Martta Asikainen and Norbert Krause
COMMUNICATIONS
added. The reaction mixture was stirred at room tempera-
ture for 48 h, and the conversion was controlled by GC anal-
ysis. The reaction mixture was then extracted 5 times with
Et2O, and the combined organic extracts were washed with
satd. NaCl solution and dried with Na2SO4. After removal
of the solvent under vacuum, the crude product was purified
by flash column chromatography (pentane/Et2O, 30:1).
4-Cyclohexylidenebut-3-en-2-yl acetate (1a): Colorless oil.
Rf =0.65 (cyclohexane/EtOAc, 4:1). 1H NMR (400 MHz,
CDCl3): d=5.35–5.29 (m, 1H), 5.11–5.09 (m, 1H), 2.15–2.09
(m, 4H), 2.04 (s, 3H), 1.62–1.52 (m, 6H), 1.31 (d, J=6.5 Hz,
3H); 13C NMR (400 MHz, CDCl3): d=198.3, 170.6, 105.7,
90.6, 69.4, 31.4, 27.5, 26.2, 21.6, 19.9; IR: n=3055, 2983,
2932, 2891, 2855, 1731, 1447, 1370, 1265, 1245, 1038,
738 cmÀ1; HR-MS: m/z=194.1301, calcd. for C12H18O2 [M+]:
194.1307. (S)-1a (93% ee); [a]D: À117.4 (c 0.45, CH2Cl2).
1-Cyclohexylidenehex-1-en-3-yl acetate (1b): Colorless
m/z=209.1448, calcd. for C13H20O2 [M+]: 208.1463. (S)-1f
(>95% ee); [a]D: À113.2 (c 0.70, CH2Cl2).
7-Methylocta-5,6-dien-4-yl acetate (1g): Colorless oil. Rf =
0.55 (cyclohexane/EtOAc, 4:1). 1H NMR (400 MHz,
CDCl3): d=5.17 (q, J=6.5 Hz, 1H,), 5.00–4–97 (m, 1H),
2.03 (s, 3H), 1.70–1.68 (m, 6H), 1.64–1.53 (m, 2H), 1.42–
1.30 (m, 2H), 0.91 (t, J=7.5 Hz, 3H); 13C NMR (400 MHz,
CDCl3): d=202.0, 170.6, 97.8, 89.4, 72.9, 36.4, 21.5, 20.4,
18.8, 14.0; IR: n=3054, 2962, 2912, 2874, 1728, 1371, 1265,
1248, 738, 704 cmÀ1; HR-MS: m/z=182.1301, calcd. for
C11H18O2 [M+]: 182.1307.
2-Methyltrideca-2, 3-dien-5-yl acetate (1h): Colorless oil.
1H NMR (400 MHz, CDCl3): d=5.18–5.13 (q, J=6.5 Hz,
1H), 5.00–4.97 (m, 1H), 2.04 (s, 3H), 1.70–1.68 (m, 6H),
1.64–1.50 (m, 2H), 1.33–1.26 (m, 12H), 0.89–0.86 (m, 3H);
13C NMR (400 MHz, CDCl3): d=202.0, 170.6, 97.8, 89.5,
77.5, 73.2, 34.3, 32.0, 29.7, 29.5, 25.5, 22.8, 20.4, 14.3; IR: n=
3154, 2928, 2856, 2253, 1971, 1726, 1250, 912, 735, 650 cmÀ1
;
1
oil. Rf =0.66 (cyclohexane/EtOAc, 4:1). H NMR (400 MHz,
HR-MS: m/z=252.2084, calcd. for C16H28O2 [M+]: 252.2089.
(S)-1h (95% ee); [a]D: À76.0 (c 0.65, CH2Cl2).
CDCl3): d=5.21–5.16 (m, 1H), 5.02–5.00 (m, 1H), 2.14–2.11
(m, 4H), 2.04 (s, 3H), 1.65–1.33 (m, 10H), 0.92 (t, J=
8.0 Hz, 3H); 13C NMR (400 MHz, CDCl3): d=198.6, 89.3,
73.0, 36.3, 31.4, 27.5, 26.2, 21.6, 18.8, 14.0; IR: n=2957,
2932, 2855, 1968, 1732, 1371, 1239, 1017, 738 cmÀ1; HR-MS:
m/z=222.1614, calcd. for C14H22O2 [M+]: 222.1620. (S)-1b
(>95% ee); [a]D: À99.6 (c 1.40, CH2Cl2).
