Amine‐Activated Iron Catalysis: Air‐ and Moisture‐Stable Alkene and Alkyne Hydrofunctionalization

Abstract

As imple alkylamine[ ( iPr) 2 NEt] has been used to activate an air-a nd moisture-stable iron(II) pre-catalyst for alkene and alkyne hydrofunctionalization reactions.T his amine activation has enabled the highly operationallys imple hydrosilylation and hydroborationo fa lkenes and alkynes using just 0.25-2 mol% iron catalyst and 1-25 mol% amine. Significantly,t hese reactions proceedi ne qual yield under both air and inert reactionc onditions.

In Situ Infrared Spectroscopic Study of Iron-Catalyzed Hydromagnesiation of Vinyl Arenes

“…However, recent advancements beginning in 2010 allowed for the use of Fe, Co, Mo, Cu, and Ni catalysts. Hydrosilylation, 95,104,[111][112][113][114][115][116][117][118][119][120][121][122][123][124] hydroboration, [116][117][118][125][126][127][128][129][130][131][132][133][134][135][136][137][138] hydroamination, [139][140][141][142] hydroformylation, [143][144][145][146][147][148][149] hydrocarboxylation, [150][151][152][153][154]…”

“…95,111,[113][114][115][116]120 Development of a well-defined ligand framework introduced a means of favoring hydrosilylation over the side reactions and in some cases increased 1,2-vs 2,1-insertion and α-(Markovnikov substitution) vs. β-(Anti-Markovnikov substitution) regioselectivity (Figure 1.8). 95,111,[113][114][115][116]120 Recently, regioselectivity of hydrosilylation has been determined for both aliphatic and aromatic olefins. For reagents containing aromatic olefins, α-silylation (Markovnikov substitution, Scheme 1.9A) is favored; whereas, aliphatic olefins favor β-silylation (Anti-Markovnikov substitution, Scheme 1.9B).…”

“…For reagents containing aromatic olefins, α-silylation (Markovnikov substitution, Scheme 1.9A) is favored; whereas, aliphatic olefins favor β-silylation (Anti-Markovnikov substitution, Scheme 1.9B). 95,111,[113][114][115][116]120,170 Based upon known limitations of iron-catalyzed hydrosilylation, future methodology development is a necessity to improve regioselectivity, reduce side product pathways, and provide catalyst control by using redox-active ligands. Iron-catalyzed hydrosilylation side reactions.…”

“…95,111,[113][114][115][116]120,169 Figure 1.8: Iron-catalyzed hydrosilylation catalysts. 95,111,[113][114][115][116]120 Scheme 1.9: Iron-catalyzed hydrosilylation. 95,111,[113][114][115][116]120 *Reproduced using ChemDraw Another class of hydrofunctionalization, hydroboration, adds a borane (B-H) across an unsaturated bond.…”

“…95,111,[113][114][115][116]120 Scheme 1.9: Iron-catalyzed hydrosilylation. 95,111,[113][114][115][116]120 *Reproduced using ChemDraw Another class of hydrofunctionalization, hydroboration, adds a borane (B-H) across an unsaturated bond. The hydroboration of C=C was first introduced by Brown and coworkers.…”