Nitrogen → Mesitylene

General procedure for the kinetic resolution of racemic 3,5-dialkyl cyclopentenones. A flame dried Schlenk flask was charged with (S)-p-tol-BINAP (5 mol %) and toluene. To this solution CuCl (5 mol %) and NaOt-Bu (5 mol %) were added in a drybox (N2 atmosphere) and to the resulting light yellow solution PMHS (0.53 equiv.) was added at room temperature to give orange solution. Stirred for 20 minutes at room temperature then cooled down to the required temperature (see Kinetic Resolution Results table for reaction temperatures) and solution of substrate and mesitylene in toluene was dropwise added and stirred for 12 hours at the addition temperature. The optimal substrate's concentration is 0.1-0.4 M. The relative substrate and internal standard (mesitylene) amounts were determined by Hewlett-Packard 6890 gas chromatograph (50 to 250° C.). Reaction is quenched by addition of water and then stirring the organic phase with TBAF. Relative amounts of remaining starting material and internal standard were determined by gas chromatography and the conversion calculated. Then water added, extracted with diethyl ether, washed with brine, dried over anhydrous magnesium sulfate, and concentrated. Purified by flash chromatography. Eluent: hexane/ethyl acetate 8:1. The remaining starting was analyzed by HPLC and product was analyzed by HPLC or GC.

1. customA flame dried Schlenk flask
2. additionwas charged with (S)-p-tol-BINAP (5 mol %) and toluene
3. additionwas added at room temperature
4. customto give orange solution
5. temperaturethen cooled down to the required

ORD-Eintrag

ord-2f07bcf6306f42f4a4f42b644fb15c2d

Quelldatensatz

uspto-grants-2004_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06787655B2