Lewis acid-catalyzed Friedel-Crafts alkylation of ferrocene with allylchlorosilanes

Authors
Ahn, SSong, YSYoo, BRJung, IN
Issue Date
2000-07-10
Publisher
AMER CHEMICAL SOC
Citation
ORGANOMETALLICS, v.19, no.14, pp.2777 - 2780
Abstract
Friedel-Crafts alkylations of ferrocene, 1, with allylchlorosilanes in the presence of Lewis acid catalysts under mild conditions gave regiospecific [1-methyl-2-(alkylchlorosilyl)ethyl]ferrocenes in fair to good yields depending upon the substituents on silicon, along with small amounts of dialkylated products. The alkylation of ferrocene with 1.2 equiv of(2-methylallyl)-dimethylchlorosilane, 2b, at 0 degrees C gave monoalkylated ferrocene 3b and an isomeric mixture of dialkylated products in 76% and 4% yields, respectively. The yield of the dialkylated ferrocene mixture increased to 21% when 2 equiv of alkylating agent 2b was used. The two components of the dialkylated product mixture were identified as 1,1'-dialkylated ferrocene 4b (17%), and 1,3-dialkylated ferrocene 4b' (4%). A higher yield of the 1,1'-diadduct compared to the 1,3-diadduct indicates that the electron-donating alkylsilyl group does not greatly enhance a second alkylation on the same ring. The reactivities of allylchlorosilanes in the ferrocene alkylations decrease in the following order: allyldialkylchlorosilane > allyl(alkyl)dichlorosilane much greater than allyldichlorosilane approximate to allyltrichlorosilane. The catalytic efficiencies of Lewis acids for the alkylations decrease in the following order: HfCl4 > ZrCl4 > AlCl3 > AlBr3 > TiCl4.
Keywords
BENZENES; BENZENES; silicon; silane; alkylation; ferrocene
ISSN
0276-7333
URI
https://pubs.kist.re.kr/handle/201004/141233
DOI
10.1021/om0000865
Appears in Collections:
KIST Article > 2000
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