Bolourtchian, M

Zadmard, R

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Indian Journal of ChemistryVol. 37B, November 1998, pp. 1171-1173Synthesis of bistrimethylsilylatedhydroxy alkynesM Bolourtchian a, R Zadmard a & M R Saidi * bachemistry & Chemical Engineering Research Center of Iran,P.O. Box 14355-186, Tehran, I R Iran.bChemistry Department, Sharif University of Technology,P.O. Box 11365-8693, Tehran, I R of IranReceived 7 February 1997; acceptedirevised] 21 January1998Synthesis of several bistrimethylsilyl and a tristrimethylsilylhydroxyalkynes 2 is described. Addition of lithium trimethyl-silylacetylene to mono- or bistrimethyl-silylated aldehyde andketones (I) followed by work-up of the reaction mixtureaffords the desired compounds 2a-f with good to moderateyields. The products are mixtures of diastereomers withdiasterioselectivity of 50 to 68%.Alkynols having the terminal alkynyl carbon protectedwith a trimethylsilyl (TMS) group are conveniently andwidely used as organic synthons due to their reactivityand large variety of related synthetic transformation.Many of these silylated alkynols are biologically active,and the develop-ment of synthetic reaction is an area ofactive study!".It is well known that silicon groups are readily, butdiscriminately cleaved from carbons. Terminaltrimethyl-silyl group can be removed selectively inbistrimethylsilylated alkynols for further transforma-tion.The synthesis of silylated aldehydes and ketones hasbeen reported earlier6-IO• In this article we wish to reporta mild and efficient conversion of silylated aldehyde andketones to bissilylated alkynols having the terminalalkynyl carbon with a TMS-group. Silylated aldehydesand ketones were prepared by different methods asracemic mixtures.Treatment of a variety of silylated aldehydes orketones with lithium trimethylsilylacetylide at roomtemperature under an atmosphere of argon furnished theexpected bistrimethylsilylated alkynols 2a-f in good toNotemoderate yields. Both sterically hindered andconjugated silylated aldehydes or ketones were suitablesubstrates (entries 3, 5 and 6), as were dialkyl andarylalkyl silylated ketones (entries 1, 2). In the case ofalkynols 2a-d, mixtures of two diastereomers wereobtained with diasterioselectivity of 50 to 68%. Thefacial selectivity was interpreted as a result of bulkysubstituted groups in «- or ~-positions. The results areshown in Table I.Experimental SectionGeneral. Diethyl ether was distilled fromNalbenzophe-none under argon atmosphere. IH NMRand J3e NMR spectra were recorded on a Bruker Ac 80spectrometer in CDCI3• IR spectra were recorded on aPerkin-Elmer model 883. The diasterioselectivity wasdetermined by IH NMR analysis.General procedure for the preparation ofbistrimethyl-silyl alkynols 4. Ketone or aldehyde (2mmoles) was dissolved in 5 mL anhydrous diethyl ether,and the mixture placed in a three-necked