396688-29-2Relevant articles and documents
Synthesis and reactivity toward alkynes of 2-formyl-and 2-acetylarylpalladium(II) (aryl = phenyl and 5-nitrophenyl) complexes. Formation of indenols and indenones
Vicente, José,Abad, José-Antonio,López-Peláez, Bego?a,Martínez-Viviente, Eloísa
, p. 58 - 67 (2008/10/08)
The imine C6H4(CH=NnBu)(NO2)-4 reacts with palladium acetate to give the cyclopalla-dated [Pd 2{κ2-C,N-C6H3(CH=N nBu)-2-(NO2)-5}2(μ2-OAc) 2] (1). This complex is hydrolyzed in the presence of bromide and 2,2′-bipyridine (bpy) or PPh3, affording the ortho-formylaryl complexes [Pd{C6H3(CHO)-2-(NO2)-5}Br(bpy)] (2) or trans-[Pd{C6H3(CHO)-2-(NO2)-5}Br-(PPh 3)2] (3), respectively. Complex 2 reacts with pyridine (py) or PPh3 in the presence of Tl(TfO) (TfO = CF3SO 3), giving the cationic species [Pd{C6H 3(CHO)-2-(NO2)-5}(py)(bPy)]-(TfO) (4) or [Pd{C 6H3(CHO)-2-(NO2)-5}(bpy)(PPh3)](TfO) (5), respectively. Similarly, the compounds [Pd{C6H 4C(O)X-2}Br(bpy)] [X = H (6), Me (7)] react with py and Tl(TfO) to give [Pd{C6H4C(O)X-2}(py)(bpy)](TfO) [X = H (8), Me (9)]. The reactions of the neutral complex 2 or 6 with Tl(TfO) and the alkynes PhC≡CPh, EtC≡CEt, or MeC≡CPh at room temperature result in the formation of 2,3-R,R′-5-X-1H-inden-1-ol [X = NO2) R = R′ = Ph (10a), Et (10b), R = Ph, R′ = Me (10c); X = H, R = R′ = Ph (11a), Et (11b), R = Ph, R′ = Me (11c)]. By contrast, the reactions of the cationic complex 4 or 8 with the same alkynes at 90°C for a long period of time give 2,3-R,R′-5-X-inden-1-ones [X = NO2, R = R′ = Ph (12a), Et (12b), R = Ph, R′ = Me (12c); X = H, R = R′ = Ph (13a), Et (13b), R = Ph, R′ = Me (13c)]. This contrasting behavior is discussed and compared with the result of the reaction of the 2-acetylarylpalladium(II) complex 7 with the same alkynes which renders 2,3-R,R′-1-methyl-1H-inden- 1-ol [R = R′ = Ph (14a), Et (14b), R = Ph, R′ = Me (14c)]. Complex 9 reacts with MeC≡CPh to give 14c.
