Ruthenium catalyzed ring rearrangement: a rapid entry to substituted aza- and oxacycles

A ring-closing metathesis (RCM) and a ring-opening metathesis (ROM) are combined in a domino process giving access to a variety of aza- and oxacyles, equipped with highly functionalized side chains, starting from readily accessible cyclopentenyl or cycloheptenyl ethers and amines. The role of different protective groups is examined as well as the influence of the relative configuration of stereocenters of the substrate molecules. Substituted 2,5-dihydro-furans and -pyrroles, 1,2,5,6-tetrahydropyranes and -pyridines as well as 2,3,4,7-tetrahydrooxepines are available via this methodology.