flask, equippedwith a magnetic stirrer and a condenser. Thereafter, 0.23g (2.2 mmoles) of 56% solution of lithiumtrimethylsilylacetylide in THF was added during 30 minat room temperature under an atmosphere of argon.After stirring for an additional 2 hr at room temperature,0.15 g (3 mmoles) of powdered ammonium chloride wasadded, and the whole mixture stirred overnight. Water(20 mL) was added and the organic material extractedwith ether (2 x 20 mL). The organic layer was driedover CaCI2, and the solvent evaporated. The purematerial was obtained by bulb-to-bulb (kugelrohr)distillation. All the new products showed satisfactory Cand H analyses. IH NMR and J3e NMR of the majordisteriomer are given in Table Il,3,5- Diphenyl-I,5-bistrimethylsilyl-pent-I-yn-3-ol4a: A yellow viscous liquid after distillation usingkugelrohr distillation unit (oven temperature 100 "C,150 mm Hg); IR (film): 3485,2164, 1250,845 em".3-Methyl- 5 -phenyl- 1, 5-bistrimethylsilylpent-l-yne-3-ol 4b: A colourless viscous liquid, afterdistillation using kugelrohr distillation unit (oventemperature 100 -c, 150 mm Hg); IR (film): 3421,R1 0I 1\ 3 1) ether, room Temp., 4 hrR-?-C~-C-R + lMS-C::C Li ~Th1S R 2 2) NH4CI(aq.)R1 OHI IR-C-C- C-C:C-lMSI 12 13lMS R R1172 INDIAN J CHEM, SEC B, NOVEMBER 1998Table I - Products from the reaction of lithium trimethylsilylacetylide with silylated aldehydes and ketones .Entry Starting material Product Yield Ratio ofRI R2 R3(%) diastereomersROHI. ph H H ph,Ph-CH-CH2-C-C=C-TMS 75 59:41, ,TMS Ph (28)OHCH3,2. ph H H Ph-CH-CH2-C-C=C-TMS 70 68:32, \TMS a-i:3 (2b)0i3 OH3. ph H CH3 CH3I ,Ph-CH-CH-C-C=C- TMS 65 53:47I \TMS a-i:3 (2c)OH,4. ph H CH3 CH3 Ph-CH-C~-C-C=C-TMS 55 59:41ITMS (2d)a-i:3 0i3 OH a-i:35. CH3 CH3 HI I / 66~< a-i:3-C-~-C-CH=~I I CH3a-i:3TMS CIII (2e)CITMS6. H r-Oi:!-C- a-t:JITMSr- ?H r-a-i:3-T-~-T-~-T-CH3TMS C TMS~ (21)ITMS622165,1249,840 crn'.2,4-Dimetbyl-5-phenyl-l,5-bistrimethylsilyl-pent-l-yne-3-ol 4c: A pale yellow viscous liquid, afterdistillation using kugelrohr distillation unit (oventemperature 100 °C, 150 mm Hg); IR (film): 3441,2165,1252,847 cm-t.5-Phenyl-l,5-bistrimetbylsilyl-pent.-l-yne-3-o1 4d:A brown liquid, after distillation using ku~elrohrdistillation unit (oven temperature 100 °C, 150 mm Hg);IR (film): 3397,2169, 1250,840 em".6-Methyl-3-(2-metbyl-2-trimetbylsilylpropyl)-4-hexene-l-yne-3-ol 4e: An orange viscous liquid, afterdistillation using kugelrohr distillation unit (oventemperature 100 °C, 150 mm Hg); IR (film): 3429,2163,1250,840 cm'.5 -Methyl- 5 -trimethylsilyl- 3 -( 2-methyl- 2 -tri-methylsilylpropyl)hex-l-yne-3-o1 4f: A dark yellowviscous liquid, after distillation using kugelrohrdistillation unit (oven temperature 100 DC, 150 mm Hg);IR (film): 3440,2060, 1250, 839 cm'.AcknowledgementFunds for the purchase of a gas chromatograph[Volkswagen-Stiftung, Federal Republic of Germany] isTable n - 1H and \3e NMR spectral data of bis-and tris-trimethylsilylated alkynols 2Compd 1H NMR (eDCl3), \3e NMR (eDel3),~,ppm ~,ppm2a 0.00 (s, 9H), 0.24 (s, -2.84 (eH3), 0.15 (eH3),9H), 2.16 (s, IH), 32.50 (eH),45.39 (eH2),2.84 (d of d, J=8.9, 74.62 (e), 90.66 (e),·3.8. Hz, IH), 3.38- 125.91 (eH), 127.953.55 (m, 2H), 6.70- (eH), 128.17 (eH),7.88 (m, 10H). 