GENERAL STEPS: The synthesis was modified with reference to the literature [6]. LiAlH4 (1.98 g, 52.0 mmol) was suspended in anhydrous THF (100 mL) under nitrogen protection, stirred and cooled to 0 °C. Subsequently, a THF solution of methyl (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (2.50 g, 13.0 mmol) was added slowly and dropwise. The reaction mixture was stirred continuously for 3 h at 0 °C and the reaction progress was monitored by thin layer chromatography (TLC) with the unfolding agent being petroleum ether: ethyl acetate (70:30, Rf = 0.43). Upon completion of the reaction, saturated sodium sulfate solution (4 mL) and THF (20 mL) were slowly added to quench the excess LiAlH4 at 0 °C. The inorganic solids were removed by filtration, and the filter cake was washed with ethyl acetate (3 × 30 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford (S)-3-hydroxymethyl-1,2,3,4-tetrahydroisoquinoline (4) as a yellow crystalline solid in a yield of 2.09 g (98% yield, melting point 95-97 °C). The specific optical rotation of the product was in agreement with that reported in the literature [6].1H NMR (400 MHz, CDCl3) δ: 2.57 (dd, 1H, J = 10.8, 11.2 Hz), 2.70 (dd, 1H, J = 4.34, 16.42 Hz), 3.05-3.10 (m, 1H), 3.49 (dd, 1H, J = 8.17, 10.82 Hz), 3.78 (dd, 1H, J = 3.98, 10.60 Hz), 4.05 (s, 2H), 7.01-7.15 (m, 4H).13C NMR (100 MHz, CDCl3) δ: 135.6, 133.9, 129.3, 126.3, 126.0, 125.9, 65.8, 55.0 , 47.83, 30.9.
