Synthesis of 3,4-Fused 2-Quinolones from an ( ortho-Aminophenyl)propiolate via Sequential Cycloaddition/Lactam Formation.

An N-phthalimide-protected ( ortho-aminophenyl)propiolate was prepared by the carboxylation of the corresponding silylalkyne precursor with carbon dioxide. The obtained propiolate was further transformed to various 3,4-fused 2-quinolones via cycloadditions and subsequent deprotection/lactam formation. [ABSTRACT FROM AUTHOR]