Au-catalyzed intramolecular hydroalkoxylation of gem-difluorinated alkynols
摘要:
The intramolecular hydroalkoxylation of gem-difluorinated alkynols was found possible under Au catalysis, allowing for the preparation of a series of fluorinated heterocycles. The nature of the solvent was found to be especially critical in the cyclization of gem-difluorohomopropargylic alcohols as it dictated whether the resulting 2,3-dihydrofuran underwent subsequent aromatization to the corresponding furan or not.
A novel approach of cycloaddition of difluorocarbene to α,β-unsaturated aldehydes and ketones: synthesis of gem-difluorocyclopropyl ketones and 2-fluorofurans
作者:Wei Xu、Qing-Yun Chen
DOI:10.1039/b212232d
日期:2003.3.27
acetals and ketals are easily obtained in moderate yields from the [1 + 2] cycloaddition of difluorocarbene to 1,3-dioxolanes of alpha,beta-unsaturated aromatic aldehydes and ketones. Hydrolysis of these fluorinated compounds under acidic conditions either gives the corresponding gem-difluorocyclopropyl ketones or 1-aryl-2-fluorofuran derivatives through intramolecular carbonium rearrangement with simultaneous
Selective Synthesis of Fluorinated Furan Derivatives via AgNO<sub>3</sub>-Catalyzed Activation of an Electronically Deficient Triple Bond
作者:Satoru Arimitsu、Gerald B. Hammond
DOI:10.1021/jo701616c
日期:2007.10.1
The transition metal-catalyzed direct activation of electron deficient triple bonds was investigated by using the combined electron withdrawing effects of two fluorine atoms to modulate the electronic density of the triple bond. With use of catalytic amounts of AgNO3 (10 mol %) the synthesis of substituted 3,3-difluoro-4,5-dihydrofurans from gem-diflou rohomopropargyl alcohols occurred in excellent NMR yields. Treatment of these dihydrofurans with SiO2 or Pd/H-2 yielded the corresponding 3-fluorinated furans and 3,3-difluorotetrahydrofurans.