Convenient One-Pot Synthesis of Allylsilanes from Enolizable Ketones

Abstract

A convenient one-pot synthesis of allylsilanes from enolizable methyl aryl ketones has been developed. The first step involves nucleophilic addition of the trimethylsilylmethyl group to ketones using the alkylation method developed by Ishihara with slight modification to generate the corresponding β-silylalkoxides. The second step entails addition of diisobutylaluminum chloride and heating at about 130 °C overnight to afford allylsilanes in fair yields.

Key words

abnormal Peterson olefination - allylsilane - one-pot synthesis

• References and Notes


For examples of synthetic uses of allylsilanes, see:
• 1a Brook MA. Silicon in Organic, Organometallic, and Polymer Chemistry. Wiley; Chichester: 2000
• 1b Fleming I, Dunoguès J, Smithers R. Organic Reactions . John Wiley & Sons, Inc; New York: 2004: 57-575
• 1c Hosomi A, Endo M, Sakurai H. Chem. Lett. 1976; 5: 941
• 1d Fleming I, Barbero A, Walter D. Chem. Rev. 1997; 97: 2063
• 1e Hosomi A, Sakurai H. Tetrahedron Lett. 1976; 1295
• 1f Sakurai H, Hosomi A, Hayashi J. Org. Synth. 1984; 62: 86
• 1g Masse CE, Panek JS. Chem. Rev. 1995; 95: 1293
• 1h Denmark SE, Fu J. Chem. Rev. 2003; 103: 2763

For examples of the preparation of allylsilanes, see:
• 2a Hayashi S, Hirano K, Yorimitsu H, Oshima K. J. Am. Chem. Soc. 2007; 129: 12650
• 2b Murakami K, Yorimitsu H, Oshima K. J. Org. Chem. 2009; 74: 1415
• 2c Bhushan V, Lohray BB, Enders D. Tetrahedron Lett. 1993; 34: 5067
• 2d Bunnellem WH, Narayanan BA. Tetrahedron Lett. 1987; 28: 6261
• 2e Fleming I, Marchi D. Synthesis 1981; 560
• 3 Batesky DC, Goldfogel MJ, Weix DJ. J. Org. Chem. 2017; 82: 9931
• 4 Peterson DJ. J. Org. Chem. 1968; 33: 780
• 5 Kwan ML, Battiste MA. Tetrahedron Lett. 2002; 43: 8765
• 6 Kwan ML, Yeung CW, Breno KL, Doxsee KM. Tetrahedron Lett. 2001; 42: 1411
• 7 Elimination of the β-silyl alkoxides with alanes (not Tebbe’s reagent) requires higher temperatures and prolonged reflux time (several days).
• 8a Imamoto T, Takiyama N, Nakamura K, Hatajima T, Kamiya Y. J. Am. Chem. Soc. 1989; 111: 4392
• 8b Krasovskiy A, Kopp F, Knochel P. Angew. Chem. Int. Ed. 2006; 45: 497
• 8c Metzger A, Gavryushin A, Knochel P. Synlett 2009; 1433
• 8d Hatano M, Ito O, Suzuki S, Ishihara K. J. Org. Chem. 2010; 75: 5008
• 9 Lucas HJ. J. Am. Chem. Soc. 1930; 52: 802
• 10 Mo J, Xu L, Xiao J. J. Am. Chem. Soc. 2005; 127: 751
• 11 Pandey SK, Greene AE, Poisson J. J. Org. Chem. 2007; 72: 7769
• 12 Fryszkowska A, Fisher K, Gardiner JM, Stephens GM. J. Org. Chem. 2008; 73: 4295
• 13 Liu J, Chu L, Qing F.-L. Org. Lett. 2013; 15: 894
• 14 Gupton JT, Layman WJ. J. Org. Chem. 1987; 52: 3683
• 15 Walkowiak J, Martinez del Campo T, Ameduri B, Gouverneur V. Synthesis 2010; 1883
• 16 Cai G, Zhou Z, Wu W, Yao B, Zhang S, Li X. Org. Biomol. Chem. 2016; 14: 8702
• 17 Isagulyants VI, Kustanovich ZD, Dessuki AM. Zh. Prikl. Khim. 1967; 40: 1355

