A Lewis Acid Catalyzed Formal [3 + 3] Cycloaddition of α,β-Unsaturated Aldehydes with 4-Hydroxy-2-pyrone, Diketones, and Vinylogous Esters.
نویسندگان
چکیده
منابع مشابه
Lewis Acid and/or Lewis Base catalyzed [3+2] cycloaddition reaction: Synthesis of pyrazoles and pyrazolines
Abstract: A facile, 1,3-dipolar cycloaddition of ethyl diazoacetate (EDA) with various activated olefins including Baylis-Hillman adducts, activated and simple alkynes to afford 3,5-disubstituted pyrazolines and pyrazoles respectively in moderate to good yields, in high regioselective manner in the presence of Indium chloride and/or DABCO is reported. All the reactions were carried out under no...
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A novel intermolecular [4 + 3] cycloaddition method to construct 1,4-dioxide seven-membered oxacycles was developed. This one-step method was carried out in the presence of catalytic amount of (C(2)H(5))(2)OBF(3) under mild conditions. Seven-membered oxacycles and some natural compounds could be easily synthesized via this protocol. Control experiments were carried out and possible mechanism fo...
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Intramolecular formal [4+2] cycloaddition between 3-ethoxycyclobutanones and a carbon-carbon double bond to the corresponding bicyclo[4.n.0]alkan-2-one derivatives proceeded effectively by using ethylaluminium dichloride.
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Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yield...
متن کاملTf2NH-catalyzed formal [3 + 2] cycloaddition of oxadiazolones with ynamides: a simple access to aminoimidazoles.
Oxadiazolones are first employed as the three-atom coupling partners in the Tf2NH-catalyzed cycloaddition with ynamides. This formal [3 + 2] cycloaddition allows a rapid synthesis of aminoimidazoles with a broad substrate scope. The approach also features a metal-free catalytic cycloaddition process, which may find applications in the synthesis of bioactive molecules. Besides, the resulting N-m...
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ژورنال
عنوان ژورنال: ChemInform
سال: 2006
ISSN: 0931-7597,1522-2667
DOI: 10.1002/chin.200621141