Asymmetric Synthesis of Enantioenriched Cyclic Allene Precursors

Cyclic allenes are reactive intermediates that require in situ generation from stable precursors. Enantioenriched variants remain limited due to reliance on costly resolutions and low-yielding asymmetric methods. Using a chiral auxiliary, precursors of unsubstituted, electron-withdrawing, and electron-donating types were synthesized in high yield and ee, with absolute configuration confirmed by X-ray analysis. The strategy is scalable and provides practical access to cyclic allene precursors for studies of stereoretention in cycloaddition reactions.