51954-17-7Relevant academic research and scientific papers
Palladium-catalyzed allylic alkylation dearomatization of β-naphthols and indoles withgem-difluorinated cyclopropanes
Fu, Zhiyuan,Zhu, Jianping,Guo, Songjin,Lin, Aijun
, p. 1262 - 1265 (2021)
A palladium-catalyzed allylic alkylation dearomatization of β-naphthols and indoles withgem-difluorinated cyclopropanes has been developed. This reaction provided an efficient route to access 2-fluoroallylic β-naphthalenones and indolenines bearing quaternary carbon centers in good yields with highZ-selectivityviaC-C bond activation, C-F bond cleavage and the dearomatization process, benefiting from the wide substrate scope and good functional group tolerance. Moreover, 2-fluoroallylic furanoindoline and pyrroloindolines were achieved in good efficiencyviacascade allylic alkylation, dearomatization and cyclization processes in the presence of Et3B.
All-carbon phosphoranesviadifluorocarbene trapping
Smirnov, Vladimir O.,Volodin, Alexander D.,Korlyukov, Alexander A.,Dilman, Alexander D.
, p. 4823 - 4826 (2021)
A reaction of intramolecularly disposed phosphonium and phenoxide (or thiophenoxide) fragments with difluorocarbene affording all-carbon λ5-phosphoranes is described. The presence of electron-withdrawing CHF2-groups at the phosphonium center is important for the phosphorane formation. In a phosphorane, both phenyl groups located in the equatorial positions undergo 1,2-P,C migration under thermal conditions.
Reaction of (bromodifluoromethyl)trimethylsilane with HMPA: Structural studies
Dilman, Alexander D.,Hu, Jinbo,Korlyukov, Alexander A.,Supranovich, Vyacheslav I.,Volodin, Alexander D.
, (2021)
The crystal structure of a low melting difluorinated silicon reagent (bromodifluoromethyl)trimethylsilane is described. Hexamethylphosphoramide (HMPA) serves as an efficient Lewis basic activator to decompose the silicon reagent to generate difluorocarbene along with the formation of silyl-capped HMPA cation. The bromide salt with Me3Si-HMPAcation was also obtained by interaction of bromotrimethylsilane with HMPA and was characterized by X-ray analysis. Interaction of silanes with HMPA was evaluated by quantum chemical calculations, which demonstrated that the Lewis base provides a significant decrease of the transition state energy for the generation of difluorocarbene by an attack at the silicon atom.
Trapping of Difluorocarbene by Frustrated Lewis Pairs
Dilman, Alexander D.,Korlyukov, Alexander A.,Smirnov, Vladimir O.,Volodin, Alexander D.
supporting information, p. 12428 - 12431 (2020/04/15)
Frustrated Lewis pairs consisting of diphenylphosphino and boryl groups located at the ortho-position can trap difluorocarbene affording stable zwitterionic adducts. The reaction can be reversed to release difluorocarbene at elevated temperatures.
Difluoromethylation of alcohols with TMSCF2Br in water: A new insight into the generation and reactions of difluorocarbene in a two-phase system
Zhang, Rongyi,Ni, Chuanfa,Xie, Qiqiang,Hu, Jinbo
supporting information, (2020/11/10)
Although many difluorocarbene-involved reactions can be performed in the presence of water, the reaction of difluorocarbene using water as the only reaction medium is rare. By using TMSCF2Br as a unique difluorocarbene reagent and KHF2 as a mild activator, the difluoromethylation of liquid alcohols in water is described. This research not only develops an environmentally benign process for the synthesis of difluoromethyl ethers, but also provides a new insight into the generation and reactions of difluorocarbene in an oil-water two-phase system.
