Highly Selective Domino Multicyclizations for Forming Polycyclic Fused Acridines and Azaheterocyclic Skeletons

Highly selective four-component domino multicyclizations for the synthesis of new fused acridines and azaheterocyclic skeletons have been established by mixing common reactants in isobutyric acid under microwave irradiation. The reactions proceeded at fast rates and were conducted to completion within 20–30 min. Up to seven new chemical bonds, four rings, and four stereocenters were assembled in a convenient one-pot operation. The resulting hexacyclic and pentacyclic fused acridines and their stereochemistry have been fully characterized and determined by X-ray structural analysis.