Asymmetric Synthesis of Dipropionate Derivatives through Catalytic Hydrogenation of Enantioenriched E-Ketene Heterodimers

A highly diastereoselective approach to dipropionate derivatives through Pd/C-catalyzed hydrogenation of enantioenriched E-ketene heterodimers is described. Catalytic hydrogenation of the E-isomer of ketene heterodimer β-lactones (12 examples) provides access to syn,anti-β-lactones (dipropionate derivatives) bearing up to three stereogenic centers (dr up to 49:1), and with excellent transfer of chirality (ee up to >99%).