Silicon-carbon unsaturated compounds. 24. Some reactions of a nickelasilacyclobutene

Article abstract of DOI:10.1021/om00110a036

The chemical behavior of 2-mesityl-4-phenyl-1,1-bis(triethylphosphine)-2,3-bis(trimethylsilyl)-1-nickela- 2-silacyclobut-3-ene (3) has been examined. When 3 was heated at 140°C in xylene, 5,6-benzo-1,3-disilacyclohexene derivatives 4a and 4b were obtained. Irradiation of 3 with a high-pressure mercury lamp also produced 4a and 4b. Compound 3 reacted with methanol to give (E)-1-(1-mesityl-1-methoxytrimethyldisilanyl)-1-phenyl-2-(trimethylsilyl)ethene and (E)-1-(1-mesityl-1-methoxytrimethyldisilanyl)-2-phenyl-1-(trimethylsilyl)ethene. Treatment of 3 with hydrogen chloride in benzene followed by sodium methoxide gave (Z)-1-(1-mesityl-1-methoxytrimethyldisilanyl)-2-phenyl-2-(trimethylsilyl)ethene. With hydrogen, 3 afforded (E)-1-(1-hydro-1-mesityltrimethyldisilanyl)-2-phenyl-1-(trimethylsilyl)ethene. In all reactions of 3 with bromine, methyl iodide, and benzyl bromide, reductive elimination of nickel species took place to give silacyclopropene 2. When 3 was treated with 1 equiv of (diphenylphosphino)ethane, compound 3 was transformed into silacyclopropene 2, quantitatively. The reaction of 3 with 1-hexyne afforded (Z)-1-(1-hexynyl-1-mesityltrimethyldisilanyl)-2-phenyl-2-(trimethylsilyl)ethene.