Studies on Biomimetic Singlet Oxygen Oxidations: Application to the Synthesis of the Alkaloid Simulenoline

The synthesis of the biologically active alkaloid simulenoline, isolated from the roots of Zanthoxylum simulans, is reported. The natural product was assembled from simple commercial reagents via initial domino Knoevenagel/oxa-6π-electrocyclization followed by a one-pot singlet-oxygen ene-reaction/reduction sequence. New insights of singlet oxygen reactivity with olefinic substrates have been revealed.