For examples of reactions of Grignard reagents with nitro-compounds, see:
• 18a Gilman H, McCracker R. J. Am. Chem. Soc. 1929; 51: 821
• 18b Bartoli G, Bosco M, Dalpozzo R. Tetrahedron Lett. 1985; 26: 115
• 18c Sapountzis I, Knochel P. Angew. Chem. Int. Ed. 2002; 41: 1610
• 19 Allylsilane Synthesis; General ProcedureTo a 100 mL Schlenk flask, ZnCl₂ (10 mol%) was added and melt-dried with a heat gun under reduced pressure (5 Torr, 5 min). LiCl (170 mol%) was then added, followed by heating with a heat gun under reduced pressure (5 Torr, 5 min). After cooling back to room temperature, trimethylsilylmethyl magnesium chloride (1 M in diethyl ether; 130 mol%) was added to the mixed dried salts under argon. The resulting heterogeneous mixture was allowed to stir for 15 min at room temperature followed by cooling to 0 °C. The requisite aryl methyl ketone (500 mg) was added dropwise by using a syringe to the heterogeneous mixture over 1 h at 0 °C and the resulting mixture was allowed to stir for an additional 2 h at 0 °C. Diisobutylaluminum chloride (140 mol%) and anhydrous THF (20 mL) were then added to the mixture at 0 °C. This mixture was then transferred by using a cannula from the 100 mL Schlenk flask to a 150 mL pressure flask. The pressure flask was capped and heated at 130 °C for 15 h. The reaction was quenched by washing the mixture with 10% sodium tartrate solution and the mixture was extracted with diethyl ether. The ether extract was dried over MgSO₄. Gravity filtration followed by solvent evaporation gave oily allyl silane products.[(2-Phenyl)allyl]trimethylsilane (1): ¹H NMR (300 MHz, CDCl₃): δ = 7.42–7.20 (m, 5 H), 5.14 (d, J = 1.8 Hz, 1 H), 4.88 (d, J = 1.8 Hz, 1 H), 2.03 (d, J = 1.2 Hz, 2 H), –0.09 (s, 9 H).[2-(4-Fluorophenyl)allyl]trimethylsilane (2): ¹H NMR (300 MHz, CDCl₃): δ = 7.34–7.30 (m, 2 H), 7.00–6.85 (m, 2 H), 5.05 (d, J = 1.8 Hz, 1 H), 4.83 (s, 1 H), 1.97 (d, J = 0.9 Hz, 2 H), –0.12 (s, 9 H).[2-(4-Chlorophenyl)allyl]trimethylsilane (3): ¹H NMR (300 MHz, CDCl₃): δ = 7.35–7.28 (m, 4 H), 5.11 (d, J = 1.5 Hz, 1 H), 4.87 (d, J = 0.9 Hz, 1 H), 1.98 (d, J = 0.9 Hz, 2 H), 0.10 (s, 9 H).[2-(4-Bromophenyl)allyl]trimethylsilane (4): ¹H NMR (300 MHz, CDCl₃): δ = 7.47–7.26 (m, 4 H), 5.12 (d, J = 1.8 Hz, 1 H), 4.89 (d, J = 1.5 Hz, 1 H), 1.98 (d, J = 0.9 Hz, 2 H), –0.08 (s, 9 H).[2-(4-Methoxyphenyl)allyl]trimethylsilane (5): ¹H NMR (300 MHz, CDCl₃): δ = 7.44–7.26 (m, 2 H), 6.90–6.80 (m, 2 H), 5.10 (s, 1 H), 4.79 (s, 1 H), 3.80 (s, 3 H), 1.98 (s, 2 H), –0.08 (s, 9 H).[2-(4-Methylphenyl)allyl]trimethylsilane (6): ¹H NMR (300 MHz, CDCl₃): δ = 7.44–7.11 (m, 4 H), 5.13 (d, J = 1.8 Hz, 1 H), 4.84 (s, 1 H), 3.56 (s, 3 H), 1.98 (s, 2 H), –0.08 (s, 9 H).[2-(4-Ethylphenyl)allyl]trimethylsilane (7): ¹H NMR (300 MHz, CDCl₃): δ = 7.44–7.11 (m, 4 H), 5.12 (d, J = 1.5 Hz, 1 H), 4.84 (d, J = 0.9 Hz, 1 H), 2,65 (m, 2 H), 2.08 (s, 2 H), 1.25 (m, 3 H), –0.08 (s, 9 H).