PAPER
(5R,7S)-Kurzilactone and Its (5S,7R)-Enantiomer
3303
H, CH2), 3.54–3.34 (m, 2 H, CH2), 2.49–2.32 (m, 2 H, CH2), 1.97–
1.44 (m, 8 H, 4 × CH2).
13C NMR (75 MHz, CDCl3): d = 165.6, 133.2, 130.4, 128.6, 117.8,
98.7, 70.9, 63.6, 61.9, 38.7, 33.5, 30.5, 25.3, 19.3.
HRMS (ESI): m/z [M + Na]+ calcd for C14H22O4Na: 277.1415;
found: 277.1418 (ppm error: +0.7969).
soln was stirred at –78 °C for 1 h. The reaction was quenched by ad-
dition of sat. aq NaHCO3 (3 mL), and the mixture was extracted
with CHCl3 (2 × 20 mL). The combined organic extracts were dried
(Na2SO4; 1 g), filtered, and concentrated. The residue was purified
by column chromatography to give (4R,6S)-9; yield: 0.257 g (92%);
Rf = 0.3 (PE–EtOAc, 3:2); [a]D25 –15.0 (c = 1, CHCl3).
IR (neat): 3478, 1717, 1646, 1609, 1576, 1406, 1273, 1198, 1050
cm–1.
(3S)-1-[2-(Tetrahydro-2 H-2-pyranyloxy)ethyl]-3-butenyl
Acrylate [(3S)-4]
1H NMR (300 MHz, CDCl3): d = 7.60–7.48 (m, 3 H), 7.42–7.33 (m,
3 H), 6.68 (dd, J = 5.2, 16.6 Hz, 1 H), 6.40 (ddd, J = 1.5, 9.0, 17.3
Hz, 1 H), 6.16–6.03 (m, 1 H), 5.86–5.68 (m, 2 H), 5.27–5.03 (m, 3
H), 4.16 (m, 1 H), 3.41 (br s, 1 H, OH), 2.99–2.66 (m, 2 H), 2.52–
2.35 (m, 2 H), 1.97–1.66 (m, 2 H).
Compound (1S)-4 was similarly obtained as a liquid from (3S)-3;
yield: 75%; [a]D25 +15.0 (c 1.0, CHCl3).
(3R)-1-Hydroxyhex-5-en-3-yl Acrylate [(3R)-5]
A catalytic amount of PPTS was added to a stirred soln of ester
(3R)-4 (0.61 g, 2.4 mmol) in MeOH (20 mL) under N2, and the mix-
ture was stirred for 12 h at r.t. The reaction was quenched with solid
NaHCO3 (1 g), and the mixture was filtered. The solvent was re-
moved under reduced pressure and the residue was purified by silica
gel column chromatography to give compound (3R)-5 as a pale yel-
low liquid; yield: 0.37 g (92%); Rf = 0.4 (PE–EtOAc, 7:3); [a]D
–17.0 (c = 1, CHCl3).
IR (neat): 3427, 1721, 1407, 1295, 1197, 1052 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.42 (dd, J = 1.5, 17.3 Hz, 1 H),
6.16–6.05 (m, 1 H), 5.88–5.68 (m, 2 H), 5.20–5.08 (m, 2 H), 5.06
(m, 1 H), 3.67–3.45 (m, 2 H), 2.47 (br s, 1 H, OH), 2.39 (m, 2 H),
1.94–1.82 (m, 1 H), 1.75–1.63 (m, 1 H).
13C NMR (75 MHz, CDCl3): d = 200.0, 166.0, 143.6, 134.1, 133.2,
131.0, 130.7, 130.6, 128.9, 128.3, 126.2, 118.1, 70.7, 64.6, 46.6,
40.5, 38.9.
HRMS (ESI): m/z [M + Na]+ calcd for C19H22O4Na: 337.1415;
found: 337.1405 (ppm error –3.200).
25
(4S,6R,9E)-6-Hydroxy-8-oxo-10-phenyldeca-1,9-dien-4-yl
Acrylate [(4S,6R)-9]
Compound (4S,6R)-9 was similarly obtained as a liquid from (3S)-
6; yield: 85%; [a]D25 +15.8 (c = 1, CHCl3).
(6R)-6-[(2S,5E)-2-Hydroxy-4-oxo-6-phenylhex-5-en-1-yl]-5,6-
dihydro-2H-pyran-2-one [Kurzilactone; (5R,7S)-1]
Grubbs’ first-generation catalyst (0.033 g, 0.0415 mmol) was added
to a soln of (4R,6S)-9 (0.132 g, 0.415 mmol) in anhyd CH2Cl2 (15
ml) at 0 °C, and the mixture was allowed to warm to r.t. over 6 h.
After completion of the reaction (TLC), the solvent was removed
under reduced pressure and the residue was purified by column
chromatography to give (5R,7S)-1 as a solid; yield: 0.114 g (95%);
mp 74–76 °C; Rf = 0.4 (PE–EtOAc, 1:4); [a]D25 +80 (c 0.2, CHCl3).
