HYDROSILYLATION OF 1-ALKENES WITH DICHLOROSILANE

Symmetrically and unsymmetrically substituted diorganodichlorosilanes have been prepared by hydrosilylation with dichlorosilane using two di fferent platinum catalysts, i. e., hexachloroplatinic acid (''Speier's catalyst'') and a platinum cyclovinylmethylsiloxane complex. Hydrosil ylation of unsubstituted 1-alkenes proved to be very efficient, yieldi ng anti-Markonikov substituted di-n-alkyldichlorosilanes. However, no reaction was observed when electron-deficient 1-alkenes were used. Oct acarbonyldicobalt enabled formation of the monoadduct of 1H,1H,2H-perf luoro-1-hexene with dichlorosilane, which was employed in a second hyd rosilylation of the olefin. Thus, the anti-Markovnikov diadduct was ob tained in 40% overall yield. The two-step synthesis has also been appl ied successfully to obtain unsymmetrically substituted diorganodichlor osilanes containing nitrile and ether groups.