CARBON-HYDROGEN AND C-X (X=CL OR SIME3) BOND ACTIVATION - 1-CYCLOPALLADATION AND OXIDATION OF SOME DERIVATIVES OF 2-[(DIMETHYLAMINO)METHYL]NAPHTHALENE

The regioselective palladation reactions of 3-substituted derivatives of 2-[(dimethylamino)methyl]-naphthalene, C10H6(CH2NMe2)-2-R-3 (R = Cl , SiMe3 or OSiMe3), were studied. For the substrate with R = Cl, no cy clopalladation at position 1 was observed and the co-ordination comple x was isolated. The 3-palladated product was formed in 10% yield via C -Cl activation. The reaction of 2-[(dimethylamino)methyl]-3-methylnaph thalene with Pd(O2CMe)2 and work-up with LiCl did lead to palladation at position 1, the resulting complex being isolated in 96% yield. The crystal structure of imethylamino)methyl]-3-methyl-1-naphthyl}palladiu m trifluoromethanesulfonate was solved. Monoclinic, space group P2(1)/ n, with a = 13.193(l), b = 11.801 (1), c = 14.797(l) angstrom, beta = 105.15(l)-degrees, Z = 4. The structure was refined to R = 0.042 for 3 455 reflections with / > 2.5sigma(I). Palladation at position 1 was al so achieved by oxidative addition of 1 -bromo-2-[(dimethylamino)methyl ]-naphthalene to [Pd(dba)2] (dba = dibenzylideneacetone). Protection o f C(3) with R = SiMe3 resulted in quantitative replacement of the SiMe 3 group by palladium. Silicon oxygen bond cleavage was observed when t he substrate with R = OSiMe3 was treated with Pd(O2CMe)2. Palladium bi s{3-[(dimethylamino)methyl]-2-naphtholate} was obtained quantitatively . Oxidation of several arylpalladium complexes with ButO2H was achieve d in the presence of [VO(acac)2] (acac = acetylacetonate) or [{RhCl(co d)}2] (cod = cycloocta-1,5-diene) as catalyst. The corresponding 1 -na phthols were prepared in yields varying from 33 to 78%. In a number of cases the corresponding 1,4-naphthoquinones were prepared in yields v arying from 18 to 38%.