Mercurated and Palladated Iminophosphoranes. Synthesis and Reactivity

Reaction of the iminophosphorane Ph3PNC6H4Me-4 (1a) with Hg(OAc)2 and LiCl gives
the mercurated iminophosphorane [Hg{C6H3(NPPh3)-2-Me-5}Cl] (2). The latter reacts with
NaBr to give [Hg{C6H3(NPPh3)-2-Me-5}Br] (3). 2 reacts with MeC6H4NCO-4 or CX2 (X =
O, S) to give [Hg{C6H3(NCNC6H4Me-4‘)-2-Me-5}Cl] (4) or [Hg{C6H3{NCNC6H3(HgCl)-1‘-Me-5‘}-2-Me-5}Cl] (5), respectively. Iminophosphoranes Ph3PNC6H4R-4 (1b) react with
Pd(OAc)2 to give the complexes [Pd{κ2-C,N-C6H4(PPh2NC6H4R-4‘)-2}(μ-OAc)]2 (R = Me (6a),
MeO (6b)), in which the palladation takes place at one of the phenyl substituents of the
PPh3 group. Complex 6b reacts with NaBr or tBuNC to give [Pd{κ2-C,N-C6H4(PPh2NC6H4OMe-4‘)-2}(μ-Br)]2 (7) or [Pd{κ2-C,N-C6H4(PPh2NC6H4OMe-4‘)-2}(OAc)(CNtBu)] (8), respectively. Complexes 6a,b react with NaClO4 and N,N,N‘,N‘-tetramethylethylenediamine
(tmeda), yielding [Pd{κ2-C,N-C6H4(PPh2NC6H4R-4‘)-2}(tmeda)]ClO4 (R = Me (9a), MeO
(9b)). The compound Ph3PNC6H4I-2 (1c) adds oxidatively to [Pd2(dba)3]·dba (dba =
dibenzylideneacetone) in the presence of tmeda, resulting in the formation of complex [Pd{C6H4(NPPh3)-2}I(tmeda)] (10). The complex 10 reacts (i) with PPh3 and TlOTf (TfO =
CF3SO3) to give [Pd{C6H4(NPPh3)-2}(tmeda)(PPh3)]TfO (11·TfO), (ii) with XyNC (Xy =
C6H3Me-2,6) (1:3 molar ratio) to give [Pd{κ2-C,N-C(NXy)C6H4(NPPh3)-2}I(CNXy)] (12),
and (iii) with XyNC and TlOTf (1:3:1) to give [Pd{κ2-C,N-C(NXy)C6H4(NPPh3)-2}(CNXy)2]TfO (13). An excess of the alkyne MeO2CC⋮CCO2Me reacts with 10 and AgClO4 (4:1:1) to
give the inserted compound [Pd{κ2-C,N-C(CO2Me)C(CO2Me)C6H4(NPPh3)-2}(tmeda)]ClO4
(14·ClO4). The crystal structures of 2, 6a·CH2Cl2, 9a, 11·TfO, and 14·ClO4 have been
determined by X-ray diffraction studies.