Rh(I)-catalyzed intramolecular hydroacylation in ionic liquids

Rh(I)-catalyzed hydroacylation of 4-alkenal or 4,6-dienal using ionic liquids (ILs) as reaction media proceeded smoothly, giving cyclopentanone or cycloheptenone derivatives in good yields. It was found that the IL recovered after the reaction, which should contain the Rh(I) catalyst, could be recycled 5–10 times without the loss of catalytic activity and enantioselectivity (in the case of asymmetric hydroacylation).