Portal de Periódicos da CAPES

Palladium-Assisted Formation of Carbon−Carbon Bonds. 4. 1 Synthesis and Reactivity of a Water-Soluble (2,3,4-Trimethoxy-6-(ethoxymethyl)phenyl)palladium(II) Complex. Reactions with Alkynes of Its Derivatives: Further Insight into the Pathway of Formation of Highly Functionalized Organic Spirocycles and X-ray Structures of Model Intermediates

1996; American Chemical Society; Volume: 15; Issue: 1 Linguagem: Inglês

10.1021/om950603x

1520-6041

José Vicente, José‐Antonio Abad, Rocío Fernández-de-Bobadilla, Peter G. Jones, Carmen Ramı́rez de Arellano,

Catalytic C–H Functionalization Methods

Mercuration of 3,4,5-trimethoxybenzyl chloride with mercury(II) acetate in ethanol, and further addition of aqueous NaCl, affords the compound [Hg(Ar)Cl] (1) [Ar = C6H(CH2OEt)-6-(OMe)3-2,3,4], which reacts with (Me4N)Cl to give [Hg(Ar)2] (2). Complex 2 reacts with K2[PdCl4] in water/acetone to give solutions from which, after addition of 2,2'-bipyridine (bpy), N,N,N',N'-tetramethylethylenediamine (tmeda) or pyridine (py), complexes [Pd(Ar)Cl(bpy)] (3), [Pd(Ar)Cl(tmeda)] (4), or trans-[Pd(Ar)Cl(py)2] (5), respectively, can be isolated. Complex 3 reacts with PPh3 and NaClO4 to give [Pd(Ar)(bpy)(PPh3)]ClO4 (6). Treatment of 5 with AgClO4 and py affords [Pd(Ar)(py)3]ClO4 (7), which reacts with PPh3 to give cis-[Pd(Ar)(py)2(PPh3)]ClO4 (8). A comparative study of the reactions of 3-5 with various alkynes has been carried out. Thus, 3 reacts with Tl(CF3SO3) and EtC⋮CEt or with AgClO4 and PhC⋮CPh to give the (π-allyl)palladium complex (η3-10-(ethoxymethyl)-6,7,8-trimethoxy-1,2,3,4-tetraethylspiro[4.5]-1,3,6-decatrien-8-enyl)(bpy)palladium(II) trifluoromethanosulfonate (9) or the monoinserted complex [Pd{cis-C(Ph)C(Ph){C6H(CH2OEt)-6-(OMe)3-2,3,4}}(bpy)]ClO4 (10), respectively. Complex 10 reacts with PPh3 giving [Pd{cis-CPhCPh(Ar)}(PPh3)(bpy)]ClO4 (14). Complex 4 reacts with Tl(CF3SO3) and MeO2CC⋮CCO2Me or EtC⋮CEt yielding the vinyl-substituted complex [Pd{cis-C(CO2Me)C(CO2Me){C6H(CH2OEt)-6-(OMe)3-2,3,4}}(tmeda)]CF3SO3 (11) or the spirocyclic compound 10-(ethoxymethyl)-6,7-dimethoxy-1,2,3,4-tetraethylspiro[4.5]-1,3,6,9-decatetraen-8-one (12a). When 5 reacts with EtC⋮CEt, PhC⋮CPh, or ToC⋮CTo (To = C6H4Me-4), in the presence of Tl(CF3SO3) or AgClO4, the corresponding spirocyclic compounds 12a, 12b (tetraphenyl), or 12c (tetratolyl), respectively, are obtained, whereas the reaction with MeO2CC⋮CCO2Me gives the diinserted complex trans-[Pd{cis,cis-C(CO2Me)C(CO2Me)C(CO2Me)C(CO2Me)(Ar)}{OS(O)2CF3}(py)2] (13). The structures of compounds 6, 11, 12c, and 13 have been determined by X-ray diffraction.