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 CF₃-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 β-amino epoxides, analogues of key precursors of various HIV protease inhibitors.