Fig. 2: Strategies for synthesis of chiral exocyclic allenes.

a–c Previous works on synthesis of chiral exocyclic allenes. d This work: Cu(I)-catalyzed intramolecular reductive coupling of 1,3-enynes to enones.
a–c Previous works on synthesis of chiral exocyclic allenes. d This work: Cu(I)-catalyzed intramolecular reductive coupling of 1,3-enynes to enones.