Cascade Synthesis of 3-Quinolinecarboxylic Ester via Benzylation/Propargylation-Cyclization

Reactions of 2-amino-aryl alcohols with beta-ketoesters catalyzed by a catalytic amout of FeCl3 via tandem benzylation-cyclization produce the corresponding 3-quinolinecarboxylic esters in good to high yields. Extending this methodology to propargylation-cyclization, 2-nitrophenyl proparoyl alcohols with beta-ketoesters catalyzed by FeCl3 and SnCl, also produce the 4-alkyne-3-quitiolinecarboxylic esters. The mechanistic details of this benzylation/proparoylation and cyclization cascade process are also discussed.