74764-33-3Relevant academic research and scientific papers
Reactions of 2-Substituted Pyridines with Titanocenes and Zirconocenes: Coupling versus Dearomatisation
Rei?, Fabian,Altenburger, Kai,Becker, Lisanne,Schubert, Kathleen,Jiao, Haijun,Spannenberg, Anke,Hollmann, Dirk,Arndt, Perdita,Rosenthal, Uwe
, p. 3361 - 3369 (2016)
Reactions of group 4 metallocene sources with 2-substituted pyridines were investigated to evaluate their coordination type between innocent and reductive dearomatisation as well as to probe the possibility for couplings. A dependence on the cyclopentadienyl ligands (Cp, Cp?), the metals (Ti, Zr), and the substrates (2-phenyl-, 2-acetyl-, and 2-iminopyridine) was observed. While 2-phenylpyridine is barely reactive, 2-acetylpyridine reacts vigorously with the Cp-substituted complexes and selectively with their Cp? analogues. With 2-iminopyridine, in all cases selective reactions were observed. In the isolated [Cp2Ti], [Cp2Zr], and [Cp?2Zr] compounds the substrate coordinates by its pyridyl ring and the unsaturated side-chain. Subsequently, the pyridine was dearomatised, which is most pronounced in the [Cp?2Zr] compounds. Using [Cp?2Ti] leads to the unexpected paramagnetic complexes [Cp?2TiIII(N,O-acpy)] and [Cp?2TiIII(N,N'-impy)]. This highlights the non-innocent character of the pyridyl substrates.
