1-Acetoxy-9,9-dimethoxynonane (6). A reaction mixture containing 5 (2.97 g, 14.58 mmole), dry pyridine (36 mL),
Ac O (24.5 mL), and a catalytic amount of DMAP (4-dimethylaminopyridine) was stirred at room temperature for 24 h and
2
evaporated in vacuo. The solid was dissolved in t-butylmethyl ether (100 mL), washed successively with cold H SO solution
2
4
(
(
5%) and saturated NaHCO and NaCl solutions until the pH was ~7, dried over Na SO , and evaporated to give acetate 6
3
2
4
3.58 g, 98%).
-1
IR spectrum (KBr, ν, cm ): 1060, 1080, 1130, 1255 (C–O), 1753 (C O). PMR spectrum (CDCl , δ, ppm, J/Hz): 1.21-
3
3
1
4
2
.39 (m, H-3—H-7, 10H), 1.46-1.65 (m, H-2, H-8, 4H), 2.03 (s, CH CO, 3H), 3.30 (s, CH O, 6H), 4.05 (t, J = 6.7, H CO, 2H),
3
3
2
3
13
.34 (t, J = 5.7, HCO, 1H). C NMR spectrum (CDCl ): 20.92 (q, CH CO ), 24.47 (t, C-7), 25.80 (t, C-3), 28.49 (t, C-2),
3
3
2
9.06 (t, C-6), 29.31 (t, C-4, C-5), 32.36 (t, C-8), 52.49 (q, CH O), 64.56 (t, C-9), 104.45 (d, C-1), 171.23 (s, CH CO ).
3
3
2
9-Acetoxynonal (7). A solution of 6 (3.43 g, 13.93 mmole), PPTS (pyridinium tosylate, 1.02 g), and water (4.18 mL)
in acetone (140 mL) was boiled for 9 h and evaporated. The solid was dissolved in Et O (100 mL), washed successively with
2
saturated NaCl, NaHCO , and NaCl solutions, dried over MgSO , and evaporated to give aldehydoester 7 (2.55 g, 91.7%).
3
4
-1
IR spectrum (KBr, ν, cm ): 1040, 1244 (C–O), 1727 (HC O), 1750 (OC O), 2720 (H–CO). PMR spectrum (CDCl ,
δ, ppm, J/Hz): 1.21-1.45 (m, H-4—H-7, 8H), 1.50-1.63 (m, H-3, H-8, 4H), 2.02 (s, CH CO , 3H), 2.40 (td, J = 7.3, J = 1.9,
H-2, 2H), 4.02 (t, J = 6.6, H-9, 2H), 9.74 (s, J = 5.5, H-1, 1H).
,9-Diacetoxynon-1-ene (8). A reaction mixture consisting of 7 (2.86 g, 14.3 mmole), Ac O (3.32 mL, 35.7 mmole),
3
3
3
3
2
3
1
2
and fused AcOK (0.21 g) was boiled for 4 h and evaporated. The solid was treated with Et O (50 mL), washed successively
2
with H O, Na CO (5%), and H O until the pH was ~7, dried over MgSO , and evaporated. The solid was chromatographed
2
2
3
2
4
(
SiO , hexane—CH Cl , 5:2) to give enolacetate 8 (2.19 g, 63.4%).
2 2 2
-1
IR spectrum (KBr, ν, cm ): 765, 920, 950 (C C), 1040, 1070, 1120, 1250, 1270 (C–O), 1645 (C C), 1690, 1760
(
OC O), 3040, 3075 ( C–H). PMR spectrum (CDCl , δ, ppm, J/Hz): 1.20-1.44 (m, H-4—H-7, 8H), 1.51-1.67 (m, H-8, 2H),
3
2
4
5
.01 and 2.05 (both s, Z- and E-CH CO C-9, 3H), 2.09 and 2.11 (both s, Z- and E-CH CO C-1, 3H), 1.95-2.10 (m, H-3, 2H),
.04 (t, J = 6.8, H-9, 2H), 4.86 (dt, J = 6.4, J = 7.4, Z-H-2, 0.5H), 5.37 (dt, J = 7.4, J = 12.5, E-H-2, 0.5H), 6.98 (dt, J =
3
2
3
2
3
3
3
3
3
3
4
4
3
.9, J = 1.4, Z-H-1, 0.5H), 7.05 (dt, J = 1.5, J = 12.5, E-H-1, 0.5H).
