Asymmetric Synthesis via Heterocyclic Intermediates, XLVII. Asymmetric Synthesis of (+)‐(1R,2S)‐allo‐Coronamic Acid

Abstract allo‐Coronamic acid (1) was synthesized in five steps enantiomerically and diastereomerically virtually pure by starting from the bislactim ethers of cyclo(‐L‐Val‐Gly‐) (3a) or cyclo‐(‐L‐tert‐Leu‐Gly‐) (3b) in an overall yield of 31%. The key step of this synthesis is the intramolecular alkylation of the lithium azaenolate derived from the allylic chloride 4.