Abstract: An improved process to make gemcitabine hydrocrhloride, the improvement consisting essentially of making the lactone intermediate, 2-deoxy-2,2-difluoro-D-erythro-pentafuranose-1 ulose-3,5-dibenzoate: ##STR1## from D-erythro-2-Deoxy-2,2-difluoro 4,5-O-(1-ethylpropyl)-idene) pentoic acid tert Butyl ester wherein, the D-erythro-2-deoxy-2,2 difluoro-4,5-O-(1-ethylproyl)-ideno) pentoic acid tert-Butyl ester is prepared by the process of reacting S-tert-butyl difluoroethane thioate with 2,3-O (1-ethylpropylidene)-D-glyceraldehyde, in a solvent and in the presence of a strong base; with the proviso that the process is conducted in the absence of a catalyst and in the absence of a silyl containing compound.

Abstract: .alpha.,.alpha.-Difluoro-.beta.-hydroxy thiol esters of Formula (III): ##STR1## wherein: R.sup.c and R.sup.d are independently selected from the group consisting of H, C.sub.1 -C.sub.6 alkyl, substituted C.sub.1 -C.sub.6 alkyl, S-tert-butyl difluorothioacet-2-yl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.8 cycloalkenyl, substituted C.sub.3 -C.sub.8 cycloalkyl, substituted C.sub.3 -C.sub.8 cycloalkenyl, aryl, substituted aryl, C.sub.6 -C.sub.10 fused aromatic rings, and substituted C.sub.6 -C.sub.10 fused aromatic rings; orR.sup.c and R.sup.d together make up a ring selected from the group consisting of C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.8 cycloalkenyl, substituted C.sub.3 -C.sub.8 cycloalkyl and substituted C.sub.3 -C.sub.8 cycloalkenyl;R.sup.e is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, substituted C.sub.1 -C.sub.10 alkyl, aryl, substituted aryl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.8 cycloalkenyl, substituted C.sub.3 -C.sub.8 cycloalkyl and substituted C.sub.3 -C.sub.

Abstract: A process to make .alpha.,.alpha.-difluoro-.beta.-hydroxy thiol esters of formula (IIIA) ##STR1## comprising reacting a difluoroethanethioate of formula (IVA) ##STR2## with a second reactant selected from the group consisting of aldehydes, ketones, acid halides and esters; in a solvent and in the presence of a strong base; with the proviso that the process is conducted in the absence of a catalyst and in the absence of a silyl containing compound. These thiol esters are useful as intermediates in organic syntheses of pharmaceutical products.

Abstract: Processes for preparing 2,2-difluoroketene silyl O,S-acetals and .alpha.,.alpha.-difluoro-.beta.-silyloxy-1,3-dioxolane-4-propanoic acid O,S-esters.