Fig. 2: Optimized conditions for the synthesis of enantioenriched exocyclic alkene frameworks.

A One-pot synthesis of exocyclic alkene frameworks. B Screened chiral Lewis base catalysts for the synthesis of 1a. C The -CN group of 4a was changed by other groups in the presence of optimal catalyst at 0 °C. MBH, Morita–Baylis–Hillman.