Total Synthesis of (±)-α- and β-Lycoranes by Sequential Chemoselective Conjugate Addition−Stereoselective Nitro-Michael Cyclization of an ω-Nitro-α,β,ψ,ω-unsaturated Ester

An ω-nitro-α,β,ψ,ω-unsaturated ester underwent a chemoselective conjugate addition of a nitroolefin moiety with aryllithium to produce a ψ-aryl-ω-nitro-α,β-unsaturated ester, which was then stereoselectively cyclized by intramolecular nitro-Michael reaction giving a functionalized cyclohexane applicable to the total synthesis of (±)-α- and β-lycoranes.