Masked Allylic Organozinc Reagents
J . Org. Chem., Vol. 64, No. 1, 1999 193
as an eluent to give the alcohol39 (356 mg, 84%) as a colorless
a n ti-2-P h en yl-3-m eth yl-4-p en ten -2-ol (45). The reaction
was carried out according to standard procedure C using 37
(500 mg, 2.52 mmol), BuLi (2.52 mmol), acetophenone (293
µL, 2.52 mmol), and ZnCl2 (343 mg, 2.52 mmol) to give a crude
residue, which was then purified by column chromatography
on silica using 20% Et2O-hexanes as an eluent to give the
1
oil: IR (film) 3396 cm-1; H NMR (200 MHz, CDCl3) δ 5.88-
5.68 (m, 1H), 5.15-5.02 (m, 2H), 3.10 (app. t, J ) 5.8 Hz, 1H),
2.46-2.26 (m, 1H), 1.90-1.10 (m, 11H), 1.02 (d, J ) 6.8 Hz,
3H); 13C NMR (50 MHz, CDCl3) δ 140.31, 115.97, 78.75, 40.44,
40.25, 29.89, 27.00, 26.42, 26.37, 26.06, 16.90.
a n ti-3-Meth yl-5-eth yl-1-h ep ten -4-ol (41). The reaction
was carried out according to standard procedure C using 37
(500 mg, 2.52 mmol), BuLi (2.52 mmol), 2-ethylbutyraldehyde
(310 µL, 2.52 mmol), and ZnCl2 (343 mg, 2.52 mmol) to give a
crude residue, which was then purified by column chromatog-
raphy on silica using 8% Et2O-hexanes as an eluent to give
the alcohol40 (340 mg, 86%) as a colorless oil: IR (film) 3458
cm-1; 1H NMR (200 MHz, CDCl3) δ 5.87-5.67 (m, 1H), 5.19-
5.06 (m, 2H), 3.36-3.27 (m, 1H), 2.36 (app. sextet, J ) 7 Hz,
1H), 1.65-1.15 (m, 5H), 1.00 (d, J ) 6.8 Hz, 3H), 0.96-0.84
(m, 6H); 13C NMR (50 MHz, CDCl3) δ 141.03, 116.21, 75.42,
42.84, 41.40, 22.34, 20.27, 11.75, 11.32; m/z (EI-MS) 101 (M-
C4H7+, 40%, C6H13O requires 101), 59 (100). Anal. Calcd for
C10H20O: C, 76.86; H, 12.99%. Found: C, 76.60; H, 12.97%.
a n ti-3-Meth yl-5-m eth ylen yln on -2-en -4-ol (42). The reac-
tion was carried out according to standard procedure C using
37 (500 mg, 2.52 mmol), BuLi (2.52 mmol), 2-butylacrolein (335
µL, 2.52 mmol), and ZnCl2 (343 mg, 2.52 mmol) to give a crude
residue, which was then purified by column chromatography
on silica using 8% Et2O-hexanes as an eluent to give the
alcohol42 (397 mg, 90%) as a colorless oil: IR (film) 3468 cm-1
;
1H NMR (200 MHz, CDCl3) (major diastereomer) δ 7.50-7.15
(m, 5H), 5.92-5.58 (m, 1H), 5.17-5.03 (m, 2H), 2.70-2.45 (m,
1H), 1.99 (broad s, 1H), 1.51 (s, 3H), 0.96 (d, J ) 6.8 Hz, 3H),
(minor diastereomer) δ 0.86 (d, J ) 6.8 Hz, 3H); 13C NMR (50
MHz, CDCl3) (major diastereomer) δ 146.99, 139.91, 127.83,
126.56, 125.43, 116.52, 75.63, 48.72, 25.83, 14.05, (minor
diastereomer) δ 126.37, 125.15, 116.22, 51.39, 30.93, 17.23; m/z
(EI-MS) 158 (M-H2O+, 1%, C12H14 requires 158), 43 (100).
Anal. Calcd for C12H16O: C, 81.77; H, 9.15%. Found: C, 81.56;
H, 8.82%.
