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C yclopalladation of 2-[ (Dimet hylamino) met hyl] -Substituted Naphthalenes: 1vs 3-Palladation. Crystal Structures of [ Hydr otris ( pyr azolyl) borat 01 [ 2-[ (dimethylamino) methyl] -3-naphthyllpalladium and trans-[ 4,4 -Dime t h yl-2 -( 2 -nap h t h y 1) oxazoline] palladium Dichloride

A series of heteroleptic diarylpalladium compounds, containing both a naphthyl (1-C10H6CH2NMe2-2 or 1-C10H5CH2NMe2-2-Me-3) and a phenyl (1-C6H4CH2NMe2-2 or 1-C6H3CH2NMe2-2-Me-x, x = 3, 5, 6) monoanionic C,N-bidentate ligand, was reacted with tert-butyl hydroperoxide (TBHP) to give selective oxygen insertion into one of the C−Pd bonds. It was found that the order of reactivity of the palladium−carbon bonds decreases in the order 1-naphthyl−Pd > phenyl−Pd. Introduction of methyl substituents enabled us to fine-tune the regioselectivity of the oxidation reactions (i.e. the ratio of phenyl- versus naphthyl oxygenation was affected) but not to reverse the order. The methyl groups have a deactivating influence on the aromatic substrates that contain them, indicating an oxidatively induced nucleophilic pathway for the actual oxygenation step. The yields of mono-oxygenated product RPdOR‘ varied from 82 to 97% and were independent of the presence of a VO(acac)2 or [RhCl(cod)]2 catalyst, although the reaction rates were strongly enhanced in the presence of these catalysts.

Several (aryl)trimethylsilane derivatives containing a potentially intramolecularly coordinating dimethylaminomethyl group were prepared and treated with Li,PdCl, or Pd(OAc),. Highly selective cleavage of the aryl-C-Si bond took place to give the corresponding atylpalladium complexes. Similar reactions were observed for benxylic trimethylsilyl compounds. The yields of the reactions with Li,PdCl, varied from 66 to 94%, but yields were > 90% when Pd(OAc), was used.