Yong-Zhou Hu and Derrick L. J. Clive
Vanillin and piperonal are each converted into methyl 2,3-dimethoxy-6-methyl-4-(prop-2-enyl)benzoate 12, and this is then elaborated into methyl 4-hydroxy-3-iodo-5,6-dimethoxy-2-methylbenzoate 24, which represents the aromatic unit of calicheamicin γ1I.