Conjugate Addition−Dipolar Cycloaddition Cascade for the Synthesis of Benzo[a]quinolizine and Indolo[a]quinolizine Scaffolds: Application to the Total Synthesis of (±)-Yohimbenone
A highly efficient total synthesis of (±)-yohimbenone and a formal synthesis of (±)-emetine is described. The key element of the synthesis consists of a conjugate addition−dipolar cycloaddition of 2,3-bis(phenylsulfonyl)-1,3-butadiene with an appropriate oxime. The resulting cycloadducts are cleaved reductively to provide azapolycyclic scaffolds with strategically placed functionality for further manipulation to the target compounds.
mixtures, organic synthesis, organic compounds, cyclization, chemical synthesis