B. Barnych et al. / Tetrahedron 69 (2013) 334e340
339
Co(II) bis(2,2,6,6-tetramethylheptane-3,5-dienoate) [Co(thd)2]
(1.6 mg, 3.8 mol). The flask was charged with O2 and Et3SiH (7.3 L,
45.8 mol) was added. The reaction mixture was stirred under O2
1.27 (br s, 14H), 1.34 (s, 3H), 1.50e1.76 (br m, 4H), 2.13 (d, J¼12.6 Hz,
1H), 2.59 (t, J¼7.7 Hz, 2H), 2.72 (d, J¼12.6 Hz, 1H), 3.00 (br s, 1H),
3.80 (s, 3H), 4.24 (s, 1H), 7.16e7.29 (m, 5H). 13C NMR (100 MHz,
m
m
m
atmosphere for 4 h, filtered through a pad of silica gel and evapo-
rated. As determined by 1H NMR, the crude mixture was composed
of diene 9 and peroxy ether 24 in a ratio: 1:4, unseparable by
chromatography on silica gel.
CDCl3):
d
¼20.3, 21.8, 24.5, 29.4e29.7 (5C), 30.1, 31.6, 36.1, 39.8, 52.6,
52.8, 74.8, 87.0, 87.2,125.7,128.3 (2C),128.5 (2C),143.0,172.6. HRMS
(ESI): calculated for C24H38NaO5 (MNaþ) 429.2611, found 429.2609.
4.4. General procedure for the preparation of
thionocarbonate esters 28a,b
4.3.10. (1S)-1-((3R)-3,5-Dimethyl-5-(10-phenyldecyl)-1,2-dioxolan-
3-yl)prop-2-en-1-ol (25). The crude TES hydroperoxy ether 24 was
dissolved in dichloromethane (1 mL) and Amberlyst-15
(4.7 mequiv/g, 8.1 mg) was added. After stirring for 2 h at room
temperature, the reaction mixture was filtered and evaporated. The
residue was chromatographed on silica gel (Et2O/petroleum
ether¼1:3) to provide 25 (mixture of 1/1 diastereomers) (7.3 mg,
51%) as a colorless oil. IR (neat): 1722, 2854, 2927, 3026, 3521. 1H
To
dichloromethane (3 mL) was added at 0 ꢁC, O-phenyl thiono-
chloroformate (28 L, 4 equiv) followed by pyridine (21 L,
a solution of alcohols 27a,b (20 mg, 0.050 mmol) in
m
m
5 equiv). After being stirred at room temperature for 5 h, the mix-
ture was diluted with ether, washed with 2 N HCl followed by
water. The combined organic extracts were dried with Na2SO4 and
evaporated. Flash chromatography (Et2O/petroleum ether¼1:10) of
the residue afforded desired thionocarbonate esters 28a,b as
a mixture of epimers.
NMR (400 MHz, CDCl3):
d
¼1.26e1.43 (br m, 20H), 1.57 (br m, 4H),
2.00 (d, J¼12.2 Hz, 0.5H), 2.12 (d, J¼12.3 Hz, 0.5H), 2.32 (d,
J¼12.3 Hz, 0.5H), 2.38 (d, J¼12.2 Hz, 0.5H), 2.53 (d, J¼2.7 Hz, 0.5H),
2.54 (d, J¼2.7 Hz, 0.5H), 2.60 (t, J¼6 Hz, 2H), 4.19 (m, 1H), 5.27 (d,
J¼10.5 Hz, 1H), 5.39 (dd, J¼17.2, 1.5 Hz, 0.5H), 5.40 (dd, J¼17.2,
1.5 Hz, 0.5H), 5.81 (m, 1H), 7.17e7.29 (m, 5H). 13C NMR (100 MHz,
4.4.1. Methyl-2-((3R,5S)-3,5-dimethyl-5-(10-phenyldecyl)-1,2-
dioxolan-3-yl)-2-((phenoxycarbonothioxyl)oxy)acetate
(28a). Obtained as a colorless oil (94% yield). IR (neat): 2924, 2862,
CDCl3):
d
¼18.2, 22.4, 24.6, 25.2, 25.2, 29.5e29.7 (6C), 31.7, 36.1, 38.3,
39.9, 52.8, 53.2, 76.3, 76.4, 87.0, 87.3, 87.9, 88.2, 118.3, 125.7, 128.4
(2C), 128.5 (2C), 135.2, 135.3, 143.1. HRMS (ESI): calculated for
C24H38NaO3 (MNaþ) 397.2713, found 397.2707.
