Publications de Thierry Rausis

The reactivity of 2-fluoro- and 2-chloropyridines toward sodium ethoxide: Factors governing the rates of nucleophilic (het)aromatic substitutions

The relative displacement rates of the halide substituent from 2-fluoro- and 2-chloropyridines by EtONa in EtOH at +25 Deg were assessed by competition kinetics. The 2-fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the ...

2005

Rerouting Nucleophilic Substitution from the 4-Position to the 2- or 6-Position of 2,4-Dihalopyridines and 2,4,6-Trihalopyridines: The Solution to a Long-Standing Problem

Thierry Rausis, Carla Bobbio

2,4-Difluoro-, 2,4,6-trifluoro-, and 2,3,4,6-tetra(fluoro)pyridine undergo nucleophilic substitution preferentially if not exclusively at the 4-position. However, after the introduction of a trialkylsilyl group at C-3 or C-5, the halogen at the 6-(2-)posit ...

2005

Removal of fluorine from and introduction of fluorine into polyhalopyridines: an exercise in nucleophilic hetarenic substitution

Thierry Rausis, Carla Bobbio

Starting from six industrially available fluorinated pyridines, an expedient access to all three tetrafluoropyridines, all six trifluoropyridines, and the five non-com. difluoropyridines was developed. The methods employed for the selective removal of fluo ...

2005

Fluorine in an heteroaromatic context : functionalization of halopyridines

Thierry Rausis

The organometallic approach to the functionalization of arenes and heteroarenes has recently been investigated by our group introducing modifications of the standard methods. This includes, in particular, the basicity-driven heavy halogen migration, which ...

EPFL2005

Promoting or preventing haloaryllithium isomerizations: differential basicities and solvent effects as the crucial variables

Christophe Heiss, Thierry Rausis

Deprotonation-triggered heavy halogen migrations should become a favorite tool in arene synthesis if their occurrence and outcome could be made predictable. Particularly attractive, though extremely rare, are stop-and-go situations where a first intermedia ...

Georg Thieme Verlag2005

Regiochemically flexible substitutions of di-, tri-, and tetrahalopyridines: the trialkylsilyl trick

Thierry Rausis, Carla Bobbio

2,4-Difluoropyridine, 2,4-dichloropyridine, 2,4,6-trifluoropyridine, 2,4,6-trichloropyridine and 2,3,4,6-tetrafluoropyridine react with std. nucleophiles exclusively at the 4-position under halogen displacement. However, the regioselectivity can be complet ...

2005