2-Methyl-1-oxaspiroACHTUNTRGNENUG[4.5]dec-3-ene (3a): Rf =0.74 (cyclo-
hexane/EtOAc, 4:1). 1H NMR (400 MHz, CDCl3): d=5.87
(dd, J=6.0/2.5 Hz, 1H), 5.70 (d, J=6.0 Hz, 1H), 4.90 (dd,
J=6.5/2.0 Hz, 1H), 1.63–1.73 (m, 2H), 1.53–1.61 (m, 4H),
1.37–1.50 (m, 4H), 1.25 (d, J=6.5 Hz, 3H); 13C NMR
(400 MHz, CDCl3): d=133.4, 130.4, 89.6, 80.5, 39.6, 37.6,
25.6, 23.5; IR: n=2972, 2934, 2858, 2253, 1087 (cyclic ether),
1-Cyclohexyl-3-cyclohexylideneallyl acetate (1c): Color-
less viscous oil. Rf =0.57 (cyclohexane/EtOAc, 4:1).
1H NMR (400 MHz, CDCl3): d=5.00–4.92 (m, 2H), 2.14–
2.08 (m, 4H), 2.05 (s, 3H), 1.78–1.72 (m, 4H), 1.64–1.49 (m,
8H), 1.26–0.99 (m, 5H); 13C NMR (400 MHz, CDCl3): d=
199.0, 170.6, 104.5, 87.6, 41.8, 31.4, 31.3, 28.9, 28.6, 27.4, 26.6,
26.2, 26.1, 26.1; IR: n=2930, 2854, 2253, 1725, 1248, 909,
733 cmÀ1; HR-MS: m/z=262.1927, calcd. for C17H26O2 [M+]:
262.1933.
907, 734, 650 cmÀ1
; HR-MS: m/z=152.1196, calcd. for
C10H16O [M+]: 152.1201. (R)-3a (86% ee); [a]D: À90.4 (c
0.38, CH2Cl2).
2-Propyl-1-oxaspiroACHTUNTRGNENUG[4.5]dec-3-ene (3b): Rf =0.67 (cyclo-
hexane/EtOAc, 4:1). 1H NMR (400 MHz, CDCl3): d=5.09
(dd, J=6.0/2.0 Hz, 1H), 5.72 (dd, J=5.5/1.0 Hz, 1H), 4.81–
4.78 (m, 1H), 1.76–1.64 (m, 4H), 1.60–1.49 (m, 9H), 1.48–
1.37 (m, 1H), 0.93 (t, J=7.3 Hz, 3H); 13C NMR (400 MHz,
CDCl3): d=129.0, 89.2, 84.5, 39.6, 39.1, 37.7, 25.7, 23.8, 18.8,
14.4; IR: n=3053, 2933, 1448, 1265, 1109, 705 cmÀ1; HR-
MS: m/z=180.1509, calcd. for C12H20O [M+]: 180.1514. (R)-
3b (95% ee); [a]D: À100.6 (c 0.74, CH2Cl2).
1-Cyclohexylidene-5-methylhex-1-en-3-yl acetate (1d):
Yellow oil. Rf =0.64 (cyclohexane/EtOAc, 10:1). 1H NMR
(400 MHz, CDCl3): d=5.28–5.23 (m, 1H), 5.02–4.99 (m,
1H), 2.14–2.06 (m, 4H), 2.04 (s, 3H), 1.69–1.42 (m, 9H),
0.91 (dd, J=6.5/3.0 Hz, 6H); 13C NMR (400 MHz, CDCl3):
d=198.6, 170.6, 105.1, 89.4, 71.8, 43.2, 31.4, 31.3, 27.5, 27.4,
26.2, 24.9, 22.8, 22.7, 21.6. IR: n=3054, 2934, 2305, 1726,
1421, 1265, 896, 739, 705 cmÀ1; HR-MS: m/z= 236.1772,
calcd. for C15H24O2 [M+]: 236.1776.
