Synthesis of Chiral Cyclobutenes with All-Carbon Quaternary Stereocenters

Significance

The synthesis of enantioenriched molecules with all-carbon quaternary stereocenters is exceedingly difficult. The authors use a previously developed transition-metal-catalyzed ring expansion of chiral alkylidenecyclopropanes to access cyclobutenes with high regioselectivity and no loss in enantiopurity.