Notes
J . Org. Chem., Vol. 61, No. 8, 1996 2907
nane 3.3e12 (128 mg, 0.27 mmol) and cyclohexanecarboxaldehyde
(27 mg, 0.24 mmol) in 1.5 mL of CH2Cl2 was added BF3‚OEt2
(31 µL, 0.30 mmol). After 1.5 h, TLC analysis indicated that
all the aldehyde had been consumed and the reaction was
quenched with saturated NaHCO3 solution. After warming to
rt, the mixture was extracted with CH2Cl2, dried over Na2SO4,
and concentrated under reduced pressure. The crude residue
was purified by flash chromatography on silica gel. Elution with
5% ethyl acetate in hexane provided 71.5 mg (65%) of a 45:55
mixture of (E)- and (Z)-isomers of adduct 3.4e. Data for the (Z)-
isomer: 1H NMR δ 6.16 (dd, J ) 5.8, 0.8 Hz, 1H), 4.33 (dd, J )
9.2, 5.8 Hz, 1H), 3.19 (dd, J ) 6.0, 6.0 Hz, 1H), 2.86 (dm, J )
6.9 Hz, 1H), 1.90 (m, 1H), 1.83-1.35 (m, 6H), 1.36-1.02 (m, 4H),
0.98 (d, J ) 6.9 Hz, 3H), 0.92 (s, 9H), 0.12 (s, 6H) ppm; IR (film)
(r el 4S,5R,E)-1-((ter t-Bu tyld im eth ylsilyl)oxy)-4-m eth yl-
6-u n d ecen -2-yn -5-ol (7.2a ). The procedure described for 3.4e
was employed with stannane 7.1a 19 (91 mg, 0.19 mmol), (E)-2-
heptenal (21 mg, 0.19 mmol), and BF3‚OEt2 (22 µL, 0.22 mmol).
The product was purified by flash chromatography on silica gel.
Elution with 5% ethyl acetate in hexane provided 40 mg (69%)
of a 65:35 mixture of syn and anti isomers of adduct 7.2a . Data
for the syn isomer: 1H NMR δ 5.71 (ddd, J ) 15.3, 7.2, 6.5 Hz,
1H), 5.45 (ddd, J ) 15.3, 7.0, 1.4 Hz, 1H), 4.32 (dd, J ) 5.8, 1.9
Hz, 2H), 3.89 (dd, J ) 9.9, 6.8 Hz, 1H), 2.54 (dq, J ) 9.9, 7.2 Hz,
1H), 2.03 (m, 2H), 1.91-1.48 (m, 3H), 1.47-1.22 (m, 4H), 1.15
(d, J ) 7.0 Hz, 3H), 0.12 (s, 6H) ppm; 13C NMR δ 134.3, 19.9,
85.8, 81.7, 75.8, 51.9, 33.7, 31.9, 31.2, 25.8, 22.1, 18.3, 17.0, 13.9,
-5.1 ppm; IR (film) ν 3415, 2200 cm-1
18H34O2Si: C, 69.62; H, 11.04. Found: C, 69.35; H, 11.10.
(r el 4S,5R,E)-1-(P iva loyloxy)-4-m eth yl-6-u n d ecen -2-yn -
. Anal. Calcd for
ν 3415 cm-1
.
C
(r el 3S,4R,E,E)-1-((ter t-Bu tyld im eth ylsilyl)oxy)-3-m eth -
yl-1,5-d eca d ien -4-ol (4.2e). The above procedure was em-
ployed with stannane 3.3e12 (300 mg, 0.63 mmol), (E)-2-heptenal
(64 mg, 0.56 mmol), and BF3‚OEt2 (77 µL, 0.75 mmol). The crude
residue was purified by flash chromatography on silica gel.
Elution with 5% ethyl acetate in hexane provided 139 mg (83%)
of a 79:21 mixture of (E)- and (Z)-isomers of silyl enol ether 4.2e.