2-Propyl-1-oxaspiroACHTUNTRGNENUG[4.4]non-3-ene (3f): Rf =0.60 (cyclo-
hexane/EtOAc, 4:1). 1H NMR (400 MHz, CDCl3): d=5.70
(s, 2H), 4.77 (t, J=5.8 Hz, 1H), 1.80–1.70 (m, 4H), 1.62–
1.59 (m, 4H), 1.52–1.49 (m, 2H), 1.41–1.33 (m, 2H), 0.92 (t,
J=7.3 Hz, 3H); 13C NMR (400 MHz, CDCl3): d=133.4,
128.8, 84.8, 40.2, 39.2, 38.8, 27.1, 24.8, 24.7, 18.6, 14.5; IR:
n=2959, 2253, 1466, 1383, 912, 742, 650 cmÀ1; HR-MS:
m/z=166.1354, calcd. for C11H18O [M+]: 166.1358. (R)-3f
(88% ee); [a]D: À94.4 (c 0.64, CH2Cl2).
1-Cyclohexylidene-5-phenylpent-1-en-3-yl acetate (1e):
1
Colorless oil. Rf =0.59 (cyclohexane/EtOAc, 4:1). H NMR
(400 MHz, CDCl3): d=7.31–7.18 (m, 5H), 5.23 (q, J=
6.2 Hz, 1H,), 5.09–5.07 (m, 1H), 2.73–2.65 (m, 2H), 2.21–
2.10 (m, 4H), 2.06 (s, 3H), 1.68–1.49 (m, 8H); 13C NMR
(400 MHz, CDCl3): d=198.7, 170.5, 141.6, 128.5, 128.5,
126.0, 105.3, 89.1, 72.5, 35.8, 31.8, 31.4, 31.3, 27.4, 27.0, 26.1,
21.4; IR: n=3027, 2928, 2852, 2253, 1967, 1735, 1448, 1371,
1245, 1020, 911, 738, 650 cmÀ1; HR-MS: m/z=284.1776,
calcd. for C19H24O2 [M+]: 284.1776.
2,2-Dimethyl-5-propyl-2,5-dihydrofuran (3g): Rf =0.59 (cy-
clohexane/EtOAc, 4:1). Due to solvent residues in this very
volatile product, not all NMR peaks could be resolved.
1H NMR (400 MHz, CDCl3): d=5.68 (dd, J=6.0/2.0 Hz,
1H), 5.64 (dd, J=6.0/1.0 Hz, 1H), 1.49 (s, 6H), 1.40–0.95
(m, 4H), 0.92 (t, J=7.6 Hz, 3H); 13C NMR (400 MHz,
CDCl3): d=135.4, 128.4, 87.1, 85.0, 39.4, 29.3, 28.0, 27.1,
1-Cyclopentylidenehex-1-en-3-yl acetate (1f): Colorless
1
26.0, 18.8; IR: n=2977, 2873, 2253, 1110, 907, 732, 650 cmÀ1
HRMS: m/z=140.1195, calcd. for C9H16O [M+]: 140.1201.
;
oil. Rf =0.58 (cyclohexane/EtOAc, 4:1). H NMR (400 MHz,
CDCl3): d=5.19 (q, J=6.5 Hz, 1H), 5.10–5.05 (m, 1H),
2.38–2.31 (m, 4H), 2.03 (s, 3H), 1.70–1.64 (m, 4H), 1.62–
1.51 (m, 2H), 1.38–1.29 (m, 2H), 0.90 (t, J=7.5 Hz, 3H);
13C NMR (400 MHz, CDCl3): d=197.4, 170.6, 106.3, 91.8,
73.0, 36.3, 31.33, 31.25, 27.2, 27.0, 21.5, 18.8, 14.0; IR: n=
2960, 2253, 1727, 1372, 1248, 911, 741, 650 cmÀ1; HR-MS:
2,2-Dimethyl-5-octyl-2,5-dihydrofuran (3h): Rf =0.62 (cy-
clohexane/EtOAc, 4:1). 1H NMR (400 MHz, CDCl3): d=
5.70 (dd, J=6.0/2.5 Hz, 1H), 5.65 (dd, J=6.0/1.5 Hz, 1H),
4.81–4.78 (m, 1H), 1.55–1.49 (m, 2H), 1.32 (s, 6H), 1.29–
1.25 (m, 12H), 0.87 (t, J=8.0 Hz, 3H); 13C NMR (400 MHz,
2308
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2009, 351, 2305 – 2309