The use of well-defined (N-heterocyclic carbene)–Ag(I) complexes for the A³ reaction allows for the coupling of unactivated aldehydes at room temperature and very short reaction times.

A series of magnesium bis(amido-oxazolinate) complexes have been described. Reactions of six amido-oxazolinate ligand precursors, HNC₂ ^MeOxa, HNC₂ ^OMeOxa, HNC₂ ^StBuOxa, HNPhOxa, HNPh^OMeOxa or HNPh^SMeOxa, with half molar equivalent of MgⁿBu₂ in hexane yield the magnesium bis(amido-oxazolinate) complexes, (NC₂ ^EOxa)₂Mg [C₂ ^E = propyl, (NC₂ ^MeOxa)₂Mg (1); C₂ ^E = 2-methoxyethyl, (NC₂ ^OMeOxa)₂Mg (2); C₂ ^E = 2-tert-butylthioethyl, (NC₂ ^StBuOxa)₂Mg (3)], or magnesium bis(anilido-oxazolinate) complexes, (NArOxa)₂Mg [Ar = phenyl, (NPhOxa)₂Mg (4); Ar = 2-methoxyphenyl, (NPh^OMeOxa)₂Mg (5); Ar = 2-methylthiophenyl, (NPh^SMeOxa)₂Mg (6)], respectively. The molecular structures are reported for compounds 1, 2, 5 and 6. Their catalytic activities toward the ring opening polymerisation of L-lactide in the presence of benzyl alcohol are also under investigation.

Three new anilido-oxazolines, ortho-C₆H₄(NHAr′)(4,4-dimethyl-2-oxazoline) [Ar′ = 2,4,6-trimethylphenyl, HNPh^TriMeOxa (1); 2,6-diisopropylphenyl, HNPh^DiiPrOxa (2); 2-methoxyphenyl, HNPh^OMeOxa (3)], have been prepared. Reactions of 1 or 2 with one molar equivalent of ZnEt₂ in tetrahydrofuran or hexane solution give the zinc ethyl complexes (NPh^TriMeOxa)ZnEt (4) and (NPh^DiiPrOxa)ZnEt (5). The dinuclear zinc benzyloxide complexes, [(NAr′Oxa)Zn(µ-OBn)]₂, [Ar′ = 2,4,6-trimethylphenyl, (6); 2-methoxyphenyl, (7)], were synthesized by the reaction of 4 with one molar equivalent of benzyl alcohol in tetrahydrofuran solution (for 6) or by treatment of 3 with one molar equivalent of ZnEt₂ in tetrahydrofuran solution followed by the addition of one molar equivalent of benzyl alcohol (for 7). The molecular structures are reported for compounds 6 and 7. Their catalytic activities toward the ring opening polymerization reactions are under investigation.

Several zinc complexes bearing amido-oxazolinate ligands are described. Reactions of ligand precursors, HNC₂ ^EOxa (HNC₂ ^EOxa = HNC₂ ^MeOxa, HNC₂ ^OMeOxa, HNC₂ ^StBuOxa and HNC₂ ^NMe2Oxa) or HNPh^SMeOxa, with half or one molar equivalent of ZnEt₂ afford bis(chelate) zinc complexes, (NC₂ ^EOxa)₂Zn [C₂ ^E = propyl, (1); C₂ ^E = 2-methoxyethyl, (2); C₂ ^E = 2-N,N′-dimethylethyl, (3)] or zinc ethyl complexes, (NC₂ ^StBuOxa)ZnEt(4) and (NPh^SMeOxa)ZnEt(5), using tetrahydrofuran or hexane as solvents. The zinc benzyl oxide complexes, [(NC₂ ^EOxa)Zn(μ-OBn)]₂ [C₂ ^E = propyl, (6); C₂ ^E = 2-methoxyethyl, (7); C₂ ^E = 2-tert-butylthioethyl, (8)], are obtained from the reactions of ligand precursors, HNC₂ ^EOxa, with one molar equivalent of ZnEt(OBn) (generated in situ on 1 : 1 ratio of ZnEt₂ and BnOH) in tetrahydrofuran. The molecular structures are reported for compounds 1, 3, 5, 6 and 7. All eight compounds were assessed as efficient catalyst precursors towards the ring-opening polymerization of L-lactide and ε-caprolactone.