Data for the (E)-isomer: 1H NMR δ 6.24 (dd, J ) 5.9, 1.0 Hz,
1H), 5.62 (ddd, J ) 15.3, 6.7, 6.7 Hz, 1H), 5.43 (ddd, J ) 15.4,
6.9, 1.2 Hz, 1H), 4.30 (dd, J ) 9.0, 6.0 Hz, 1H), 3.93 (dd, J )
5.5, 5.5 Hz, 1H), 2.85 (m, 1H), 2.01 (m, 2H), 1.47-1.20 (m, 4H),
1.85-0.75 (m, 16H), 0.13 (s, 6H) ppm; 13C NMR δ 132.5, 130.1,
111.5, 76.4, 34.8, 31.8, 31.2, 25.6, 25.5, 21.9, 18.0, 16.4, 13.7,
5-ol (7.2b). The procedure described for 3.4e was employed with
stannane 7.1b18 (89 mg, 0.20 mmol), (E)-2-heptenal (21 mg, 0.19
mmol), and BF3‚OEt2 (22 µL, 0.22 mmol). The product was
purified by flash chromatography on silica gel. Elution with 10%
ethyl acetate in hexane provided 28 mg (60%) of a 68:32 mixture
of syn and anti isomers of adduct 7.2b. Data for the syn
isomer: 1H NMR δ 5.72 (ddd, J ) 15.4, 8.3, 6.2 Hz, 1H), 5.45
(dd, J ) 15.7, 7.2 Hz, 1H), 4.66 (s, 2H), 3.89 (dd, J ) 6.6, 6.4
Hz, 1H), 2.58 (m, 1H), 2.08 (m, 3H), 1.58-1.22 (m, H), 1.22 (s,
9H), 1.16 (d, J ) 7.2, 3H), 0.91 (d, J ) 6.9, 3H) ppm; IR (film) ν
3475, 2200 cm-1
.
-5.6, -5.7 ppm; IR (film) ν 3450 cm-1
17H34O2Si: C, 68.39; H, 11.48. Found: C, 68.48; H, 11.43.
(r el 3S,4R,E,E)-1-(Meth oxym eth oxy)-3-m eth yl-1,5-d eca -
. Anal. Calcd for
Ack n ow led gm en t. We are grateful to the National
Science Foundation for support of this study through a
research grant (CHE 9220166). We thank Drs. Shiping
Xie and Mark Wolf and Ms. Michelle Elliott for provid-
ing the various stannanes used in this study.
C
d ien -4-ol (4.2f). The above procedure was employed with
stannane 3.3f11 (255 mg, 0.63 mmol), (E)-2-heptenal (64 mg, 0.56
mmol), and BF3‚OEt2 (77 µL, 0.75 mmol). The product was
purified by flash chromatography on silica gel. Elution with 20%
ethyl acetate in hexane provided 88 mg (69%) of a 60:40 mixture
of (Z)- and (E)-isomers of enol ether 4.2f. Data for the (E)-
isomer: 1H NMR δ 6.18 (d, J ) 6.4 Hz, 1H), 5.66 (ddd, J ) 15.3,
6.7, 2.2 Hz, 1H), 5.35 (ddd, J ) 15.4, 5.8, 1.4 Hz, 1H), 4.80 (s,
2H), 3.66 (dd, J ) 9.5, 6.5 Hz, 1H), 3.94 (dd, J ) 6.0, 6.0 Hz,
1H), 3.40 (s, 3H), 2.90 (m, 1H), 2.02 (m, 2H), 1.40-1.20 (m, 4H),
0.98 (d, J ) 7.0 Hz, 3H), 0.90 (d, J ) 6.8 Hz, 3H), 0.87 (d, J )
7.2 Hz, 3H) ppm; 13C NMR (100 MHz) δ 143.0, 133.0, 130.0,
110.2, 96.4, 76.8, 55.8, 35.4, 32.0, 31.4, 22.2, 16.7, 13.9 ppm; IR
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra for
previously unknown adducts (5 pages). This material is
contained in libraries on microfiche, immediately follows this
article in the microfilm version of the journal, and can be
ordered from the ACS; see any current masthead page for
ordering information.
J O9519975
(film) ν 3450 cm-1
.
(19) Marshall, J . A.; Xie, S. J . Org. Chem. 1995, 60, 7230.