Silicon-carbon unsaturated compounds LIV: Nickel-catalyzed reactions of 3,4-benzo-1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene with alkynes

Article abstract of DOI:10.1016/0022-328X(95)00329-O

The nickel-catalyzed reactions of 3,4-benzo-1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene (1) with disubstituted acetylenes have been investigated.Treatment of I with 3-hexyne and diphenylacetylene at 150 deg C gave two types of adducts: 5,6-benzo-1,4-disilacyclohexa- 2,5-dienes and 5,6-benzo-1,2-disilacyclohexa-3,5-dienes.With methylphenylacetylene,1 afforded a 5,6-benzo-1,4-disilacyclohexa-2,5-di- ene and 5,6-benzo-1,2-disilacyclohexa-3,5-diene, together with a small amount of the other isomer.The reaction of I with phenyl(trimethylsilyl)acetylene produced 5,6-benzo-1,1,4,4-tetraethyl-3-phenyl-2-trimethylsilyl-1,4-disilacyclohexa-2,5-diene and 4,5-benzo-1,1,3,3-tetraethyl-2--1,3-disilacyclopent-4-ene (IO).Similar reaction of 1 with 1-(trimethylsilyl)hexyne also afforded 5,6-benzo-3-butyl-1,1,4,4-tetraethyl-2-trimethylsilyl-1,4-disilacyclohexa-2,5-diene and 4,5-benzo-2--1,1,3,3-tetraethyl-1,3-disilacyclopent-4-ene (12).A vinylidene carbene-nickel complex is proposed for the formation of 10 and 12, as a key intermediate.Keywords: Silicon; Transition metals; o-Quinodisilane; Nickel