128.60 (eH), 129.63(eH), 131.71 (eH),143.97 (e), 144.56 (e).2b 0.04 (s, 9H), 0.14 (s, 3.11 (eH3), -O.IO(eH3),9H), 1.22 (s, 3H), 29.86 (eH3), 33.39 (eH),2.18 (s, lH), 2.25- 43.28 (eH2), 70.25 (e),2.75 (m, 3H), 6.90- 109.62 (C), 113.17 (e),7.40 (rn, 5H). 124.36 (eH), 127.69(eH), 128.52 (eH),143.51 (e).2c 0.08 (s, 9H), 0.22 (s, -1.17 (eH3), -0.01 (eH3),911), 0.99 (d, J=4.1, 14.06 (eH3), 27.61 (eH3),Hz, 1H), 1.31 (d, 38.70 (CH), 44.69 (CH),J=7.1Hz, 3H), 1.58 72.99 (e), 103.11 (e),(s, 3H), 2.13-2.39 (m, 107.70 (e), 124.95 (eH),1H), 2.05 (s, 1H), 127.69(eH),7.22 (s, 5H). 130.73(eH), 141.44 (C).2d 0.00 (s, 9H), 0.22 (s, -2.97 (eH3), -0.01 (eH3),9H), 1.82-2.01 (m, 33.57 «nn, 60.67 (eH2),1H), 2.13 (s, lH), 78.62 (e), 106.98 (C),3.72 (t, J=4.5 Hz, 124.47(CH),1H), 4.02-4.38 (dd, 127.58(eH), 128.29J=8.51, lH), 7.15 (s, (eH), 142.53 (C).5H).2e 0.00 (s, 9H), 0.18 (s, -4.46 (eH3), -O.45(eH3),9H), 0.94 (s, 6H), 18.72 (eH3), 22.88(eH3),1.52 (s, lH), 1.74 (d, 26.78 (CH3), 49. 14(eH2),J=1.4 Hz, 3H), 1.86 69.79 (e), 103.50 (e),(s, 2H), 1.92 (d, 110.33 (C), 131.14 (eH),J=1.19 Hz, 3H), 5.39 134.49 (C).(m,IH).Table II - ContdNOTES 1173Table II - 1H and \3e NMR spectral data of bis- and tris-trimethylsilylated alkynols 2- ContdCornpd 1H NMR (eDeI3)~,ppm2f 0.00 (s, 18H), 0.17(s, 9H), 1.02 (s,12H), 2.17 (s, 4H),2.28 (s, IH)-4. 17(eH3), -0.49(eH3), 23.47 (eH3),30.67(C),49.99(eH2), 73.06(C),103.52 (C) •.11O.34(C).AcknowledgementFunds for the purchase of a gas chromatograph[Volkswagen-Stiftung, Federal Republic of Germany] isgratefully acknowledged. We thank Mr M M Mojtahedifor the preparation of starting materials.ReferencesBridges A J, Fedij V & Turowski E C, Chem Commum,1983,1093.2 Kuroda S, Katsuki T & Yamaguchi M, Tetrahedron Lett,28,1987,803.3 Pomet J, Damour D, Randrianoelina B & Miginia, L,Tetrahedron, 42, 1986, 2501.4 Lautens M & Huboux A ,H, Tetrahedron Lett, 42, 1990,3105; Soai K, ChemAbstr, 113,1990, 171485t.5 Lutjens H, Nowotny S & Knochel P, TetrahedronAsymmetry, 6, 1995, 2675.6 Calas R, Dounogues J & Bolourtchian M, JOrganometallic Chem, 26, 1971, 195.7 Dounogues J, Calas R, Bolourtchian M, Biran e &Duffaut N, J Organometallic Chem, 57,1973,55.8 Dounogues J, Bolourtchian M, Calas R, Duffaut N &Picard J, J Organometallic Chem, 43,1972, 157.9 Boulourtchian M & Saednya A, J Sci I R Iran, 1, 1990,277.10 Bou1ourtchian M & Saednya A, Bull Soc Chem Fr, II,1978, 170

Synthesis of bistrimethylsilylated hydroxy alkynes

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Synthesis of bistrimethylsilylated hydroxy alkynes

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