Abstract
The photochemical precursors, 1,1,1,3,3,3-hexamethyl-2-phenyltrisilane(2) and 2,3-dicarbomethoxy-1,4,5,6,7-pentaphenyl-7-silanorbornadiene(5) were synthesized in the yield of 10% and 73%, respectively. Irradiation of 2 at 254 nm in the presence of triethylsilane gave 1,1,1-triethyl-2-phenyldisilane (6) in 44% yield which was the product of phenylsilylene insertion into the Si-H bond. Irradiation of 2 in the presence of diphenylacetylene gave 1-phenyl-1-silacyclopenta-2,4-diene(4) in 68% yield together with 1,2-diphenyl-1,2-disilacyclohexa-2,5-diene(26%) which were formed from [2+2] addition of the silacyclopropene to diphenylacethylene and formed from dimerization of silacyclopropene, respectively. From the neat photolysis of precursor 2,1,5-dihydrosilanthrene(11), intermolecular C-H insertion product of phenylsilylene and 1,2-diphenyltrisilane(12), Si-H insertion product of phenylsilylene to the precursor were obtained in the yield of 5% and 7%, respectively. In the same experimental condition, both photolyses of 5 in the presence of triethylsilane and methanol showed that the intramolecular 1,5-sigmatropic rearrangement of precursor 5 to give the formation of silylenolether was more favorable process than the generation of phenylsilylene.
Phenylsilylene(PhHSi:)의 광분해 전구체인, 1,1,1,3,3,3-hexamethyl-2-phenyltrisilane(2)과 2,3-dicarbomethoxy-1,4,5,6,7-pentaphenyl-7-silanorbornadiene(5)을 10%와 73%의 수율로 각각 합성하였다. 전구체 2를 254 nm의 빛을 조사시켜 광분해 실험시킨 결과 triethylsilane 존재하에서는 phenylsilylene이 Si-H 결합에 삽입된 생성물인 1,1,1-triethyl-2-phenyldisilane (6)이 44%의 수율로 얻어졌고, diphenylacetylene 존재하에서는 phenylsilylene이 삼중결합에 첨가된 후 diphenylacetylene과 [2+2] 첨가반응이 일어나 얻어진 생성물, 1-phenyl-1-silacyclopenta-2,4-diene(4)과 phenyl-silylene이 삼중결합에 첨가된 다음 곧 이합체화되어진 화합물인 1,2-diphenyl-1,2-disilacyclohexa-2,5-diene(10)이 각각 68% 와 26%의 수율로 얻어졌다. Neat 광반응에서는 생성된 phenylsilylene이 분자간 C-H 삽입반응을 하여 생성된 화합물, 1,5-dihydrosilanthren(11)과 전구체 2가 Si-H 결합에 삽입된 화합물, 1,2-diphenyltrisilane(12)이 5%와 7%의 수율로 각각 얻어졌다. 같은 조건에서 화합물 5를 triethylsilane과 methanol 존재하에서 광분해시킨 결과 phenylsilylene은 생성되지 않고 분자내 1,5-sigmatropic 자리옮김에 의한 silylenolether가 생성됨을 확인하였다.