Silicon compounds with strong intramolecular steric interactions, 78 - Reactions of silylenes with acetylenes and 1,3-diacetylenes linked by C-C multiple-bond units

The reaction of di-tert-butylsilylene (2), gene-rated photochemically from hexa-tert-butylcyclotrisilane (1), with a (Z)-3-hexene-1,5-diyne furnishes a product built up of two silirene rings linked by an olefinic double bond. A similar reaction of 2 with (Z)-6-dodecene-2,4,8,10-tetrayne yields two rearranged 2,5-disilabicyclo[2.2.0]hexane-1(6),3-diene units linked by a C-C double bond. The oligoene frameworks of both compounds adopt the all-trans configuration. Treatment of 1,3,5-tris((trimethylsilyl)ethynyl)benzene and 1,2-diethynylbenzene with 1 affords a 1,3,5-tris(silacyclopropenyl)benzene and a 1H-indeno[2,1-b]silete derivative with an exocyclic tBu(2)SiH group at position 7 of the tricyclic system.