Iodine-catalyzed one-pot three-component synthesis of homoallyl benzyl ethers from aldehydes

Iodine has been found to be an effective catalyst for one-pot synthesis of homoallyl benzyl ethers under mild reaction conditions. Various homoallyl benzyl ethers were synthesized in moderate to high yield by three-component condensation of aldehydes, benzyloxytrimethylsilane, and allyltrimethylsilane in presence of iodine (10 mol %) in dichloromethane at 0 °C.     

A general and mild copper-catalyzed three-component synthesis of protected homoallyl amines

A mild and highly efficient copper-catalyzed, one-pot, three-component reaction is developed for the synthesis of homoallyl amines. Reaction of an aldehyde, a carbamate, and allyltrimethylsilane in the presence of 5 mol % Cu(OTf)₂ furnishes the corresponding protected homoallylic amines in good to excellent yields.     

Iron(III) p-toluenesulfonate catalyzed synthesis of homoallyl ethers from acetals and aldehydes

Iron(III) p-toluenesulfonate, Fe(OTs)₃·6H₂O, is an inexpensive, versatile and commercially available catalyst for the allylation of acetals using allyltrimethylsilane to yield homoallyl ethers in moderate to good yields. The one-pot conversion of aldehydes to homoallyl ethers using alkoxysilanes has also been accomplished using Fe(OTs)₃·6H₂O as a catalyst. The use of mild reaction conditions and a relatively non-corrosive catalyst make this method an attractive option for the synthesis of a range of homoallyl ethers.     

Iron(III) chloride-catalyzed convenient one-pot synthesis of homoallyl benzyl ethers starting from aldehydes

[reaction: see text] Iron(III) chloride-catalyzed effective allylation reactions of acetals with allyltrimethylsilane proceeded smoothly in high to excellent yields. In addition, this method could be applied to the one-pot synthesis of homoallyl benzyl ethers by a combination of dibenzyl acetalization of aldehydes and consecutive allylation of dibenzyl acetals.     

Synthesis of 2,6-disubstituted dihydropyrans via an efficient BiBr3-initiated three component, one-pot cascade

The rapid synthesis of cis-2,6-disubstituted dihydropyrans is achieved in a three-component, one-pot cascade reaction. BiBr₃-mediated addition of ketene silyl acetals or silyl enol ethers to β,γ-unsaturated cis-4-trimethylsilyl-3-butenal provides a Mukaiyama aldol adduct containing a vinylsilane moiety tethered to a silyl ether. Addition of a second aldehyde initiates a domino sequence involving intermolecular addition followed by an intramolecular silyl-modified Sakurai (ISMS) reaction. Isolated yields of this one-pot reaction vary from 44 to 80% and all compounds were isolated as the cis-diastereomers (10 examples).     

Three-component,one-pot synthesis of 3,4-dihydropyrimidin-2-(1<Emphasis Type="Italic">H</Emphasis>)-ones catalyzed by bromodimethylsulfonium bromide

An efficient synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives by one-pot three-component condensation reaction between an alkyl or aryl aldehyde, a 1,3-dicarbonyl compound, and urea or thiourea in the presence of catalytic amount of bromodimethylsulfonium bromide has been developed. The condensation product was obtained in excellent yields in refluxing ethanol and easily separated from the reaction mixture and purified.     

Highly efficient iron‐catalyzed allylation of aromatic aldehydes with allyltriethoxysilane: one‐pot and practical synthesis of homoallyl ethers

FeCl₃ was found to be an active catalyst for the one‐pot allylation reaction of aromatic aldehydes with allyltriethoxysilane under mild and simple conditions, which resulted in the direct synthesis of homoallyl ethers with very high chemoselectivity and yields. Various types of homoallyl ethers were obtained in excellent yields (up to 99%). Copyright © 2008 John Wiley & Sons, Ltd.     

A stereoselective three-component reaction: The facile synthesis of fluorinated tetrahydropyrimido[1,2-b]benzothiazoles

A one-pot, catalyst- and solvent-free approach has been developed for the stereoselective synthesis of fluorinated tetrahydropyrimido[1,2-b]benzothiazoles. The three-component condensation reaction of an aldehyde and a trifluoromethyl ??-dicarbonyl compound in the presence of 2-aminobenzothizole occurs in high yields at 90 °C.     

