Synthesis of Functionalized Vinylgermanes through a New Ruthenium-Catalyzed Coupling Reaction

Inorganometallics (Transition Metal-Metalloid Complexes) and Catalysis

While the formation and breaking of transition metal (TM)–carbon bonds plays a pivotal role in the catalysis of organic compounds, the reactivity of inorganometallic species, that is, those involving the transition metal (TM)–metalloid (E) bond, is of key importance in most conversions of metalloid derivatives catalyzed by TM complexes. This Review presents the background of inorganometallic catalysis and its development over the last 15 years. The results of mechanistic studies presented in the Review are related to the occurrence of TM–E and TM–H compounds as reactive intermediates in the catalytic transformations of selected metalloids (E = B, Si, Ge, Sn, As, Sb, or Te). The Review illustrates the significance of inorganometallics in catalysis of the following processes: addition of metalloid–hydrogen and metalloid–metalloid bonds to unsaturated compounds; activation and functionalization of C–H bonds and C–X bonds with hydrometalloids and bismetalloids; activation and functionalization of C–H bonds with vinylmetalloids, metalloid halides, and sulfonates; and dehydrocoupling of hydrometalloids. This first Review on inorganometallic catalysis sums up the developments in the catalytic methods for the synthesis of organometalloid compounds and their applications in advanced organic synthesis as a part of tandem reactions.

Synthesis of a new class of silsesquioxanes with alkynyl and germyl functionality

Although there are a variety of functional compounds in the vast family of silsesquioxanes (POSS), the number of protocols describing specific monosubstituted silsesquioxanes is limited. There are even fewer reports on alkynyl and/or germyl functionalities appearing together with the POSS compounds. Here, a series of novel kinds of cubic monosubstituted POSS bearing alkynyl and germyl functionality in one molecule are reported. These compounds were synthesized by effective germylative coupling of terminal alkynes with vinylgermanes in the presence of a Ru-H complex. The structures of the products were determined. Moreover, stoichiometric reactions of a complex possessing Ru-Ge were also performed to propose the general mechanistic scheme of this reaction.

Shuffle off the classic β-Si elimination by Ni-NHC cooperation: implication for C-C forming reactions involving Ni-alkyl-β-silanes

Via a cooperation of NHC, Si substituents and a M center, β-Si elimination was attenuated, revealing a new way to attain a high Ni-β-SiR(3):Ni-σ-SiR(3) ratio. The scope is illustrated by a head-to-tail vinylsilane-α-olefin hydroalkenylation.

Catalytic coupling of sp2- and sp-hybridized carbon-hydrogen bonds with vinylmetalloid compounds

In the Account given herein, it has been shown that silylative coupling of olefins, well-recognized as a new catalytic route for the activation of double bond C-H bond of olefins and double bond C-Si bond of vinylsilicon compounds with ethylene elimination, can be extended over both other vinylmetalloid derivatives (double bond C-E) (where E = Ge, B, and others) as well as the activation of triple bond C-H, double bond C aryl-H, and -O-H bond of alcohols and silanols. This general transformation is catalyzed by transition-metal complexes (mainly Ru and Rh) containing or initiating TM-H and/or TM-E bonds (inorganometallics). This new general catalytic route for the activation of double bond C-H and triple bond C-H as well as double bond C-E bonds called metallative coupling or trans-metalation (cross-coupling, ring-closing, and polycondensation) constitutes an efficient method (complementary to metathesis) for stereo- and regioselective synthesis of a variety of molecular and macromolecular compounds of vinyl-E (E = Si, B, and Ge) and ethynyl-E (E = Si and Ge) functionality, also potent organometallic reagents for efficient synthesis of highly pi-conjugated organic compounds. The mechanisms of the catalysis of this deethenative metalation have been supported by equimolar reactions of TM-H and/or TM-E with initial substances and reactions with deuterium-labeled reagents.