Two structurally dissimilar, chiral fluoro ketones have been prepared and their potential as enantioselective catalysts for asymmetric epoxidation with Oxone has been evaluated. The tropinone-based ketone (-)-5 was easily prepared and showed excellent reactivity but only modest enantioselectivity. The biphenyl-based ketone (-)-6 was prepared in a somewhat lengthy synthesis (along with its monofluoro and geminal fluoro analogues). This ketone exhibited only modest reactivity; 30 mol % of (-)-6 was needed to bring about complete conversion in a reasonable time. The enantioselectivity of this catalyst was generally much higher, but again very substrate dependent.
ASJC Scopus subject areas
- Organic Chemistry