461-56-3Relevant academic research and scientific papers
Catalytic Formation of C(sp3)-F Bonds via Heterogeneous Photocatalysis
Tarantino, Giulia,Hammond, Ceri
, p. 10321 - 10330 (2018/11/21)
Due to their chemical, physical, and biological properties, fluorinated compounds are widely employed throughout society. Yet, despite their critical importance, current methods of introducing fluorine into compounds suffer from severe drawbacks. For example, several methods are noncatalytic and employ stoichiometric equivalents of heavy metals. Existing catalytic methods, on the other hand, exhibit poor activity, generality, selectivity and/or have not been achieved by heterogeneous catalysis, despite the many advantages such an approach would provide. Here, we demonstrate how selective C(sp3)-F bond synthesis can be achieved via heterogeneous photocatalysis. Employing TiO2 as photocatalyst and Selectfluor as mild fluorine donor, effective decarboxylative fluorination of a variety of carboxylic acids can be achieved in very short reaction times. In addition to displaying the highest turnover frequencies of any reported fluorination catalyst to date (up to 1050 h-1), TiO2 also demonstrates excellent levels of durability, and the system is catalytic in the number of photons required; i.e., a photon efficiency greater than 1 is observed. These factors, coupled with the generality and mild nature of the reaction system, represent a breakthrough toward the sustainable synthesis of fluorinated compounds.
Catalytic formation of C(sp3)-F bonds via decarboxylative fluorination with mechanochemically-prepared Ag2O/TiO2 heterogeneous catalysts
Tarantino,Botti,Dimitratos,Hammond
, p. 30185 - 30190 (2017/07/11)
Mechanochemically-prepared, Ag2O-containing solid materials, are shown to be efficient heterogeneous catalysts for the synthesis of C(sp3)-F bonds via decarboxylative fluorination. Five catalytic cycles without loss of intrinsic activity could be performed with the optimal catalyst, composed of 1 wt% Ag2O supported on TiO2 (P25), despite the challenging conditions. The catalyst is easily prepared from the corresponding oxides in 20 minutes by simple mechanical mixing methods. In addition to ease of separation and re-use, the turnover numbers obtained over the solid catalyst are over one order of magnitude higher than those obtained with the state-of-the-art homogeneous catalyst, AgNO3, under otherwise identical conditions. To the best of our knowledge, this represents the first true heterogeneous catalyst for the selective formation of C(sp3)-F bonds with electrophilic fluorine donors, representing a major breakthrough in the field of catalytic fluorination.
Visible light-promoted metal-free sp3-C-H fluorination
Xia, Ji-Bao,Zhu, Chen,Chen, Chuo
supporting information, p. 11701 - 11704 (2015/05/20)
Photoexcited acetophenone can catalyze the fluorination of unactivated C(sp3)-H groups. While acetophenone, a colorless oil, only has a trace amount of absorption in the visible light region, its photoexcitation can be achieved by irradiation with light generated by a household compact fluorescent lamp (CFL). This operational simple method provides improved substrate scope for the direct incorporation of a fluorine atom into simple organic molecules. CFL-irradiation can also be used to promote certain classic UV-promoted photoreactions of colorless monoarylketones and enones/enals.
6-Substituted pyrido-pyrimidines
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, (2008/06/13)
The present invention provides compounds of the Formula I and II: wherein R1, R3, W, Z, X1, X2, Ar1, R8 and R9 are as defined herein, and methods and intermediates for their preparation and uses thereof.
