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J. Marco-Contelles et al. / Tetrahedron 58 (2002) 1147±1158
CH3), 0.73(s, 3H, CH 3); 13C NMR (75 MHz, CDCl3) d
211.5 (C-2), 190.0 (C-3a), 141.6 (C-4b), 123.4 (C-3),
115.8 (C-4c), 74.9 (C-4), 56.4 (C-5), 53.4 (C-6a), 47.3
(C-4a), 36.9 (C-6), 36.8 (C-1), 29.5 (CH3), 24.5
(CH3CvCH2), 22.6 (CH3); MS (70 eV) m/z 220 (6), 192
(13), 165 (100), 149 (51), 137 (81), 121 (27), 109 (37),
108 (63), 95 (27). Anal. calcd for C14H20O2: C, 76.33; H,
9.15. Found: C, 76.41; H, 8.99.
1090, 1067, 814 cm21 1H NMR (300 MHz, CDCl3) d
;
6.02 (d, J3,6a2.6 Hz, 1H, H-3), 4.89 (s, 1H, H-4c), 4.75
(s, 1H, H-4c0), 3.15 (dt, J6a,16.6 Hz, J6a,1 J6a,32.6 Hz,
0
0
1H, H-6a), 2.68 (br d, J4a,4a 14.7 Hz, 1H, H-4a), 2.41 (dd,
0
J1,1 18.6 Hz, J1,6a6.6 Hz, 1H, H-1), 2.36 (s, 2H, CH2Br),
0
0
2.22 (d, J5,5 14.1 Hz, 1H, H-5), 2.15 (d, J4a,4a 14.7 Hz,
1H, H-4a), 2.14 (dd, J1,1 18.6 Hz, J1 ,6a2.6 Hz, 1H, H-10),
0
0
0
0
2.01 (d, J5,5 14.1 Hz, 1H, H-5 ), 1.79 (s, 3H, CH3CpCH2),
1.14 (s, 3H, CH3), 0.64 (s, 3H, CH3), 0.22 (s, 6H, Si(CH3)2);
13C NMR (75 MHz, CDCl3) d 210.0 (C-2), 189.5 (C-3a),
141.8 (C-4b), 125.2 (C-3), 115.3 (C-4c), 78.0 (C-4), 56.9
(C-5), 54.2 (C-6a), 48.2 (C-4a), 36.7 (C-1), 29.7 (C-6), 29.5
(CH3), 24.3( CH3CpCH2), 22.2 (CH3), 17.1 (CH2Br), 20.82
(Si(CH3)2); MS (70 eV) m/z 317 (99), 315 (100), 275 (22),
273 (27), 260 (39), 258 (39), 152 (51), 150 (53), 124 (46),
122 (42), 91 (26), 79 (16), 77 (18), 75 (33), 55 (21), 41 (21).
Anal. calcd for C17H27O2BrSi: C, 54.98; H, 7.33. Found: C,
55.06; H, 7.63. Product 29 could not be isolated in a pure
state.
