Platinum-catalyzed reactions of 3,4-benzo-1,1,2,2-tetra(isopropyl)-1,2-disilacyclobut-3-ene with mono-and di-substituted alkynes

Article abstract of DOI:10.1016/S0022-328X(97)00215-5

The reactions of 3,4-benzo-1,1,2,2-tetra(isopropyl)-1,2-disilacyclobut-3-ene (1) with phenylacetylene and 1-hexyne in the presence of a catalytic amount of (η²-ethylene)bis(triphenylphosphine)platinum(0) at 200°C for 24 h gave two types of 1: 1 adducts, 2-phenyl-and 2-butyl-substituted 5,6-benzo-1,1,4,4-tetra(isopropyl)-1,4-disilacyclohexa-2,5-diene and 2-benzylidene-and 2-pentylidene-substituted 4,5-benzo-1,1,3,3-tetra(isopropyl)-1,3-disilacyclopent-4-ene, respectively. With mesityl-and dimethylphenylsilylacetylene, 1 afforded 2-(mesityl)methylene-and 2-(dimethylphenylsilyl)methylene-4,5-benzo-1,1,3,3-tetra(isopropyl)-1,3-disilacyclopent-4-ene. A similar reaction of 1 with trimethylsilylacetylene produced an adduct arising from sp-hybridized C-H bond activation of the acetylene, together with a benzodisilacyclopentene derivative. The reaction of 1 with diphenylacetylene yielded a 2,3-diphenyl-5,6-benzodisilacyclohexa-2,5-diene derivative, while with methylphenylacetylene and 2-hexyne, 1 gave 2-benzylidene-and 2-butylidene-5,6-benzo-1,4-disilacyclohex-5-ene, along with the benzodisilacyclohexa-2,5-diene derivatives. Similar treatment of 1 with methyl(trimethylsilyl)acetylene produced a 5,6-benzo-2-(trimethylsilyl)methylenedisilacyclohexene derivative.