Oxidative Addition and Reductive Elimination at Main-Group Element Centers

Abstract

Oxidative addition and reductive elimination are key steps in a wide variety of catalytic reactions mediated by transition-metal complexes. Historically, this reactivity has been considered to be the exclusive domain of d-block elements. However, this paradigm has changed in recent years with the demonstration of transition-metal-like reactivity by main-group compounds. This Review highlights the substantial progress achieved in the past decade for the activation of robust single bonds by main-group compounds and the more recently realized activation of multiple bonds by these elements. We also discuss the significant discovery of reversible activation of single bonds and distinct examples of reductive elimination at main-group element centers. The review consists of three major parts, starting with oxidative addition of single bonds, proceeding to cleavage of multiple bonds, and culminated by the discussion of reversible bond activation and reductive elimination. Within each subsection, the discussion is arranged according to the type of bond being cleaved or formed and considers elements from the left to the right of each period and down each group of the periodic table. The majority of results discussed in this Review come from the past decade; however, earlier reports are also included to ensure completeness.

Cycloaddition of Dialkylalumanyl Anion toward Unsaturated Hydrocarbons in (1+2) and (1+4) Modes

“…Main‐group‐element compounds, especially in low oxidation state, have been known to undergo oxidative addition at the main‐group‐element center to give oxidized compounds . Among them, aluminum‐containing molecules in the low oxidation state have been extensively studied in the last three decades, especially for dialumane derivatives having an Al−Al bond, oligomeric form of Al I species, and Al=Al doubly bonded compounds –.…”

Adduct of NacNacAl with Benzophenone and Its Coupling Chemistry

“…Activation of strong bonds by reduced main‐group compounds has received significant attention in the context of development of main‐group surrogates for the common transition‐metal‐based catalysts . In this context, NacNacAl ( 1 , (NacNac=[ArNC(Me)CHC(Me)NAr] − , Ar=2,6‐ i Pr 2 C 6 H 3 ), a diketiminate‐supported Group 13 carbenoid, is noteworthy because of its well‐documented propensity to cleave strong H−X bonds, [5] C−F and C−O bonds, E−E (E=S, P) bonds, and even the C=X (X=S, N) multiple bonds in thiourea and guanidines .…”

Cycloaddition versus Cleavage of the C=S Bond of Isothiocyanates Promoted by Digallane Compounds with Noninnocent α‐Diimine Ligands

“…For example, ligand‐stabilized heavier group 14 carbene analogues, that is, silylene, germylene, and stannylene compounds, can react with fluorinated arenes through carbon–fluorine or carbon–hydrogen bond functionalization . The group 13 aluminum and gallium “carbenes” [(NacNac)M:] (NacNac=[ArNC(Me)CHC(Me)NAr], Ar=2,6‐ i Pr 2 C 6 H 3 ), monovalent compounds MCp* (M=Al, Ga, In; Cp*=η 5 ‐C 5 Me 5 ), as well as metal–metal‐bonded species R 2 MMR 2 (M=Al, Ga, In; R=Me 3 SiCH 2 ) and Ar i Pr4 MMAr i Pr4 (M=Ga, Ar i Pr4 =C 6 H 3 ‐2,6‐(C 6 H 3 ‐2,6‐ i Pr 2 ) 2 ) have been reported to undergo oxidative addition with substrates containing H−H, O−H, N−H, P−H bonds, acidic C−H, H−Si, H−B, H−Al, Bi−Bi, and Sb−Sb bonds, and the more robust C−O, C−F, and other single bonds.…”