TMSCF3 as a Convenient Source of CF2=CF2 for Pentafluoroethylation, (Aryloxy)tetrafluoroethylation, and Tetrafluoroethylation
Li, Lingchun,Ni, Chuanfa,Xie, Qiqiang,Hu, Mingyou,Wang, Fei,Hu, Jinbo
supporting information, p. 9971 - 9975 (2017/08/08)
A new method for the on-site preparation of tetrafluoroethylene (TFE) and a procedure for its efficient use in pentafluoroethylation by fluoride addition were developed by using a simple two-chamber system. The on-site preparation of TFE was accomplished by dimerization of difluorocarbene derived from (trifluoromethyl)trimethylsilane (TMSCF3) under mild conditions. Other fluoroalkylation reactions, such as (aryloxy)tetrafluoroethylation and tetrafluoroethylation processes, were also achieved using a similar approach. This work not only demonstrates a convenient and safe approach for the generation and use of TFE in academic laboratories, but also provides a new strategy for pentafluoroethylation.
Pd-Catalyzed Regioselective Activation of gem-Difluorinated Cyclopropanes: A Highly Efficient Approach to 2-Fluorinated Allylic Scaffolds
Xu, Jun,Ahmed, Ebrahim-Alkhalil,Xiao, Bin,Lu, Qian-Qian,Wang, Yun-Long,Yu, Chu-Guo,Fu, Yao
supporting information, p. 8231 - 8235 (2015/07/07)
An unprecedented Pd-catalyzed regioselective activation of gem-difluorinated cyclopropanes induced by C-C bond cleavage is reported. It provides a general and efficient access to a variety of 2-fluoroallylic amines, ethers, esters, and alkylation products in high Z-selectivity, which are important skeletons in many biologically active molecules. In addition, the transformation represents the first general application of gem-difluorinated cyclopropanes as reaction partners in transition-metal-catalyzed cross-coupling reaction. C-C bond cleavage under Pd catalysis induces a regioselective activation of gem-difluorinated cyclopropanes. The reaction provides access to a variety of 2-fluoroallylic scaffolds with high Z-selectivity and represents the first general application of gem-difluorinated cyclopropanes as reaction partners in transition-metal-catalyzed cross-coupling reactions.
Nucleophilic bromodifluoromethylation of iminium ions
Tsymbal, Artem V.,Kosobokov, Mikhail D.,Levin, Vitalij V.,Struchkova, Marina I.,Dilman, Alexander D.
, p. 7831 - 7835 (2015/03/18)
A method for bromodifluoromethylation of iminium ions using Me3SiCF2Br is described. The reaction involves room temperature activation of the silicon reagent by HMPA to generate difluorocarbene, which upon interacting with excess of bromide ion provides bromodifluoromethyl carbanionic species. The iminium electrophiles are generated in situ from aldehydes, secondary amines, proton sponge, and silyl triflate. The reaction can be extended for introduction of chlorodifluoromethyl and iododifluoromethyl groups.
An improved method for difluorocyclopropanation of alkenes
Gill, Duncan M.,McLay, Neil,Waring, Michael J.,Wilkinson, Christopher T.,Sweeney, Joseph B.
, p. 1756 - 1758 (2014/08/05)
Difluorocyclopropanation of alkenes using fluorinated acetate salts using convential heating is often a slow, inefficient, and energy-intensive process. We report here a modified protocol which enables the rapid (5 min) preparation of 1,1-difluorocyclopropanes, using microwave irradiation. The new procedure is not only considerably faster than previously reported methods, but it also employs easily removed, low boiling-point solvents and avoids the use of highly toxic or ozone-depleting substances. Georg Thieme Verlag Stuttgart. New York.
Synthesis of gem-difluorocyclopropa(e)nes and O-, S-, N-, and P-difluoromethylated compounds with TMSCF2Br
Li, Lingchun,Wang, Fei,Ni, Chuanfa,Hu, Jinbo
supporting information, p. 12390 - 12394 (2013/12/04)
Two-in-one: Me3SiCF2Br is an efficient difluorocarbene source and is compatible with both neutral and aqueous basic conditions. Bromide-ion-initiated [2+1] cycloaddition with alkenes/alkynes and hydroxide ion promoted α-addition with (thio)phenols, (thio)alcohols, sulfinates, heterocyclic amines, and H-phosphine oxides give the corresponding gem-difluorinated compounds with broad functional-group tolerance. Copyright
