General Procedure for the Synthesis of Boc-Protected Piperidines (General Procedure A)

To a solution of tert-butyl 4-methylenepiperidine-1-carboxylate (1 equiv) in THF (10 mL) was added a 0.5 M solution of 9-BBN in THF (1.05 equiv). After stirring an hour, the solution was added to a preprepared solution of the corresponding bromines (1.2 equiv), potassium carbonate (1 equiv), and Pd(dppf)Cl₂ complexed with dichloromethane (0.05 equiv) in a 5:1 solution of DMF/H₂O (50 mL). The solution was heated to 60 °C and allowed to stir overnight. The reaction was quenched by the addition of 1 M NaOH, extracted with EtOAc, and dried over NaSO₄. The product was run on a column of hexane/EtOAc with a gradient from 8:2 to 6:4, yielding the product.