A Sustainable 1-Pot, 3-Step Synthesis of Boscalid Using Part per Million Level Pd Catalysis in Water

Boscalid is an active ingredient in several fungicides marketed by the BASF. Literature approaches use multipot processes, organic solvents, and unsustainable levels of palladium catalysis. Herein is disclosed a 1-pot, 3-step route using nanomicelles in water as the reaction medium and a very low loading (700 ppm or 0.07 mol %) of costly and endangered Pd. The sequence developed involves an initial Suzuki–Miyaura cross-coupling, the product from which is not isolated. The second step relies on a carbonyl iron powder (CIP) reduction of the aryl nitro group, followed by the third and final step involving an acylation with the required 2-chloronicotinyl chloride. The overall isolated yield for these three steps is 83%.