1749. 1H NMR (400 MHz, CDCl3):
d
¼1.20e1.38 (m, 12H), 1.31 (s, 3H),
1.48 (s, 2.1H), 1.49 (s, 0.9H), 1.52e1.67 (m, 3H), 1.69e1.82 (m, 1H),
2.19 (d, J¼12.8 Hz, 1H), 2.61 (t, J¼7.7 Hz, 2H), 2.86 (d, J¼12.9 Hz,
0.3H), 2.91 (d, J¼12.9 Hz, 0.7H), 3.82 (s, 3H), 5.1 (s, 0.3H), 5.47 (s,
0.7H), 7.12e7.23 (m, 2H), 7.23e7.31 (m, 3H), 7.31e7.47 (m, 2H). 13C
4.3.11. (2R,3R)-Methyl
3-methyl-3-(2-methyl-12-phenyl-2-((tri-
ethylsilyl)peroxy)dodecyl) oxirane-2-carboxylate (26). To a solution
of the epoxy ester 23 (118 mg, 0.32 mmol) in dichloroethane (3 mL)
NMR (100 MHz, CDCl3):
d
¼20.7 (0.3C), 21.1 (0.7C), 21.7, 24.4,
29.0e30.1 (8C), 31.6, 36.1, 39.7, 52.4, 52.9, 82.8, 85.47 (0.3C), 85.57
(0.7C), 87, 121.1e129.7 (8C), 143.0, 153.5, 167.9, 194.2. HRMS (ESI):
calculated for C31H42NaO6S (MNaþ) 565.2594, found 565.2605.
was added Co(thd)2 (13.5 mg, 32
mmol) and the flask was charged
with O2. Et3SiH (101 L, 0.63 mmol) was added and the reaction
m
mixture was stirred for 2 h under O2 atmosphere. Evaporation of
the reaction mixture and chromatography of the residue on silica
gel (Et2O/petroleum ether¼1:10) afforded 26 (mixture of 1/1 di-
astereomers) (142 mg, 86%) as a colorless oil. IR (neat): 1737, 1756,
4.4.2. Methyl-2-((3R,5R)-3,5-dimethyl-5-(10-phenyldecyl)-1,2-
dioxolan-3-yl)-2-((phenoxycarbonothioxyl)oxy)acetate
(28b). Obtained as a colorless oil (83% yield). IR (neat): 2922, 2865,
2854, 2926, 3026. 1H NMR (300 MHz, CDCl3):
d¼0.67 (q, J¼7.8 Hz,
1747. 1H NMR (400 MHz, CDCl3):
d
¼1.2e1.42 (m, 11H), 1.38 (s, 3H),
6H), 0.98 (t, J¼7.8 Hz, 9H), 1.07 (s, 1.5H), 1.26 (m, 15.5H), 1.51 (s,
1.5H), 1.52 (s, 1.5H), 1.61 (m, 4H), 1.98 (s, 1H), 2.00 (s, 1H), 2.59 (t,
J¼7.5 Hz, 2H), 3.24 (s, 0.5H), 3.27 (s, 0.5H), 3.76 (s, 3H), 7.16e7.29
1.5 (s, 3H), 1.53e1.65 (5H), 2.07 (d, J¼12.8 Hz, 1H), 2.59 (t, J¼7.8 Hz,
2H), 2. 92 (d, J¼12.8 Hz, 0.15H), 2.96 (d, J¼12.8 Hz, 0.85H), 3.81 (s,
3H), 5.07 (s, 0.15H), 5.44 (s, 0.85H), 7.11e7.23 (m, 5H), 7.23e7.33 (m,
(m, 5H). 13C NMR (75 MHz, CDCl3):
d
¼3.9, 6.9, 21.7, 22.2, 23.4, 23.5,
3H), 7.36e7.47 (m, 2H). 13C NMR (100 MHz, CDCl3):
d¼21.1, 24.9,
23.8, 29.5e29.7 (6C), 30.28, 30.30, 31.7, 36.1, 37.2, 37.7, 38.1, 38.5,
52.26, 52.27, 59.6, 59.7, 61.9, 62.1, 84.1, 84.3, 125.63, 125.65, 128.3
(2C), 128.5 (2C), 143.02, 143.05, 169, 169.3. HRMS (ESI): calculated
for C30H52NaO5Si (MNaþ) 543.3476, found 543.3492.
