Generation of the Reformatsky reagent of difluoracetate from the iodide ( ) and the difluoroketene silyl acetal ( ), and their aldol reaction are described. High anti-selectivity with chiral aldehyde ( , ) was found in the case of the ketene silyl acetal ( ). 2,2-Difluoro-2-deoxy analogs of D-ribo- and L-galactopyranosides ( , ) were effectively prepared. ... J. Fried, EA Hallinan, M. Swedo Jr. ... (4 mmol) in the same solvent (3 ml) dropwise during 5 min at 0°C. 19 F-nmr ...
