Organocatalytic Enantioselective Michael–Michael–Michael–Aldol Condensation Reactions: Control of Five Stereocenters in a Quadruple-Cascade Asymmetric Synthesis of Highly Functionalized Hexa­hydro­phenan­threnes

A cascade organocatalysis has been developed for the enantioselective synthesis of a highly functionalized hexahydrophenanthrene-2-carbaldehyde containing five contiguous stereogenic centers with high diastereoselectivity and high enantioselectivity (>99% ee). The one-pot method comprises a cascade of organocatalytic Michael–Michael–Michael–aldol reactions of 2-methyl-1,5-dinitro-3-((E)-2-nitrovinyl)­benzene and α,β-unsaturated aldehydes (e.g., cinnamaldehyde). The structure and absolute configuration of a product were confirmed by X-ray analysis of an appropriate derivative.