Bifunctional telechelics with defined structure can be prepared by oligomerization of oxiranes, β‐butyrolactone and L‐lactide using aluminium Schiff's base complexes as initiators. Chiral initiator (SALCENAlCl) shows a stereoelective character leading to preferential oligomerization of one enantiomer from a racemic monomer mixture. The reaction with β‐butyrolactone proceeds through O‐alkyl cleavage. Alkoxy Schiff's bases aluminium complexes are used for oligomerization of L‐lactide. All the prepared oligomers were fully characterized by IR, elemental analysis, 1H and 13C NMR and GPC.
Samples of dimer and trimer derived from chiral propylene oxide, having head-to-tail linkages were prepared using an aluminium complex of a Schiff's base and were studied by means of I3C NMR spectroscopy. Based on these spectroscopic data and on J-Modulated Spin Echo Technique (JMSET), analysis of a racemic oligomer (m, = 11) was carried out. Resonances of carbon atoms of central and terminal units were identified. End-group carbon atoms (with the exception of cH2C1) present large configurational effects as compared to internal carbon atoms.
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