Copper-catalyzed trifluoromethylselenolation of aryl and alkyl halides: The silver effect in transmetalation

10.1021/ol403406yOrganic Letters162524-527ORLE

Cooperative effect of silver in copper-catalyzed trifluoromethylation of aryl iodides using Me3SiCF3

10.1021/om200204yOrganometallics30113229-3232ORGN

Octakis(tert-butoxo)dicerium(IV) [Ce-2((OBu)-Bu-t)(8)]: Synthesis, Characterization, Decomposition, and Reactivity

An advanced synthesis for the homometallic derivative [Ce-2((OBu)-Bu-t)(8)] (1) starting from [Ce((OBu)-Bu-t)(2){N(SiMe3)(2)}(2)] was developed. Structural characterization of a cerium(IV) complex and its decomposition products confirmed the coexistence of both ether elimination and Ce-O bond cleavage processes, which lead to the formation of [Ce3O((OBu)-Bu-t)(10)] and [Ce-3((OBu)-Bu-t)(11)] (2) derivatives, respectively. Variable-temperature NMR spectroscopy under strict exclusion of moisture enabled insight into the decomposition processes in noncoordinating solvents and at elevated temperature. In addition, structural analysis of the heterovalent 2 and of two new complexes of the general formula [Ce-2((OBu)-Bu-t)(8)(L)] [L = (HOBu)-Bu-t (3), OCPh2 (4)] is described

On the Stability of Perfluoroalkyl-Substituted Singlet Carbenes: A Coupled-Cluster Quantum Chemical Study

Rozhenko AB, Schoeller W, Leszczynski J. On the Stability of Perfluoroalkyl-Substituted Singlet Carbenes: A Coupled-Cluster Quantum Chemical Study. The Journal of Physical Chemistry A. 2014;118(8):1479-1488.A series of trifluoromethyl-substituted carbenes R-C(:)-CF3 (R = NMe2, OMe, F, PMe2, P(NMe2)(2), P(N(Pr-i)(2))(2), SMe, Cl); (dimethylamino)-(perfluoroalkyl)carbenes Me2N-C(:)-R (R = CF3, C2F5, n-C3F7, i-C3F7, and t-C4F9) and symmetrically substituted carbenes R-C(:)-R (R = NMe2, OMe, F, PMe2, SMe, Cl) have been investigated by means of quantum chemistry methods. Different levels of approximation were used, including the CCSD(T) approach also known in quantum chemistry as the "golden standard", in combination with three different basis sets (TZVP, cc-pVDZ, -cc-pVTZ). Relative stabilities of carbenes have been estimated using the differences between the singlet and triplet ground state energies (Delta E-ST) and energies of the hydrogenation reaction for the singlet and triplet ground states of the carbenes. The latter seem to correlate better with stability of carbenes than the Delta E-ST values. The C-13 NMR chemical shifts of the methylidene carbon indicate the more high-field chemical shift values in the known, isolable carbenes compared to the unstable ones. This is the first report on the expected chemical shifts in the highly unstable singlet carbenes. Using these criteria, some carbene structures from the studied series (as, for instance, Me2N-C(:)-CF3, Me2N-C(:)-C3F7-i) are proposed as good candidates for the experimental preparation

Stable and Storable N(CF 3

Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF$_{3}$)$_{2}$ group are rare. One reason is that transfer reagents are scarce and metal-based storable reagents are unknown. Herein, a set of Cu$^{I}$ and Ag$^{I}$ bis(trifluoromethyl)amido complexes stabilized by N- and P-donor ligands with unprecedented stability are presented. The complexes are stable solids that can even be manipulated in air for a short time. They are bis(trifluoromethyl)amination reagents as shown by nucleophilic substitution and Sandmeyer reactions. In addition to a series of benzylbis(trifluoromethyl)amines, 2-bis(trifluoromethyl)amino acetate was obtained, which, upon hydrolysis, gives the fluorinated amino acid N,N-bis(trifluoromethyl)glycine