Orthopalladated complex

McFarlane has studied the orthopalladated complexes of enantiomeri-cally pure l-phenyl-l-(A, A-dimethylamino)ethane and Chiraphos, shown in... 

Figure 4.10 An orthopalladated complex with a phosphine chiral at the P atom.

Orthopalladated complex [Pd(/i-Gl)(G6H4-2-PPh2=NPh-/ -6 ,A)]2 and related complexes have been obtained by the reaction of Pd(OAc)2 with iminophosphoranes. ... 

The specific ortho functionalization of arylamines is obviously important in quinoline synthesis (cf. the rc-allyl procedure devised for the preparation of o-allylanilines used as indole and quinoline precursors).76 Recently acetanilides have been subjected to orthopalladation and the ensuing complexes converted into useful precursors of 2-substituted quinoline derivatives (Scheme 143).215... 

Albisson DA,Bedford RB, Lawerence SE, Scully PN (1998) Orthopalladated triaryl phosphite complexes as highly active catalysts in biaryl coupling reactions. Chem Commun 2095-2096... 

Pd/trifurylphosphane catalyst Albisson et al. [27] carried out orthopalladation of the inexpensive, commercially available tris(2,4-di-tert-butylphenyl)phosphite the product, a dimeric complex, was very effective in biaryl couphng reactions with turnover numbers of up to 830 000. 

The cyclopalladated complex (naphthyl)ethylamine-6, iV]-dipalladium has been used as a chiral template to promote the intramolecular [4 -h 2] Diels-Alder reaction between diphenyl-vinylphosphine and 1-phenyl-3,4-dimethylphosphole. Halide-bridged palladium(ii) dimers of orthopalladated (S)-(-h)-7V,7V-dimethyl-Q -methylbenzylamine and (naphthyl)ethyl]amine were reported by the same authors.Solution and solid-state structures were determined as well as reactions with 3,4-dimethyl-1-phenylphosphole and allyldiphenylphosphine carried out. 

An example of a doubly orthopalladated aryl bis(phosphinite) ligand 95 has been reported. " Aryloxopalladium(ii) complexes were synthesized using the Herrmann-Beller palladacycle. Coordination of the 2-acylphenolates to palladium results in a significant perturbation of the delocalization within the aromatic ring. Another example involves a doubly orthometallated complex from o-G6H4(PBu )2 and Pd(OAc)2. ... 

An orthometallated complex was obtained from dibenzylamine and Pd(OAc)2, subsequent reaction with NaBr gives a bridged dimer [Pd(/x-OAc) G6H4(GH2NHGH2Ph)-2 ]2 Insertion reactions with alkynes were carried out. It is noted that double insertion can occur. Furthermore, reactions with Tl(acac), PPh3NH(GH2Ph)2, and AgX were studied. Internal acetylenes can be inserted into orthopalladated a-methylbenzylamine. Double and tri-insertion may occur depending on the alkyne. 

Baena et al. [137] introduced the idea that perturbing the high symmetry of the molecular shape of this family of compounds might lead to lower melting points and less ordered mesophases. Azomethines were orthopalladated to give the binuclear complex and these were treated with Tl(acac) (acac = acetylacetonate) to give a mononuclear species. These mononuclear complexes gave rise to mesophases below 90 °C. N, SmA and SmC phases were found. 

---