Nucleophilic and electrophilic substitutions of difluoropropargyl bromides
作者:Gerald B. Hammond
DOI:10.1016/j.jfluchem.2005.12.024
日期:2006.5
electrophilically substituted difluoropropargyl derivatives via magnesium and fluoride promoted reactions. An indium-mediated reaction of silyldifluoropropargyl bromide, followed by electrophilic trapping with bromine led to a very useful bromoallene, which was then used in reactions with nucleophiles (C, O, N, P, S, Hal) to yield a de facto bimolecular nucleophilic substitution of a difluoropropargyl
A series of unsymmetrical S-(bromodifluoromethyl)diarylsulfonium salts 1 were readily synthesized by treatment of corresponding (bromodifluoromethyl)arylsulfoxides 2 and substituted benzenes 3 with triflic anhydride in moderate to good yields. The unsymmetrical sulfonium salts 1 with different aryl groups having electron-donating or electron-withdrawing substituents can be nicely constructed depending on the choice of 2 and 3. Bromodifluoromethylation of alkynes was evaluated by using the selected diarylsulfonium salts 1 to provide the desired bromodifluoromethylated alkynes in moderate to good yields.
Newelectrophilic fluoroalkylating agents based on the sulfoximine skeleton as a common platform are described. We demonstrate the importance of the activating group, attached to the nitrogen, and its specificity for the fluorinated group to be delivered. As an application, a variety of unknown dichlorofluoro, bromodifluoro, and trifluoromethyl alkynes have been prepared using these reagents.
Characterization of gem-difluoropropargyl synthons through HF loss from protonated molecules in methane chemical ionization mass spectra
作者:Gerald B. Hammond、Masayuki Mae、Jiyoung A. Hong、Harrell E. Hurst
DOI:10.1016/j.jfluchem.2005.10.011
日期:2006.1
Electron impact and methane chemical ionization mass spectra were obtained following gas chromatography/mass spectrometry for several gem-difluoropropargyl compounds, which had been synthesized as potential intermediates for synthesis of gem-difluoromethylene-containing C-3 acetylenes. EI spectra were variable with respect to the presentation of molecular ions, depending on substituent functional groups
通过气相色谱/质谱法对几种宝石-二氟炔丙基化合物进行了电子碰撞和甲烷化学电离质谱分析,这些化合物已被合成为潜在的中间体,用于合成含宝石-二氟亚甲基的C-3乙炔。EI谱关于分子离子的呈现是可变的,取决于存在的取代基官能团。甲烷-CI谱图的特征是所有被检测化合物的分子量损失了19个质量单位。这些[ M -19] +离子通常作为CI谱的基峰呈现,并且比[ M + 1] +更可靠地存在且含量更高这些化合物的离子。这些离子可能是通过在甲烷化学电离的条件下从质子化的分子中消除HF形成的。
Mg(0)-promoted debromometalation of gem-difluoropropargyl bromides
作者:Masayuki Mae、Jiyoung A. Hong、Gerald B. Hammond、Kenji Uneyama
DOI:10.1016/j.tetlet.2005.01.130
日期:2005.3
Mg(0)/Me3SiCl was found to be effective for the preparation of difluoropropargylsilanes. This method, using Me3SnCl, produced the corresponding propargylstannane. (C) 2005 Elsevier Ltd. All rights reserved.