Intramolecular diels-alder reaction with furan-diene. An expeditious entry into a functionalized gibbane.

A short synthesis of a functionalized gibbane is described. The key-step involves the intramolecular Diels-Alder reaction of furan-diene $\text{12}$, leading to a 3:1 ration of two diastereoisomers, tentatively identified as $\text{14a}$ and $\text{14b}$. The precursor $\text{12}$ is obtained form-m-methoxybenzoic acid in 7 steps.