Reactivity of a palladium fluoro complex towards silanes and Bu3SnCH=CH2: Catalytic derivatisation of pentafluoropyridine based on carbon-fluorine bond activation reactions.
The chloro and azido complexes trans-[PdCl(4-C5NF4)(PiPr3)2] (3) and trans-[Pd(N3)(4-C5NF4)(PiPr3)2] (4) can be prepared by reaction of [PdF(4-C5NF4)(PiPr3)2] (2) with Et3SiCl or MeSiN3, respectively. In contrast, reactions of 2 with Ph3SiH or Me2FSiSiFMe2 give the products of reductive elimination 2,3,5,6-tetrafluoropyridine (5) or 4-(fluorodimethylsilyl)tetrafluoropyridine (6) as well as [Pd(PiPr3)2] (1). In a catalytic experiment, pentafluoropyridine can be converted with Ph3SiH into 5 in 62% yield, when 10% of 2 is employed as catalyst. Treatment of trans-[PdF(4-C5NF4)(PiPr3)2] (2) with Bu3SnCH=CH2 in THF at 50 degrees C results in the formation of [Pd(PiPr3)2] (1) and 4-vinyltetrafluoropyridine (7). Complex 2 is also active as a catalyst towards a Stille cross-coupling reaction of pentafluoropyridine with Bu3SnCH=CH2 to give 4-vinyltetrafluoropyridine (7) with a TON of 6. The molecular structure of the complex 3 has been determined by X-ray crystallography.
Braun
Thomas
T
Fakultät für Chemie, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany. thomas.braun@uni-bielefeld.de
Izundu
Joseph
J
Steffen
Andreas
A
Neumann
Beate
B
Stammler
Hans-Georg
HG
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D005461:Fluorine / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D017646:Organosilicon Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism; D005466:Fluorocarbons
D002244:Carbon; D005461:Fluorine; D009942:Organometallic Compounds; D017646:Organosilicon Compounds; D010165:Palladium; D011725:Pyridines; C486857:pentafluoropyridine; D005466:Fluorocarbons