Diastereoselective Ring-Rearrangement Metathesis to Set the Stereochemistry of All-Carbon Quaternary Centres

A highly diastereoselective ring-rearrangement metathesis of cyclopentene derivatives containing all-carbon quaternary centres is reported. This tandem metathesis process provides cyclohexenes derivatives with two contiguous stereogenic centres, one of which is an all-carbon quaternary stereogenic centre, in high yields and excellent diastereoselecitivity. The efficacy of this methodology is showcased in the total synthesis of spiropiperidine alkaloid nitramine. In the meantime, it has been found that metathesis of the corresponding acyclic triene derivatives affords the same products with the same level of efficiency and diastereoselectivity.