We have developed a unified set of conditions for the direct photochemical functionalization of azetidine-2carboxylic acids with alkenes. The reaction has been realized in batch and in flow allowing the rapid preparation of alkyl azetidines in mg-, g-, and even multigram quantities. The obtained products, -sulfonyl fluorides, boropinacolates, potassium, trifluoroborates, P(O)Me2-derivatives, PROTAClinkers, etc -are valuable building blocks for drug discovery.