20320-37-0Relevant academic research and scientific papers
Reactivity of ortho-palladated benzamides toward CO, isocyanides, and alkynes. synthesis of functionalized isoindolin-1-ones and 4,5-disubstituted benzo[ c ]azepine-1,3-diones
Frutos-Pedreno, Roberto,Gonzalez-Herrero, Pablo,Vicente, Jose,Jones, Peter G.
, p. 4664 - 4676 (2013/09/23)
Aryl palladium complexes [Pd{C6H4C(O)NRR′-2} I(tmeda)] [NRR′ = NH2 (1a), NHMe (1b), NMe2 (1c); tmeda = N,N,N′,N′-tetramethylethylenediamine] are prepared by oxidative addition of the corresponding 2-iodophenylbenzamides to "Pd(dba)2" ([Pd2(dba)3]·dba; dba = dibenzylideneacetone) in the presence of tmeda. Cationic cyclometalated derivatives [Pd{κ2C,O-C6H4C(O)NRR′- 2}(tmeda)]TfO (2a-c) are obtained by iodide abstraction from the appropriate complex 1 with AgTfO, while the deprotonation of the amide function of 1a or 1b with KOtBu gives the neutral amidate complexes [Pd{κ 2C,N-C6H4C(O)NR-2}(tmeda)] [R = H (3a), Me (3b)]. Complexes 2a,b and 3a,b react with CO under mild conditions to yield phthalimide (4a) or N-methylphthalimide (4b), whereas the reactions of derivatives 1c and 2c with CO are very slow and give N1,N 1,N2,N2-tetramethylphthalamide and phthalic anhydride. The reaction of 1b with 1 equiv of XyNC (Xy = 2,6-dimethylphenyl) or tBuNC affords Pd(0), (tmedaH)I, and 3-(2,6-dimethylphenylimino)-2- methylisoindolin-1-one (5b) or 3-(tert-butylimino)-2-methylisoindolin-1-one (5b′), respectively, while complex 1c reacts with 3 equiv of XyNC to give trans-[Pd{C(i=NXy)C6H4C(O)NMe2-2}I(CNXy) 2] (6). The seven-membered palladacycles [Pd{κ2C,O- C(X)i=C(X′)C6H4C(O)NRR′-2}(tmeda)]TfO [NRR′ = NH2 and X = Ph, X′ = Me (7a); NRR′ = NHMe and X = Ph, X′ = Me (7b), X = X′ = Ph (8b), Et (9b), CO 2Me (10b), X = CO2Me, X′ = Ph (11b), X = CO 2Et, X′ = Ph (12b); NRR′ = NMe2 and X = X′ = Ph (8c), Et (9c)] are obtained from the reactions of 2a-c with alkynes. Treatment of complexes 7a, 7b, 8b, and 9b with CO at room temperature gives the corresponding 2H-benzo[c]azepine-1,3-diones (14), resulting from the insertion of a molecule of CO into the Pd-C bond followed by a C-N reductive coupling. In contrast, the reactions of 11b or 12b with CO in the presence of residual water or 2 equiv of ROH (R = Me, Et) lead to 2-methyl-3- phenylisoindolin-1-one derivatives (15), resulting from a CO insertion followed by an intramolecular aza-Michael addition of the NHMe moiety to the activated vinyl group and subsequent hydrolysis or alcoholysis of the acyl-Pd bond. The neutral complex [Pd(κ2C,O-C14H13O 5)(tmeda)] (18) was synthesized by reacting the cationic derivative 10b with NaOMe in MeOH. Depalladation of 18 gives (E)-4- [methoxy(methoxycarbonyl)methylene]-2-methylisoquinoline-1,3(2H,4H)-dione (19).
