New developments in asymmetric Bradsher cycloadditions: use of chiral dienes

Several serinol derivatives have been prepared and condensed following the Zincke reaction with 2,7-naphthyridine. The resulting naphthyridinium salts were engaged in Bradsher cycloadditions with enol ethers and afforded tetracyclic adducts, potential synthetic precursors of manzamine A alkaloid.