FIGR ID=ol702947nn00002>f7/10/i04/figures/ol702947nn00002.gif" ALIGN="left" HSPACE=5> |
The reaction o
f chiral 5,6-dihydro-2
H-1,4-oxazin-2-ones with TMSCF
3 in the presence o
f a suitable activator leads to tri
fluoromethyl lactols,which can be selectively reduced to
anti-
fchars/beta2.gi
f" BORDER=0 ALIGN="middle">-amino-
fchars/alpha.gi
f" BORDER=0>-tri
fluoromethyl alcohols. The corresponding syn diastereoisomers are obtained when thestarting imines are reduced and the nitrogen atom is conveniently protected. In addition, a novel rearrangement o
f the CF
3 group in the lactolintermediates has been observed. This represents a
formal CF
3 addition to the imine
function in the starting substrates.