Synthèse et réactions de didésoxy‐5,6‐halogéno‐6‐α‐D‐xylo‐hepténo‐5‐furannurononitriles. Communication préliminaire

Abstract

Synthesis and reactions of 5,6-dideoxy-6-halogeno-a-D-sylo-hept-5-eno-f~an~ononi~ril~ SummaryThe 5,6-dideoxy-6-chloro-, 6-iodo-and 6-fluoro-3-O-methyl-a-~-xylo-hept-5-enofuranurononitriles have been prepared, their properties described as well as the methods used for the assignment of the configuration of the geometrical isomers. Some new reactions of the 6-bromo analog (1) of these compounds are reported. For example, when reacted with 2-mercaptoethanol or N, N'-dimethyl-ethylenediamine in the presence of NaOH, 1 gave the corresponding six-membered ring, stereo-isomers of an oxathiane or of a pexhydrodiazine respectively. When the base used was Et3N and the binucleophile the N-methyl-ethanolamine or the N , N'-dimethyl-ethylenediamine the major product was a cyano-enamine which could be hydrolysed to a p-cyanoketone or cyclized to a five-membered ring, an oxazolidine or an imidazolidine respectively. Nous avons rtcemment decrit [3][4] la synthese du dtrivt 1 d'un sucre insaturt et quelques unes de ses rtactions. Nous avons en particulier not6 qu'oppost & des binucltophiles, ces composts donnaient lieu A toute une strie de rtactions d'anntlation rtgio-stlectives dont I'orientation Ctait commandte par la nature du binucltophile. Pour augmenter encore la richesse synthttique potentielle du systhme, nous avons prtpart les analogues chlorts, iodts et fluorts de 1. Nous rapportons tgalement ci-dessous de nouvelles proprittts du dtrivt 1 de sucre insaturt. 1)Utilisation d'ylides du phosphore en chimie des sucres, XXVII. Pour la XXVIeme communication voir [l]. Communication considbree egalement comme la XXXIIIeme de la skrie <(Derives C-glycosyliquesa. XXXIIeme communication voir [2]. Une communication plus detaillke paraitra ultkrieurement. 2)

Haloalkenes activated by geminal groups in reactions with N-nucleophiles

“…89,115 As a rule, reactions of haloalkenes 1 with binucleophiles afford heterocyclic compounds. However, in some cases, 18,29,80,119 b-aminoalkenes of type 4 have been obtained as the reaction products. This cannot be always explained by steric hindrance at the electrophilic centre of the substrate or by steric inaccessibility of a particular heteroatom in the nucleophile.…”