Sodium Bicarbonate → 3,5-Dichlorobenzyl 4-(((tert-butoxycarbonyl)amino)methyl)-2-methylpiperidine-1-carboxylate

A mixture comprising tert-butyl((2-methylpiperidin-4-yl)methyl)carbamate (step 2) (1.15 g, 5.04 mmol) and 3,5-dichlorobenzyl carbonochloridate (1.327 g, 5.54 mmol) in DCM (15 ml) was treated with aq. saturated sodium bicarbonate (0.504 ml, 5.04 mmol) and stirred at room temperature for 18 hours. The organic portion was separated and the aqueous phase extracted with DCM (2×10 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. Further purification by chromatography on silica, eluting in 0-20% 2M ammonia in MeOH in DCM afforded the title compound;