Salt Formation: To a 5 L flask equipped with an internal temperature probe, a heating mantle and a mechanical stirrer were added tert-butyl 3-(isoquinolin-5-ylamino)pyrrolidine-1-carboxylate (250 g, 0.798 mol, from Example 1) and 3 L of 2-propanol. The mixture was stirred and warmed to 42° C. to form a homogeneous solution. To the stirred solution was added dibenzoyl-D-tartaric acid (D-DBTA) (242.9 g, 0.678 mol) in one portion and another 0.9 L of 2-propanol. The mixture was stirred at 40° C. for 15 minutes to form a solution. The mixture was stirred at 40° C. to form a yellow slurry. The slurry was cooled to 30° C. The suspension was filtered, washed with 2×250 mL of 2-propanol and dried in a vacuum oven at ˜35° C. Approximately 204.3 g of (R)-tert-butyl 3-(isoquinolin-5-ylamino)pyrrolidine-1-carboxylate dibenzoyl-D-tartaric acid salt crude product was obtained as a yellow solid (84% ee, 38% yield).
