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DOI:10.15227/orgsyn.068.0182

Organic Syntheses, Coll. Vol. 8, p.609 (1993); Vol. 68, p.182 (1990).

(Z)-4-(TRIMETHYLSILYL)-3-BUTEN-1-OL[3-Buten-1-ol, 4-(trimethylsilyl)-, (Z)-]

Submitted by Larry E. Overman, Mark J. Brown, and Stephen F. McCann1.
Checked by Ronald C. Newbold and Andrew S. Kende.

1. ProcedureA. Preparation of 4-(trimethylsilyl)-3-butyn-1-ol. A flame-dried, three-necked, 2-L, round-bottomed
flask is fitted with a 1-L pressure-equalizing addition funnel, a mechanical stirrer, and a nitrogen inlet.
The flask is flushed with dry nitrogen and charged with 3-butyn-1-ol (Note 1) (freshly distilled, 31.4 g,0.448 mol) and 900 mL of anhydrous tetrahydrofuran (Note 2). The stirred solution is cooled to 0°C
under nitrogen and to it is added over 1 hr a solution of ethylmagnesium bromide in tetrahydrofuran(493 mL of 2.0 M solution, 0.986 mol) (Note 1). The resulting heterogeneous mixture is rapidly stirred
at 0°C for 1 hr, allowed to warm to room temperature for 1 hr, and then recooled to 0°C. To this mixture
is slowly added over 30 min with rapid stirring freshly distilled (Note 3) chlorotrimethylsilane (125 mL,0.986 mol). The mixture is stirred for 1 hr at 0°C and allowed to warm to room temperature over 1–2 hr.
The entire reaction mixture is poured slowly with rapid stirring into a 4-L Erlenmeyer flask that
contains 1 L of ice-cold 3 M hydrochloric acid, and is stirred at 25°C for an additional 2 hr. The organic
phase is separated and the aqueous phase is extracted with three 200-mL portions of ether.
The combined organic phases are washed with two 200-mL portions of water, four 200-mL portionsof saturated sodium bicarbonate solution, and two 200-mL portions of saturated sodium chloride. Theorganic phase is dried over anhydrous magnesium sulfate, filtered, and concentrated under reducedpressure at room temperature using a rotary evaporator. The crude product is distilled through a shortpath distillation apparatus under reduced pressure to give 45.2 g (0.318 mol, 71% yield) of 4(trimethylsilyl)-3-butyn-1-ol, bp 78–79°C (10 mm), as a colorless liquid (Note 4) and (Note 5).
B. Preparation of (Z)-4-(trimethylsilyl)-3-buten-1-ol. A dry, 250-mL, round-bottomed flask with astirring bar is charged with 8.84 g (0.062 mol) of 4-(trimethylsilyl)-3-butyn-1-ol, 0.4 g of 5% palladiumon barium sulfate (Note 6), 0.45 g of synthetic quinoline (Note 7), and 78 mL of methanol. The flask isplaced in a hydrogenation apparatus equipped with a gas burette, and the stirred mixture is thoroughly
purged with nitrogen. The nitrogen is then replaced by hydrogen and the reaction mixture is stirred at
atmospheric pressure and room temperature until 1.46 L (0.065 mol) of hydrogen is consumed. Theflask is flushed with nitrogen and the solution is filtered through a thick pad of Celite. The filtrate isconcentrated on a rotary evaporator at room temperature to afford 10–15 mL of an oil, which is diluted
with 150 mL of ether. The ether solution is thoroughly washed once with 200 mL of ice-cold 0.2 M
sulfuric acid, then once with 20 mL of 5% sodium bicarbonate solution. The ether layer is dried overanhydrous magnesium sulfate, filtered, and concentrated to yield 8.4 g (0.058 mol) of the crude buten-1ol (Note 8). Short-path distillation under reduced pressure gives 7.60 g (0.0527 mol, 85% yield) of (Z)4-(trimethylsilyl)-3-buten-1-ol, bp 95–100°C (25 mm) as a colorless liquid (Note 9) and (Note 10).

