Organocatalytic Enantioselective Michael–Michael–Henry Reaction Cascade. An Entry to Highly Functionalized Hajos–Parrish-Type Ketones with Five to Six Contiguous Stereogenic Centers and Two Quaternary Carbons

An organocatalytic enantioselective reaction of 2-methylcyclopentane-1,3-dione, nitroalkene, and α,β-unsaturated aldehyde with the diphenylprolinol catalyst was developed to give the highly functionalized Hajos–Parrish-type ketones with five to six contiguous stereocenters and two quaternary carbon stereogenic centers with high diastereoselectivity and enantioselectivity. The structures of the adducts were unambiguously confirmed by single-crystal X-ray crystallographic analyses of the appropriate products.