Toward Silicon Metathesis

Abstract

Metathesis reactions for making compounds that contain carbon-carbon multiple bonds are one of the most important sets of processes in the chemical industry. The alkene or alkyne products are widely used, for example, in poly­merizations to make plastics. Chemists have been interested in extending metathesis methods to carbon’s heavier analogs, such as silicon, which one day could lead to new types of polymeric materials. The holdup has been the lack of suitable silicon precursors. A research team led by Vladimir Ya. Lee and Akira Sekiguchi of the University of Tsukuba, in Japan, has now cleared that hurdle (J. Am. Chem. Soc., DOI: 10.1021/ja401072j). To make their precursors, the researchers coupled a bicyclic tetrasilicon molecule to titanocene dichloride to form a Ti=Si complex called a silylene. This species is a heavy analog of the alkylidene metal complexes that are catalysts for alkene and alkyne metathesis reactions. When they tried mimicking alkyne ...