Titre: ‘‘ Hypervalent Iodine Reagents for the Functionalization of Diazo Compounds and Radicals ’’

Endroit : Pavillon Roger-Gaudry, salle S-142 

Heure : 11:00 AM

Hôte : Professeure Hélène Lebel

Résumé :

 The non-classical four-electron three-center bonds of hypervalent iodine reagents are weaker than normal classical bonds. This confers an exceptional reactivity to these compounds as oxidants or atom-transfer reagents. Cyclic hypervalent iodine reagents are especially interesting, as they combine enhanced stability with unique opportunities for reactivity modulation.1 In particular, our group has been interested in the development of alkynylation methods using cyclic EthynylBenziodoXolone (EBX) hypervalent iodine reagents. These reagents can be used to transfer alkynes to the C-H bonds of heterocycles,2 C-C double bonds3 or hetero atom nucleophiles.4 They were also successful in the oxyalkynylation of diazo compounds.5  The use of cyclic hypervalent iodine reagents is not limited to alkynylation. Recently, we also demonstrated their use for azidation6 and cyanation,7 and their use for trifluoromethylation (Togni reagents) is now well established.8  Herein, our most recent results in the use of cyclic hypervalent iodine reagents for the functionalization of diazo compounds and radicals will be presented.

(1) Review: Y. Li, D. P. Hari, M. V. Vita, J. Waser, Angew. Chem., Int. Ed. 2016, 55, 4436.

(2) J. P. Brand, J. Charpentier, J. Waser, Angew. Chem., Int. Ed. 2009, 48, 9346.

(3) S. Nicolai, C. Piemontesi, J. Waser, Angew. Chem., Int. Ed. 2011, 50, 4680.

(4) R. Frei, M. D. Wodrich, D. P. Hari, P. A. Borin, C. Chauvier, J. Waser, J. Am. Chem. Soc. 2014, 136, 16563.

(5) D. P. Hari, J. Waser, J. Am. Chem. Soc. 2016, 138, 2190.

(6) S. Alazet, F. Le Vaillant, S. Nicolai, T. Courant, J. Waser, Chem. Eur. J. 2017, 23, 9501.

(7) F. Le Vaillant, M. D. Wodrich, J. Waser, Chem. Sci. 2017, 8, 1790.

(8) J. Charpentier, N. Frueh, A. Togni, Chem. Rev 2015, 115, 650.

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