Ligand-controlled regiodivergence in cobalt-catalyzed hydrosilylation of isoprene

Abstract

In this article, we disclosed a method for the regiodivergent and stereoselective hydrosilylation of isoprene using earth-abundant cobalt catalyst via variation of ligands. With a less sterically hindered bidentate ligand,...

Recent Advances in Ligand-Controlled Regio- or Stereodivergent Transition-Metal-Catalyzed Hydroelementation (H[E]) (E = H, B, Si, Ge) of C–C Unsaturated Systems

“…In 2023, the same group extended the scope of catalyst to a Co system. 60 The Co-based regiodivergent hydrosilylation procedure worked with pyridine imine-supported ligands to generate (Z)-allylic or homoallylic silanes upon 4,1-and 2,1-addition, respectively. A variety of pyridine imine ligands were screened over the hydrosilylation of isoprene with Ph2SiH2 in a catalytic mixture of Co(acac)3 and NaBEt3H to reveal that a steric bulkiness of the ortho-substituent on the pyridine ring strongly influenced on the insertion mode of hydrosilane:…”

“…66 In most of the catalytic systems, the origin of the observed regio-or stereodivergence by ligands is assumed to stem from mainly differential steric bulkiness of the employed ligands, while the ligand's electronic factors are shown to influence on the selectivity divergence in some catalytic systems. 30,54 Among 13 pairs of ligands in the metal catalysts for the divergent hydroelementation reactions, 10 pairs of ligands are the same or similar type of ligands based on P or N, 30,33,42,46,54,[59][60][61][65][66]69 while the remaining 3 pairs of ligands 37,49,53 have been found upon judicious ligand selection without decent rationales, hampering in depth discussions regarding the ligand effects. Overall, most of the regio-or stereodivergent catalytic procedures work under mild conditions solely depending on two different ligands, whereas the selectivities and the yields of the divergently formed two products often remarkably differ, indicating different degrees of kinetic preferences depending on the ligands towards high regio-or stereoselectivity.…”

Co‐Catalyzed Hydrosilylation of Ketones under Base‐Free Conditions: A Convenient Route to Silyl Ethers or Secondary Alcohols

“…[9][10][11][12][13] The major research area has intensified on manganese, [14][15][16][17] iron, [18][19][20][21][22][23][24][25] nickel, [25][26][27][28] and cobalt. [24,25,29,30] However, despite numerous protocols for the highly selective Co-catalyzed hydrosilylation of alkynes and alkenes, the modification of carbonyl groups seemed more challenging. [31][32][33][34][35][36][37][38] Therefore, the application of cobalt complexes in the functionalization of aldehydes or ketones by silicon atoms was for a long time limited to just a few examples.…”