rearrangement and nitrogen extrusion. Thep roposed mechanism and observed regiochemistry are in accordance with quantum calculations performed to estimate transition-state activation energies for alkyl, aryl, and vinyl azides.B oth experimental data and calculations indicate that protonation of the initial triazoline cycloaddition product is required before rearrangement to adiazonium ion and nitrogen extrusion can occur to form the final N-vinyl amides.T hese investigations contribute useful data to aid the ongoing development of atom-efficient methods for amide formation and offer new possibilities in synthesis for drug discovery and the applications of industrially important N-vinyl amide polymeric materials.Finally,this study suggests that, given recent progress in batch and flow reaction technology, [21] (cautious) reevaluation of azidoethene as auseful synthetic reagent may be warranted.…”

“…Thep roposed mechanism and observed regiochemistry are in accordance with quantum calculations performed to estimate transition-state activation energies for alkyl, aryl, and vinyl azides.B oth experimental data and calculations indicate that protonation of the initial triazoline cycloaddition product is required before rearrangement to adiazonium ion and nitrogen extrusion can occur to form the final N-vinyl amides.T hese investigations contribute useful data to aid the ongoing development of atom-efficient methods for amide formation and offer new possibilities in synthesis for drug discovery and the applications of industrially important N-vinyl amide polymeric materials.Finally,this study suggests that, given recent progress in batch and flow reaction technology, [21] (cautious) reevaluation of azidoethene as auseful synthetic reagent may be warranted. Thep roposed mechanism and observed regiochemistry are in accordance with quantum calculations performed to estimate transition-state activation energies for alkyl, aryl, and vinyl azides.B oth experimental data and calculations indicate that protonation of the initial triazoline cycloaddition product is required before rearrangement to adiazonium ion and nitrogen extrusion can occur to form the final N-vinyl amides.T hese investigations contribute useful data to aid the ongoing development of atom-efficient methods for amide formation and offer new possibilities in synthesis for drug discovery and the applications of industrially important N-vinyl amide polymeric materials.Finally,this study suggests that, given recent progress in batch and flow reaction technology, [21] (cautious) reevaluation of azidoethene as auseful synthetic reagent may be warranted.…”

Azidation in the Difunctionalization of Olefins

“…Phukan’s group also achieved the bromoazidation of alkenes by using other bromine sources [85,86]. Moreover, a route to 1,2-azidochlorides from alkenes was developed by Finn and co-workers (Scheme 40b) [87].…”