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Dichloroketene−Chiral Olefin-Based Approach to Pyrrolizidines: Highly Stereocontrolled Synthesis of (+)-Amphorogynine A
journal contribution
posted on 2003-04-24, 00:00 authored by Caroline Roche, Philippe Delair, Andrew E. GreeneA highly stereoselective route to (+)-amphorogynine A, a novel pyrrolizidine recently isolated from the New Caledonian plant Amphorogynine
spicata, has been realized. The key step in the approach is a diastereoselective [2 + 2] dichloroketene−chiral enol ether cycloaddition (dr ≥
93:7) to access a dichlorocyclobutanone intermediate, which is converted into the alkaloid natural product via a pyrrolidinone derivative.