Synthesis of Decanolide, Massoialactone, and Verbalactone
3135
column chromatography (pet. ether–EtOAc 9:1) to afford 8 as a colorless
liquid (9.0 g, 90%). [d]D25: ꢀ3.4 (c 0.5, CHCl3); 1H NMR (CDCl3,
300 MHz): d 0.87 (t, J ¼ 7.5 Hz, 3H), 1.04 (bs, 9H), 1.08–1.63 (m, 10H),
1.73 (t, J ¼ 6.7 Hz, 2H), 3.27–3.45 (m, 2H), 3.63–3.77 (m, 2H), 3.78–3.93
(m, 1H), 4.40 (m, 1H), 7.28–7.41 (m, 6H), 7.65 (dd, J ¼ 7.5, 1.5 Hz, 4H);
13C NMR (75 MHz, CDCl3): d 134.7, 134.5, 129.4, 127.3, 98.6, 71.1, 64.2,
62.1, 36.7, 36.3, 31.8, 30.7, 27.0, 25.5, 24.4, 24.3, 22.5, 19.5, 13.9; IR
(neat): 2933, 2859, 1589, 1466, 1427, 1381, 1200, 1111, 1073, 1032,
704 cmꢀ1; LCMS: m=z 491 (Mþ þ Na); HRMS (ESI): m=z calcd. for
C29H44O3 Si Na (Mþ þ Na): 491.2957; found: 491.2937.
(3R)-3-[1-(tert-Butyl)-1, 1-diphenylsilyl]oxyoctan-1-ol (9)
To a stirred solution of compound 8 (7.0 g, 14.9 mmol) in methanol
(35 mL), a catalytic amount of pyridine p-toluenesulfonate (PPTS)
(0.8 g) was added. The reaction mixture was stirred at room temperature
for about 2 h, and methanol was removed under reduced pressure. The
crude residue was purified by silica-gel column chromatography to afford
9 (4.9 g, 86%) as a viscous liquid. [a]D25: ꢀ19.2 (c1.95, CHCl3); 1H NMR
(CDCl3, 300 MHz): d 0.80 (t, J ¼ 7.5 Hz, 3H), 0.98–1.20 (m, 16H), 1.25–
1.68 (m, 3H), 1.73–1.86 (m, 2H), 3.55–3.67 (m, 2H), 3.68–3.80 (bs, 1H),
3.90 (q, J ¼ 6.7 Hz, 1H), 7.30–7.44 (m, 6H), 7.63–7.70 (m, 4H);
13C NMR (75 MHz, CDCl3): d 135.9, 134.8, 129.7, 127.5, 72.4, 59.8,
37.6, 36.2, 31.6, 27.0, 24.7, 22.4, 19.2, 13.9; IR (neat): 3381, 3069, 2930,
2857, 1587, 1466, 1427, 1382, 1108, 1051, 737, 702 cmꢀ1; LCMS: m=z
407 (Mþ þ Na); HRMS (ESI): m=z calcd. for C24H36O2Si Na (Mþ þ Na):
407.2382; found: 407.2362.
(8R)-8-[1-(tert-butyl)-1, 1-diphenylsilyl]oxytridecane-4, 6-dione (11)
To an ice-cooled solution of 2-iodoxybenzoic acid (5.1 g, 18.2 mmol) in
DMSO (6 mL, mmol), a solution of alcohol 9 (3.5 g, 9.1 mmol) in anhyd.
CH2Cl2 (20 mL) was added. The mixture was stirred at room temperature
for 3 h and then filtered through a Celite1 pad and washed with Et2O
(3 ꢂ 60 ml). The combined organic filtrates were washed with H2O
(2 ꢂ 20 ml) and brine (20 ml), dried (anhyd. Na2SO4), and concentrated
under vacuum at temperatures colder than 45 ꢁC. The crude product was
purified by column chromatography to afford aldehyde 10 as an unstable
viscous liquid (2.8 g, 80%), which was directly used for the next stage.
CH2Cl2 (10 mL) followed by ethyl diazoacetate (0.6 ml, 4.7 mmol)
were added with stirring at room temperature to anhydrous tin(II) chlor-
ide (0.075 g, 0.39 mmol). A few drops of compound 10 (1.5g, 3.9 mmol) in