Synthesis, Structure, and Reactivity of Organochalcogen (Se, Te) Compounds Derived from 1-(N,N-Dimethylamino)naphthalene andN,N-Dimethylbenzylamine

A series of intramolecularly coordinated organochalcogen compounds incorporating the 8-(dimethylamino)-1-naphthyl and 2-[(dimethylamino)methyl]phenyl groups has been synthesized. All the compounds were synthesized using the ortholithiation methodology. Insertion of elemental selenium into the Li−C bond of RLi ( 6 ) (R = 8-(dimethylamino)-1-naphthyl) afforded the lithium areneselenolate RSeLi ( 7 ). Oxidative workup of 7 yielded the yellow diselenide 8 in good yield. Reaction of 8 with a stoichiometric amount of sulfuryl chloride gave the monochloro derivative ( 9 ). Controlled bromination of diselenide ( 8 ) with bromine in carbon tetrachloride gave the stable selenenyl bromide ( 10 ). Compound 8 underwent facile reaction with a stoichiometric amount of iodine to give the corresponding novel monoiodo compound ( 11 ) in which selenium is covalently bonded to iodine. Attempts to synthesize the chalcogenides, R 2 E, 12 (E = Se) and 13 (E = Te), by the reaction of 6 with Se(dtc) 2 and Te(dtc) 2 (dtc = diethyldithiacarbamate), respectively, were unsuccessful. The reaction of 6 with Te(dtc) 2 afforded the stable RTe(dtc) ( 14 ) instead of the expected telluride R 2 Te ( 13 ). In contrast, the reaction of R‘Li ( 17 ) (R‘ = 2-[(dimethylamino)methyl)phenyl] with Se(dtc) 2 and Te(dtc) 2 afforded the expected selenide R‘ 2 Se ( 18 ) and telluride R‘ 2 Te ( 19 ), respectively, in moderate yields. The compounds were characterized by elemental analysis, NMR ( 1 H, 13 C, 77 Se, 125 Te), and mass spectral techniques. The structures of the compounds 9, 11, 14, and 18 were determined by X-ray crystallography. Although N···E (E = Se or Te) nonbonded interactions are present in the solid state in all the derivatives, in solution the pyramidal inversion at the nitrogen center is not blocked, and as a result, the NMe 2 signals are observed as sharp signals in the 1 H NMR spectra.