| Abstract
| - Syntheses of the three key building blocks (65, 98, and 100) required for the total synthesis ofthe proposed structure of azaspiracid-1 (1a) are described. Key steps include a TMSOTf-induced ring-closing cascade to form the ABC rings of tetracycle 65, a neodymium-catalyzed internal aminal formationfor the construction of intermediate 98, and a Nozaki−Hiyama−Kishi coupling to assemble the requiredcarbon chain of fragment 100. The synthesized fragments, obtained stereoselectively in both theirenantiomeric forms, were expected to allow for the construction of all four stereoisomers proposed aspossible structures of azaspiracid-1 (1a−d), thus allowing the determination of both the relative and absolutestereochemistry of the natural product.
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