Diastereoselective Birch reduction-alkylation reactions of bicyclic beta-alkoxy-alpha,beta-unsaturated carbonyl compounds and tricyclic analogues were investigated. Although the relative configuration of the product was altered according to the structure of the starting material, stereoselectivity of the reaction could be accounted for by similar reaction pathways. The product from the tricyclic beta-alkoxy-alpha,beta-unsaturated carbonyl compound corresponded to the trichothecene skeleton.
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