tert-Butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3,6,7-tetrahydro-1H-azepine-1-carboxylate is a reagent used in the preparation of heteroarylcarboxamides and arylcarboxamides as inhibitors of WDR5 protein-protein binding.