Palladium-Assisted Formation of Carbon−Carbon Bonds. 9. † Synthesis of (2-Alkenylaryl)- and Indenylpalladium Complexes

(o-Formylaryl)palladium complexes [Pd{C6H(CHO)-6-R3-2,3,4}X(N−N)] [R = OMe; X = Cl; N−N = bpy (2,2‘-bipyridine) (1a), tmeda (N,N,N‘,N‘-tetramethylethylenediamine) (1b). R = H; X = Br; N−N = bpy (2a), tmeda (2b)] react with ylides PhCHPPh3, pyCHPPh3 (py = 2-pyridyl), or ClCHPPh3 to give the (o-alkenylaryl)palladium derivatives [Pd{C6HCHCHPh-6-(OMe)3-2,3,4}Cl(N−N)] [N−N = bpy (3a), N−N = tmeda (3b)], [Pd{C6HCHCHpy-6-(OMe)3-2,3,4}Cl(N−N)] [N−N = bpy (4)], [Pd{C6H(E-CHCHCl)-6-(OMe)3-2,3,4}Cl(tmeda)] (5), or [Pd(C6H4CHCHPh-2)Br(N−N)] [N−N = bpy (6a), N−N = tmeda (6b)]. The compounds 3a, 4, and 6a,b are obtained as mixtures of E and Z isomers, whereas the formation of 3b and 5 is stereoselective (E isomer). The reaction of the (o-acetylaryl)palladium complexes [Pd{C6HC(O)Me-6-(OMe)3-2,3,4}Cl(tmeda)] (7) and [Pd{C6H4(C(O)Me)-2}Br(bpy)] (8) with bases results in the formation of the 3-palladaindan-1-ones [Pd(κ2-{C6HC(O)CH2-6-(OMe)3-2,3,4})(tmeda)] (9) and [Pd(κ2-{C6H4C(O)CH2-2}(bpy)] (10). Complexes 3b and 6a,b react with alkynes RC⋮CR‘ to give indenylpalladium complexes [Pd{η-C9HBn-1-R-2-R‘-3-(OMe)3-5,6,7}(tmeda)]TfO [Bn = benzyl, TfO = CF3SO3, R = R‘ = Me (11); R = C(O)Me, R‘ = H (12)] and [Pd{η-C9H4Bn-1-R-2-R‘-3}(N−N)]TfO [R = R‘ = H, N−N = bpy (13a), tmeda (13b); R = R‘ = Me, N−N = bpy (14a), tmeda (14b); R = R‘ = Et, N−N = bpy (15a), tmeda (15b); R = R‘ = Ph, N−N = bpy (16a), tmeda (16b); R = Ph, R‘ = H and R = H, R‘ = Ph, N−N = bpy (17a); R = H, R‘ = Ph, N−N = tmeda (17b); R = Ph, R‘ = Me, N−N = bpy (18a), N−N = tmeda (18b)]. Complex 3b reacts with Me2CCCH2, CS2, or MeNCS to give [Pd(η3-CMe2C{C6H(E-CHCHPh)-6-(OMe)3-2,3,4}CH2)(tmeda)]Tf O (19), [Pd(S2C{C6H(E-CHCHPh)-6-(OMe)3-2,3,4})(tmeda)]TfO (20), or [Pd(SC(NMe){C6H(E-CHCHPh)-6-(OMe)3-2,3,4})(tmeda)]TfO (21). The crystal structures of 12, 17b, and 18a have been determined; the hapticities of the indenyl five-membered rings are intermediate betwen η3 and η5.