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

Chapter 8 175Na 2 SO 4 . After removal of the solvent the resulting products wereseparated and purified by flash chromatography on silica gel. Theenantiomeric purities of the products were determinated by chiral GC.The enantiomeric excess of both the purified alcohol and the chloroacetatewere identical to those obtained directly from the reaction mixture.In no case indications for a racemization during the work up orpurification were found.See chapter 5, table 5.12 for products, starting materials, reactiontimes, E-values, % e.e. and chemical yields.8.29 Hydrolysis of enantiopure acetate (S)-60 and chloroacetate(S)-61:In 10 ml of satured K 2 CO 3 the acetate (S)-60 or the chloroacetate(S)-61 ( 2 mmol) were dissolved at 0°C. The raction mixture was stirredfor 30 min until the complete consumption of the starting material wasobserved on TLC.The mixture was diluted with ethylacetate and water,the organic phase was separated and washed with saturated NaCl and driedover anhydrous Na 2 SO 4 to afford the clean product (S)-(+)-58 which wasrecovered in high yield.See chapter 5, table 5.13 for substrates, products, % e.e andchemical yields.8.30 Synthesis of Aryl-2-benzo[b]furanyl carbinoles 27g,l and63a-d in racemic and enantiopure form via palladiumcatalyzedheteroannulation (general procedure).Argon was bubbled into a solution of tetramethylguanidine (TMG,376 µl, 3 mmol) in 2.5 ml of DMF for 15 min at 40°C before the additionof 2-iodophenol (220.01 mg, 1 mmol), bis-triphenylphosphine palladium(II) dichloride ( 17.5 mg, 0.025 mmol), CuI (4.5mg, 0.025 mmol) and 1-Phenyl-2-propyn-1-ol (±)-39a ( 123.9 µl, 1mmol). The mixture wasstirred under argon at 40°C for four hours, whereby the color changedfrom pale yellow to red/brown. After cooling, the reaction mixture wasdiluted with 1N HCl (100ml) solution and ethyl acetate (200ml). Theorganic layer was separated and washed with water, saturated NaCl