Categories: C-Cl Bond Formation >
Synthesis of aryl chlorides
N-Halosuccinimides are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity.
G. K. S. Prakash, T. Mathew, D. Hoole, P. M. Esteves, Q. Wang, G. Rasul, G. A. Olah, J. Am. Chem. Soc., 2004, 126, 15770-15776.
The Lewis base Trip-SMe (Trip = triptycenyl) catalyzes an electrophilic halogenation of unactivated aromatic compounds using N-halosuccinimides (NXS) at ambient temperature in the presence of AgSBF6 as source of a non-coordinating anion. The π system of the triptycenyl functionality exerts a crucial role for the enhancement of electrophilicity.
Y. Nishii, M. Ikeda, Y. Hayashi, S. Kawauchi, M. Miura, J. Am. Chem. Soc., 2020, 142, 1621-1629.
A highly para-selective halogenation of arenes bearing electron-donating coordinating groups in the presence of a dimidazolium salt rpovides p-haloarenes in good yields. A plausible mechanism for the catalytic reaction is proposed.
J. Chen, X. Xiong, Z. Chen, J. Huang, Synlett, 2015, 26, 2831-2834.
A mild, efficient, Cu(I)-catalyzed method for the synthesis of aryl chlorides from arylboronic acids is particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient in the absence of Cu catalysis.
H. Wu, J. Hynes, Jr., Org. Lett., 2010, 12, 1192-1195.
A mild and metal-free method for the chlorodeboronation of organotrifluoroborates using trichloroisocyanuric acid (TCICA) converts aryl-, heteroaryl-, alkenyl-, alkynyl-, and alkyltrifluoroborates into the corresponding chlorinated products in good yields. This method tolerates a broad range of functional groups.
G. A. Molander, L. N. Cavalcanti, J. Org. Chem., 2011, 76, 7195-7203.
A mild palladium-catalyzed, regioselective chlorination, bromination, and iodination of arene C-H bonds using N-halosuccinimides as oxidants is described. These transformations can provide products that are complementary to those obtained via conventional electrophilic aromatic substitution reactions.
D. Kalyani, A. R. Dick, W. Q. Anani, M. S. Sanford, Org. Lett., 2006, 8, 2523-2526.
ridium-catalyzed borylation of 1,3-disubstituted arenes with B2pin2, followed by reaction of the boronic ester with copper(II) bromide or chloride converts arylboronic esters to the corresponding meta-halogenated aryl halides. Various functional groups, such as alkoxy, alkyl, halogen, nitrile, ester, amide, and pivaloyl and TIPS-protected alcohols, are tolerated.
J. M. Murphy, X. Liao, J. F. Hartwig, J. Am. Chem. Soc., 2007, 129, 15434-15435.
A facile Pd-catalyzed conversion of aryl and vinyl triflates allows convenient access to various aryl, heteroaryl, and vinyl halides in good to excellent yields and with greatly simplified conditions relative to our previous report.
J. Pan, X. Wang, Y. Zhang, S. L. Buchwald, Org. Lett., 2011, 13, 4974-4976.
Using cyano as the directing group, a palladium-catalyzed ortho-halogenation (I, Br, Cl) reaction gave good to excellent yields. The method is compatible to arylnitriles with either electron-withdrawing or electron-donating groups. The present method was successfully applied to the synthesis of the precursors of paucifloral F and isopaucifloral F.
B. Du, X. Jiang, P. Sun, J. Org. Chem., 2013, 78, 2786-2791.
Silver carbonate or nickel(II) chloride catalyzes an ortho-C-H bond halogenation of anilides and N-aryl carbamates with N-halosuccinimides to provide 2-haloanilides and carbamates, which may serve as starting materials for the synthesis of pharmaceutically and biologically active compounds.
E. Kianmehr, H. Afaridoun, Synthesis, 2021, 53, 1513-1523.