Fluorination of Aryl Boronic Acids Using Acetyl Hypofluorite Made Directly from Diluted Fluorine
Inna Vints, Julia Gatenyo and Shlomo Rozen*
*School of Chemistry, Tel-Aviv University, Tel-Aviv 69978,
Israel, Email: rozens
post.tau.ac.il
I. Vints, J. Gatenyo, S. Rozen, J. Org. Chem., 2013, 78, 11794-11795.
DOI: 10.1021/jo401832f
Abstract
Electron-rich aryl boronic acids or pinacol esters were converted in good yields and fast reactions to the corresponding aryl fluorides using readily obtainable solutions of AcOF. In reactions with aryl boronic acids containing EWG at the para position, fluorination ortho to the boronic acid is in competition with an ipso substitution. With EWG meta to the boronic acid, substitution ipso to the boron moiety takes place in good yields.
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Note
It should be stressed that acetyl hypofluorite can serve as a powerful fluorinating agent many times for tasks very difficult to achieve by any other means. The fact that it is made from diluted fluorine should not deter chemists from working with it. Thus, for example, fluorine is less toxic than chlorine,[i] and in concentrations of 10 - 20% in N2 is also much less corrosive than both chlorine and bromine. Working with it is not as complicated as one may think. Technical commercial fluorine can be diluted on the spot[ii] or premixed fluorine/nitrogen mixtures could be purchased.
[i]. American Enviromental Group ltd, AEGL (Acute Exposure Guideline
Level) (50) October 2 2009.
[ii]. S. Dayan, M. Kol, S. Rozen, Synthesis, 1999, 1427.
Shlomo Rozen, January 2, 2015
Key Words
ID: J42-Y2013
