Copper-free defluorinative alkylation of allylic difluorides through Lewis acid-mediated C–F bond activation
摘要:
The reactions of difluorohomoallyl alcohols with trialkylaluminiums smoothly proceeded in CH2Cl2 at room temperature to give (Z)-fluoro-olefin products in excellent yields. On the basis of this chemistry, fluoro-olefinic dipeptide isostere of norvalinyl glycine was synthesized in stereoselective manner. (C) 2011 Elsevier Ltd. All rights reserved.
The reaction of difluorohomoallyl alcohols with Me2AlCl in CH2Cl2 selectively gave (Z)-fluoroallyl chlorides via S(N)2' type defluorinative chlorination. These chlorides were easily converted to the corresponding (Z)-fluoroallyl azides by the sequential nucleophilic azidation reaction using NaN3. Direct defluorinative azidation of the difluorohomoallyl alcohols was also achieved by treating with Me3SiN3 in the presence of Al(Oi-Pr)(3). Fluoroallyl azides thus obtained successfully applied to the Huisgen. 1,3-dipolar cycloaddition chemistry. (C) 2014 Elsevier Ltd. All rights reserved.