Continuous‐Flow Synthesis of β‐Ketoesters and Successive Reactions in One‐Flow using Heterogeneous Catalysis

Abstract A continuous‐flow procedure for the synthesis of β‐ketoesters has been developed through Roskamp reaction between aldehydes and diazoesters in the presence of a Sn‐MCM‐41 catalyst. The viability of this methodology was confirmed with a range of aromatic and aliphatic aldehydes with diazoesters and provided good to excellent yields. Catalyst activity was tested over three days (84 hours) of operation, and the yield of the desired β‐ketoester was maintained between 73 to 89%. The prepared β‐ketoesters were smoothly transformed into coumarin derivatives and 5‐pyrazolone through condensation reactions in a sequential flow. magnified image