6920 J . Org. Chem., Vol. 64, No. 18, 1999
Notes
1,1-Dich lor o-4-m et h yl-2-p en t a n ol
4-Met h ylb en zen e-
Eth yn ylcyclop r op a n e (5a ). A solution of 1.4 M MeLi in
ether (72.8 mL, 101.9 mmol) was added dropwise to a stirred
solution of 4a (9.00 g, 29.1 mmol) in THF (290 mL) at -30 °C
(typically, -10 °C was sufficient). The solution was warmed to
0 °C over 1 h and quenched with saturated aqueous ammonium
chloride (120 mL). The mixture was diluted with hexane and
the layers were separated. (If the product was not hexane
soluble, methyl tert-butyl ether was used instead throughout this
experiment.) The aqueous phase was extracted with hexane. The
combined organic layers were washed with brine, dried over
MgSO4, and filtered. This produced 1.81 g of 5a within 720 g of
THF/ether/hexane solution (94% solution yield). Neat 5a (99.2
GC area %) could be isolated as an oil by vacuum distillation
(1.78 g, 93%): bp 53-55 °C; 1H NMR δ 1.75 (d, J ) 6.1, 1H),
1.24 (m, 1H), 0.78 (m, 2H), 0.72 (m, 2H); 13C NMR δ 87.6, 63.3,
8.0, -0.88.
The following procedure for cyclopropyl acetylene 5a is
representative for the conversion of dibromosulfonates using
sodamide. Solid 4h (30.0 g, 75.3 mmol) was added over 1 h at
15-20 °C to a solution of sodium amide (14.7 g, 376.8 mmol) in
DMSO (90 mL). After 1 h, the reaction was quenched with water
(15 mL). Methylcyclohexane was charged as a cosolvent, and
the mixture was distilled. The distillate was collected at 50-80
°C to produce a 29 wt % solution of 5a (11.0 g, 67%).
su lfon a te (4c): white crystals; yield 79%; mp 62-63 °C; 1H δ
NMR 0.74 (d, J ) 10.0 Hz, 3H), 0.91 (d, J ) 10.0 Hz, 3H), 1.45-
1.65 (m, 2H), 1.80-1.87 (m, 1H), 2.45 (s, 3H), 4.77 (dd, J 1 ) 5.2,
5.0 Hz, 1H), 6.0 (d, J ) 5.8 Hz, 1H) 7.35 (d, J ) 10.1 Hz, 2H),
7.82 (d, J ) 10.1 Hz, 2H); 13C NMR δ 21.0, 21.8, 23.0, 23.7, 36.2,
71.0, 80.9, 127.8, 128.9, 129.7, 129.8, 133.2, 145.7. Anal. Calcd
for C13H18Cl2O3S: C, 48.00; H, 5.58; S, 9.85. Found: C, 48.03;
H, 5.58; S, 9.84.
1,1-Dich lor o-2-d eca n ol 4-Meth ylben zen esu lfon a te (4d ):
1
oil; yield 74%; H NMR δ 0.88 (t, J ) 9.8, 10.0 Hz, 3H), 1.19-
1.55 (m, 12H), 1.80-1.91 (m, 2H), 2.42 (s, 3H), 4.48 (m, 1H),
5.87 (d, J ) 6.4 Hz, 1H), 7.35 (d, J ) 10.8 Hz, 2H), 7.80 (d, J )
10.8 Hz, 2H); 13C NMR δ 14.0, 21.9, 22.1, 24.2, 27.2, 28.0, 29.4,
29.6, 31.92, 72.0, 81.0, 128.4, 128.5, 129.8, 129.9, 133.0, 145.3.
