Analogues of key precursors of aspartyl protease inhibitors: synthesis of trifluoromethyl amino epoxides

The synthesis of the title compound is described through original and tailored synthetic protocols. The addition of vinylmagnesium bromide to CF(3)-N-aryl and N-alkyl aldimines was efficient and did not require an activating N-substituent. The resultant CF3-allylamines were converted in an efficient and completely stereoselective route to syn CF3-epoxides 3 via formation of bromhydrins 8. The same sequence performed from the aldimine substituted with the methyl ether of the (R)-phenylglycinol provided the homochiral (R,R)-amino epoxide (de >98%). This study has allowed access to the novel racemic and homochiral trifluoromethyl beta-amino epoxides, analogues of key precursors of various HIV protease inhibitors.