Synthesis of the Tricyclic Core of the Marine Alkaloid Lepadiformine

Abstract

A stereoselective synthesis of the tricyclic core in ra­cemic form of the marine alkaloid Lepadiformine is described from 4-methoxy-3-pyrrolin-2-one (methyl tetramate). Key steps involve 5,5-dialkylation of the tetramate, metathesis closure to an A/C 1-azaspirocycle and stereoselective hydrogenation for the trans A/B 1-azadecalin system.

marine alkaloid - metathesis - silyloxypyrrole alkyl­ation - tetramate reduction - 1-azaspiro[4.5]decane

References

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Prepared from the phosphonium bromide in ref. [17b] by treatment with KOH.

Prepared from the bromide:

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Several papers have appeared on asymmetric synthesis of 5,5-disubstituted pyrrolidin-2-ones:

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