Depalladation Reactions of Iminoacyl- and 2-Acetylarylpalladium(II) Complexes

Reaction with Tl(TfO) (TfO = triflate, CF 3 SO 3 ), in some cases in the presence of CO or EtOH, causes the depalladation of complexes trans -[Pd{C( NR)C 6 H 4 {C(O)Me}-2}Br(CNR) 2 ] [R = 2,6-dimethylphenyl (Xy) ( 1a ), R = t Bu ( 1a ‘)], trans -[Pd{C( NXy)C 6 H(OMe) 3 -2,3,4-{C(O)Me}-6}Br(CNXy) 2 ] ( 1b ), trans -[Pd{C( NR)C 6 H 4 (CH CH 2 )-2}Br(CNR) 2 ] [R = Xy ( 2 ), t Bu ( 2 ‘)], trans -[Pd{C( NXy)C(NHXy) CC 6 H 4 {C(O)NXy}-2}Br(CNXy) 2 ] ( 3 ), trans -[Pd{C 6 H 4 {C(O)Me}-2}Br(PPh 3 ) 2 ] ( 4 ), and [Pd{C 6 H 4 {C(O)Me}-2}Br(bpy)] (bpy = 2,2‘-bipyridine) ( 5 ) to give organic compounds. Complexes 1a, 1a ‘, and 1b react with Tl(TfO) in Me 2 CO or CH 2 Cl 2 to give the isoindolinones 2-(2,6-dimethylphenyl)-3-methylene-2,3-dihydroisoindol-1-one ( 6a ), 2- tert -butyl-3-methylene-2,3-dihydroisoindol-1-one ( 6a ‘), and 2-(2,6-dimethylphenyl)-5,6,7-trimethoxy-3-methylene-2,3-dihydroisoindol-1-one ( 6b ), respectively. When the reaction with 1a ‘ is carried out in the presence of a small amount of EtOH, in addition to 6a ‘, the isoindolinone 2- tert -butyl-3-ethoxy-3-methyl-2,3-dihydroisoindol-1-one ( 7 ) and 2-acetyl- N - tert -butylbenzamide ( 8 ) are obtained. Complex 2 reacts with Tl(TfO) in the presence of CO to give N -(2,6-dimethylphenyl)-2-vinylbenzamide ( 9 ); however, the analogous compound 2 ‘ reacts with Tl(TfO) to give a mixture containing ortho -cyanostyrene ( 10 ). Complex 3 reacts with Tl(TfO) to give a separable mixture of N -(2,6-dimethylphenyl)-2-(2,6-dimethylphenylamino)-2-[2-(2,6-dimethylphenyl)-3-oxo-2,3-dihydroisoindol-1-ylidene]acetamide ( 11 ) and N -(2,6-dimethylphenyl)-2-(2,6-dimethylphenylamino)-2-[2-(2,6-dimethylphenyl)-3-oxo-2,3-dihydroisoindol-1-ylidene]acetamidic acid ( 12 ). When this reaction is carried out in the presence of a small amount of EtOH, 11, 12, and its ethyl ester 13 are obtained. Complex 4 or 5 reacts with CO and Tl(TfO) in Me 2 CO to give 3-methylenephthalide ( 14 ) or a complex mixture, respectively. Complexes 4 and 5 react with Tl(TfO) in CH 2 Cl 2 in the presence of a small amount of EtOH, affording 3-ethoxy-3-methyl-3 H -isobenzofuran-1-one ( 15 ). The crystal and molecular structures of 6a, 6b, 8 ·0.11H 2 O, 9, 11 ·0.5Et 2 O, 13, and 14 have been determined by X-ray diffraction studies.