8.25 Hydrometallation Group 4 (Si, Sn, Ge, and Pb)

Formation of Ruthenium Carbenes by gem‐Hydrogen Transfer to Internal Alkynes: Implications for Alkyne trans‐Hydrogenation

“…Whereas the preparative significance of these transformations stems from their stereochemical complementarity to the existing arsenal,[ 10 ] little is known about their mechanism. They formally violate the reigning paradigm that metal-catalyzed additions to π-bonds proceed through suprafacial delivery of H 2 , H–BR 2 , or H–ER 3 (E=Si, Ge, Sn).…”

Synthesis of Vinylgermanes via the Au/TiO2-Catalyzedcis-1,2-Digermylation of Alkynes and the Regioselective Hydrogermylation of Allenes

“…In contrast to organosilicon compounds whose synthesis and C–C cross coupling reactions have been extensively studied, organogermanes have not received significant attention . Very recently, however, the field of organogermanium chemistry has been revived, particularly by the findings by the group of Schoenebeck, who have uncovered a series of novel and selective metal-catalyzed C–C cross coupling protocols of C­(sp 2 )-germyl linkages .…”

(Z)-Selective Hydrosilylation of Terminal Alkynes with HSiMe(OSiMe3)2 Catalyzed by a Ruthenium Complex Containing an N-Heterocyclic Carbene

“…Alkenylsilanes have received substantial attention on account of their utility in organic chemistry . The hydrosilylation of alkynes using late-transition-metal catalysts represents a reliable and straightforward synthetic route to alkenylsilanes. , As the silane source, the cost-effective HSiMe­(OSiMe 3 ) 2 is particularly attractive, given that alkenylsiloxanes derived from HSiMe­(OSiMe 3 ) 2 are resistant toward hydrolysis due to the siloxane linkages, but still readily undergo Hiyama cross-coupling reactions owing to the presence of two electron-withdrawing (trimethylsilyl)­oxy groups. , …”

“…During the hydrosilylation of terminal alkynes, several possible isomers can be produced, , and the β-( E )-selective reaction of terminal alkynes with HSiMe­(OSiMe 3 ) 2 has been established using well-defined platinum complexes. , However, the β-( Z )-selective reaction with HSiMe­(OSiMe 3 ) 2 remains challenging with respect to both catalytic efficiency of the transition-metal catalysts, as well as the regio- and stereoselectivity of the products. In fact, the ruthenium–N,S-heterocyclic-carbene-catalyzed hydrosilylation of phenylacetylene with HSiMe­(OSiMe 3 ) 2 affords a mixture of isomers in low yield (Scheme , eq 1), while a latent ( Z )-to-( E ) isomerization was observed when using an Ir–Cr bimetallic catalyst (Scheme , eq 2) .…”