[CH3:1][C:2]1([C:7]2[CH:8]=[C:9]([CH:12]=[CH:13][CH:14]=2)[C:10]#[N:11])[O:6][CH2:5][CH2:4][O:3]1.[H-].[Al+3].[Li+].[H-].[H-].[H-].C(OCC)(=O)C.O>C1COCC1>[CH3:1][C:2]1([C:7]2[CH:8]=[C:9]([CH2:10][NH2:11])[CH:12]=[CH:13][CH:14]=2)[O:3][CH2:4][CH2:5][O:6]1A solution of cyano ketal 19 (290 mg, 1.53 mmol) in dry THF (10 mL) was cooled to 0° C. under a nitrogen atmosphere. Then a solution of 2 M lithium aluminum hydride (3 mmol) in THF was added over a 10-min period. The reaction mixture was stirred for 1.5 h and then ethyl acetate was added followed by slow addition of water to decompose the excess LAH. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in chloroform, washed with brine, dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by column chromatography using chloroform and methanol as an eluent to give 20 (176 mg, yield 60%). 1H NMR (CDCl3, 400 MHz) δ 1.66 (s, 3H), 3.79 (t, J=6 Hz, 2H), 3.88 (s, 2H), 4.04 (t, J=6 Hz, 2H), 7.24-7.42 (m, 4H).
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