Unsaturated, PCy2-bridged Re-M heterobimetallics (M = rhodium, iridium, palladium; Cy = cyclohexyl): metal-metal bond isomerism, reversible phosphorus-hydrogen bond activation and cooperative reactivity

Aluminum(I) and magnesium(I) compounds are reported for the C–C s-bond activation of strained alkylidene cyclopropanes. These reactions result in the formal addition of the C–C s-bond to main group center either at a single site (Al) or across a metal–metal bond (Mg–Mg). Mechanistic studies suggest that rather than occurring by a concerted oxidative addition, these reactions involve stepwise processes in which substrate binding to the main group metal acts as a precursor to a- or b-alkyl migration steps that break the C–C s-bond. This mechanistic understanding is used to develop the magnesium-catalyzed hydrosilylation of the C–C s-bonds of alkylidene cyclopropanes.

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Activation and Functionalization of C–C σ-Bonds of Alkylidene Cyclopropanes at Main Group Centers

10.26434/chemrxiv.12034296.v1 ◽

2020 ◽

Author(s):

Mark Crimmin ◽

Richard Y Kong

Keyword(s):

Bond Activation ◽

Substrate Binding ◽

Oxidative Addition ◽

Main Group ◽

Single Site ◽

Mechanistic Studies ◽

Metal Bond ◽

Main Group Metal ◽

Metal Metal ◽

Group Center

Aluminum(I) and magnesium(I) compounds are reported for the C–C s-bond activation of strained alkylidene cyclopropanes. These reactions result in the formal addition of the C–C s-bond to main group center either at a single site (Al) or across a metal–metal bond (Mg–Mg). Mechanistic studies suggest that rather than occurring by a concerted oxidative addition, these reactions involve stepwise processes in which substrate binding to the main group metal acts as a precursor to a- or b-alkyl migration steps that break the C–C s-bond. This mechanistic understanding is used to develop the magnesium-catalyzed hydrosilylation of the C–C s-bonds of alkylidene cyclopropanes.

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Activation and Functionalization of C–C σ-Bonds of Alkylidene Cyclopropanes at Main Group Centers

10.26434/chemrxiv.12034296.v2 ◽

2020 ◽

Author(s):

Mark Crimmin ◽

Richard Y Kong

Keyword(s):

Bond Activation ◽

Substrate Binding ◽

Oxidative Addition ◽

Main Group ◽

Single Site ◽

Mechanistic Studies ◽

Metal Bond ◽

Main Group Metal ◽

Metal Metal ◽

Group Center

Aluminum(I) and magnesium(I) compounds are reported for the C–C s-bond activation of strained alkylidene cyclopropanes. These reactions result in the formal addition of the C–C s-bond to main group center either at a single site (Al) or across a metal–metal bond (Mg–Mg). Mechanistic studies suggest that rather than occurring by a concerted oxidative addition, these reactions involve stepwise processes in which substrate binding to the main group metal acts as a precursor to a- or b-alkyl migration steps that break the C–C s-bond. This mechanistic understanding is used to develop the magnesium-catalyzed hydrosilylation of the C–C s-bonds of alkylidene cyclopropanes.

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Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

10.26434/chemrxiv.11742687 ◽

2020 ◽

Author(s):

Shubham Deolka ◽

Orestes Rivada Wheelaghan ◽

Sandra Aristizábal ◽

Robert Fayzullin ◽

Shrinwantu Pal ◽

...

Keyword(s):

Alkyl Group ◽

Bond Activation ◽

Bond Cleavage ◽

Terminal Alkyne ◽

Alkyl Aryl ◽

Metal Metal ◽

The Stability ◽

Selective Formation ◽

Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

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