A general procedure for synthesis of bicyclo[n.2.0]alkane-l,n-diols is described. The synthesis involves thermal cycloaddition of dichloroketene to a cyclic alkene to generate the bicyclic skeleton (e.g., 6), cine substitution with a carboxylate anion to give a bridgehead oxygen substituent (e.g., 12), removal of the remaining halogen with chromous chloride, and reduction to give diol (e.g., 14). The procedure allows for the synthesis of either cis or trans diols selectively.

Trichloracetylbromid (I) liefert in Gegenwart von Cyclohexen (II) bei der Behandlung mit Zink unter intermediärer Bildung von Dichlorketen das Addukt (III), das mit Natriumäthylat, Triäthylammoniummesitoat oder"Triäthylammoniumacetat zu (IVa)‐(IVc) substituiert wird.