A. S. ElDouhaibi et al. / Tetrahedron 62 (2006) 11460–11469
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4.3.2. (E)-2-Benzylidene-3-tert-butyl-cyclohex-3-enol
(2b). Following the general procedure in Section 4.3,
compound 1b (72 mg, 0.23 mmol), Ni(COD)2 (8.3 mg
0.03 mmol) tributylphosphine (0.016 mL, 0.06 mmol), and
triethylborane (0.6 mL, 0.6 mmol in 1.0 M solution) were
employed to produce, after column chromatography (10:1
hexane/ethyl acetate), 38 mg (52%) of a light yellow oil.
1H NMR (500 MHz, CDCl3) d 7.23–7.28 (m, 4H), 7.16–
7.19 (m, 1H), 6.51 (s, 1H), 5.97 (t, J¼5.0 Hz, 1H), 4.42
(br s, 1H), 2.25–2.31 (m, 1H), 2.15–2.22 (m, 1H), 2.04–
2.12 (m, 1H), 1.69 (br s, 1H), 1.53–1.61 (m, 1H), 0.91 (s,
9H); 13C NMR (125 MHz, CDCl3) d 148.9, 142.5, 139.8,
129.2, 128.2, 127.1, 126.6, 122.6, 74.8, 35.9, 32.9, 31.7,
22.5; IR (film, cmꢁ1) 3364, 3024, 2958, 2866, 1297, 1492,
1476, 1446, 1392, 1364, 1249, 927, 738, 697; HRMS (EI)
m/e calcd for C17H22O 242.1671, found 242.1670 (M+).
4.3.5. (E)-2-Benzylidene-5-methyl-3-phenyl-cyclohex-3-
enol (2e). Following the general procedure in Section
4.3, compound 1e (78 mg, 0.28 mmol), Ni(COD)2
(8.0 mg, 0.028 mmol) tributylphosphine (0.015 mL,
0.05 mmol), and triethylborane (0.57 mL, 0.57 mmol in
1.0 M solution) were employed to produce, after column
chromatography (8:1 hexane/ethyl acetate), two separable
diastereomers (1.4:1) (49 mg, 63% yield). Major isomer
(light yellow thick gum): 1H NMR (500 MHz, CDCl3)
d 7.04–7.06 (m, 2H), 6.83–6.95 (m, 9H), 5.86 (d,
J¼3.5 Hz, 1H), 4.57 (dd, J¼10.5, 2.5 Hz, 1H), 2.73–2.81
(m, 1H), 2.35–2.40 (ddd, J¼11.0, 6.8, 4.5 Hz, 1H), 1.86
(br s, 1H), 1.58 (ddd, J¼13.0, 11.0, 9.5 Hz, 1H), 1.23 (d,
J¼7.5 Hz, 3H); 13C NMR (125 MHz, CDCl3) d 140.4,
139.3, 138.6, 137.4, 136.7, 129.5, 127.67, 127.65, 127.1,
126.4, 126.1, 123.0, 72.3, 41.8, 31.9, 22.4; IR (film, cmꢁ1
)
3328, 3078, 3055, 3021, 2955, 2925, 2867, 1599, 1575,
1491, 1444, 1347, 1322, 1264, 1196, 1125, 1078, 1028,
758, 734, 696; HRMS (EI) m/e calcd for C20H20O
276.1514, found 276.1516 (M+). Minor isomer (light yellow
4.3.3. (E)-2-Benzylidene-3-benzyloxymethyl-cyclohex-3-
enol (2c). Following the general procedure in Section 4.3,
compound 1c (105 mg, 0.345 mmol), Ni(COD)2 (4.2 mg,
0.035 mmol) tributylphosphine (0.018 mL, 0.069 mmol),
and triethylborane (0.69 mL, 0.69 mmol in 1 M solution)
were employed to produce, after column chromatography
(2:1 hexane/ethyl acetate), 48 mg (45%) of a light yellow
oil. 1H NMR (500 MHz, CDCl3) d 7.21–7.29 (m, 8H),
7.15–7.16 (m, 2H), 6.66 (s, 1H), 6.05 (m, 1H), 4.41 (m,
1H), 4.08 (s, 2H), 3.66–3.72 (m, 2H), 2.46–2.50 (m, 1H),
2.34–2.4 (m, 1H), 2.07 (m, 1H), 1.93–2.05 (m, 2H); 13C
NMR (125 MHz, CDCl3) d 138.8, 138.7, 138.5, 132.3,
131.7, 129.2, 128.4, 128.1, 127.9, 127.6, 127.1, 124.4,
72.4, 71.3, 31.0, 23.4; IR (film, cmꢁ1) 3398, 3056, 3026,
2923, 2862, 1596, 1492, 1453, 1360, 1259, 1208, 1118,
1070, 1028, 920, 844, 803, 734, 697; HRMS (EI) m/e calcd
for C21H22O2 306.1620, found 306.1619 (M+).
1
oil): H NMR (500 MHz, CDCl3) d 7.04–7.06 (m, 2H),
6.87–6.95 (m, 8H), 6.72 (s, 1H), 5.93 (d, J¼3.0 Hz, 1H),
4.62 (br d, J¼4.0 Hz, 1H), 2.79–2.87 (m, 1H), 2.24 (dt,
J¼13.5, 6.5 Hz, 1H), 1.93 (br s, 1H), 1.74 (ddd, J¼13.5,
8.5, 2.5 Hz, 1H), 1.24 (d, J¼7.0 Hz, 3H); 13C NMR
(125 MHz, CDCl3) d 140.8, 139.3, 138.1, 137.0, 135.6,
129.5, 127.7, 127.65, 127.1, 126.5, 126.4, 126.3, 73.5,
39.6, 29.1, 21.8; IR (film, cmꢁ1) 3336, 3078, 3056, 3021,
2955, 2925, 2868, 1599, 1492, 1444, 1373, 126, 1203,
1128, 1076, 1030, 989, 958, 917, 863, 760, 740, 696;
HRMS (EI) m/e calcd for C20H20O 276.1514, found
276.1517 (M+).
