A new mode of aromatic metamorphosis has been developed, which allows thiophenes and their benzo‐fused derivatives to be converted to a variety of exotic heteroles. This transformation involves 1) the efficient generation of key 1,4‐dianions by means of desulfurative dilithiation with lithium powder and 2) the subsequent trapping of the dianions with heteroatom electrophiles in a one‐pot manner. Via
Diels-Alder reactions of 1,1-dimethyl-2,3,4,5-tetraphenyl-1-silacyclopentadiene, 1,1-dimethyl-2,5-diphenyl-1-silacyclopentadiene and 1,1-dimethyl-3,4-diphenyl-1-silacyclopentadiene with maleic anhydride; kinetic measurements
作者:George K. Henry、Ronald Shinimoto、Qingshan Zhou、William P. Weber
DOI:10.1016/0022-328x(88)80355-3
日期:1988.8
Diels-Alderreactions of 1,1-dimethyl-2,3,4,5-tetraphenyl-1-silacyclopentadiene, 1,1-dimethyl-2,5-diphenyl-1-silacyclopentadiene and 1,1-dimethyl-3,4-diphenyl-2-silacyclopentadiene with maleicanhydride have been carried out. The rates of these second order reactions have been measured by 1H FT NMR over a range of temperatures. Arrhenius plot of these data yield the activation parameters for these
Die chemie der schweren carben-analogen R2M, M = Si, Ge, Sn
作者:Hubertus Appler、Lutz W. Gross、Bernd Mayer、Wilhelm P. Neumann
DOI:10.1016/0022-328x(85)80198-4
日期:1985.8
1]heptadienes thermolysis in order to generate free silylenes and the corresponding benzene derivatives are investigated. For this purpose, 29 new compounds of the types VII–X have been prepared. No indications for a polar mechanism or an intermediate biradical could be found. The degradation is exactly of first order in all cases investigated sofar, and is enhanced by phenyl groups at the bridgehead C atoms
Tetramethyldigermene, generated for the first time by pyrolysis of 1,4-diphenyl-2,3-benzo-7,7,8,8-tetramethyl-7,8-digermabicyclo[2.2.2]octadiene, was successfully trapped by [4+2] cycloaddition with anthracene and 1,1-dimethyl-2,5-diphenyl-1-silacyclopentadiene.
Electron-transfer reaction of 1,2-disila-3,5-cyclohexadienes
作者:Masahiro Kako、Hideki Takada、Yasuhiro Nakadaira
DOI:10.1016/s0040-4039(97)00693-x
日期:1997.5
Photolysis of 1,2-disila-3,5-cyclohaxadienes 1a-b in the presence of methylene blue as a sensitizer led to efficient formation of the corresponding siloles as ring contraction products. The reaction mechanism is best rationalized by electron-transfer from 1a-b to the excited state of methylene blue. Semiempirical molecular orbital calculation was also carried out to characterize the geometric and electronic