No abstract

Es wird eine Synthese für eine neue Reihe von Prostaglandin‐Analoga, den I l‐Desoxy‐7‐oxa‐pro.

Die V‐katalysierten Epoxidationen von olefinischen Alkoholen wie (I), (IIIa)‐(IIIc) bzw. (V) verlaufen z.T. in hohem Maße stereoselektiv (Zahlenangaben in Klammern bezeichnen die Stereoselektivitäten); mit den Olefinen (IIId) sowie (VII) ‐ dem (Id)‐E‐Isome‐ ren ‐ ist die Stereoselektivität jedoch geringer bzw. wird fast völlig verloren.

A synthesis of ll-deoxy-7-oxa prostanoids is presented. The synthesis of this new series of prostaglandin analogues commences with cis-2,3-epoxycyclopentanol (1), protected as an appropriate ether. The key step is the highly regioselective opening of that epoxide with an alkynyl alane reagent. For definition of the scope of that reaction, a brief study of the behavior of other carbon-centered nucleophiles with epoxide 1 was undertaken. It was found that only the alanyl reagent is selective in the desired direction. A rationalization for that selectivity is offered.Following the synthesis herein, over 30 analogues were prepared. Among them are eight optically pure compounds, including four isomers of 1 l-deoxy-7-oxaprostaglandin Ev