Synthesis of aryl cobalt and iron complexes and their catalytic activity on hydrosilylation of alkenes

Abstract

Four aryl cobalt and iron complexes, [(F4C5N)Co(Cl)(PMe3)3] (1), [(F4C5N)Fe(PMe3)4] (2), [(F5C6)Co(Cl)(PMe3)3] (3) and [(F5C6)Fe(Cl)(PMe3)3] (4) were synthesized from the reactions of 3-chloro-2,4,5,6-tetrafluoro-pyridine and chloropentafluorobenzene with Co(PMe3)4 and Fe(PMe3)4 respectively. Under...

(NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes

“…This substratedependent reversal in selectivity is precedented in base-metal hydrosilylation systems. 32,36,42,58,60,77,95,97,98 Illustrating the breadth of catalyst 1e to functionalize vinylarene derivatives, we further diversified the substrate scope by synthesizing a collection of electronically (3b−3e) and sterically modified diarylsilanes (3f−3i) and examined their hydrosilylation reactivity with 2a. The reactivity of 1e with modified silanes maintained outstanding selectivity for the branched product (l/b = 1:>99) and achieved moderate to high isolated yields (51−99%) to obtain products 4ab−4ae (electronic modification) and 4af−4ai (steric modification).…”

“…Even fewer examples enabling activation of 2°silanes have been reported. 32,52,57,58,60,98,99 To our knowledge, examples with 3°silanes are limited to the (pincer)Co-catalyzed hydrosilylation of 1-octene using (EtO) 3 SiH 73 and the ([P∼C]-chelate)Co-catalyzed hydrosilylation of styrene with Ph 3 SiH and Me(EtO) 2 SiH. 58 A significant challenge remaining in base-metal-catalyzed alkene hydrosilylation is the synthesis of branched hydrosilylation products using 3°silanes with alkyl-, aryl-, alkoxy-, or chloro-substituents (Figure 1b).…”

“…Catalysts composed of base metals ,− like Ni, − Mn, − Co, − and Fe ,− have been developed for linear-selective alkene hydrosilylation. As a congener of Pt, Ni is especially promising as a base-metal candidate for alkene hydrosilylation.…”

“…In the emergent field of base-metal-catalyzed branched-selective alkene hydrosilylation, noteworthy work achieving high regioselective control employs Mn, Co, ,,,, Fe, , Ni, − and Cu complexes that readily react with 1° silanes. Even fewer examples enabling activation of 2° silanes have been reported. ,,,,,, To our knowledge, examples with 3° silanes are limited to the (pincer)­Co-catalyzed hydrosilylation of 1-octene using (EtO) 3 SiH and the ([P∼C]-chelate)­Co-catalyzed hydrosilylation of styrene with Ph 3 SiH and Me­(EtO) 2 SiH . A significant challenge remaining in base-metal-catalyzed alkene hydrosilylation is the synthesis of branched hydrosilylation products using 3° silanes with alkyl-, aryl-, alkoxy-, or chloro-substituents (Figure b).…”

Reactivity of Pt(0) bromosilylene complexes towards ethylene

“…As they can be readily incorporated in various ligand scaffolds, this field has seen rapid development. [3][4][5][6][7][8][9][10][11][12][13] Platinum complexes, in particular, have been known to catalyse silane dehydropolymerization, 14 hydrosilylation 15 or substituent redistribution reactions on silicon 16 since the 1970s. However, the isolation of a platinum silylene complex remained until in 1993, the cationic Fischer-type complex [trans-(Cy 3 P) 2 (H)PtvSi(SEt) 2 ][BPh 4 ] (I) was synthesised by Tilley and Rheingold via anion abstraction from a platinum silyl precursor (Scheme 1).…”