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Evaluation of the biosynthetic proposal for the synthesis of marineosins A and B.

The first synthetic efforts toward marineosins A and B, novel spiroaminals from a Streptomyces actinomycete, are described by evaluation of the proposed biosynthesis. The hypothesized biosynthetic C1-C25 Diels-Alder substrate was prepared in 8 steps in 5.1% overall yield; however, the proposed biomimetic inverse-electron-demand hetero-Diels-Alder reaction failed to deliver the marineosin core. Molecular mechanics supports this observation.