Synthetic Studies Towards Crinine-Type Amaryllidaceae Alkaloids: Synthesis of (±)-Oxocrinine and Formal Synthesis of (±)-Crinine

Abstract

A flexible strategy leading to the synthesis of crinine-type Amaryllidaceae alkaloids, (±)-oxocrinine and (±)-crinine, has been developed. A notable feature in this synthetic route is the construction of tetrahydro-1 H-benzo[c]azepine framework using an intramolecular Heck reaction and the formation of the sterically congested spiro cyclohexenone intermediate with a Robinson annulation.