Selective hydrosilylation of allyl chloride with trichlorosilane.

The transition-metal-catalysed hydrosilylation reaction of alkenes is one of the most important catalytic reactions in the silicon industry. In this field, intensive studies have been thus far performed in the development of base-metal catalysts due to increased emphasis on environmental sustainability. However, one big drawback remains to be overcome in this field: the limited functional group compatibility of the currently available Pt hydrosilylation catalysts in the silicon industry. This is a serious issue in the production of trichloro(3-chloropropyl)silane, which is industrially synthesized on the order of several thousand tons per year as a key intermediate to access various silane coupling agents. In the present study, an efficient hydrosilylation reaction of allyl chloride with trichlorosilane is achieved using the Rh(I) catalyst [RhCl(dppbzF)]2 (dppbzF = 1,2-bis(diphenylphosphino)-3,4,5,6-tetrafluorobenzene) to selectively form trichloro(3-chloropropyl)silane. The catalyst enables drastically improved efficiency (turnover number, TON, 140,000) and selectivity (>99%) to be achieved compared to conventional Pt catalysts.

Synthesis of hydrosilanes via Lewis-base-catalysed reduction of alkoxy silanes with NaBH4.

Hydrosilanes were synthesized by reduction of alkoxy silanes with BH3 in the presence of hexamethylphosphoric triamide (HMPA) as a Lewis-base catalyst. The reaction was also achieved using an inexpensive and easily handled hydride source NaBH4, which reacted with EtBr as a sacrificial reagent to form BH3in situ.

Insertion of a Cationic Metallogermylene into E-H Bonds (E = H, B, Si).

A cationic germylene containing tungsten and N-heterocyclic carbene units reacted with H2 in fluorobenzene at 60 °C, resulting in its insertion into the H-H bond. It also activated the Si-H bond of ethyldimethylsilane and the B-H bond of pinacolborane at ambient temperature to give the insertion products. The latter insertion reactions against hydrosilane and hydroborane were found to be reversible.

Cationic metallogermylene and dicationic dimetallodigermenes: synthesis by chloride abstraction from N-heterocyclic carbene-stabilized chlorometallogermylenes.

Reaction of NHC-stabilized dichlorogermylenes (NHC = N-heterocyclic carbene) with an anionic tungsten complex produced NHC-stabilized chlorometallogermylenes. Subsequent chloride abstraction from the products with NaBAr4 (Ar = 3,5-(CF3)2C6H3) gave a cationic metallogermylene or dicationic dimetallodigermenes.