Nouveaux types de sucres acétyléniques. Communication préliminaire

Novel types of acetylenic sugars The coupling, following Cadiot's procedure, of a 6‐bromo‐5,6‐dideoxy‐1,2‐O‐isopropylidène‐3‐O‐methyl‐α‐D‐xylo‐hex‐5‐yno‐1, 4‐furanose (1) with phenylacetylene, 2‐propyn‐1‐ol or terminal acetylenic sugars gave with excellent yields the expected diynes (an enediyne when the terminal acetylene was the 3,5, 6‐trideoxy‐1,2‐O‐isopropylidene‐α‐D‐glycero‐hex‐3‐en‐5‐yno‐1,4‐furanose 7). The chloro analogue 8 of 1 on treatment with lithium thiophenate gave the corresponding phenylthio‐acetylenic sugar 9. An acetylene was also formed by reacting the gem‐difluoro‐olefinic sugar 10 with butyllithium whereas the same olefinic sugar and its 3‐O‐benzyl analogue 11 gave only a gem‐fluoro‐arylthio‐olefinic sugar (13–15) as a mixture of the Z and E isomers (Z/E > 4) when treated with the conjugate base of an arylmercaptan.