Advances in the stereoselective synthesis of antifungal agents and ...

Chapter 8 172In 10 ml of MTBE 100 mg of 1-(4-cyanophenyl)-2-propyn-1ol (±)-58e were suspended, 50 mg of lipase and 150 mg of vinylacetate wereadded. The reaction mixtures were stirred at room temperature for 7days, and monitored every 24h by chiral GC. The analysis wasquantitative and allowed the determination of the conversion and theenantiomeric excess of both product and starting material. Using thismethod ten different lipases were tested, see chapter 5, table 5.5 forqualitative results and enzymes tested. Only the lipases SAM I and SAMIIwere considered for futher applications.8.25 Synthesis of 1-aryl-2-propyn-1-ol acetate :8.25.1 General method a:To a solution of 1-phenyl-2-propyn-1ol (±)-58a (10 mmol) andpyridine (10 ml) at 0°C, acetanhydride (10 mmol) was added dropwiseover 30 min. Reactions were carried out under stirring at rt for 12 h. Thereaction mixture was poured into 1 N HCl solution and the productextracted with ethyl acetate. The organic phase was washed with 1 N HClsolution and saturated NaCl solution and finally dried over anhydrousNa 2 SO 4 . The crude oil was purified by flash chromatography on silicagel. 1-phenyl-2-propyn-1ol acetate (±)-60a was recovered in 95.5 %yield.See chapter 5, table 5.6 for substrates, products and chemical yields.8.25.2 General method b:To a solution of aryl propynol (±)-58 (10 mmol) and triethylamine(11 mmol) in dichloromethane (40 ml) at 0°C, acetyl chloride (10.5mmol) was added dropwise over 30 min. The reaction mixture wasstirred for 1 h at room temperature, it was then diluted with CH 2 Cl 2 andwashed consecutively with 1 N HCl solution, saturated NaCl solution andthen dried over anhydrous Na 2 SO 4. The crude product was so clean thatfurther purification was unnecessary.See chapter 5, table 5.6 for substrates, products and chemical yields.