(4Sp)-4,5,6,6aa-Tetrahydro-4-hydroxy-6,6-dimethyl-4-(2-
methyl-2-propenyl)-2(1H)-pentalenone (25): oil; IR (neat)
3442, 2954, 1697, 1626, 1230, 895 cm21 1H NMR
;
(300 MHz, CDCl3) d 6.02 (d, J3,6a2.5 Hz, 1H, H-3), 5.02
0
(dq, J4c,CH30.5 Hz, J4c,4c 1.0 Hz, 1H, H-4c), 4.86 (q,
J4c, 4c J4c , C H2(4a) 1.0 Hz, 1H, H-4c 0), 2.89 (dt,
0
0
0
J6a,16.4 Hz, J6a,1 J6a,32.5 Hz, 1H, H-6a), 2.48 (s, 2H,
2£H-4a), 2.41 (dd, J1,1 18.6 Hz, J1,6a6.4 Hz, 1H, H-10),
0
0
0
2.37 (s, 1H, OH), 2.23 (dd, J1,1 18.6 Hz, J1 ,6a2.5 Hz, 1H,
H-1 0), 2.09 (d, J5,5 14.1 Hz, 1H, H-5 ), 1.90 (d,
0
0
0
J5,5 14.1 Hz, 1H, H-5), 1.81 (dt, J0.9, 0.5 Hz, 3H,
CH3CvCH2), 1.14 (s, 3H, CH3), 0.88 (s, 3H, CH3); 13C
NMR (75 MHz, CDCl3) d 210.4 (C-2), 193.7 (C-3a),
141.2 (C-4b), 125.1 (C-3), 116.3 (C-4c), 76.6 (C-4), 56.5
(C-5), 54.5 (C-6a), 49.5 (C-4a), 38.3 (C-6), 36.9 (C-1), 28.7
(CH3), 24.4 (CH3CvCH2), 21.7 (CH3); MS (70 eV) m/z 220
(6), 192 (9), 165 (100), 164 (22), 149 (24), 137 (77), 109
(42), 108 (30), 95 (24). Anal. calcd for C14H20O2: C, 76.33;
H, 9.15. Found: C, 76.08; H, 9.40.
3.7.5. 2,4,4-Trimethyl-nona-1,8-dien-5-ol (31). To a cold
(2788C) solution of aldehyde 3023 (856 mg, 6.8 mmol) in
THF (8 mL) was added dropwise 3-butenylmagnesium
bromide (6.7 mL, 10.2 mmol, 1.5 equiv., 1.5 M solution of
in THF). The reaction mixture was then warmed to rt for the
completion of the reaction and treated with a saturated solu-
tion of NH4Cl. After extraction with ether, the organic
layers were washed with brine and dried over MgSO4. Puri-
®cation by chromatography (PE/EE 90:10) gave product 31
(525 mg, 42% yield): IR (neat) 3400, 3080, 2950, 1640,
3.7.3. Pauson±Khand reaction of precursor (5). Follow-
ing the general method for PK reaction, compound 5
(73mg, 0.22 mmol) gave products 26 and 27 (58 mg,
73%) in 2.6:1 ratio, after chromatography (hexane/EA
95:5). (4Rp)-4-(Bromomethyldimethylsilyloxy)-4,5,6,6aa-
tetrahydro-6,6-dimethyl-4-(2-propenyl)-2(1H)-pentalenone
(26): oil; IR (neat) 2959, 1713, 1629, 1253, 1145, 1070,
1460, 1390 cm21 1H NMR (200 MHz, CDCl3) d 5.82
;
(ddt, J16.7, 9.8, 6.9 Hz, 1H), 5.08±4.68 (m, 4H), 3.28
(dd, J10, 1.5 Hz, 1H), 2.30 (m, 1H), 2.13 (m, 1H), 1.98
(AB, J13Hz, 2H), 1.78 (s, 3H), 1.68±1.53(m, 1H), 1.47±
1.27 (m, 1H), 0.89 (s, 6H); 13C NMR (50 MHz, CDCl3) d
144.0, 138.9, 114.8, 114.6, 78.5, 46.6, 38.5, 31.4, 30.5, 25.4,
24.1, 23.3.
