Enantioselective Catalytic Fluorinative Aza-semipinacol Rearrangement

An
efficient and highly stereoselective fluorinative aza-semipinacol
rearrangement is described. The catalytic reaction requires use of
Selectfluor in combination with the chiral, enantiopure phosphate
anion derived from acid L3. Under optimized conditions,
cyclopropylamines A were transformed into β-fluoro
cyclobutylimines B in good yields and high levels of
diastereo- and enantiocontrol. Furthermore, the optically active cyclobutylimines
were reduced diastereoselectively with L-Selectride in the corresponding
fluorinated amines C, compounds of significant interest
in the pharmacological industry.