Catalytic Asymmetric Synthesis of Hexahydro-furofuran-3-ol and Its Pyran Derivatives

The catalytic asymmetric synthesis
of hexahydro-furofuran-3-ol,
a key fragment of HIV protease inhibitors, is reported. A signature
event is represented by the sequential metal catalysis that combines
the Pd-catalyzed asymmetric hydroalkoxylation of ene-alkoxyallene
and ring-closing metathesis (RCM). Notably, this unprecedented and
highly chemoselective approach allows for a unified access to pyranofuranol
and furopyranol derivatives.