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

Abstract

SummaryThe 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.

Batch versus Flow Photochemistry: A Revealing Comparison of Yield and Productivity

“…The FEP reactor concept has now been used and adapted for a number of reactions, resulting in the synthesis of a wide range of complex, photochemically derived products. [19][20][21][22][23][24][25][26][27][28] Perhaps the most striking of these has been the use of an FEP flow reactor in the scaled-up continuous synthesis of the frontline anti-malarial drug artemisinin described by Seeberger and co-workers. [29,30] Many groups have now reported the advantages of flow photochemistry over previously reported batch results.…”

Photochemical Transformations with Iodine Azide after Release from an Ion‐Exchange Resin

“…Chemically, the haloate(I) anions in 3 a – d behave like Br‐OAc, I‐OAc, I‐OTfa, and I‐N 3 . It can be assumed that these species are liberated from 3 a – d prior to the reaction with different nucleophiles …”

Managing Hazardous Reactions and Compounds in Process Chemistry

“…The approach can be modified to prepare triazoles and tetrazoles. The intermediate azirine can also be isolated (82).…”