T. K. Chakraborty et al. / Tetrahedron 57 *2001) 9461±9467
9465
85%) as a colorless liquid. Rf0.4 )silica, 50% EtOAc in
4.7 Hz, 1H, C5±H), 3.30 )s, 3H, OCH3), 2.52±2.38 )m,
1H, C4±H), 1.06 )d, J6.6 Hz, 3H, C4±CH3), 0.88 )s,
9H, )CH3)3C±Si), 0.02 )s, 6H, )CH3)2Si); 13C NMR
)CDCl3, 50 MHz): d 136.79, 133.01, 132.49, 129.63,
128.48, 127.54, 126.49, 86.49, 64.02, 56.54, 41.26, 25.95,
18.36, 15.90, 25.08; MS )LSIMS): m/z )%): 345 )15)
[M12H], 315 )29) [M12OMe]; HRMS )LSIMS): calcd
for C21H33O2Si [M12H]: 345.2249, found: 345.2244.
20
petroleum ether); [a]D 110.77 )c 1.01, CHCl3); IR
)Neat): nmax 3325, 2965, 2898, 1502, 968, 753,
698 cm21;1H NMR )CDCl3, 200 MHz): d 7.44±7.20 )m,
5H, ArH), 6.60 )d, J16.3 Hz, 1H, C7±H), 6.24 )dd, J
16.3, 5.4 Hz, 1H, C6±H), 5.88±5.66 )m, 2H, C2±H, C3±H),
4.25 )t, J5.4 Hz, 1H, C5±H), 4.14 )d, J4.5 Hz, 2H,
C1±H2), 2.60±2.45 )m, 1H, C4±H), 1.10 )d, J6.6 Hz,
3H, C4±CH3); 13C NMR )CDCl3, 100 Hz): d 136.68,
133.81, 131.19, 130.33, 129.63, 128.45, 127.53, 126.33,
75.90, 63.19, 42.35, 14.92; MS )LSIMS): m/z )%): 241 )8)
[M11Na], 217 )4) [M2H], 201 )34) [M12OH]; HRMS
)LSIMS): calcd for C14H19O2 [M11H]: 219.1385, found:
219.1386.
3.1.7. 5-Methoxy-4-methyl-7-phenyl-ꢀ2E,4S,5S,6E)-2,6-
heptadiene-1-ol ꢀ15). To
a solution of 14 )3.7 g,
10.69 mmol) in MeOH/CH2Cl2 )1:2, 30 mL) at 08C,
camphor sulfonic acid )2.48 g, 10.69 mmol) was added
portionwise and stirred for 1 h, while the temperature was
allowed to rise from 08C to room temperature. The reaction
mixture was cooled to 08C and neutralized by the addition of
saturated aqueous NaHCO3, diluted with EtOAc )100 mL),
washed with brine )50 mL), dried )Na2SO4) and concen-
trated in vacuo. Column chromatographic puri®cation
)SiO2, 20±30% EtOAc in petroleum ether eluent) of the
3.1.5. 1-tert-Butyldimethylsilyloxy-4-methyl-7-phenyl-
ꢀ2E,4S,5S,6E)-2,6-heptadiene-5-ol ꢀ13). To a solution of
12 )3.3 g, 15.13 mmol) in dry THF )40 mL) at 08C, imida-
zole )1.34 g, 19.6 mmol) was added portionwise followed
by TBDMSCl )2.5 g, 16.64 mmol) in one portion. The
reaction mixture was stirred for 1 h with the temperature
slowly reaching room temperature. It was quenched with
saturated aqueous NH4Cl solution )10 mL), diluted with
EtOAc )100 mL), washed with brine )50 mL), dried
)Na2SO4) and concentrated in vacuo. Puri®cation by column
chromatography )SiO2, 20±30% EtOAc in petroleum ether
eluent) of the crude afforded 13 )4.12 g, 82%) as a colour-
less oil. Rf0.5 )silica, 30% EtOAc in petroleum ether);
crude afforded 15 )2.2 g, 89%) as a colourless liquid.
20
Rf0.4 )silica, 30% EtOAc in petroleum ether); [a]D
15.78 )c 1.04, CHCl3); IR )Neat): nmax 3404, 2933, 1451,
1090, 965, 753, 690 cm21; H NMR )CDCl3, 200 MHz): d
1
7.40±7.20 )m, 5H, ArH), 6.50 )d, J16.3 Hz, 1H, C7±H),
6.00 )dd, J16.3, 7.3 Hz, 1H, C6±H), 5.80±5.58 )m, 2H,
C2±H, C3±H), 4.10 )d, J4.7 Hz, 2H, C1±H2), 3.52 )dd,
J5.4, 4.0 Hz, 1H, C5±H), 3.30 )s, 3H, OCH3), 2.55±2.38
)m, 1H, C4±H), 1.08 )d, J6.6 Hz, 3H, C4±CH3); 13C NMR
)CDCl3, 50 MHz): d 136.55, 133.78, 133.20, 129.61,
128.44, 127.98, 127.55, 126.37, 86.27, 63.35, 56.41,
41.12, 15.81; MS )LSIMS): m/z )%): 231 )8) [M12H];
HRMS )LSIMS): calcd for C15H19O2 [M12H]: 231.1385,
found: 231.1387.