1,1-Dich lor o-3,3-d im eth yl-2-bu ta n ol 4-Meth a n esu lfon a te
(4e): white crystals; yield 68%; mp 70-71 °C; 1H δ NMR 1.17
(s, 9H), 3.32 (s, 3H), 5.07 (d, J ) 4.8 Hz, 1H), 6.10 (d, J ) 4.6
Hz, 1H); 13C NMR δ 28.2, 28.5 (3C), 39.0, 40.0, 94.0.
r-(Dich lor om eth yl)ben zen em eth a n ol 4-Meth ylben zen e-
su lfon a te (4f): white crystals; yield 84%; mp 85-86 °C; 1H
NMR δ 2.37 (s, 3H), 5.63 (d, J ) 8.3 Hz, 1H), 5.84 (d, J ) 8.7
Hz, 1H), 7.14 (d, J ) 10.4 Hz, 2H), 7.22-7.30 (m, 5H), 7.63 (d,
J ) 10.4 Hz, 2H); 13C NMR δ 21.9, 71.7, 84.0, 127.7, 127.8, 127.9,
127.9, 128.0, 128.1, 128.3, 128.4, 129.7, 132.5, 133.2, 145.6. Anal.
Calcd for C15H14Cl2O3S: C, 52.18; H, 4.07; S, 9.29. Found: C,
52.15; H, 4.09; S, 9.30.
r-(Dich lor om eth yl)ben zen ep r op a n ol 4-Meth ylben zen e-
su lfon a te (4g): white solids; yield 82%; mp 58-59 °C; 1H NMR
δ 2.18-2.30 (m, 2H), 2.31-2.44 (m, 1H), 2.42 (s, 3H), 2.60-2.70
(m, 1H), 4.71 (dd, J 1 ) 4.8, 4.6 Hz, 1H), 5.92 (d, J ) 5.2 Hz,
1H), 7.17 (d, J ) 10.0 Hz, 2H), 7.12-7.30 (m, 3H), 7.34 (d, J )
9.8 Hz, 2H), 7.82 (d, J ) 10.0 Hz, 2H); 13C NMR δ 21.9, 29.9,
30.9, 71.7, 82.0, 126.9, 128.0, 128.2, 128.3, 128.4, 128.5, 129.2,
129.8, 130.2, 133.6, 139.8, 145.5. Anal. Calcd for C17H18Cl2O3S:
C, 54.76; H, 4.86; S, 8.60. Found: C, 54.78; H, 4.84; S, 8.58.
P r ep a r a tion of Dibr om otosyla tes (4h ,i). The following
procedure for the cyclopropyl tosylate derivative 4h is repre-
sentative for the preparation of the dibromotosylates and the
method for proceeding without isolation of the carbinol inter-
mediate 3 for both the dichloro and dibromo series.
r-(Dib r om om et h yl)cyclop r op a n em et h a n ol 4-Met h yl-
b en zen cesu lfon a t e (4h ). A solution of lithium diisopropyl-
amide (105 mmol) in THF/hexane (∼70 mL) was added to a
stirred solution of cyclopropylcarboxaldehyde (4.5 g, 68 mmol)
and dibromomethane (20.0 g, 114 mmol) in THF (30 mL) at -30
°C over 1 h. The mixture was stirred another 20 min at -20 °C,
and p-toluenesulfonyl chloride (10.0 g, 52 mmol) was charged
over 10 min. The reaction was aged 1.5 h at -15 °C and
quenched with water (60 mL). The organic phase was separated,
and the aqueous layer was re-extracted with toluene. The
combined organic phase was washed with water and dried
(MgSO4). The solution was filtered, the filtrate was concentrated,
and the product was crystallized by the addition of heptane at
50 °C followed by cooling to 25 °C. The crystals were collected
by filtration, washed with heptane, and dried under vacuum to
produce white crystals (16.3 g, 64%): mp 80-81 °C; 1H NMR δ
0.40 (m, 1H), 0.60 (m, 2H), 0.80 (m, 1H), 1.40 (m, 1H), 2.45 (s,
3H), 4.13 (dd, J ) 0.3, 0.9 Hz, 1H), 5.80 (d, J ) 0.3 Hz, 1H),
7.38 (d, J ) 0.8 Hz, 2H), 7.80 (d, J ) 0.8 Hz, 2H); 13C NMR δ
3.5, 5.9, 12.9, 21.7, 44.6, 87.6, 127.8, 129.8, 133.7, 145.2. Anal.
Calcd for C12H14Br2O3S: C, 36.21; H, 3.54; S, 8.04. Found: C,
36.49; H, 3.32; S, 8.13.
