TETRAHEDRON LETTERS Tetrahedron Letters 39 (1998) 943-946 Pergamon Oxidative Coupling of 4-Substituted 2-Methoxy Phenols Using Methyltributylammonium Permanganate in Dichloromethane- Francisco A. Marque**, Fabio Simonelli, Alfredo R. M. Oliveira, George L Gohr and Paulo C. Leal Departamento de Quimica, Universidade Federal do Paran~, C.P. 19081, BRASIL. Received 13 October 1997; accepted 10 November 1997 Abstract: Dimers of 4-substituted 2-methoxy phenols were prepared using methyltributylammonium permanganate (MTBAP) in dichloromethane. This methodology allows the selective coupling of such compounds preserving other moieties easily oxidized by permanganate anion in aqueous solution. © 1998 ElsevierScienceLtd. All fightsreserved. One of the chemical properties of phenols is their facile oxidation, which can be accomplished with almost any oxidant leading to quinones, or to dimeric, trimeric or polymeric coupling products1,2. Not only are these reactions of synthetic importance, but they are also implicated in many biogenetic pathways3,4, 5, including the biosynthesis of lignoids. More than two hundred of the lignoids recorded in the literature are described to have antibiotic, antihepatotoxic, antioxidant, anti-PAF (platelet activating-factor) antitumoral, calcium antagonistic, cytostatic, cytotoxic and enzyme inhibitor activity6. In this work we have studied the oxidative coupling of 4-substituted 2-methoxy phenols using methyltributylammonium permanganate (MTBAP) in dichloromethane. It has been reported 7 that the permanganate anion exhibits a lower oxidizing power in organic solvents compared with in aqueous solution. This behaviour was exploited to effect selective oxidations of phenols bearing other moieties easily oxidized by permanganate anion under other conditions. This reaction led to the formation of the dimeric products whose structures, in the case of dimers 5, 6 and 7, resemble the structures of lignoids. 0040-4039/98/$19.00 © 1998 Elsevier ScienceLtd. All fights reserved. PIh S0040-4039(97)10665-7