Polysubstituted furan has been found as a key structural unit in many bioactive natural products and pharmaceuticals. [1] It is also a reactive species that, upon appropriate activation, can be engaged in complex chemical transformations. [2] The development of efficient furan syntheses has thus attracted chemists for decades and continues to be an active and rewarding research area. [3, Besides polysubstituted furans, various annulated derivatives such as benzo-, thieno-, isoxazolo-, furo-, pyridino-, pyridazino-, and indolofuran have been synthesized and their properties investigated. Cyclization of acyclic precursors and derivatization of an appropriately functionalized furan ring are two main strategies used for the elaboration of polysubstituted furans. New technologies such as solid-phase synthesis [6] and multicomponent reactions [7] have recently been developed for the preparation of this heterocycle.
Furoquinoline alkaloids, typical constituents of the Rutaceae and Solanaceae plant species, are the most widely distributed of quinoline alkaloids. [8] Antimicrobial, antitumor, and antiemetic activities have been attributed to both natural and synthetic analogues of these molecules. While several synthetic routes to individual furoquinolines have been developed, most of them were linear and involved harsh reaction conditions. [10, In connection with our ongoing project aimed at using oxazoles as a starting point to reach diverse druglike heterocycles, we report herein a conceptually novel multicomponent domino synthesis of furo[2,3c]quinoline 1 (Scheme 1) from readily available substrates.