2. Notes1. The reagents, 3-butyn-1-ol and 2.0 M ethylmagnesium bromide in tetrahydrofuran, were purchasedfrom Aldrich Chemical Company, Inc. The ethylmagnesium bromide concentration can be easily
checked by titration with menthol using 1,10-phenanthroline as indicator.2
2. Tetrahydrofuran was distilled from sodium and benzophenone under a nitrogen atmosphere.
3. Chlorotrimethylsilane was purchased from Aldrich Chemical Company, Inc., and was distilled fromcalcium hydride under an atmosphere of nitrogen immediately prior to use.
4. The product, 4-(trimethylsilyl)-3-butyn-2-ol, shows the following proton NMR spectrum at 300 MHzin CDCl3 δ: 0.03 (s, 9 H, SiCH3), 1.8 (broad s, 1 H, OH), 2.47 (t, 2 H, CH2), 3.67 (m, 2 H, CH2OH); andinfrared spectrum (neat) cm−1: 3350 (very broad), 2178, 1250, 1031, 894, 842, 760.
5. Similar yields can be obtained in this silylation by using the chloromagnesium salt (frombutylmagnesium chloride) as described in Org. Synth., Coll. Vol. VIII 1993, 606.
6. The 5% palladium on barium sulfate was purchased from Engelhard Industries, Newark, NJ.
7. Synthetic quinoline was purchased from Aldrich Chemical Company, Inc. and was distilled prior touse.
8. The proton NMR spectrum of the crude buten-1-ol was essentially identical to that of the distilled
product, except for traces of solvent. This crude silylbuten-1-ol was of sufficient purity for thetetrahydropyridine synthesis described in the next procedure.
9. Distilled product showed a proton NMR at 250 MHz in CDCl3 as follows δ: 0.14 (s, 9 H, SiCH3),
1.61 (broad s, 1 H, OH), 2.37–2.46 (m, 2 H, CH2CH2OH), 3.68 (broadened t, 2 H, J = 6.5, CH2OH),
5.66–5.71 (dt, 1 H, J = 14.1, J = 1.2, Me3SiCH=CHR), 6.29 (overlapping dt, 1 H, J = 14.1, J = 7.1,
R3SiCH=CHR). Gas chromatographic analysis using a 25-m 5% methylphenylsilicone column showedthat this sample was a 92:8 mixture of Z and E isomers and contained <2% of other impurities.
10. The submitters report that Z-4-(trimethylsilyl)-3-buten-1-ol of >98% isomeric purity can be obtainedin ca. 60% overall yield by a more lengthy sequence involving hydroalumination–protonolysis3 of thetetrahydropyranyl (THP) ether of 4-(trimethylsilyl)-3-butyn-1-ol4 followed by cleavage5 of the THPether with pyridinium p-toluenesulfonate in methanol. This sequence is less convenient for the
tetrahydropyridine synthesis described in the next procedure, since the isomeric purity of the vinylsilane
is not important for the cyclization reaction.6

3. Discussion
The direct silylation of 3-butyn-1-ol follows the Danheiser modification7 of the Westmuze–Vermeer8 method. The subsequent semihydrogenation is a modification9 of the Lindlar procedure andyields the Z-alkene isomer in >90% isomeric purity.
Another Organic Syntheses procedure10 illustrates one6 of the uses of the four-carbon organosilane
intermediates described in this preparation.
This preparation is referenced from:zOrg. Syn. Coll. Vol. 8, 358

References and Notes
1. Department of Chemistry, University of California, Irvine, CA 92717.
2. Watson, S. C.; Eastham, J. F. J. Organomet. Chem. 1967, 9, 165; Bergbreiter, D. E.; Pendergrass,E. J. Org. Chem. 1981, 46, 219.
3. Hammoud, A.; Descoins, C. Bull. Soc. Chim. Fr. 1978, 299.
4. Zweifel, G.; Lewis, W. J. Org. Chem. 1978, 43, 2739.
5. Miyashita, M.; Yoshikoshi, A.; Grieco, P. A. J. Org. Chem. 1977, 42, 3772.
6. Flann, C.; Malone, T. C.; Overman, L. E. J. Am. Chem. Soc. 1987, 109, 6097.
7. Danheiser, R. L.; Carini, D. J.; Fink, D. M.; Basak, A. Tetrahedron 1983, 39, 935.
8. Westmuze, H.; Vermeer, P. Synthesis 1979, 390.
9. Cram, D. J.; Allinger, N. L. J. Am. Chem. Soc. 1956, 78, 2518.
10. Overman, L. E.; Flann, C. J.; Malone, T. C. Org. Synth. Coll. Vol VIII 1993, 358.

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);(Registry Number)tetrahydropyranyl (THP) ether of 4-(trimethylsilyl)-3-butyn-1-ol
THP ethersulfuric acid (7664-93-9)hydrochloric acid (7647-01-0)
methanol (67-56-1)
ether (60-29-7)hydrogen (1333-74-0)
sodium bicarbonate (144-55-8)
sodium chloride (7647-14-5)
nitrogen (7727-37-9)
barium sulfate (7727-43-7)
Benzophenone (119-61-9)
sodium (13966-32-0)
palladium (7440-05-3)
Quinoline (91-22-5)
menthol (15356-60-2)
ethylmagnesium bromide (925-90-6)
magnesium sulfate (7487-88-9)
Tetrahydrofuran (109-99-9)
calcium hydride (7789-78-8)
3-butyn-1-ol (927-74-2)
1,10-phenanthroline (66-71-7)
CHLOROTRIMETHYLSILANE (75-77-4)

TETRAHYDROPYRIDINE
vinylsilane (7291-09-0)(Z)-4-(Trimethylsilyl)-3-buten-1-ol,3-Buten-1-ol, 4-(trimethylsilyl)-, (Z)-,Z-4-(trimethylsilyl)-3-buten-1-ol (87682-77-7)
Butylmagnesium chloride (693-04-9)4-(trimethylsilyl)-3-butyn-1-ol (2117-12-6)4-(trimethylsilyl)-3-butyn-2-ol (6999-19-5)
pyridinium p-toluenesulfonate
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