Iridium-Promoted Conversion of Chlorosilanes to Alkynyl Derivatives in a One-Pot Reaction Sequence

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.

Fluoride Ion-Initiated Decarboxylation of Silyl Alkynoates to Alkynylsilanes

This communication describes the development of a metal-free catalytic decarboxylation of silyl alkynoates to alkynylsilanes. Treatment of a silyl alkynoate with a catalytic amount of tetrabutylammonium difluorotriphenylsilicate (TBAT) in N,N-dimethylformamide at 150 °C resulted in decarboxylation to give the corresponding alkynylsilane in good to excellent yield (75 → 95%). The TBAT system was applicable to the decarboxylation of sterically demanding silyl alkynoates such as tert-butyldiphenylsilyl 3-phenylpropiolate. Mechanistic studies revealed that the tetrabutylammonium alkynoate derived from TBAT and the silyl alkynoate act as a catalyst for the decarboxylation.

Mechanistic investigation of zinc-promoted silylation of phenylacetylene and chlorosilane: a combined experimental and computational study

The zinc-promoted silylation method is of great importance to synthesize high-performance silicon-containing arylacetylene (PSA) resins in the industry. However, it is difficult to eliminate the accompanied by-product of terminal alkenes due to the lack of mechanistic understanding of the silylation. The initiation of zinc-promoted silylation is facilitated by the interaction between zinc and phenylacetylene. Our DFT calculations indicated that the intermolecular hydrogen transfer of phenylacetylene follows an ionic pathway, which generates a phenylacetylene anion and the corresponding alkene moieties on the zinc surface. The styrene by-product is observed in this stage, with its alkene moieties desorbing as radicals into the solvent under the high reaction temperature. Three possible intermediates of surface phenylacetylene anions were proposed including PhC[triple bond, length as m-dash]C-Zn, PhC[triple bond, length as m-dash]CZnCl, and (PhC[triple bond, length as m-dash]C)2Zn. These carbanion-zinc intermediates undergo an SN2 reaction with Me3SiCl to afford the alkynylsilane on the zinc surface, which is calculated to be the rate-determining step for the zinc-promoted silylation reaction.

A substituent-induced post-assembly modification cascade of a metallosupramolecular imine-type Co-complex

Here, we report a reaction cascade employing the substituent-induced post-assembly modification of a Co(iii) complex. Unexpectedly, we found that the (triisopropylsilyl)alkynyl moiety introduced to the Sonogashira reaction with the bromo-functionalized Co(iii) assembly plays a "Trojan horse" role, triggering a subsequent, second step of the cascade, i.e. Co(iii) to Co(ii) reduction. The reported substituent-activated Sonogashira-redox cascade reaction might set a new direction in the construction of specific chemical sensors.