Catalytic asymmetric synthesis of new halogenated chiral synthons
摘要:
AbstractTwo‐step and practical asymmetric syntheses of enantiomerically pure 4‐trifluoromethyl‐2,2‐dioxo‐1,3,2‐dioxathiolane and 4‐trichloromethyl‐2,2‐dioxo‐1,3,2‐dioxathiolane (>98% ee) have been achieved. Catalytic asymmetric dihydroxylation (AD) of 3,3,3‐trifluoropropene and 3,3,3‐trichloropropene, respectively, is followed by direct cyclic sulfate formation by reaction with sulfuryl chloride. Opening of the cyclic sulfates with various nucleophiles provides easy access to important chiral synthons.
Chemo- and Regioselective Functionalization of Polyols through Catalytic C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Kumada-Type Coupling of Cyclic Sulfate Esters
作者:Rodrigo Ramírez-Contreras、Bill Morandi
DOI:10.1021/acs.orglett.6b01745
日期:2016.8.5
This contribution describes a copper-catalyzed, C(sp3)–C(sp3) cross-coupling reaction of cyclic sulfate esters, a distinct class of electrophilic derivatives of polyols, with alkyl Grignard reagents to afford functionalized alcohol products in good yields. The method is operationally simple and highlights the potential of cyclic sulfate esters as highly reactive substrates in catalytic, chemoselective
Ring-opening reactions of functionalized 1,2-cyclic sulfates and oxetanes with the phosphonodifluoromethyl carbanion are reported. This approach allows an easy access to fluorinated beta-hydroxyphosphonates that are building blocks in the synthesis of acyclic nucleosides. Synthesis of precursors of nucleoside phosphorylase inhibitors from these alcohols is described.
New approach to cyclic sulfites and sulfates through reactions of sulfur oxychlorides with glycidols
作者:A. A. Bredikhin、A. v. Pashagin、Z. A. Bredikhina、S. N. Lazarev、A. T. Gabaidullin、I. A. Litvinov
DOI:10.1007/bf02495163
日期:2000.9
Reactions of 2,3-epoxyalcohols (glycidols) with thionyl chloride or sulfuryl chloride afford cyclicsulfites or sulfates, respectively. These reactions yield predominantly 4-chloroalkyl-1,3,2-dioxathiolane oxides. The configuration of the C(4) atom in the latter compounds exactly corresponds to that of the C(2) atom of the parent glycidol, whereas the configuration of the exocyclic atom is almost completely
Cyclic sulphates of formula: ##STR1## are prepared by oxidation of a cyclic sulphite of formula: ##STR2## with a hypohalite of an alkali or alkaline-earth metal and a catalytic quantity of a ruthernium derivative (RuO.sub.2, RuCl.sub.3). In formulae (I) and (II), R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are identical or different and each represents hydrogen, halogen, alkyl, alkoxy, aryl, aryloxy or alkoxycarbonyl.