Catalytic Asymmetric Synthesis of Tertiary Alcohols and Oxetenes Bearing a Difluoromethyl Group

The catalytic asymmetric ene reaction
with difluoropyruvate as
an electrophile in the presence of a dicationic palladium complex
is shown. This is the reliable and practical catalytic asymmetric
synthesis for various α-CF2H tertiary alcohols in
high yields and enantioselectivities. The reaction with isobutene
can be catalyzed efficiently under solvent-free conditions with low
catalyst loading (up to S/C 2000). Furthermore, difluoropyruvate is
applicable to the [2 + 2] cycloaddition reaction in high yields and
enantioselectivities.