20
[a]D 15.95 )c 0.5, CHCl3); IR )Neat): nmax 3443,
1
2918, 2863, 1459, 1239, 965, 831, 745 cm21; H NMR
)CDCl3, 200 MHz): d 7.40±7.18 )m, 5H, ArH), 6.55 )d,
J16.3 Hz, 1H, C7±H), 6.20 )dd, J16.3, 5.4 Hz, 1H,
C6±H), 5.74±5.54 )m, 2H, C2±H, C3±H), 4.25±4.04 )m,
3H, C1±H2, C5±H), 2.55±2.38 )m, 1H, C4±H), 1.10 )d,
J6.6 Hz, 3H, C4±CH3), 0.88 )s, 9H, )CH3)3C±Si), 0.02
)s, 6H, )CH3)2Si); 13C NMR )CDCl3, 50 MHz): d 136.87,
131.84, 131.12, 130.92, 130.23, 128.46, 127.47, 126.44,
75.98, 63.77, 42.60, 25.92, 18.35, 15.28, 25.13; MS
)LSIMS): m/z )%): 331 )12) [M12H], 315 )32) [M12
OH]; HRMS )LSIMS): calcd for C20H31O2Si [M12H]:
331.2093, found: 331.2092.
3.1.8. 3-[2-Methoxy-1-methyl-4-phenyl-ꢀ1S,2S,3E)-3-
butenyl]-ꢀ2R,3R)-oxiran-2-yl methanol ꢀ16). To dichloro-
Ê
methane )20 mL) containing ¯ame-dried 4 A molecular
sieves powder )0.4 g) at 2208C, Ti)OiPr)4 )2.5 mL,
8.6 mmol) and )2)-DIPT )1.8 mL, 8.6 mmol) were added
sequentially and stirred for 20 min. The allylic alcohol 15
)2 g, 8.62 mmol) in CH2Cl2 )5 mL) was then added drop-
wise and the reaction stirred for another 0.5 h. Next, TBHP
)3.3 M in toluene, 6.5 mL, 21.5 mmol) was added dropwise
and stirring continued at 2208C for 1 h. Afew drops of
water were added to the reaction mixture and stirred for
20 min. It was then warmed to 08C and 1 M NaOH
)1 mL) was added and stirred at this temperature for 0.5 h.
The reaction mixture was diluted with EtOAc )100 mL),
washed with brine )50 mL), dried )Na2SO4) and concen-
trated in vacuo. Column chromatography )SiO2, 25±35%
EtOAc in petroleum ether eluent) of the crude afforded 16
)1.98 g, 93%) as a syrupy liquid. Rf0.45 )silica, 50%
3.1.6. 1-tert-Butyldimethylsilyloxy-5-methoxy-4-methyl-
7-phenyl-ꢀ2E,4S,5S,6E)-2,6-heptadiene ꢀ14). To a solu-
tion of 13 )4.1 g, 12.35 mmol) in dry THF )30 mL) at 08C,
NaH )60% dispersion in oil, 1.0 g, 24.69 mmol) was added
portionwise and stirred for 10 min. Then methyl iodide
)0.84 mL, 13.58 mmol) was added dropwise followed by
tetrabutylammonium iodide )0.45 g, 1.2 mmol) in one
portion and the reaction mixture was stirred for 4 h. It was
then cooled to 08C and quenched with saturated aqueous
NH4Cl solution )10 mL) and diluted with EtOAc )100
mL), washed with saturated aqueous Na2S2O3 solution
)50 mL), brine )50 mL), dried )Na2SO4) and concentrated
in vacuo. Column chromatographic puri®cation )SiO2,
5±15% EtOAc in petroleum ether eluent) of the crude
afforded 14 )3.76 g, 88%) as a syrupy liquid. Rf0.6 )silica,
20
EtOAc in petroleum ether); [a]D 120.8 )c 1.05,
CHCl3); IR )Neat): nmax 3427, 2925, 1435, 1074, 965,
1
745, 690 cm21; H NMR )CDCl3, 200 MHz, numbering
started from primary hydroxy group attached carbon): d
7.42±7.20 )m, 5H, ArH), 6.58 )d, J16.3 Hz, 1H, C7±H),
6.12 )dd, J16.3, 7.3 Hz, 1H, C6±H), 3.95±3.82 )m, 2H,
C1±H, C5±H), 3.62 )dd, J12.7, 5.0 Hz, 1H, C1±H0), 3.36
)s, 3H, OCH3), 3.04 )dd, J9.0, 2.7 Hz, 1H, C3±H), 2.90
)m, 1H, C2±H), 1.60 )m, 1H, C4±H), 1.00 )d, J6.7 Hz,
3H, C4±CH3); 13C NMR )CDCl3, 100 MHz): d 136.44,
20
20% EtOAc in petroleum ether); [a]D 112.11 )c 0.3,
CHCl3); IR )Neat): nmax 2941, 2870, 1223, 1114, 972,
1
824, 784 cm21; H NMR )CDCl3, 200 MHz): d 7.40±7.18
)m, 5H, ArH), 6.48 )d, J16.3 Hz, 1H, C7±H), 6.00 )dd,
J16.3, 7.3 Hz, 1H, C6±H), 5.72±5.46 )m, 2H, C2±H, C3±
H), 4.10 )d, J4.7 Hz, 2H, C1±H2), 3.50 )dd, J5.4,