New access to 2,3-disubstituted quinolines through cyclization of o-alkynylisocyanobenzenes

[GRAPHICS] o-Alkynylisocyanobenzenes underwent nucleophile-induced intramolecular cycl ization to give 2,3-disubstituted quinoline derivatives in high yields. In addition to the oxygen and nitrogen nucleophiles such as methanol and dieth ylamine, the nucleophilic carbon of the enolate of malonate induced the cyc lization effectively. Reaction of 1,4-di(trimethylsilylethynyl)-2,3-diisocy anobenzene with methanol afforded 2,9-dimethoxy-1,10-phenanthroline in good yield.