A chemoenzymatic total synthesis of the hirsutene-type sesquiterpene (+)-connatusin B from toluene

The first total synthesis of the hirsutene-type sesquiterpenoid natural product (+)-connatusin B (2) is reported. The cis-1,2-dihydrocatechol 3, which is obtained in enantiomerically pure form via the enzymatic dihydroxylation of toluene, served as the starting material. Diels-Alder cycloaddition and oxa-di-π-methane rearrangement reactions represent key chemical steps in the reaction sequence leading to the cyclopropane ring-fused linear triquinane 14. Reductive cleavage of the three-membered ring within this framework and various functional group interconversions then provide the title compound 2.