Synthese von racemischen,isomeren Desoxo-4, 14-didemethyl-cassain-Derivaten. 4. Mitteilung über Cassain-Analoga

For the synthesis of demethyl analogues of Erythrophleum alkaloids, the tricyclic ketone 14 (trans-anti-trans) was prepared. The Horner reaction on 14 led to a mixture of cis/trans compounds, which could be separated into the homogeneous racemic isomers 21 and 22 . These compounds were transformed into the corresponding 2-dimethylamino-ethyl esters of their 3-dehydro and 3-O-carbamoyl derivatives.