REGIOSELECTIVITY IN THE LITHIATION OF 1,3-DISUBSTITUTED ARENES

The regioselectivity of the lithiation of 1,4,5,8-tetramethoxynaphthal ene-2-carbaldehyde (7) with butyllithium or phenyllithium in the prese nce of N,N,N'-trimethylethylenediamine and the subsequent bromination of the lithiated species so generated with 1,2-dibromotetrafluoroethan e were investigated. Similar investigations with butyllithium as base in the presence of N,N,N',N'-tetramethylethylenediamine or potassium t -butoxide were carried out on 1,4,5,8-tetramethoxynaphthalene-2-methan ol (14). These studies were extended to 1,5,8-trimethoxynaphthalene-3- methanol (25), 3-methoxybenzenemethanol (29) and 3,5-dimethoxybenzenem ethanol (32). The X-ray crystal structure of 6-bromo-1,4,5,8-tetrameth oxynaphthalene-2-methanol (17) is described.