| 摘要 |
PURPOSE: Provided are a process for preparing a 2,2-difluoroketene silyl acetals useful as pharmaceutical intermediates and a process for employing these acetals in the preparation of an α,α-difluoro-β-silyloxy-1,3-dioxolane-4-propionic acid ester intermediates. CONSTITUTION: A process for preparing α,α-difluoro-β-silyloxy-1,3-dioxolane-4-propionic acid ester of the formula(1) comprises the steps of: contacting a 2,2-difluoroketene silyl acetal of the formula(1), which is prepared by contacting a chlorodifluoroacetate of the formula(2) with a halosilane of the formula(3) of XSiR¬1R¬2R¬3, with a glycerylaldehyde derivative of the formula(5), in a solvent selected from the group consisting of cyclic and acyclic tetraalkyl ureas or mixtures thereof, in the presence of a reducing agent.
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