Ruthenium-catalyzed oxidative coupling and cyclization between 2-aminobenzyl alcohol and secondary alcohols leading to quinolines

2-Aminobenzyl alcohol is oxidatively coupled and cyclized with secondary alcohols in dioxane at 80degreesC in the presence of a catalytic amount of RuCl2(PPh3)(3) and KOH along with 1-dodecene as a sacrificial hydrogen acceptor to give the corresponding quinolines in good yields. The cyclization is applicable to a wide range of alkyl(aryl) and alkyl(alkyl) carbinols. The catalytic pathway seems to be proceeded via a sequence involving initial oxidation of both substrates to carbonyl compounds, cross aldol reaction, and cyclodehydration. (C) 2003 Elsevier Ltd. All rights reserved.