title: Improving selectivity in catalytic hydrodefluorination by limiting SNV reactivity.
abstract: Catalytic hydrodefluorination of perfluoroallylbenzene with Cp2TiH in THF is unselective and yields a variety of previously unknown compounds, predominantly activated in the allylic position. Several different mechanisms have been examined in detail using solvent corrected (THF) DFT(M06-2X) calculations for the archetypal perfluorinated olefin perfluoropropene and perfluoroallylbenzene: (a) single electron transfer, (b) hydrometallation/fluoride elimination, (c) σ-bond metathesis (allylic or vinylic), and (d) nucleophilic vinylic substitution (SNV, w/o Ti-F contacts in the TS). SNV is shown to be a competitive mechanism to hydrometallation and proceeds via ionic species from which F-elimination is facile and unselective leading to low selectivity in polar solvents. Subsequent experiments show that selectivity can be increased in a non-polar solvent.
authors: Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany. dieter.lentz@fu-berlin.de.
authors: Juliane
authors: J
authors: Krüger
authors: Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy. christian.ehm@unina.it.
authors: Christian
authors: C
authors: Ehm
authors: Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany. dieter.lentz@fu-berlin.de.
authors: Dieter
authors: D
authors: Lentz