A solution of 3.06 g (10.0 mmol) of Aldehyde 1, 1.06 g (10.5 mmol) of 3-azetidine carboxylic acid and 5 mL of acetic acid in 150 mL of methanol was stirred for 20 min at rt. A solution of sodium cyanoborohydride (380 mg, 5.0 mmol) in 20 mL of methanol was added. The reaction mixture was stirred for 1 h then was filtered. The solids were washed with 30 ml of methanol and dried to afford 2.88 g (74%) of the title compound: 1H NMR (400 Mhz, CD3OD) δ 0.95 (d, J=6.6, 6H), 1.96 (m, 1H), 2.62 (d, J=7.3, 2H), 3.42 (m, 1H), 4.19 (m, 4H), 4.41 (s, 2H), 7.43 (d, J=8.0, 2H), 7.64 (d, J=8.2, 2H), 8.14 (d, J=8.0, 2H), 8.23 (d, J=8.2, 2H); ESI-MS 392 (M+H); LC-1: 3.0 min.
