Regioselective Condensation of Ethynyl Vinyl Ketone or 2-Propynyl Ether Derivatives with Silyl Enol Ethers Catalyzed by Trityl Perchlorate
نویسندگان
چکیده
منابع مشابه
Formal (3+3) cycloaddition of silyl enol ethers catalyzed by trifric imide: domino Michael addition-claisen condensation accompanied with isomerization of silyl enol ethers.
We describe here a Tf₂NH-catalyzed formal (3+3) cycloaddition of silyl enol ethers with acrylates as a new domino reaction. In the domino sequence, the catalyst activates Michael addition, deprotonation of the resulting silyloxonium cation and intramolecular Claisen condensation. It was found that reaction modes significantly depend on the reaction temperature. We also examined the mechanistic ...
متن کاملFacile isomerization of silyl enol ethers catalyzed by triflic imide and its application to one-pot isomerization–(2 + 2) cycloaddition
A triflic imide (Tf(2)NH) catalyzed isomerization of kinetically favourable silyl enol ethers into thermodynamically stable ones was developed. We also demonstrated a one-pot catalytic reaction consisting of (2 + 2) cycloaddition and isomerization. In the reaction sequence, Tf(2)NH catalyzes both of the reactions.
متن کاملGold-catalyzed alkylation of silyl enol ethers with ortho-alkynylbenzoic acid esters
Unprecedented alkylation of silyl enol ethers has been developed by the use of ortho-alkynylbenzoic acid alkyl esters as alkylating agents in the presence of a gold catalyst. The reaction probably proceeds through the gold-induced in situ construction of leaving groups and subsequent nucleophilic attack on the silyl enol ethers. The generated leaving compound abstracts a proton to regenerate th...
متن کامل1-Phenylthio-3-vinyl-3-cyclohexenol, a new reagent for bis-annelation of silyl enol ethers
1-Phenylthio-3-vinyl-cyclohex-1-en-3-ol (2) has been synthesized and investigated as a new bis-annelation reagent for silyl enol ethers. Reagent 2 can be synthesized by a Grignard reaction of vinyl magnesium bromide with 3-phenylthiocyclohexenone. The reaction with silyl enol ethers takes place under Lewis acid catalysis and generally proceeds in good yields. The resulting phenylthiodienes can ...
متن کاملIridium-catalyzed enantioselective allylation of silyl enol ethers derived from ketones and α,β-unsaturated ketones.
The unified Ir-catalyzed enantioselective allylic substitution reactions of silyl enol ethers derived from ketones and α,β-unsaturated ketones with branched, racemic allylic alcohols are described. This transformation is catalyzed by the Carreira system and proceeds without fluoride, and with high ee and b : l ratio. The synthetic utility of this method was illustrated by the concise enantiosel...
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ژورنال
عنوان ژورنال: Bulletin of the Chemical Society of Japan
سال: 1990
ISSN: 0009-2673,1348-0634
DOI: 10.1246/bcsj.63.2687