4-alkyloxycarbonyl-2-oxetanones and 3-alkyl-4-alkyloxycarbonyl-2-oxetanones as versatile chiral precursors in the design of functionalized polyesterswith a controlled architecture

The necessity for accessing a very large variety of high-molecular-weight r acemic and optically active polyesters aimed at biomedical or chemical al,p lications has lied to the growth of a large series of racemic and optically active 4-alkyloxycarbonyl-2-oxetanones and 3-alkyl-4-alkyloxycarbonyl-2-ox etanones. Different synthesis routes have been established to prepare these monomers according to the bound ester group structure and the required ena ntiomeric or diastereomeric excess. The basic molecules were aspartic acid, malic acid or their 3-alkyl derivatives. The introduced ester group can be chiral, reactive, hydrophobic, hydrophilic or bioactive. The major interes t in this enlarged monomer family lies in the possibility of have at one's disposal beta-substituted beta-lactones with very strict control of the ste reogenic center configuration. This property is important with regard to th e tailoring of well-defined polymeric materials. A second benefit lies in t he tailor-making of complex architectures by the copolymerization of two or more beta-substituted beta-lactones. In al cases, the resulting materials have the composition of the monomer feed and a completely controlled config urational structure.