C(O)(C)(C)C.N.C([O:14][CH2:15][CH2:16][CH2:17][CH2:18][C:19]1([CH3:30])[CH2:25][CH2:24][CH2:23][C:22]2([O:29][CH2:28][CH2:27][O:26]2)[CH2:21][O:20]1)C1C=CC=CC=1.[Na]>O1CCCC1>[CH2:28]1[CH2:27][O:26][C:22]2([CH2:21][O:20][C:19]([CH2:18][CH2:17][CH2:16][CH2:15][OH:14])([CH3:30])[CH2:25][CH2:24][CH2:23]2)[O:29]1
t-Butyl alcohol (8.88 g, 0.12 mol) is added to freshly distilled ammonia (360 ml) cooled to 78° C. in an argon atmosphere. The cooling bath is removed and 2-(4'-benzyloxybutyl)-6,6-ethylenedioxy-2-methyloxepane (6.7 g, 0.02 mol) in tetrahydrofuran (90 ml) is added. Freshly cut sodium metal (1.0 g, 0.04 mol) is added in small pieces and the resulting blue solution is stirred for 30 minutes. The reaction is quenched by adding ether (350 ml) followed by water (5 ml). The ammonia is evaporated at room temperature and the ether phase is washed with satd. NaCl (300 ml). The aqueous phase is extracted with ether (5×100 ml). The ether phases are combined, dried (MgSO4) and the solvents are removed under reduced pressure to give 6,6-ethylenedioxy-2-(4'-hydroxybutyl)-2-methyloxepane (13) (4.88 g, 99%): nmr (CDCl3) δ1.18 (s, 3H, CH3), 1.30 (s, 1H, OH), 3.42 (s, 2H, --O--CH2), 3.60 (m, 2H, HO--CH2 --CH2) 3.98 (s, 4H, ketal).
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