Synthesis
GENERAL METHOD: A mixture of phenylacetylene (0.5 mmol), isopropanol pinacol borate (0.75 mmol), triphenylphosphine (PPh3), ligand L1 (1 mol%), silver chloride (AgCl, 1 mol%) and cesium carbonate (Cs2CO3, 1.1 mmol) in N,N-dimethylformamide (DMF, 5 mL) was reacted under argon (Ar) The reaction was stirred at 50°C for 24 hours under the protection of argon (Ar). After completion of the reaction, the reaction mixture was acidified with 1 M hydrochloric acid solution in an ice-water bath and the aqueous phase was extracted with ethyl acetate (three times). The combined organic layers were washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford the target compound 4,4,5,5-tetramethyl-2-(phenylalkynyl)-1,3,2-dioxaborolane.
References
[1] Organic Letters, 2014, vol. 16, # 17, p. 4670 - 4673
[2] Journal of the American Chemical Society, 2007, vol. 129, # 42, p. 12634 - 12635
[3] Tetrahedron, 2014, vol. 70, # 35, p. 5815 - 5819
[4] Angewandte Chemie - International Edition, 2012, vol. 51, # 2, p. 521 - 524
[5] Patent: WO2010/146172, 2010, A2. Location in patent: Page/Page column 37
