A practical synthesis of 11-membered C 2-symmetric binaphthyl ketone (R)-1, a catalyst for asymmetric epoxidation, was developed. (±)-1,1'-Binaphthyl-2,2'-dicarboxylic acid [(±)-6] was efficiently resolved by (R)-(-)-1-cyclohexylethylamine to give (R)-6 in > 99% ee and in 38% yield. Condensation of the acid chloride derived from (R)-6 with 1,3-dihydroxyacetone dimer at 60-70 °C provided the desired chiral ketone (R)-1 in 61-63% yield without need for high dilution techniques.
A practical synthesis of 11-membered C2-symmetric binaphthyl ketone (R)-1, a catalyst for asymmetric epoxidation, was developed. This manuscript describes the single example of chiral resolution of (±)-1,1’-Binaphthyl-2,2’-dicarboxylic acid [(±)-6].
Several Recommendations for Improved Synthesis
Summary:
A practical synthesis of 11-membered C2-symmetric binaphthyl ketone (R)-1, a catalyst for asymmetric epoxidation, was developed. This manuscript describes the single example of chiral resolution of (±)-1,1’-Binaphthyl-2,2’-dicarboxylic acid [(±)-6].
The Reaction...