816 cm21
;
1H NMR (300 MHz, CDCl3) d 6.03(d,
0
J3,6a2.6 Hz, 1H, H-3), 5.88 (ddt, J4b,4c17.0 Hz, J4b,4c
9.9 Hz, J4b,4a7.0 Hz, 1H, H-4b), 5.18±5.09 (m, 2H, 2£H-
3.7.6. 2,4,4-Trimethyl-nona-1,8-dien-5-one (32). Follow-
ing the general method for the Swern oxidation, alcohol 31
(2.43g, 13.3mmol) gave ketone 32 (2.17 g, 90% yield)
after puri®cation by chromatography (PE/EE 9:1): IR
0
4c), 3.19 (dt, J6a,16.6 Hz, J6a,1 J6a,32.6 Hz, 1H, H-6a),
0
2.67 (d br d, J4a,4a 14.3Hz, J4a,4b7.0 Hz, 1H, H-4a), 2.44
0
(dd, J1,1 18.8 Hz, J1,6a6.6 Hz, 1H, H-1), 2.41 (s, 2H,
(neat) 3080, 2950, 1700, 1640, 1460, 1360 cm21 1H
;
0
0
0
CH2Br), 2.31 (ddt, J4a,4a 14.3Hz, J4a ,4b7.0 Hz, J4a ,4c
0
1.1 Hz, 1H, H-4a), 2.16 (dd, J1,1 18.8 Hz, J1,6a2.6 Hz,
NMR (200 MHz, CDCl3) d 5.80 (ddt, J16.7, 9.8, 6.9 Hz,
1H), 4.99±4.59 (m, 4H), 2.58 (t, J7.4 Hz, 2H), 2.29 (m,
4H), 1.62 (s, 3H), 1.12 (s, 6H); 13C NMR (50 MHz, CDCl3)
d 214.6, 142.3, 137.6, 115.0, 114.2, 47.5, 47.3, 36.6, 27.9,
25.0 (2C), 24.3.
0
1H, H-1), 2.09 (d, J5,5 14.2 Hz, 1H, H-5), 2.03(d,
0
0
J5,5 14.2 Hz, 1H, H-5 ), 1.18 (s, 3H, CH3), 0.67 (s, 3H,
CH3), 0.27, 0.25 (Si(CH3)2); 13C NMR (75 MHz, CDCl3)
d 210.9 (C-2), 188.9 (C-3a), 133.2 (C-4b), 125.0 (C-3),
118.8 (C-4c), 77.7 (C-4), 57.0 (C-5), 54.0 (C-6a), 44.8
(C-4a), 36.6 (2C, C-1, C-6), 29.7 (CH3), 22.6 (CH3), 17.2
(CH2Br), 20.73(Si(CH 3)2); MS (70 eV) m/z 317 (100), 315
(100), 275 (20), 273 (22), 260 (36), 258 (37), 152 (52), 150
(53), 124 (45), 122 (42), 91 (24), 75 (37), 41 (24). Anal.
calcd for C16H25O2BrSi: C, 53.78; H, 7.05. Found: C, 54.00;
H, 7.30. Product 27 could not be isolated in a pure state.
3.7.7. 5-Ethynyl-2,4,4-trimethyl-nona-1,8-dien-5-ol (7).
Following the general method for the reaction of lithium
trimethylsilylacetylide
with
carbonyl
derivatives,
compound 32 (2.17 g, 12 mmol) gave a crude alcohol
(3.35 g, quantitative yield), which was submitted to the
general method for the potassium ¯uoride promoted desilyl-
ation to give alcohol 7 (1.84 g, 74% yield over two steps)
after puri®cation by chromatography (PE/EE 95:5): oil; IR
(neat) 3500, 3300, 3080, 2980, 1640, 1450, 1350 cm21; 1H
NMR (200 MHz, CDCl3) d 5.91 (ddt, J16.7, 9.8, 6.9 Hz,
1H), 5.10±4.80 (m, 4H), 2.52 (s, 1H), 2.47±2.12 (m, 4H),
1.84 (s, 3H), 1.70 (m, 2H), 1.08 (s, 3H), 1.05 (s, 3H); 13C
NMR (50 MHz, CDCl3) d 144.6, 139.13, 115.5, 115.0, 85.6,
77.9, 74.6, 45.1, 42.4, 34.7, 29.4, 25.6, 23.0, 22.0.
3.7.4. Pauson±Khand reaction of precursor (6). Follow-
ing the general method for PK reaction, compound 6
(79 mg, 0.23mmol) gave products 28 and 29 (59 mg,
69%) in 1.5:1 ratio, after chromatography (hexane/EA
9:1).
tetrahydro-6,6-dimethyl-4-(2-methyl-2-propenyl)-2(1H)-
pentalenone (28): oil; IR (neat) 2958, 1714, 1627, 1253,
(4Rp)-4-(Bromomethyldimethylsilyloxy)-4,5,6,6aa-