Event
CCVC Seminar: Dr. Antonio Togni - The Trifluoromethyl Group in Catalysis and Organometallic Chemistry
Tuesday, October 25, 2016 13:00to14:30
Maass Chemistry Building
Rm 10, 801 rue Sherbrooke Ouest, Montreal, QC, H3A 0B8, CA
The lecture will give an overview on trifluoromethylation reactions carried out with hypervalent iodine reagents of type 1 and 2 [1]. These transformations, upon which an intact CF3 group may be transferred to a large variety of substrates, are catalyzed or assisted by Br酶nsted and Lewis acids, or by a number of transition-metal complexes. N- and P-trifluoromethylations of benzimidazole or both primary and secondary phosphines, respectively, are used for the preparation of corresponding carbene ligands [2] and novel Pstereogenic phosphines [3] for applications in homogeneous catalysis. Thus, Grubbs-II-type complexes 3 provide high selectivities in e.g. ethenolysis reactions while ligand 4 affords enantioselectivities in the Ir-catalyzed hydrogenation of cyclic iminium salts that are higher than with the parent ligand. Structural modifications [4] and modes of activation of the reagents as well as mechanistic insight deriving from both experiments and quantumchemical calculations [5] will also be presented.
References
[1] For a comprehensive review, see (a) J. Charpentier, N. Fr眉h, A. Togni, Chem. Rev. 2015, 115, 650, and references cited therein.
[2] (a) P.S. Engl, R. Senn, E. Otth, A. Togni, Organometallics 2015, 34, 1384. (b) P.S. Engl, A. Fedorov, C. Cop茅ret, A. Togni, Organometallics 2016, 35, 887.
[3] R. Schwenk, A. Togni, Dalton Trans. 2015, 44, 19566.
[4] V. Matousek, J. Vaklavik, P. Hajek, J. Charpentier, Z.E. Blastik, E. Pietrasiak, A. Budinska, A. Togni, P. Beier, Chem. Eur. J. 2016, 22, 417.
[5] (a) O. Sala, H. P. L眉thi, A. Togni, M. Iannuzzi, J. Hutter, J. Comput. Chem. 2015, 36, 785. (b) O. Sala, N. Santschi, S. Jungen, H.P. L眉thi, M. Iannuzzi, N. Hauser, A. Togni,
Chem. Eur. J. 2016, 22, 1704.