Photoinduced Brook-Type Rearrangement of Acylcyclopolysilanes.
Previously unknown 1,1,4-tris(trimethylsilyl)-4-acyldodecamethylcyclohexasilanes (Me3Si)2Si6Me12(Me3Si)COR (16a, R =tert-butyl;16b, R = 1-adamantyl) have been synthesized by the reaction of the potassium silanides (Me3Si)2Si6Me12(Me3Si)K with acid chlorides ClCOR, and their photochemical rearrangement reactions have been studied. The molecular structures of16a,bas determined by single-crystal X-ray diffraction analysis exhibit an unusual twist-boat conformation of the cyclohexasilane ring. When16a,bwere photolyzed with λ >300 nm radiation, they underwent Brook type 1,3-Si → O migration reactions to generate the cyclohexasilanes17a,bwith exocyclic Si=C bonds along with smaller amounts of the ring-enlarged species19a,bwith endocyclic Si=C double bonds. While17a,bwere stable enough to allow characterization by NMR and UV absorption spectroscopy, the less stable products19a,bcould only be observed in the form of their methanol adducts.
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Harald
H
Stueger
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Bernd
B
Hasken
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Michael
M
Haas
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Martin
M
Rausch
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Roland
R
Fischer
Institute of Inorganic Chemistry, Graz University of Technology , Stremayrgasse 9, A-8010 Graz, Austria.
Ana
A
Torvisco