3-ter t-Bu tyl-2,2-d im eth yl-4-eth ylh ex-5-en -3-ol (46). This
was prepared in a manner similar to that for 37 using
1-chloropent-2-ene (3.06 g, 29.3 mmol) and pivaldehyde (3.23
mL, 29.3 mmol). The crude residue was purified by column
chromatography on silica using 2% Et2O-hexanes as an eluent
to give the alcohol (2.63 g, 74%) as a colorless oil: IR (film)
1
3578 cm-1; H NMR (200 MHz, CDCl3) δ 5.95-5.74 (m, 1H),
5.24 (dd, J ) 10.0, 2.2 Hz, 1H), 5.05 (dd, J ) 17.0, 2.2 Hz,
1H), 2.63-2.49 (m, 1H), 2.18-1.98 (m, 1H), 1.70-1.43 (m, 1H),
1.16 (s, 9H), 1.13 (s, 9H), 0.85 (app. t, J ) 7 Hz, 3H); 13C NMR
(50 MHz, CDCl3) δ 141.81, 119.51, 80.16, 56.16, 43.56, 43.04,
30.44, 29.63, 25.19, 14.22; m/z (EI-MS) 143 (M-C5H9+, 1%,
C9H19O requires 143), 57 (100%). Anal. Calcd for C14H28O: C,
79.18; H, 13.29. Found: C, 79.14; H, 13.56%.
alcohol (321 mg, 76%) as a colorless oil: IR (film) 3441 cm-1
;
1H NMR (200 MHz, CDCl3) δ 5.88-5.63 (m, 1H), 5.21-4.87
(m, 4H), 3.79 (d, J ) 7.3 Hz, 1H), 2.48-2.28 (m, 1H), 2.25-
1.85 (m, 2H), 1.79 (broad s, 1H), 1.56-1.28 (m, 4H), 1.04-
0.86 (m, 6H); 13C NMR (50 MHz, CDCl3) δ 149.68, 140.38,
116.41, 111.29, 79.18, 41.89, 30.45, 30.00, 22.66, 16.68, 13.98;
m/z (EI-MS) 113 (M-C4H7+, 20%, C7H13O requires 113), 71
(100%). Anal. Calcd for C11H20O: C, 78.51; H, 11.98%. Found:
C, 78.55; H, 12.06%.
a n ti-2-Meth yl-1-(1-n a p h th yl)-3-bu ten -1-ol (43). The re-
action was carried out according to standard procedure C using
37 (500 mg, 2.52 mmol), BuLi (2.52 mmol), 1-naphthylaldehyde
(342 µL, 2.52 mmol), and ZnCl2 (343 mg, 2.52 mmol) to give a
crude residue, which was then purified by column chromatog-
raphy on silica using 10% Et2O-hexanes as an eluent to give
the alcohol (490 mg, 92%) as a pale-yellow oil: IR (film) 3427
cm-1; 1H NMR (200 MHz, CDCl3) δ 8.26-8.15 (m, 1H), 7.95-
7.77 (m, 2H), 7.64-7.44 (m, 4H), 6.01-5.81 (m, 1H), 5.27-
5.16 (m, 3H), 2.86 (app. sextet, J ) 7 Hz, 1H), 2.26 (broad s,
1H), 0.99 (d, J ) 6.7 Hz, 3H); 13C NMR (50 MHz, CDCl3) δ
140.16, 138.33, 133.81, 130.91, 128.86, 128.03, 125.79, 125.37,
125.19, 124.41, 123.51, 116.75, 74.67, 45.14, 17.09; m/z (EI-
MS) 212 (M+, 1%, C15H16O requires 212), 157 (100%). Anal.
Calcd for C15H16O: C, 84.87; H, 7.60%. Found: C, 84.68; H,
7.46%.
a n ti-1-(2-F u r yl)-2-m eth yl-3-bu ten -1-ol (44). The reaction
was carried out according to standard procedure C using 37
(500 mg, 2.52 mmol), BuLi (2.52 mmol), furfural (209 µL, 2.52
mmol), and ZnCl2 (343 mg, 2.52 mmol) to give a crude residue,
which was then purified by column chromatography on silica
using 20% Et2O-hexanes as an eluent to give the alcohol41
(320 mg, 84%) as a colorless oil: IR (film) 3431 cm-1; 1H NMR
(200 MHz, CDCl3) (major diastereomer) δ 7.43-7.33 (m, 1H),
6.36-6.28 (m, 2H), 5.90-5.68 (m, 1H), 5.28-5.12 (m, 2H), 4.42
(d, J ) 7.6 Hz, 1H), 2.80-2.60 (m, 1H), 2.18 (broad s, 1H),
0.93 (d, J ) 6.7 Hz, 3H), (minor diastereomer) δ 7.28-7.24
(m, 1H), 5.10-5.02 (m, 2H), 4.55 (d, J ) 6.2 Hz, 1H), 1.06 (d,
J ) 6.7 Hz, 3H); 13C NMR (50 MHz, CDCl3) (major diastere-
omer) δ 154.96, 141.88, 139.93, 116.84, 110.01, 107.15, 71.28,
43.49, 16.14, (minor diastereomer) δ 155.29, 141.88, 139.93,
116.76, 109.96, 106.76, 71.28, 42.96, 14.99; m/z (EI-MS) 152
(M+, 1%, C9H12O2 requires 152), 97 (100).
