Magnetite: a Green, Sustainable and Recyclable Catalyst for Direct Synthesis of Thioesters by C‐H Activation

A green and sustainable approach to the direct synthesis of thioesters has been developed using Fe3O4 as a low‐cost, easily prepared, reusable and environmentally safe catalyst. The cross dehydrogenative coupling (CDC) of various thiols and aldehydes in water, or even in the absence of solvent, using tert‐butylhydroperoxide as oxidant, under ligand and base‐free mild conditions, afforded the corresponding thioesters in good to excellent yields. This simple protocol features broad substrate scope, good compatibility with different functional groups, as well as high atom‐efficiency. The scalability, ease of (magnetic) recovery and reuse of the magnetite catalyst are additional eco‐friendly attributes of this methodology. Moreover, the broad synthetic applications of thioesters further highlight the potential utility of the present protocol.