Organocatalytic Enantioselective Michael–Acetalization–Henry Reaction Cascade of 2‑Hydroxynitrostyrene and 5‑Oxohexanal for the Entry to the Hexahydro‑6<i>H</i>‑benzo[<i>c</i>]chromenones with Four Consecutive Stereogenic Centers and an Approach to Aflatoxin Analogues

A domino reaction with the organocatalytic enantioselective Michael–acetalization–Henry reaction of 2-hydroxynitrostyrene and 5-oxohexanal was developed for the synthesis of hexahydro-6H-benzo­[c]­chromenones with four consecutive stereogenic centers and high enantioselectivity (up to >99% ee). The transformation of a NaBH4-reduced adduct to the aflatoxin system via the Nef-cyclization process was achieved by the assistant of ZnBr2.