25.5, 29.4e30.2 (8C), 31.6, 36.1, 37.8, 52.2, 52.9, 82.9, 85.4, 87.3,
121.9e129.6 (8C), 143.1, 153.6, 167.9, 194.3. HRMS (ESI): calculated
for C31H42NaO6S (MNaþ) 565.2594, found 565.2584.
4.5. General procedure for the deoxygenation of 28a,b
4.3.12. (R)-Methyl
2-((3R,5R,S)-3,5-dimethyl-5-(10-phenyldecyl)-
1,2-dioxolan-3-yl)-2-hydroxyacetate (27a,b). To an ice-cooled solu-
tion of the peroxy 26 (140 mg, 0.269 mmol) in MeOH (5 mL) was
To a solution of 28a,b (20 mg, 0.037 mmol) in toluene (3 mL) was
added HSnBu3 (30 mL, 3 equiv) and AIBN (6 mg, 1 equiv). The solu-
added K2CO3 (11 mg, 80.7
m
mol). The reaction mixture was stirred
tion was stirred at 80 ꢁC for 1 h and evaporated. Flash chromatog-
at 0 ꢁC for 5 h, water (10 mL) was added and the resulting mixture
was extracted with Et2O (5ꢂ5 mL). The combined organic extracts
were dried (Na2SO4) and evaporated. The crude mixture was pu-
rified by preparative TLC (Et2O/petroleum ether¼1:2, two elutions)
to give first the cis-isomer (5R) 27b (40 mg, 36%) as a colorless oil.
raphy (Et2O/petroleum ether¼1:9) of the residue afforded 29a,b.
4.5.1. Methyl 2-((3R,5S)-3,5-dimethyl-5-(10-phenyldecyl)-1,2-
dioxolan-3-yl) acetate (29a). Obtained as a colorless oil (50%
20
yield). [
a]
þ30.1 (c 0.5, CHCl3). IR (neat): 2926, 2854, 1736. 1H
D
[
a]
20 þ51.3 (c 1.65, CHCl3). IR (neat): 1733, 1738, 2854, 2927, 3498.
NMR (400 MHz, CDCl3):
d
¼1.2e1.38 (m, 12H), 1.28 (s, 3H), 1.43 (s,
D
1H NMR (400 MHz, CDCl3):
d
¼1.26 (m,14H),1.34 (s, 3H),1.37 (s, 3H),
3H), 1.48e1.75 (m, 6H), 2.23 (d, J¼12.4 Hz, 1H), 2.47 (d, J¼12.4 Hz,
1H), 2.6 (t, J¼7.9 Hz, 2H), 2.65 (d, J¼14.5 Hz, 1H), 2.77 (d, J¼14.5 Hz,
1H), 3.69 (s, 3H), 7.14e7.22 (m, 2H), 7.23e7.31 (m, 3H). 13C NMR
1.55 (br m, 4H), 2.03 (d, J¼12.3 Hz, 1H), 2.59 (t, J¼7.5 Hz, 2H), 2.78
(d, J¼12.3 Hz, 1H), 3.01 (d, J¼5.7 Hz, 1H), 3.79 (s, 3H), 4.23 (d,
J¼5.7 Hz, 1H), 7.16e7.29 (m, 5H). 13C NMR (101 MHz, CDCl3):
(100 MHz, CDCl3):
d
¼23.2, 24.1, 24.5, 29.3, 29.47, 29.53 (3C), 29.9,
d
¼20.2, 24.8, 25.2, 29.4e29.6 (5C), 30.2, 31.6, 36.1, 37.9, 52.4, 52.7,
31.5, 36.0, 39.6, 44.0, 51.7, 55.3, 83.9, 86.5, 125.5, 128.2 (2C), 128.4
(2C), 143.0, 171.1. HRMS (ESI): calculated for C24H38NaO4 (MNaþ)
413.2662, found 413.2662.
74.7, 86.9, 87.3, 125.7, 128.3 (2C), 128.5 (2C), 143.0, 172.5. HRMS
(ESI): calculated for C24H38NaO5 (MNaþ) 429.2611, found 429.2623.
The next fraction was constituted by the trans-isomer 27a (42 mg,
39%) obtained as a colorless oil. [
a
]
20 þ46.8 (c 2.3, CHCl3). IR (neat):
4.5.2. Methyl 2-((3R,5R)-3,5-dimethyl-5-(10-phenyldecyl)-1,2-
dioxolan-3-yl)acetate (29b). Obtained as a colorless oil (53%
D
1736, 2854, 2926, 3498. 1H NMR (400 MHz, CDCl3):
d¼1.25 (s, 3H),