a n ti-2-Eth yl-1-p h en yl-3-bu ten -1-ol (47). The reaction
was carried out according to standard procedure C using 46
(500 mg, 2.35 mmol), BuLi (2.35 mmol), PhCHO (239 µL, 2.35
mmol), and ZnCl2 (321 mg, 2.35 mmol) to give a crude residue
after stirring for 1 h at -78 °C and then warming to -50 °C.
This residue was then purified by column chromatography on
silica using 20% Et2O-hexanes as an eluent to give the
alcohol43 (378 mg, 91%) as a colorless oil: IR (film) 3412 cm-1
;
1H NMR (200 MHz, CDCl3) (major diastereomer) δ 7.40-7.21
(m, 5H), 5.75-5.55 (m, 1H), 5.30-5.12 (m, 2H), 4.38 (d, J )
7.8 Hz, 1H), 2.38-2.10 (m, 1H), 1.85-1.05 (m, 2H), 0.78 (app.
t, J ) 7.5 Hz, 3H), (minor diastereomer) δ 5.58-5.38 (m, 1H),
5.11-4.94 (m, 2H); 13C NMR (50 MHz, CDCl3) (major diaste-
reomer) δ 142.54, 139.04, 128.15, 127.54, 126.89, 118.83, 76.66,
54.51, 23.32, 11.69, (minor diastereomer) δ 138.20, 117.38,
53.16, 22.54, 13.95; m/z (EI-MS) 107 (M-C5H9+, 100%, C7H7O
requires 107), 79 (45%). Anal. Calcd for C12H16O: C, 81.77; H,
9.15. Found: C, 81.72; H, 9.12%.
a n ti-1-Cycloh exyl-2-eth yl-3-bu ten -1-ol (48). The reaction
was carried out according to standard procedure C using 46
(500 mg, 2.35 mmol), BuLi (2.35 mmol), cyclohexane carbox-
aldehyde (286 µL, 2.35 mmol), and ZnCl2 (321 mg, 2.35 mmol)
to give a crude residue after stirring for 2 h at -78 °C and
then slowly warming to -30 °C. The crude residue was then
purified by column chromatography on silica using 15-20%
Et2O-hexanes as an eluent to give the alcohol43 (355 mg, 83%)
as a colorless oil: IR (film) 3394 cm-1 1H NMR (200 MHz,
;
CDCl3) 5.77-5.56 (m, 1H), 5.23-5.03 (m, 2H), 3.19 (app. t, J
) 5.5 Hz, 1H), 2.18-1.99 (m, 1H), 1.95-0.95 (m, 13H), 0.87
(t, J ) 7.4 Hz, 3H); 13C NMR (50 MHz, CDCl3) δ 138.59, 117.48,
77.41, 48.45, 40.46, 29.68, 27.61, 26.48, 26.33, 26.06, 23.92,
11.84; m/z (EI-MS) 113 (M-C5H9+, 19%, C7H13O requires 113),
95 (100%). Anal. Calcd for C12H22O: C, 79.06; H, 12.16.
Found: C, 78.88; H, 12.38%.
a n ti-3,5-Dieth yl-1-h ep ten -4-ol (49). The reaction was
carried out according to standard procedure C using 46 (500
mg, 2.35 mmol), BuLi (2.35 mmol), 2-ethylbutyraldehyde (290
µL, 2.35 mmol), and ZnCl2 (321 mg, 2.35 mmol) to give a crude
residue after 3 h at -78 °C, which was then purified by column
chromatography on silica using 15% Et2O-hexanes as an
eluent to give the alcohol (325 mg, 81%) as a colorless oil: IR
(40) (a) Widler, L.; Seebach, D. Helv. Chim. Acta. 1982, 65, 1085-
1089. (b) Yamamoto, Y.; Yatagai, H.; Ishihara, Y.; Maeda, N.; Maruya-
ma, K. Tetrahedron 1984, 40, 2239-2246.
(41) Wuts, P. G. M.; Callen, G. R. Synth. Commun. 1986, 1833-
1837. Wuts reports the threo compound to display a doublet at 1.06
ppm and the erythro compound at 0.94 ppm; however, we believe due
to comparison with other spectra this is in fact reversed.
(42) Sjo¨holm, R. E. Acta Chem. Scand. 1990, 44, 82-89.