Carbene in Rigid Matrix. XI. Temperature and Matrix Effect on Phenylcarbene Processes in Ether and Amine
作者:Hideo Tomioka、Shinji Suzuki、Yasuji Izawa
DOI:10.1246/bcsj.55.492
日期:1982.2
Product distributions from reactions of phenylcarbene with diethyl or diisopropyl ether or diethylamine were found to be highly dependent on reaction temperature. As temperature decreases, the C–O displacement reaction and N–H insertion are decreased. Concomitantly, primary C–H insertionproducts markedly increase especially at lower matrix temperatures.
The reaction of dialkyl acetals derived from α,β-unsaturated aldehydes with Grignard reagents using TiCl4in THF afforded the cross coupling products, allyl ethers, in high yields. The TiCl4-promotedreaction of alkyl 2,4-dichlorophenyl acetals, synthesized from 3,4-dihydro-2H-pyran or ethyl vinyl ether and 2,4-dichlorophenol, with Grignard reagents in THF at low temperature afforded the corresponding
Modification of singlet carbene reactivities by solvent
作者:H. Tomioka、Y. Ozaki、Y. Izawa
DOI:10.1016/s0040-4020(01)96743-2
日期:1985.1
The solventeffect on the reactivity of singlet carbenes has been investigated. Competition reactions between pairs of alcohols for arylcarbenes in various solvents indicates that the O—H insertion selectivity is influenced only by 1,4-dioxane. Thus, phenylcarbene is some 33 times more reactive toward methanol relative to t-butyl alcohol in 90 mol% dioxane than without solvent. Similar competition
Fluorination with xenon difluoride, Part XXXV. Reaction with grignard reagents
作者:Zvonko Bregar、Stojan Stavber、Marko Zupan
DOI:10.1016/s0022-1139(00)83938-x
日期:1989.8
represent 98% of products formed, with 2% of the reaction mixture containing at least up to seven unidentified products, while with benzyl magnesium bromide (1b), the three main products 2b, 3b and 4b represent 80% of the reaction mixture, the remaining 20% containing up to nine products with benzyl bromide being the main side product. The complexity of the reaction increases even more in the case of phenyl
Regiospecific insertion of benzylidene ligands into the α-C–H bond of ethers
作者:Helmut Fischer、Johann Schmid、Robert Märkl
DOI:10.1039/c39850000572
日期:——
The benzylidene complexes (CO)5WCH(p-C6H4R)(R = H, Me) react with diethyl or tetrahydrofuran to give regiospecifically the products of the insertion of the benzylideneligand into the α-C–Hbond of the ethers; the insertion reaction follows an associative mechanism initiated by a nucleophilic attack of the ethers at the benzylideneligand.
亚苄基配合物(CO)5 W CH(p -C 6 H 4 R)(R = H,Me)与二乙基或四氢呋喃反应,形成区域特异性的亚苄基配体插入α-C–H键的产物醚 插入反应遵循由醚在亚苄基配体上的亲核攻击而引发的缔合机制。