Russian Chemical Bulletin, International Edition, Vol. 53, No. 2, pp. 370—375, February, 2004 370 1066-5285/04/5302-0370 © 2004 Plenum Publishing Corporation Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 356—361, February, 2004. Synthesis of (azidomethyl)phenylboronic acids A. Yu. Fedorov, a A. A. Shchepalov, a A. V. Bol´shakov, a A. S. Shavyrin, b Yu. A. Kurskii, b J.-P. Finet, c and S. V. Zelentsov a a N. I. Lobachevsky University of Nizhnii Novgorod, 23 prosp. Gagarina, 603950 Nizhnii Novgorod, Russian Federation. Fax: +7 (831 2) 65 8592. E-mail: afnn@rambler.ru b G. A. Razuvaev Institute of Organometallic Chemistry of the Russian Academy of Sciences, 49 ul. Tropinina, 603600 Nizhnii Novgorod, Russian Federation. Fax: +7 (831 2) 12 7497. E-mail: andrew@imoc.sinn.ru c Faculty of Science of St. Jerome, Aix-Marseille University, 13397 Marseille, France.* Fax: +33 4 91 288758. E-mail: finet@srepir1.univ-mrs.fr The synthesis of 2-, 3-, and 4-(azidomethyl)phenylboronic acids was carried out. The geometric and electronic structures were studied by quantum-chemical methods. The sugges- tion is made that there are weak intramolecular interactions between the boron atom and the nitrene nitrogen atom of the azido group. Key words: azidomethylphenylboronic acids, synthesis, quantum-chemical calculations. Boronic acids have found wide use in fine organic synthesis. For example, Suzuki cross-coupling involving arylboronic acids 1—10 is one of the most convenient and ecologically safe methods 11,12 for the construction of new C—C bonds. In the presence of copper salts as catalysts, arylboronic acids serve as efficient O-, 13,14 N-, 15 and S-arylating reagents. 16 Mild synthesis conditions, high regioselectivity of these processes, the possibility of per- forming arylation of optically active substrates without epimerization, and high yields of N-, O-, and S-arylation products favorably distinguish the reactions with aryl- boronic acids from the classical Ullmann reaction. 17 In the present study, we synthesized previously unknown arylboronic acids containing the 2-, 3-, or 4-azidomethylphenyl groups and investigated their struc- tures and the electron density distribution. Organic azides are extensively used for performing various chemical trans- formations. 18,19 Hence, arylboronic acids, which allow one to insert the benzylazide fragments into organic sub- strates to form new C—C, C—N, C—O, and C—S bonds, are of considerable interest. Radical bromination of known ortho-, meta-, and para-tolylboronic acids using NBS as a brominating agent afforded 2-, 3-, and 4-(bromomethyl)phenylboronic ac- ids 2a—c as polycrystalline products in 58, 37, and 39% yields, respectively. In the next step, (azidomethyl)phenyl- boronic acids 3a—c were prepared in 46, 48, and 49% yields, respectively, as viscous oils by the reactions of (bromomethyl)phenylboronic acids with NaN 3 in dry DMF. Acids 3a—c were obtained as solvates with DMF. Scheme 1 Reagents and conditions: i. NBS, (BzO) 2 ; ii. NaN 3 , DMF. All the derivatives synthesized were identified by 1 H, 13 C, and 11 B NMR, IR, and UV spectroscopy as well as by elemental analysis. It should be noted that in the 1 H and 13 C NMR spectra of some bromo- and azido-substi- tuted derivatives, the protons of the methylene groups and aromatic rings and the corresponding carbon atoms appear as several signals with insignificantly differ- ent chemical shifts (the differences are 0.02—0.40 and 0.10—1.3 ppm for the 1 H and 13 C NMR spectra, re- * CNRS-Universites d'Aix-Marseille 1 et 3, UMR 6517, Faculte des Sciences de Saint-Jerome, 13397 Marseille Cedex 20, France.