Large-Scale Synthesis of New Pyranoid Building Blocks Based on Aldolase-Catalysed Carbon-Carbon Bond Formation



A new large-scale approach to the synthetically versatile chloromethyl-substituted, α,β-unsaturated δ-lactone 3 is described. The synthesis is based on a biocatalytic process performed on an industrial scale. Conjugate addition of C-, N-, O-, and S-nucleophiles to lactone 3 affords a variety of new pyranoid building blocks in a highly diastereoselective manner. The operational simplicity of the whole sequence allows for preparing these building blocks on an attractive scale.