Cobalt bis(2‐ethylhexanoate) and terpyridine derivatives as catalysts for the hydrosilylation of olefins

Abstract

A simple method for the hydrosilylation of olefins by using air-stable cobalt catalysts is developed. The catalyst system is composed of simple, cheap, and readily available cobalt(II) salts and well-defined terpyridine derivatives as cocatalysts or ligands, and the hydrosilylation processes can be processed smoothly under mild conditions without either Grignard reagents or NaHBEt 3 as activator.

Base Metal‐terpyridine Complex Immobilized on Stationary Phase Aimed as Reusable Hydrosilylation Catalyst

“…Several activator-free catalyst systems using base metal complexes, which typically have both pincer and carboxylato ligands, [5][6][7]11,22] have been reported for hydrosilylation. Therefore, Co(OAc) 2 was employed as the Co source instead of CoBr 2 .…”

“…Current research in this field is heavily shifted towards base metal catalysts, thereby facilitating sustainable development. [1] In hydrosilylation reactions, pincer-type ligands such as NNN [2][3][4][5][6][7][8] and PNN types [2,[9][10][11] have been widely used as supporting ligands for base metal complex catalysts. In addition, most of them have large substituents on the pincer framework that allow stereo-and chemo-selectivity.…”

“…Some transition metal complexes bearing tpy as a ligand ([M(tpy)X n ] (n = 2-3, X=Br, OAc, or THF)) have been reported to exhibit catalytic activity for hydrosilylation in homogeneous systems. [6][7][8] Therefore, the immobilization of a base metal complex can be conducted with tpy as a ligand and in a stationary phase and the catalytic activity of this complex can be examined. To this end, herein, complexes of base metals, such as Mn, Fe, Co, Ni, and Cu, and bearing a tpy ligand were immobilized on a silica gel surface, and the catalytic activity of the modified silica gels for olefin hydrosilylation was investigated.…”

Carboxylate-Functionalized P, N-Ligated Cobalt Catalysts for Alkene Hydrosilylation

“…Moret [ 13 ] demonstrated the catalytic activity of well-characterized Co(II) and Co(I) complexes of the p -Tol-dpbp ligand in the hydrosilylation of 1-octene with phenylsilane. In addition, there have been several studies on hydrosilylations catalyzed by cobalt salts [ 14 - 23 ]. Our group also synthesized a series of acylphosphines and investigated the hydrosilylation of alkenes that were catalyzed using RhCl 3 -acylphosphine.…”

TMSOTf-mediated Kröhnke pyridine synthesis using HMDS as the nitrogen source under microwave irradiation

“…Pyridines serve as an essential framework, and their derivatives have gained considerable interest in organic chemistry owing to their presence in a wide range of natural products such as NAD (nicotinamide adenine dinucleotide) nucleotides, pyridoxine (vitamin B 6 ), pyridine alkaloids, 1 pharmaceuticals (as antimalarial, vasodilatory, anaesthetic, anticonvulsant and antiepileptic drugs), 2 agrochemicals (as fungicides, pesticides, and herbicides), 3 electrochemical, 4 functionalized materials, 5 organocatalysts, 6 and synthetic ligands. 7 Among them, 2,4,6-triarylpyridines (TAPs, known as Kröhnke pyridines) are practical intermediates in the synthesis of drugs, herbicides, insecticides, desiccants, and surfactants. 8 Due to their excellent π-stacking ability and thermal stability, these substituted pyridines can be used in fluorescent small molecules, polymers, supramolecules, and for asymmetric catalysis and coordination.…”