Telescoped Flow Synthesis of Azacyclic Scaffolds Exploiting the Chromoselective Photolysis of Vinyl Azides and Azirines.

An efficient chromoselective photochemical process is presented for the synthesis of 2H-azirines and 1,3-diazabicylo[3.1.0]hex-3-enes from readily available vinyl azides. The method exploits continuous flow photochemistry to enable the safe consumption of the hazardous azide group and provides uniform irradiation using high-power LEDs at 365-450 nm. Additionally, a scaled telescoped process has been developed providing access to drug-like 1,6-dihydropyrimidines and pyrimidines via integrated ring-expansion and oxidation reactions. Given the prevalence of various azacyclic targets in pharmaceutical, agrochemical and materials applications it is anticipated that this methodology will enable further exploitations of these important scaffolds.