Etherification of Functionalized Phenols with Chloroheteroarenes at Low Palladium Loading: Theoretical Assessment of the Role of Triphosphane Ligands in C-O Reductive Elimination was written by Platon, Melanie;Cui, Luchao;Mom, Sophal;Richard, Philippe;Saeys, Mark;Hierso, Jean-Cyrille. And the article was included in Advanced Synthesis & Catalysis in 2011.Electric Literature of C11H9NO This article mentions the following:
The present study highlights the potential of robust tridentate ferrocenylphosphanes with controlled conformation as catalytic auxiliaries in C-O bond formation reactions. Air-stable Pd triphosphane systems are efficient for selective heteroaryl ether synthesis by using ≥0.2 mol% of catalyst. These findings represent an economically attractive and clean etherification of functionalized phenols, electron-rich, electron-poor and para-, meta- or ortho-substituted substrates, with heteroaryl chlorides, including pyridines, hydroxylated pyridine, pyrimidines and thiazole. The etherification tolerates very important functions in various positions, such as cyano, methoxy, amino, and fluoro groups, which is useful to synthesize bioactive mols. DFT studies also demonstrate that triphosphane ligands open up various new pathways for the C-O reductive elimination involving the 3rd phosphane group. In particular, the rate for one of these new pathways is ∼1000 times faster than for reductive elimination from a complex with a similar ferrocenyl ligand, but without a phosphane group on the bottom Cp-ring. Coordination of the 3rd phosphane group to the Pd(II) center is calculated to stabilize the transition state in this new pathway, thereby enhancing the reductive elimination rate. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Electric Literature of C11H9NO).
2-Phenoxypyridine (cas: 4783-68-0) belongs to pyridine derivatives. Pyridine’s the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.Electric Literature of C11H9NO