Fig. 3: Scope of β,γ-alkynyl-α-imino esters.

Reaction conditions: 1 (0.10 mmol), 2a (0.20 mmol), Cu(BF₄)₂ ∙ H₂O (10 mol%), L8 (15 mol%), 4 Å MS (40 mg), acetone (1.0 ml), 0 °C, 24 h; the yield refers to isolated yield; the ee value was determined by HPLC.