Application of the Rh(II) cyclization/cycloaddition cascade for the total synthesis of (±)-aspidophytine

A new strategy for the synthesis of (+/-)-aspidophytine has been developed and is based on a Rh(II)-catalyzed cyclization/dipolar cycloaddition sequence. The resulting [3+2]-cycloadduct undergoes an efficient Lewis acid mediated cascade that rapidly provides the complete skeleton of aspidophytine. The synthesis also features a mild decarbomethoxylation reaction.