A sustainable and chemoselective continuous flow hydrogenation of functionalized 2-azetines to azetidines

The synthesis of functionalized azetidines from azetines is poorly explored. Here, we report the safe and sustainable continuous flow hydrogenation of 2-azetines using ethyl acetate and CPME as environmentally responsible solvents. The chemoselective saturation of the endocyclic double bond of 2-azetines bearing additional functional groups sensitive to hydrogenation has been additionally disclosed. Moreover, the protocol has been successfully combined with the continuous flow preparation of the substrates, accessing to a bio-relevant azetidine through a telescoped multistep approach.