13C NMR (75 MHz, CDCl3): d = 166.4, 133.1, 131.0, 128.2, 117.8,
70.7, 58.2, 38.7, 36.6.
HRMS (ESI): m/z [M + Na]+ calcd for C9H14O3Na: 193.0840;
found: 193.0849 (ppm error +4.3287).
(3S)-1-Hydroxyhex-5-en-3-yl Acrylate [(3S)-5]
Compound (3S)-5 was similarly obtained as a liquid from (3S)-4;
yield: 92%; [a]D25 +17.0 (c = 1, CHCl3).
IR (neat): 3447, 1712, 1652, 1606, 1386, 1253, 1178, 1051 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.58 (d, J = 16 Hz, 1 H), 7.54–7.39
(m, 5 H), 6.90 (m, 1 H), 6.73 (d, J = 16 Hz, 1 H), 6.00 (dd J = 2, 10
Hz, 1 H), 4.77 (m, 1 H), 4.5 (m, 1 H), 3.52 (br s, 1 H, OH), 2.93 (dd,
J = 2.8, 17.4 Hz, 1 H), 2.81 (dd, J = 8.8, 17.5 Hz, 1 H), 2.39 (m, 2
H), 1.88 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 200.4, 164.2, 145.1, 144.0, 134.1,
130.9, 129.0, 128.5, 126.1, 121.5, 75.0, 64.2, 46.9, 41.7, 30.0.
(3R)-1-Oxohex-5-en-3-yl Acrylate [(3R)-6]
A soln of alcohol (3R)-5 (0.3 g, 1.76 mmol) in anhyd CH2Cl2 (8 mL)
was added to an ice-cooled soln of 2-iodoxybenzoic acid (0.71 g,
1.65 2.64 mmol) in anhyd DMSO (2.0 mL). The mixture was stirred
at r.t. for 12 h then filtered through a pad of Celite that was subse-
quently washed with Et2O (10 mL). The combined organic filtrates
were washed with H2O (2 × 5 mL) and brine (5 mL), dried (Na2SO4;
1 g), and concentrated in vacuo. The residue was purified by column
chromatography to give (3R)-6; yield: 0.281 g (95%); Rf = 0.5 (PE–
EtOAc, 9:1).
HRMS (ESI): m/z [M + Na]+ calcd for C17H18O4Na: 309.1102;
found: 309.1094 (ppm error –2.8435).
(6S)-6-[(2R,5E)-2-Hydroxy-4-oxo-6-phenylhex-5-en-1-yl]-5,6-
dihydro-2H-pyran-2-one [(5S,7R)-1]
IR (neat): 1722, 1407, 1191, 985 cm–1.
1H NMR (300 MHz, CDCl3): d = 9.75 (m, 1 H, CHO), 6.39 (dd,
J = 1.3, 17.3 Hz, 1 H), 6.09 (dd J = 10.3, 17.1 Hz, 1 H), 6.0–5.8 (m,
2 H), 5.25–5.12 (m, 3 H), 3.22 (d, J = 6.9 Hz, 2 H, CH2), 2.83 (t,
J = 6.4 Hz, 2 H, CH2).
13C NMR (75 MHz, CDCl3): d = 205.3, 165.9, 130.9, 129.9, 128.1,
119.2, 59.2, 47.9, 40.8.
Compound (5S,7R)-1 was similarly obtained as a liquid from
(4S,6R)-9; yield: 89%; [a]25D –78 (c 0.2, CHCl3).
Acknowledgment
P.G. thanks CSIR, and C.N.R. thanks UGC, New Delhi, for awards
of fellowships.
+
MS (ESI, 70 eV): m/z 186 [M + NH4 ].
(3S)-1-Oxohex-5-en-3-yl Acrylate [(3S)-6]
Compound (3S)-6 was similarly obtained as a liquid from (3S)-5;
yield: 95%.
References
(1) Fu, X.; Sévenet, T.; Hamid, A.; Hadi, A.; Remy, F.; Païs, M.
Phytochemistry 1993, 33, 1272.
(2) Jiang, B.; Chen, Z. Tetrahedron: Asymmetry 2001, 12,
(4R,6S,9E)-6-Hydroxy-8-oxo-10-phenyldeca-1,9-dien-4-yl
Acrylate [(4R,6S)-9]
2835..
BF3·OEt2 (0.144 mL, 1.16 mmol) was added dropwise to a soln of
the aldehyde (3R)-6 (0.15 g, 0.89 mmol) and silyl enol ether 8 (0.25
g, 1.16 mmol) in anhyd CH2Cl2 (10 mL) at –78 °C, and the resulting
(3) (a) Sabitha, G.; Sudhakar, K.; Reddy, N. M.; Rajkumar, M.;
Yadav, J. S. Tetrahedron Lett. 2005, 46, 6567. (b) Sabitha,
G.; Narjis, F.; Swapna, R.; Yadav, J. S. Synthesis 2006,
Synthesis 2009, No. 19, 3301–3304 © Thieme Stuttgart · New York