4.3.6. (E)-2-Benzylidene-3-hexyl-1,2,4a,5,6,7,8,8a-octa-
hydronaphthalen-1-ol (2f). Following the general proce-
dure in Section 4.3, compound 1f (80 mg, 0.25 mmol),
Ni(COD)2 (14 mg, 0.0496 mmol) tributylphosphine
(0.026 mL, 0.099 mmol), and triethylborane (0.50 mL,
0.50 mmol in 1.0 M solution) were employed to produce, af-
ter column chromatography (25:1 hexane/ethyl acetate),
146 mg (75%) of partially separable diastereomers of light
4.3.4. (E)-2-Benzylidene-3,4-diethyl-6-methyl-cyclohex-
3-enol (2d). Following the general procedure in Section
4.3, compound 1d (412 mg, 1.62 mmol), Ni(COD)2
(45 mg,
0.16 mmol)
tributylphosphine
(0.085 mL,
0.32 mmol), and triethylborane (3.24 mL, 3.24 mmol in
1 M solution) were employed to produce, after column chro-
matography (25:1 hexane/ethyl acetate), 326 mg (79%) of
two separable diastereomers (2:1) of a light yellow oil.
1
yellow oil. H NMR (500 MHz, CDCl3) for mixture of all
diastereomers d 7.29–7.17 (m, 5H), 6.75, 6.67, 6.54 (s, 1H
each isomer), 5.50, 5.40, 5.33 (s, 1H), 4.37, 4.08, 4.02 (s,
s, d, J¼9.5 Hz, 1H), 2.717 (s, 1H), 0.76–2.14 (m, 23H);
13C NMR (125 MHz, CDCl3) for mixture of all isomers
d 141.1, 139.5, 138.5, 136.1, 134.7, 133.4, 129.04, 129.0,
127.6, 126.4, 126.3, 121.8, 121.0, 75.4, 75.3, 49.8, 43.2,
42.4, 37.3, 34.4, 34.3, 32.5, 31.5, 31.47, 29.2, 29.0, 28.7,
28.5, 26.4, 26.1, 24.7, 22.6, 22.5, 21.1, 14.1; IR (film,
cmꢁ1) 3354, 3019, 2923, 2853, 1491, 1446, 1377, 1018,
846, 698; HRMS (EI) m/e calcd for C23H32O 324.2453,
found 324.2455 (M+).
1
Major isomer: H NMR (500 MHz, CDCl3) d 7.25–7.28
(m, 2H), 7.17–7.22 (m, 3H), 6.41 (s, 1H), 4.09 (d,
J¼4.5 Hz, 1H), 2.36 (dd, J¼19.0, 6.8 Hz, 1H), 2.16–2.24
(m, 1H), 2.08–2.14 (m, 2H), 2.00–2.08 (m, 1H), 1.85–1.97
(m, 2H), 1.44 (d, J¼6.5 Hz, 1H), 1.04–1.07 (m, 6H), 0.70
(t, J¼7.5 Hz, 3H); 13C NMR (125 MHz, CDCl3) d 141.7,
140.3, 138.9, 130.2, 129.3, 128.0, 126.7, 123.1, 77.9, 35.3,
34.9, 26.2, 22.1, 17.7, 14.5, 13.5; IR (film, cmꢁ1) 3336,
2960, 2929, 2872, 1598, 1490, 1456, 749, 698; HRMS
(EI) m/e calcd for C18H24O 256.1827, found 256.1829
1
(M+). Minor isomer: H NMR (500 MHz, CDCl3) d 7.20–
7.31 (m, 5H), 6.48 (s, 1H), 3.94 (d, J¼5.5 Hz, 1H), 2.55
(dd, J¼18.5, 6.5 Hz, 1H), 1.90–2.21 (m, 6H), 1.72 (br s,
1H), 1.07 (t, J¼14.5 Hz, 3H), 1.03 (d, J¼7.0 Hz, 3H), 0.74
(t, J¼7.5 Hz, 3H); 13C NMR (125 MHz, CDCl3) d 140.0,
138.9, 138.6, 131.1, 129.3, 128.1, 126.6, 122.7, 78.7, 35.8,
35.7, 26.2, 22.4, 19.5, 14.6, 13.5; IR (film, cmꢁ1) 3409,
2961, 2928, 2871, 1597, 1491, 1456, 850, 758, 697;
HRMS (EI) m/e calcd for C18H24O 256.1827, found
256.1827 (M+).
4.3.7. (E)-2-Heptylidene-3-hexyl-5-methylcyclohex-3-
enol (2g). Following the general procedure in Section 4.3,
compound 1g (194 mg, 0.669 mmol), Ni(COD)2 (18 mg,
0.067 mmol) tributylphosphine (0.035 mL, 0.13 mmol),
and triethylborane (1.34 mL, 1.34 mmol in 1.0 M solution)
were employed to produce, after column chromatography
(25:1 hexane/ethyl acetate), 146 mg (75%) of two in-
separable diastereomers (2.4:1) of light yellow oil. Major
1
isomer: H NMR (500 MHz, CDCl3) d 5.45–5.49 (m, 1H),