Novel synthetic approaches to the palmarumycin skeleton

Oxidation of readily available aminonaphthols 7a and 7b with activated manganese dioxide gives palmarumycin analogues 8a and 8b in good yield. The related benzoquinone monoacetals 10a–c undergo cycloaddition with 3-methoxy-2-pyrone at high pressure to give adducts 12a–c, also possessing the palmarumycin framework.