Searching for New Four‐membered Palladacycles Derived from Anilines: Influence of the <i>N</i>‐Substituents in the Reaction Outcome

Abstract The reactions of iodoanilines IC 6 H 4 NRR′‐2 with [Pd(PPh 3 ) 4 ] gave complexes [Pd(C 6 H 4 NRR′‐2}I(PPh 3 ) 2 ] [R=H, R’=H ( 1 a ), Me ( 1 b ); R=R’=Me ( 1 c )] while a mixture of 1 a , and the dimeric [Pd{μ‐ C,N ‐C 6 H 4 NH 2 ‐2)I(PPh 3 )] 2 ( 2 a ) was obtained when the appropriate iodoaniline was reacted with [Pd(dba) 2 ] (dba=dibenzylideneacetone) and 1 equiv. of PPh 3 . The phosphonium salts [Ph 3 PC 6 H 4 NRMe‐2]OTf [R=H ( 3 b ), Me ( 3 c )] formed upon reacting complexes 1 b,c with TlOTf (OTf=CF 3 SO 3 ). Complexes of the type [Pd(C 6 H 4 NRR′‐2}I(N N)] ( 4 ) were obtained from the reaction of [Pd(dba) 2 ] with the appropriate iodoaniline and a N N bidentate ligand (N N=4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridine or N , N , N ′, N ′‐tetramethylethylenediamine). Complexes 4 reacted with TlOTf and PPh 3 or XyNC (Xy=C 4 H 4 Me 2 ‐2,6) to give [Pd(C 6 H 4 NRR′‐2)(N N)(PPh 3 )]OTf ( 5 ) or [Pd{ C,N ‐C(=NHXy)C 6 H 4 NRR′‐2)(N N)]OTf ( 6 ), respectively. In the absence of any added ligand, the reactions of complexes 4 with TlOTf produced the dimeric complexes [Pd{μ‐ C,N ‐C 6 H 4 NHR‐2)(N N)] 2 (OTf) 2 ( 7 ) or the four‐membered palladacycles [Pd( κ 2 ‐C 6 H 4 NMe 2 ‐2)(N N)]OTf ( 8 ), depending on the substitution degree of the aniline reagent.