Alkaline earth metal complexes of a chiral polyether as initiator for the ring-opening polymerization of lactideElectronic supplementary information (ESI) available: Fig. S1-S14. CCDC 884447-884450. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2dt31309j

A chiral, tetradentate polyether ligand with a trans -1,2-cyclohexanediyl backbone, bis(methoxyethoxy)- trans -1,2-cyclohexane ( 5 ), was synthesized as both a racemate and the ( S , S ) enantiomer. 5 was found to form stable adducts with alkaline earth metal amides [M{N(SiMe 3 ) 2 } 2 (thf) x ] (M = Mg ( x = 0), Ca ( x = 2) and Sr ( x = 2/3)), [Ca{N(SiHMe 2 ) 2 } 2 (thf)] as well as with hydrocarbyl compounds [Mg(CH 2 SiMe 3 ) 2 ] and [Ca(η 3 -C 3 H 5 ) 2 ]. X-ray diffraction study of the bis(amide) [(( S , S )- 5 )Ca{N(SiMe 3 ) 2 } 2 ] and of the bis(allyl) [( rac - 5 )Ca(η 3 -C 3 H 5 ) 2 ] was performed. The complexes obtained were tested as initiators for the ring-opening polymerization of meso -, racemic and l -lactide. Alkaline earth complexes containing a chiral, tetradentate polyether ligand initiate the ring-opening polymerization of lactide monomers.