One-pot enyne metathesis/Diels–Alder reaction for the construction of highly functionalized novel polycyclic aza-compounds

Various tricyclic dienes were synthesized via enyne metathesis using the first generation Grubbs catalyst. The enyne metathesis proceeded smoothly in refluxing CH2Cl2 with a low catalyst loading (3.0 mol %), giving good yields (72–89%) of the tricyclic products 6 and 16. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels–Alder process. One-pot RCM/Diels–Alder reactions of the enyne products with dienophiles proceeded smoothly to afford polycyclic compounds as a single cycloadduct. The structures of the Diels–Alder adducts were determined by 1H NMR spectra and X-ray analysis. The cycloadducts were formed via the approach of the dienophiles towards the diene in endo mode.