No abstract

The details of the previously observed lithium diethylamide isomerization of 2,3-epoxybicyclo [2.2.1] heptane to nortricyclanol have been examined. By deuterium labeling methods, it has been shown that reversible metalation occurs a t the epoxide ring and that base attack does not remove the ex0 hydrogens of the transannular bridge.The endo-5-methyl derivative 5 is transformed into the analogous tricyclic alcohol 7, whereas epoxide 6, with both transannular endo positions blocked with methyl groups, isomerizes to bicyclic ketone 9. Bornylene oxide gives camphor, epicamphor, and tricyclic alcohols 13 and 14. 2,3-Epoxybicyclo [2.2.2]octane gives ketone 19 along with minor amounts of tricyclic alcohol 20. 2,3-Epoxybicyclo[3.3.0]octane yields allylic alcohol 25 as well as lesser amounts of ketones 23 and 24. These results are used to outline the scope of the base-promoted isomerization of epoxides as a source of products derived from carbenoid insertion into transannular C-H bonds.These observations support a carbenoid mechanism for the rearrangement.

No abstract

Die Umlagerung zahlreicher Bicyclo(2,2,l )hepten‐ und Bicyclo(2,2,2)octenoxide, die aus den entsprechenden Olefinen mit Persäure erhalten wurden, in Gegenwart von Li‐amiden liefert neben Ketonen unter Cyclisierung Nortricyclanole und deren Homoverbindungen (siehe Formelschema).