Trimethylsilyl fluorosulfonyldifluoroacetate (TFDA): a new, highly efficient difluorocarbene reagent
作者:William R Dolbier、Feng Tian、Jian-Xin Duan、An-Rong Li、Samia Ait-Mohand、Olivia Bautista、Saiwan Buathong、J Marshall Baker、Jen Crawford、Pauline Anselme、Xiao Hong Cai、Aneta Modzelewska、Henryk Koroniak、Merle A Battiste、Qing-Yun Chen
DOI:10.1016/j.jfluchem.2003.12.002
日期:2004.3
TFDA is readily prepared from the reaction of fluorosulfonyldifluoroacetic acid with trimethylsilyl chloride, and it is a very effective and efficient source of difluorocarbene for use in addition reactions to alkenes of a broad scope of reactivities. Acid-sensitive substrates may require an additional purification step involving treatment of the distilled TFDA with sufficient Et3N to remove the acid
Synthesis of gem-Difluorinated Cyclopropanes and Cyclopropenes: Trifluoromethyltrimethylsilane as a Difluorocarbene Source
作者:Fei Wang、Tao Luo、Jinbo Hu、Ying Wang、Hema S. Krishnan、Parag V. Jog、Somesh K. Ganesh、G. K. Surya Prakash、George A. Olah
DOI:10.1002/anie.201101691
日期:2011.7.25
Highly versatile: The Ruppert–Prakash reagent (Me3SiCF3) can be an efficient source of difluorocarbene. By varying the nonmetallic initiator that is used (F− at lower temperatures and I− at higher temperatures), a range of structurally diverse alkenes and alkynes can be converted into the corresponding gem‐difluorinated cyclopropanes and cyclopropenes in good yields (see scheme).
The trifluoromethylation of carbonyl compounds is accomplished by the stable (trifluoromethyOzinc reagent generated and then isolated from CF3I and ZnEt2, which can be utilized as a trifluoromethyl anion source (CF3-). The reaction proceeds smoothly with diamine as a ligand and ammonium salt as an initiator, providing the corresponding trifluoromethylated alcohol products. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source (:CF2) not only for gem-difluoroolefination of carbonyl compounds with phosphine but also for gem-difluorocyclization of alkenes or alkynes via the thermal decomposition, respectively.
Difluorocarbene Generation from TMSCF<sub>3</sub>: Kinetics and Mechanism of NaI-Mediated and Si-Induced Anionic Chain Reactions
作者:Andrés García-Domínguez、Thomas H. West、Johann J. Primozic、Katie M. Grant、Craig P. Johnston、Grant G. Cumming、Andrew G. Leach、Guy C. Lloyd-Jones
DOI:10.1021/jacs.0c06751
日期:2020.8.26
functional theory (DFT) calculations. The reactions evolve with profoundly different kinetics, undergoing auto-inhibition (TBAT) or stochastic auto-acceleration (NaI), and co-generating perfluoroalkene side products. An overarching mech- anism involving direct and indirect fluoride transfer from a CF3-anionoid to TMSCF3 (1) has been elucidated. It allows rationalization of why the NaI-mediated process is