Acetylenes of higher boiling point were stripped of most of
their solvents, and the purity was either measured by GC versus
dilutions of the known standard or stated as GC area %.
Acetylenes that were distilled are listed as such. All acetylenes
are known compounds.
Eth yn ylcycloh exa n e11 (5b): oil; yield 91%; 98.0 GC area
%.
4-Meth ylp en tyn e12 (5c): oil; yield 92%; 92.2 wt %.
n -Octyn e13 (5d ): oil (distilled); yield 93%; 97.1 GC area %.
3,3-Dim eth yl-1-bu tyn e14 (5e): oil; yield 78%; 81.0 wt %.
Eth yn ylben zen e15 (5f): oil (distilled); yield 93%; 98.3 GC
area %. Ethynylbenzene (5f) derived from 4i (dibromo analog):
yield 80%; 1.5 wt % solution.
3-Bu tyn ylben zen e16 (5 g): oil; yield 97%; 98.8 GC area %.
Ack n ow led gm en t. We are grateful to the Chemical
Process Analytical Group for their support of this
work and to Barbara W. Dotts, Cristina Gebreyesus,
and Latasha R. J ones for deriving some of the nomen-
clature.
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra for 4d and 4e. This material is available free of charge
J O990623Z
(11) (a) Preparation: Theus, V.; Schinz H. Helv. Chem. Acta 1956,
39, 1290. (b) Proton and carbon spectra: Aithen, R. A.; Atherton, J . I.
J . Chem. Soc., Perkin Trans. 1 1994, 1281.
(12) (a) Preparation: Miller, H. N.; Greenlee, K. W.; Derfer, J . M.;
Boord, C. E. J . Org. Chem. 1954, 19, 1882. (b) Proton spectrum:
Bernadou, F.; Mesnard, D.; Miginiac, L. J . Chem. Res., Miniprint 1978,
1, 1501. (c) Carbon spectrum: Dubois, J . E.; Doucet, J . P. J . Chem.
Res., Miniprint 1980, 3, 1101.
(13) (a) Preparation: Vaughn, T. H.; Vogt, R. R.; Nieuwland, J . A.
J . Am. Chem. Soc. 1934, 56, 2120. (b) Proton spectrum: Vinczer, P.;
Kovacs, T.; Novak, L. Org. Prep. Proced. Int. 1989, 21, 232. (c) Carbon
spectrum: Bernassau, J . M.; Bertranne, M.; Collongues, C.; Fetizon,
M. Tetrahedron 1985, 41, 3063.
(14) (a) Preparation and proton spectrum: Bock, H.; Rittmeyer, P.;
Stein, U. Chem. Ber. 1986, 119, 3766. (b) Carbon spectrum: Fraenkel,
G.; Pramanik, P. J . Chem. Soc., Chem. Commun. 1983, 1527.
(15) a) Proton and carbon spectrum: Aithen, R. A.; Atherton, J . I.
J . Chem. Soc., Perkin Trans. 1 1994, 1281.
r-(Dibr om om eth yl)ben zen em eth a n ol 4-Meth ylben zen e-
su lfon a te (4i): white solids; yield 56%; mp 64-66 °C; 1H NMR
δ 2.37 (s, 3H), 5.6-5.8 (m, 2H), 7.17 (d, J ) 8.1 Hz, 2H), 7.2-
7.4 (m, 5H), 7.63 (d, J ) 8.4 Hz, 2H); 13C NMR δ 21.6, 44.1,
84.8, 127.9, 127.9, 128.2, 129.51, 129.55, 133.2, 133.7, 144.9.
Anal. Calcd for C15H14Br2O3S: C, 41.50; H, 3.25; S, 7.39; Br,
36.81. Found: C, 41.47; H, 3.38; S, 7.56, Br, 36.57.
P r ep a r a tion of Acetylen es (5a -g). The following procedure
for cyclopropyl acetylene 5a is representative for the conversion
of both dichloro- and dibromosulfonates using methyllithium.
(16) (a) Preparation: J ohnson, J . R.; McEwen, W. L. J . Am. Chem.
Soc. 1926, 48, 469. (b) Proton and carbon spectra: Maercker, A.;
Fischenich, J . Tetrahedron 1995, 37, 10209.