| Abstract
| - The thermolysis of pivaloyl- and adamantoyltris(trimethylsilyl)silane (1 and 2) with diphenylketene ina sealed glass tube at 140 °C for 24 h afforded 2-tert-butyl- and 2-adamantyl-1,1-dimethyl-3-[methylbis(trimethylsiloxy)silyl]-4,4-diphenyl-1-silacyclobut-2-ene (6 and 7) in 44% and 50% isolated yields,respectively. Related thermolysis of mesitoyltris(trimethylsilyl)silane (3) with diphenylketene at 160 °Cfor 24 h, however, proceeded with high stereospecificity to give cis-3-diphenylmethylene-4-mesityl-2-trimethylsiloxy-2,4-bis(trimethylsilyl)-2-siloxetane (8) in 44% yield. When 8 was heated at 200 °C for24 h, 1-mesityl-3,3-diphenyl-1-(trimethylsilyl)propadiene was obtained in 43% yield. Computationalanalyses for the formation of siloxetanes arising from addition of silenes to ketene and succesiveisomerization of the siloxetanes thus formed, leading to the products, are described. The results of X-raycrystallographic analysis for the product 6 formed by the co-thermolysis of 1 and diphenylketene arereported.
- The thermal reaction of acylpolysilanes (1 and 2) with diphenylketene in a sealed glass tube at 140 °C for 24 h afforded the silacyclobutene derivatives (6 and 7), while compound 3 gave the siloxetane derivative 8.
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