- ON THE MECHANISM OF SELECTIVE CHLORINATION OF ETHERS WITH SULFURYL CHLORIDE IN THE DARK
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Alkyl 4-chlorobutyl ethers reacted in the dark with an excess of sulfuryl chloride at 70-85 deg C (bath) to afford α,β,β-trichlorinated ethers.The reactions were accelerated 3- to 6-fold by N,N-dimethyloctylammonium salts (0,12 to 1 mmol/mol ether).This catalyst promoted decomposition of sulfuryl chloride to chlorine and sulfur dioxide and thereby caused serious loss of sulfuryl chloride.The proportions of chlorination at α or α1 position were identical in the catalyzed or uncatalyzed version and depended on inductive effects, correlating well with Taft's linear free energy relationship log k/kref=ρ*?* for R = H, Me, Et, Pr in RCH2O(CH2)4Cl with ρ* = -2.6 +/- 0.1.The overall reactivity of ethers appears to vary like the nucleophilicity of the ether oxygen.It is concluded that hydride abstraction occurs indirectly, probably involving a chloroxonium ion pair.
- Buyck, Laurent De,Pooter, Herman De
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p. 807 - 816
(2007/10/02)
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