Synthesis of Nitrogen-Functionalized Cyclohexanes Using Chemoselective Conjugate Addition of Phenyllithium to Linear ω-Nitro-α,β,ψ,ω-Unsaturated Ester and Subsequent Stereoselective Intramolecular Nitro-Michael Cyclization

Abstract

Nitrogen-functionalized cyclohexane derivatives with three contiguous chiral centers were synthesized by nitroalkene-selective conjugate addition of phenyllithium to a ω-nitro-α,β,ψ,ω-unsaturated ester and subsequent stereocontrolled intramolecular nitro-Michael cyclization with cesium fluoride and a quaternary ammonium bromide. The cyclohexanes were applicable to the total synthesis of α-, β- and γ-lycoranes.