Mercurated and Palladated Iminophosphoranes. Synthesis and Reactivity

Reaction of the iminophosphorane Ph 3 P NC 6 H 4 Me-4 ( 1a ) with Hg(OAc) 2 and LiCl gives the mercurated iminophosphorane [Hg{C 6 H 3 (N PPh 3 )-2-Me-5}Cl] ( 2 ). The latter reacts with NaBr to give [Hg{C 6 H 3 (N PPh 3 )-2-Me-5}Br] ( 3 ). 2 reacts with MeC 6 H 4 NCO-4 or CX 2 (X = O, S) to give [Hg{C 6 H 3 (N C NC 6 H 4 Me-4‘)-2-Me-5}Cl] ( 4 ) or [Hg{C 6 H 3 {N C NC 6 H 3 (HgCl)-1‘-Me-5‘}-2-Me-5}Cl] ( 5 ), respectively. Iminophosphoranes Ph 3 P NC 6 H 4 R-4 ( 1b ) react with Pd(OAc) 2 to give the complexes [Pd{κ 2 - C, N- C 6 H 4 (PPh 2 NC 6 H 4 R-4‘)-2}(μ-OAc)] 2 (R = Me ( 6a ), MeO ( 6b )), in which the palladation takes place at one of the phenyl substituents of the PPh 3 group. Complex 6b reacts with NaBr or t BuNC to give [Pd{κ 2 - C, N- C 6 H 4 (PPh 2 NC 6 H 4 OMe-4‘)-2}(μ-Br)] 2 ( 7 ) or [Pd{κ 2 - C, N- C 6 H 4 (PPh 2 NC 6 H 4 OMe-4‘)-2}(OAc)(CN t Bu)] ( 8 ), respectively. Complexes 6a, b react with NaClO 4 and N, N, N ‘, N ‘ -tetramethylethylenediamine (tmeda), yielding [Pd{κ 2 - C, N- C 6 H 4 (PPh 2 NC 6 H 4 R-4‘)-2}(tmeda)]ClO 4 (R = Me ( 9a ), MeO ( 9b )). The compound Ph 3 P NC 6 H 4 I-2 ( 1c ) adds oxidatively to [Pd 2 (dba) 3 ]·dba (dba = dibenzylideneacetone) in the presence of tmeda, resulting in the formation of complex [Pd{C 6 H 4 (N PPh 3 )-2}I(tmeda)] ( 10 ). The complex 10 reacts (i) with PPh 3 and TlOTf (TfO = CF 3 SO 3 ) to give [Pd{C 6 H 4 (N PPh 3 )-2}(tmeda)(PPh 3 )]TfO ( 11 ·TfO), (ii) with XyNC (Xy = C 6 H 3 Me-2,6) (1:3 molar ratio) to give [Pd{κ 2 - C, N- C( NXy)C 6 H 4 (N PPh 3 )-2}I(CNXy)] ( 12 ), and (iii) with XyNC and TlOTf (1:3:1) to give [Pd{κ 2 - C, N- C( NXy)C 6 H 4 (N PPh 3 )-2}(CNXy) 2 ]TfO ( 13 ). An excess of the alkyne MeO 2 CC⋮CCO 2 Me reacts with 10 and AgClO 4 (4:1:1) to give the inserted compound [Pd{κ 2 - C, N -C(CO 2 Me) C(CO 2 Me)C 6 H 4 (N PPh 3 )-2}(tmeda)]ClO 4 ( 14 ·ClO 4 ). The crystal structures of 2, 6a ·CH 2 Cl 2, 9a, 11 ·TfO, and 14 ·ClO 4 have been determined by X-ray diffraction studies.