tert-Butyl 3-((6-chloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-3-yloxy)methyl)pyrrolidine-1-carboxylatet-Butyl 3-((6-chloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-3-yloxy)methyl)pyrroltert-Butyl 3-((6-chloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-3-yloxy)methyl)pyrrolidine-1-carboxylate