Lewis acid mediated multisegment coupling cascade is designed for the synthesis of densely substituted 4-alkoxy quinolines via an oxonium ion triggered alkyne carboamination sequence involving C–C and C–N bond formations. Cyclic ether fused-quinolines could also be accessed using this fast, operationally simple, high yielding, chemoselective and functional group tolerant method. Versatility and utility of this methodology is demonstrated by postfunctionalization of products obtained and its use in synthesis of potent drug molecules.