Scandium complexes carboxylates

Glycine (gly) can act as a bidentate ligand with the carboxyl groups bridging metal atoms. This occurs in the six-coordinate scandium complex [Sc2(gly)6(C104)2]ra where an infinite chain of dimeric units with three bridging glycines per dimeric unit is formed.217... 

The complexation constants Ki for interaction of Sc3+ ions with substituted and unsubstituted carboxylates in aqueous solution have been determined potentiometrically at 25 °C and 0.1 MKN03 ionic background. They are listed in Table 1, the AH values being derived with the aid of additional measurements at 40°C.61 These values for scandium are greater than those for the lanthanides by roughly one order of magnitude.62... 

Enantioselective additions of a,f)-unsaturated 2-acyl imidazoles, catalyzed by bis(oxazolinyl)pyridine-scandium(III)triflate complex, were used for the asymmetric synthesis of 3-substituted indoles. The complex 114 was one of the most promising catalysts. The choice of acetonitrile as the solvent and the use of 4 A molecular sieves were also found to be advantageous. The 2-acyl imidazole residue in the alkylation products of u,(i-unsaturated 2-acyl imidazoles could be transformed into synthetically useful amides, esters, carboxylic acid, ketones, and aldehydes (Scheme 32) [105]. Moreover, the catalyst 114 produced both the intramolecular indole alkylation and the 2-substituted indoles in good yield and enantioselectivity (Scheme 33) [106]. The complex... 

---