3.1.12. (3*S*,4*S*)-7-ethynyl-4-methoxy-5,8-bis(methoxymethoxy)-3-pentylisochroman-1-one (**8a**)

To a solution of aldehyde **12a** (5.4 mg, 13.6 μmol) in MeOH (0.14 mL) were added K2CO3 (5.7 mg, 40.9 μmol) and Ohira–Bestmann reagent (3.9 mg, 20.4 μmol) at room temperature. After stirring for 40 min at the same temperature, the mixture was concentrated under reduced pressure. The residue was purified with column chromatography (EtOAc:*n*-hexane = 1:4 to 1:1) to give diMOM alkyne derivative **8a** (6.3 mg, quant) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 7.52 (1H, s), 5.27 (1H, d, *J* = 6.0 Hz), 5.22 (2H, s), 5.17 (1H, d, *J* = 6.0 Hz), 4.59 (1H, d, *J* = 1.3 Hz), 4.27 (1H, ddd, *J* = 1.3, 5.8, 7.4 Hz), 3.65 (3H, s), 3.49 (3H, s), 3.32 (3H, s), 2.05 (1H, m), 1.82 (1H, m), 1.65–1.50 (1H, overlapped), 1.42 (1H, m), 1.40–1.25 (4H, overlapped), 0.91 (3H, t, *J* = 7.1 Hz); 13C-NMR (125 MHz, CDCl3) δ 161.2, 154.6, 149.5, 130.0, 123.5, 120.4, 120.1, 101.0, 95.2, 82.7, 80.7, 79.3, 68.3, 58.1, 57.0, 56.5, 31.6, 30.5, 24.8, 22.5, 14.0.; IR (KBr) 3260, 2954, 2932, 2861, 2830, 1730, 1155, 1012, 931 cm<sup>−</sup>1; HRMS (ESI) *m*/*z* (M + H)<sup>+</sup> calculated for (C21H29O7) <sup>+</sup> 393.1913, found 393.1903.
