The synthesis is aimed at the unknown hydrocarbon 5, which is expectedlaSc to be thermally unstable with respect to 1. Although all attempts to convert the known ketone 9 directly to 5 by methylenation so far have led to intractable products, 6 two indirect methods are feasible (Scheme I).'Both involve protection of the endocyclic double bond of 9 before methylenation. In method A, the endocyclic double bond is restored by, respectively, a ...
![6-methylenebicyclo[3.1.0]hex-3-ene-2-one Structure](https://image.chemsrc.com/caspic/065/71946-85-5.png)
![benzoic acid,2,6-dimethylidenebicyclo[3.1.0]hexan-4-ol Structure](https://image.chemsrc.com/caspic/329/89032-31-5.png)
![1-(2,6-dimethylidene-4-bicyclo[3.1.0]hexanyl)propan-2-one Structure](https://image.chemsrc.com/caspic/291/89032-32-6.png)
![2,6-dimethylidenebicyclo[3.1.0]hexan-4-ol,methanesulfonic acid Structure](https://image.chemsrc.com/caspic/253/89032-33-7.png)
![2-(2,6-dimethylidene-4-bicyclo[3.1.0]hexanyl)-1-phenylethanone Structure](https://image.chemsrc.com/caspic/215/89032-34-8.png)
