Selective Preparation. 37. Bromination of 2,2',-Dihydoxy-3,3',5,5'-tetra-tert-butylbiphenyl and Preparation of Hydroxydibenzofurans

Article abstract of DOI:10.1021/jo00144a007

Treatment of 2,2'-dihydroxy-3,3',5,5'-tetra-tert-butylbiphenyl (3) with excess bromine in alcohols afforded the 2-alkoxy-1-bromo-4,6,8-tri-tert-butyldibenzofurans 6a,b in 68 percent and 44 percent yields, respectively.When compound 6a was treated with AlCl3 in boiling toluene, 2-hydroxydibenzofuran (14) was obtained in 79 percent yield together with bromotoluenes (15) and tert-butyltoluenes (10).However, at room temperature, this reaction afforded 1-bromo-2-methoxy-4-tert-butyldibenzofuran (16) in 74 percent yield.Futhermore, it was found that AlCl3-CH3NO2-catalyzed reaction of 6a in toluene gave 1-bromo-2-methoxy-4,6-di-tert-butyldibenzofuran (17) in 71 percent yield together with 10.From 6a were obtained 1,2,8-trihydroxy-(26) and 1,2,7,8-tetrahydroxydibenzofuran (27) in several steps.