Fig. 3. Substrate scope in isomerization/α-Michael addition reaction.

Unless otherwise noted, all reactions were performed with Y(OTf)₃/L₃-RaPr₂ (1:1, 2.5 mol%), 1 (0.20 mmol), NEt₃ (10 mol%) in toluene (1.0 mL) at 25 °C under N₂ atmosphere. The yield was based on isolated anti-isomer. The dr value was determined by ¹H NMR of crude products. The ee value was determined by HPLC analysis on chiral stationary phases. The substrates 1l and 1n–1r were used as Z/E mixutres. [a] 5 mol% catalyst was used for 2s and 2t. [b] With 5 mol% Y(OTf)₃/L₃-RaPr₂-1-Ad as a catalyst and CH₂Cl₂ as a solvent in the absence of NEt₃ for 2u–2w.