[3 + 2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions

Abstract

The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal formation of 2H-azirines. Photochemically, the ring of the 2H-azirines was opened to yield the nitrile ylides, which underwent a [3 + 2]-cycloaddition with 1,3-dipolarophiles. When diisopropyl azodicarboxylate serves as the dipolarophile, 1,3,4-triazoles become directly accessible starting from the corresponding vinyl azide.

Keywords

• azirines
• cycloaddition
• flow chemistry
• flow reactors
• inductive heating
• nitrile ylides
• photochemistry
• vinyl azides