To a solution of N-(7-hydroxyisoquinolin-3-yl)cyclopropanecarboxamide (68.7 mg, 0.301 mmol) in tetrahydrofuran (3.0 mL, 37 mmol) was added ethyl L-(−)-lactate (44 uL, 0.39 mmol) and triphenylphosphine (108.4 mg, 0.4133 mmol), followed by dropwise addition of diethyl azodicarboxylate (62 uL, 0.39 mmol). The resulting mixture was stirred at room temperature for 1 hour, and then ethyl L-(−)-lactate (13 uL, 0.11 mmol) and diethyl azodicarboxylate (19 uL, 0.12 mmol) were added. After an additional 2.5 hours, the reaction mixture was poured into ethyl acetate, washed with water and brine, dried over MgSO4, filtered, and evaporated in vacuo. The crude material was purified via flash chromatography on silica gel (12 g silica, solvent gradient: 0-80% ethyl acetate in heptanes) to provide a quantitative yield of (R)-methyl 2-(3-(cyclopropanecarboxamido)isoquinolin-7-yloxy)propanoate. LCMS (ESI): M+H=329.2.
