On the regioselectivity of alkylation of the (trimethylsilyl)tetramethylcyclopentadienide anion. A new approach to the 1,2,3,4-tetramethylfulveneстатьяПереводИсследовательская статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The regioselectivity of alkylation of lithium (trimethylsilyl)tetramethylcyclopentadienide C5Me4SiMe3–Li+ was studied by 1H and 13C NMR spectroscopy using its reactions with MeI, MeOTs, ClCH2CH2Br, and ClCH2CH2I in different solvents as representative examples. Sterically non-hindered MeI and MeOTs presumably attack the C atom bonded to the silyl group giving 1,2,3,4,5-pentamethylcyclopentadienylsilane. For bulkier alkyl halides, such as ClCH2CH2Br and ClCH2CH2I, the regioselectivity of alkylation changes to form preferentially gem-dialkyl-substituted cyclopentadienes. The reaction of C5Me4SiMe3–Li+ with formaldehyde affords 1,2,3,4-tetramethylfulvene in a high yield, providing an alternative synthetic approach to a number of w-functionalized peralkylated cyclopentadienes. The quantum-chemical calculations of the C5Me4SiMe3– anion by the RHF and DFT (RMPW1PW91) methods in the valence-split 6-311+G(d,p) basis set are in good agreement with the experimental data.