13
C NMR spectrum (CDCl ): 20.42 (q, E-CH CO C-1), 20.54 (q, Z-CH CO C-1), 20.70 (q, CH CO C-9), 24.41 (t,
3
3
2
3
2
3
2
Z-C-3), 25.65 (t, C-7), 26.99 (t, E-C-3), 28.40 (t, C-8), 28.81 (t, C-6), 28.92 (t, C-4, C-5), 64.30 (t, C-9), 113.82 (d, E-C-2),
14.62 (d, Z-C-2), 133.92 (d, Z-C-1), 135.32 (d, E-C-1), 167.90 (s, Z-CO C-1), 168.72 (s, E-CO C-1), 170.83 (s, CO C-9).
1
2
2
2
8-Acetoxyoctanal (9). An ozone—oxygen mixture was bubbled through a stirred solution of 8 (1.40 g, 5.79 mmole)
in a 1:1 mixture (12.5 mL) of CH Cl and absolute MeOH in the presence of NaHCO (0.22 g) at -70°C to give one mole O
2
2
3
3
per mole of 8. The reaction mixture was purged with Ar, treated with Me S (1.12 mL, -40°C), stirred at room temperature for
2
3
h, and evaporated in vacuo. The solid was dissolved in water (40 mL) and extracted with Et O (3×50 mL). The extract was
2
washed with saturated NaCl solution, dried over Na SO , and evaporated to give acetoxyaldehyde 9 (0.78 g, 72.4%). IR and
2
4
PMR spectra are practically identical to those previously reported [6].
0-Hydroxy-2E-decenoic Acid (1). A solution of 9 (0.70 g, 3.8 mmole), malonic acid (0.55 g, 5.3 mmole), pyridine
2.71 mL), and Pyp (0.13 mL) was held for 17 h at 22°C, 6 h at 30°C, and 1.5 h at 120°C, cooled to room temperature, treated
1
(
with Et O (20 mL), washed successively with HCl (15%, 10 mL) and saturated NaCl solution (15 mL), and treated with
2
saturated NaHCO solution (22 mL) until the pH was 8-9. The aqueous layer was separated, acidified with conc. HCl until the
3
pH was ~2, and extracted with Et O (3×20 mL). The extract was dried over Na SO and evaporated to give 0.46 g of an oily
2
2
4
product that was dissolved in absolute MeOH (6 mL) and treated with K CO (2.72 g). The reaction mixture was stirred at room
2
3
temperature for one day, acidified with HCl (10%) until the pH was 3, and extracted with Et O (3×20 mL). The extract was
2
washed with saturated NaCl solution, dried over MgSO , and evaporated to give hydroxyacid 1 (0.42 g, 60%), mp 63-65°C
4
(
Et O—hexane, 2:1). IR and PMR spectra are practically identical to those previously reported [7].
2
9-Oxononanoic Acid (10). Compound 4 (8.35 g, 36.0 mmole) was dissolved in absolute EtOH (100 mL), treated with
KOH (6.62 g, 118.2 mmole), boiled for 2 h, cooled to room temperature, treated with HCl (160 mL, 30%), stirred at 50°C for
4
5 min, cooled, and extracted with CHCl (3×100 mL). The combined extracts were dried over MgSO and evaporated to give
3
4
oxoacid 10 (6.08 g, 98%).
-1
IR spectrum (KBr, ν, cm ): 1720 (HC O), 1750 (OC O), 2720 (H–CO), 3500 (O–H). PMR spectrum (CDCl , δ, ppm,
3
J/Hz): 1.15-1.4 (m, H-4—H-6, 6H), 1.50-1.70 (m, H-3, H-7, 4H), 2.25-2.40 (m, H-2, H-8, 4H), 9.70 (s, H-9, 1H), 11.00 (br.s,
COOH, 1H).
9
-Hydroxydecanoic Acid (11). A solution of 10 (6.00 g, 34.9 mmole) in absolute Et O (117 mL) was treated (0°C,
2
147