Cyclohexanone, latent

Among the several screened cinchona derivatives, (DHQ)2AQN 6 was selected for a full optimization of the conditions (solvent and temperature). The reaction was carried out in DMF with a combination of benzoyl fluoride and ethanol as a latent source of HF. Enantioselectivities up to 92% ee were obtained with tetralones trimethylsilyl enol ethers Sa-d using 10 mol% of organocatalyst 6 (Table 7.1, entries 1-4). Indanone silyl enol ethers Se-g afforded the corresponding ketones 7e-g with lower selectivities (64—74% ee, Table 7.1, entries 5-7) while the 2,2,6-trimethyl-cyclohexanone was obtained with only 58% ee, the reaction being conducted at — 10 °C (data not shown in Table 7.1). 

---