- Friedel-Crafts alkylation of benzene with (polychloromethyl)silanes
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(Polychloromethyl)silanes (Cl3-mMemSiCH3-nCln: m=0-3; n=2, 3) reacted with excess benzene in the presence of aluminum chloride to give (polyphenylmethyl)silanes. Such reactions occurred at the temperatures ranging from room temperature (m=2, 3; n=2) to 80°C (m=0, 1; n=2, 3), indicating that the reactivity increases with increasing the number (m) of electron-donating methyl-group(s) at the silicon. In particular, (dichloromethyl)silanes with two or three methyl groups at the silicon (m=2 or 3; n=2) underwent the alkylation and the decomposition of their products at room temperature. The reaction with (dichloromethyl)trimethylsilane occurred immediately at room temperature to give no (diphenylmethyl)trimethylsilane, but diphenylmethane and trimethylchlorosilane via the decomposition of alkylation product. (Trichloromethyl)silanes (m=0, 1; n=3) reacted with excess benzene to give (triphenylmethyl)silanes as major products and the unusual (diphenylmethyl)silanes as minor. It was found that unusual (diphenylmethyl)silanes were formed by the decomposition of (triphenylmethyl)silanes under the reaction condition. In the alkylation to benzene, the reactivity of (polychloromethyl)silanes (Cl3-mMemSiCH3-nCln: m=0-3; n=2, 3) decreases in the following order: m=3>2>1>0; n=3>2.
- Yoo, Bok Ryul,Kim, Jeong Hyun,Cho, Bong Gwan,Jung, Il Nam
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- Synthesis and Properties of s-Alkyl-Substituted Silanediyl-Bridged and Silanetriyl-Bridged Diiron Complexes,Cp2(CO)2Fe 2(μ-CO)[μ-Si(X)CHR2] and Cp2(CO) 2Fe2(μ-CO)[μ-Si(DMAP)CHR2]+I -(X = H, I; R = Et, Ph; DMAP = 4-(Dimethylamino)pyridine)
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Photolysis of 2 molar amounts of CpFe(CO)2SiMe3 (= FpSiMe3 1) with s-alkylsilanes R2CHSiH3 (2a: R = Et; 2b: R = Ph) produces the silylene (or silanediyl)-bridged diiron complexes Cp2(CO)2Fe2(μ-CO)[μ-Si(H)CHR2] (3a: R = Et; 3b: R = Ph) which exist mainly in cis-form. The treatment of cis-3 with an excess amount of CH2I2 stereoselectively affords the iodosilylene-bridged diiron complexes Cp2(CO)2Fe2(μ-CO)[μ-Si(I)CHR2] (4a: R = Et; 4b: R = Ph) in cis-form. The reaction of complexes 4 with 4-(dimethylamino)pyridine (=DMAP) gives the base-stabilized silylyne (or silanetriyl)-bridged diiron complexes Cp2(CO)2Fe2(μ-CO)[μ-Si(DMAP)CHR 2]+I- (5a: R = Et; 5b: R = Ph) in 35 and 43% yields, respectively. The cis-trans isomerization of complexes 3 was studied under thermal and photochemical reaction conditions. The molar ratios of the cis and trans isomers of complexes 3 in the thermal equilibrium at 50 °C were 95 : 5 (3a) and 78 : 22 (3b), respectively, and in the photostationary state at 10 °C were 80 : 20 and 30 : 70, respectively. The structures of complexes 3b and 4b have been characterized by X-ray diffraction.
- Luh, Lung-Shiang,Wen, Yuh-Sheng,Tobita, Hiromi,Ogino, Hiroshi
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p. 2193 - 2200
(2007/10/03)
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