Ligand ferrocenyl

The cationic Pd(II)-7i-allyl complexes of the formula [(Ligand)Pd(ri3-C3H5)]PF6 (Ligand = ferrocenyl imino-phosphine la-e) were isolated in the solid state by the literature procedure15,61 using [(ri3-C3H5)PdCl]2 as starting material.[7] The complexes obtained were used as catalyst precursors for the asymmetric allylic... 

The diminished enantioselectivity of this substrate is due to the much smaller steric hindrance of methyl groups to compared to phenyl groups and to the absence of 7i-stacking interactions of 14 with the chiral ligands. Ferrocenyl ligands 16 and biarylic 17 have been used, leading to good yields but low stereoselectivities. 

Chiral ferrocenes have received niucli attenlion as ligands in metal-calalyzed reactions [39], bul tiieir use in copper cliemislry has been very limited [40, 41]. Hie ferrocene moiety offers die possibility of utilizing botli central and planar cliirality in die ligand. By analogy witli tlie copper arenetiiiolales described above, ferrocenyl copper complex 33 iSclieme 8.20) is extremely inleresling. 

Recently a novel chiral ferrocene-based amidinato ligand and its rhodium complexes have been described. The chiral N,N -bis(ferrocenyl)-substituted formamidine (N,N -bis[(S)-2- (lR)-l-(diphenylphosphino)ethyl ferrocen-l-yl]for-mamidine was prepared from commercially available (IR)-l-(dimethylamino) ethyl ferrocene by a multistep procedure in an overall yield of 29%. Deprotonation of the ligand with -butyllithium followed by addition of [RhCl2(COD)2] as illustrated in Scheme 167 yielded the corresponding (formamidinato)rhodium(l)... 

Scheme 20. Example of synthesis of a ferrocenyl-based P-chirogenic phosphine ligand...

Ph2SiH2,THF, l%RhCl(OTD)2L chiral ferrocenyl phosphine ligand... 

In 1997 the first asymmetric aza-Claisen rearrangement was reported by Overman et al. [55], which made use of diamines as bidentate ligands for Pd(II), allowing for moderate enantioselectivities. In the same year, Hollis and Overman described the application of the planar chiral ferrocenyl palladacycle 38 as a catalyst for the enantioselective aza-Claisen rearrangement of benzimidates 39 (Fig. 19) [56]. A related ferrocenyl imine palladacycle provided slightly inferior results, while a benzylamine palladacycle lacking the element of planar chirality was not able to provide any enantioselectivity [57]. 

These complexes were tested for in vitro antimalarial activity showing that the coordination to the Au increases the potency of chloroquine. The ferrocenyl ligands... 

Barranco, E.M., Gimeno, M.C., Laguna, A. and Villacampa, M.D. (2005) Gold and silver complexes with the ferrocenyl-pyrazolate ligand FcCH2pz. Inorganica Chimica Acta, 358 (14), 4177 182. 

Scheme 1.71 Test reaction with S/P-ferrocenyl ligands.

Scheme 1.72 Test reaction with polymer supported S/P-ferrocenyl ligand.

Scheme 1.73 Test reaction with pseudo-C2-symmetric S/P-hybrid ferrocenyl ligand and its P/P-analogue.

Scheme 1.76 Test reaction with P-aminoalkyl ferrocenyl sulfide ligands.

Scheme 1.78 Test reaction with S/N- and P/N-ferrocenyl ligands.

Scheme 1.79 Phosphinamidite-thioether ferrocenyl ligands for Pd-catalysed allylic...

Scheme 1.80 N/S/P-ferrocenyl ligand for Pd-catalysed allylic alkylations of indoles.

Scheme 1.81 Allylic etherifications with phosphinamidite-thioether ferrocenyl ligand.

Scheme 2.23 Cu-catalysed 1,4-addition of ZnEt2 to ethyl pentylidene malonate with sulfur-containing phenylphosphorus ferrocenyl ligand.

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