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

( o -Formylaryl)palladium complexes [Pd{C 6 H(CHO)-6-R 3 -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 PPh 3, pyCH PPh 3 (py = 2-pyridyl), or ClCH PPh 3 to give the ( o -alkenylaryl)palladium derivatives [Pd{C 6 HCH CHPh-6-(OMe) 3 -2,3,4}Cl(N−N)] [N−N = bpy ( 3a ), N−N = tmeda ( 3b )], [Pd{C 6 HCH CHpy-6-(OMe) 3 -2,3,4}Cl(N−N)] [N−N = bpy ( 4 )], [Pd{C 6 H( E -CH CHCl)-6-(OMe) 3 -2,3,4}Cl(tmeda)] ( 5 ), or [Pd(C 6 H 4 CH 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{C 6 HC(O)Me-6-(OMe) 3 -2,3,4}Cl(tmeda)] ( 7 ) and [Pd{C 6 H 4 (C(O)Me)-2}Br(bpy)] ( 8 ) with bases results in the formation of the 3-palladaindan-1-ones [Pd(κ 2 -{C 6 HC(O)CH 2 -6-(OMe) 3 -2,3,4})(tmeda)] ( 9 ) and [Pd(κ 2 -{C 6 H 4 C(O)CH 2 -2}(bpy)] ( 10 ). Complexes 3b and 6a,b react with alkynes RC⋮CR‘ to give indenylpalladium complexes [Pd{η-C 9 HBn-1-R-2-R‘-3-(OMe) 3 -5,6,7}(tmeda)]TfO [Bn = benzyl, TfO = CF 3 SO 3, R = R‘ = Me ( 11 ); R = C(O)Me, R‘ = H ( 12 )] and [Pd{η-C 9 H 4 Bn-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 Me 2 C C CH 2, CS 2, or MeN C S to give [Pd(η 3 -CMe 2 C{C 6 H( E -CH CHPh)-6-(OMe) 3 -2,3,4}CH 2 )(tmeda)]Tf O ( 19 ), [Pd(S 2 C{C 6 H( E -CH CHPh)-6-(OMe) 3 -2,3,4})(tmeda)]TfO ( 20 ), or [Pd(SC(NMe){C 6 H( 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 η 3 and η 5 .