CYCLOPALLADATION OF 2-[(DIMETHYLAMINO)METHYL]-SUBSTITUTED NAPHTHALENES - 1-PALLADATION VS 3-PALLADATION - CRYSTAL-STRUCTURES OF [HYDROTRIS(PYRAZOLYL)BORATO][2-[(DIMETHYLAMINO)METHYL]-3-NAPHTHYL]PALLADIUM AND TRANS-[4,4-DIMETHYL-2-(2-NAPHTHYL)OXAZOLINE]PALLADIUM DICHLORIDE

In the course of a study directed toward the selective metal-mediated oxidation of naphthalenes to 1,4-naphthoquinones, the palladation of 2-[(dimethylamino)methyl]naphthalene and 4,4-dimethyl-2-(2-naphthyl)oxazoline was investigated. Direct palladation of 2-[(dimethylamino)-methyl]naphthalene with Li2PdCl4 showed a clean selectivity for position 3 instead of the earlier reported preference for position 1. This finding was confirmed by the crystal structure of [hydrotris(pyrazolyl)borato][2-[(dimethylamino)methyl]-3-naphthyl]palladium. The complex C22H24N7BPd.0.5CH3OH crystallizes as triclinic in space group P1BAR with a = 13.170(l) angstrom, b = 13.413(1) angstrom, c = 14.112(i) angstrom, alpha = 109.34(l)-degrees, beta = 95.60(1)-degrees, gamma = 97.38(l)-degrees, and Z = 4. Final R = 0.025 for 8181 observed reflections with I > 2.5sigma(I). The second ligand, 4,4-dimethyl-2-(2-naphthyl) oxazoline, was also cyclopalladated on position 3. The fastest reaction was obtained when palladium acetate was employed. Reaction with Li2PdCl4 yielded the cyclopalladated complex as the minor product and the intermediate coordination complex trans- [4,4-dimethyl-2-(2-naphthyl)oxazoline]palladium dichloride as the major product. This latter complex C30H30-C12N2O2Pd crystallizes in orthorhombic space group Pbca with a = 20.221(1) angstrom, b = 16.000(l) angstrom, c = 8.516(1) angstrom, and Z = 4. Final R = 0.039 for 2479 reflections with I > 2.5sigma(I).