I2/p-TSA: An efficient reagent for regioselective synthesis of angularly fused diazabenzocyclo-pentafluorene via iodocyclisation of 11-(arylethynyl)-11H-indeno[1,2-b]quinoxalin-11-ol

Abstract

A metal-catalyst-free, efficient, regioselective, electrophilic iodine-p-TSA mediated 5-endo-dig cyclization of propargyl alcohol derivative of indenoquinoxalinone for the synthesis of angularly fused diazabenzocyclopentafluorene compounds has been developed. A plausible mechanism mediated by iodine-p-TSA and invoking cyclization via intramolecular nitrogen nucleophiles is provided. The synthetic transformation of products thus obtained was subjected to the following: 1. Dehalogenation, 2. Sonogashira coupling, and 3. Iodine-CAN-mediated oxidation for synthesizing functionalized derivatives of the title compounds was achieved.