A rapid synthesis of the C1-C13 fragment of biselynbyolide A and B is reported. The judicious use of catalytic transformations for C-C bond formation and stereocenter generation greatly minimizes the use of protecting groups and oxidation state changes, as compared to previously reported routes to similar fragments.

A general strategy for the synthesis of structurally and stereochemically related indolizidine and quinolizidine alkaloids was developed. The methodology involves regio‐ and stereoselective 1,3‐dipolar cycloadditions of simple nitrones with ephedrine‐derived alkylidenemorpholinones. The intermediate isoxazolidines can be converted into either the indolizidine or the quinolizidine motif depending on the nitrone and the substituent on the dipolarophile. The approach was applied to the synthesis of (+)‐epitashiromine and to the formal syntheses of (+)‐epilupinine and (+)‐tashiromine.

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