No abstract

A perfluoroalkylidene lithium mediated cyclisation approach for the enantioselective synthesis of a tetrafluorinated aldose (ribose) and of a tetrafluorinated ketose (fructose), both in the furanose and in the pyranose form, is described.

Gemcitabine, 2'-deoxy-2',2'-difluorocytidine, is currently prescribed against a number of cancers. Here we report a linear synthesis of gemcitabine with a high-yielding direct conversion of 3,5-di-O-benzoyl-2-deoxy-2,2-difluororibose into the corresponding glycosyl urea as the key step, followed by conventional conversion to the cytosine base via the uracil derivative. The process proceeded with modest anomeric selectivity.

The Synthesis of Gemcitabine -[68 refs.]. -(BROWN, K.; DIXEY, M.; WEYMOUTH-WILSON, A.; LINCLAU, B.; Carbohydr. Res. 387 (2014) 59-73, http://dx.