Umpolung of reactivity of allylsilane, allylgermane, and allylstannane via their reaction with thallium (III) salt: a new allylation reaction for aromatic compound
✍ Scribed by Masahito Ochiai; Masao Arimoto; Eiichi Fujita
- Book ID
- 104244138
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- French
- Weight
- 243 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Sumnary:
A new direct allylation of the aromatic compound has been developed. A combination of allylsilane, allylgermane, or allylstannane and thallium (III) trifluoroacetate gave rise to an ally1 cationic species which was allowed to react with an aromatic compound, a nucleophile, to give allylation product(s) in good yields. Direct allylation of the aromatic compound by the electrophilic aromatic substitution reaction is usually very difficult. Friedel-Crafts reaction using ally1 chloride or ally1 alcohol and acid catalyst for allylation of the aromatic compound has been shown to be fruitless producing many by-products,' because of an intervention of redox reaction* and instability of the product in the reaction conditions. la,3 Allylsilane, allylgermane, and allylstannane 1 bearing a highly nucleophilic double bond4 transfer the ally1 group to various kinds of electrophiles (carbonyl compound, 5a @-enone, 5b acetal, 5c acid chloride, 5d a-nitro olefin,5e epoxide, 5f etc.) as shown in eq. 1. In order to use these reagents for allylation of the aromatic compound, therefore, their reactivity must be reversed. We wish to report our device for this purpose as shown in eq. 2. M-%"' Eq* 1 \ Tl(II1) , eT1(III) Nu l Nu_ Eq 2 M: SiR3 GeR3 SnR3 Nu: ArH