Synthesis of homoallyl ethers via allylation of acetals in ionic liquids catalyzed by trimethylsilyl trifluoromethanesulfonate

The chemoselective allylation of acetals using allyltrimethylsilane in ionic liquids is catalyzed by TMS triflate (5.0-20.0 mol %). The reaction proceeds smoothly at room temperature to afford the corresponding homoallyl ether in good yield. Since the ionic liquids are easily recovered and recycled, they are a useful alternative to dichloromethane, which is the commonly used solvent for allylations. [reaction--see text]     

A controllable synthesis of homoallyl ketones and multiply substituted cyclopentadienes by direct insertion of aroyl cyanides to zirconacyclopentenes

[reaction: see text] The direct reaction of aroyl cyanides with zirconacyclopentenes was achieved cleanly under controlled reaction conditions. This methodology provided an extremely efficient, one-pot, and high-yield route for the synthesis of homoallyl ketones when the reaction was carried out at -50 degrees C. Trapping of the zirconium intermediate by a variety of electrophiles afforded functionalized homoallyl ketones. Remarkably, the insertion reaction occurred with complete chemoselectivity, that means, the Zr-sp3 carbon bond reacted preferentially, which is different from Cu-mediated elaboration of zirconacycles. Surprisingly, when the reaction was done at room temperature, 1,2,3-trisubstituted cyclopentadiene derivatives were readily formed in high yields. The direct insertion reaction of zirconacyclopentanes with acyl cyanides was also described. When bicyclic zirconacyclopentanes were used, cyclopentanol derivatives were obtained with high stereoselectivity.     

An efficient one-pot synthesis of indolyl-4H-chromene derivatives

Chemistry of Heterocyclic Compounds - A new one-pot three-component reaction for the synthesis of indolyl-4H-chromene derivatives has been developed. The synthesis was achieved by reacting...     

An efficient synthesis of imidazo[2,1-b][1,3]thiazins via a one-pot,three-component and solvent-free reaction

A simple and eco-friendly method for the synthesis of novel imidazo[2,1-b][1,3]thiazin derivatives has been developed via the one-pot, three-component and solvent-free reaction of thiohydantoins, aromatic aldehyde and 5,5-dimethylcyclohexane-1,3-dione in the presence of catalytic amount of p-toluene sulfonic acid, in good and excellent yields.     

A simple and efficient chemoselective method for the catalytic deprotection of acetals and ketals using bismuth triflate

Bismuth triflate is a highly efficient catalyst (0.1-1 mol %) for the deprotection of acetals and ketals. The procedure is very facile and selective for acetals derived from ketones and conjugated aldehydes. tert-Butyldimethylsilyl ethers are stable to the reaction conditions. The highly catalytic nature of bismuth triflate and the use of a relatively nontoxic solvent system (THF/H(2)O) make this procedure particularly attractive for large-scale synthesis.     

A regio- and stereoselective three-component synthesis of 5-(trifluoromethyl)-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidine derivatives under solvent-free conditions

An efficient one-pot method for regio- and stereoselective synthesis of 5-(trifluoromethyl)-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidines under solvent-free and catalyst-free conditions has been developed. The method involves employing a three-component condensation reaction of an aromatic aldehyde and ethyl 4,4,4-trifluoro-3-oxobutanoate or 1,1,1-trifluoropentane-2,4-dione in the presence of 1,2,4-triazol-3-amine at 90°C.     

Bismuth triflate–L(−)‐proline catalyzed synthesis of chiral 2,5‐diaryl‐2,3‐dihydropyrano[2,3‐b]quinolin‐4‐ones

The synthesis of chiral (2R) 2,5‐diaryl‐2,3‐dihydropyrano[2,3‐b]quinolin‐4‐ones, was achieved, at ambient temperature, by the reaction of 3‐acetyl‐4‐aryl‐carbostyril and an aldehyde, in the presence of bismuth triflate–L(?)‐proline complex, formed in situ. The products were obtained in 62–78% yield with high enantioselectivity (72–96% ee). J. Heterocyclic Chem., (2011).     

Three-component synthesis of imidazo[1,2-c]pyrimidines using silica sulfuric acid(SSA)简

This letter describes a simple and efficient synthesis of 3-（cyclohexylamino）-7-hydroxy-2-arylimi- dazo[1,2-c]pyrimidin-5（6H）-one via a one-pot three-component reaction of cyclohexyl isocyanide, an aldehyde, and 4-amiopyrimidine-2,6-diol in the presence of a catalytic amount of SSA.     

A Facile and Efficient Synthesis of Substituted Pyrroles by Three Component Coupling Reaction of Amines, Aldehydes and Nitroalkanes

A facile and efficient synthesis of highly substituted pyrroles has been achieved by a one-pot three-component coupling reaction of aldehyde, amine and nitroalkane by triethyl orthoformate.     

Lewis acid mediated reactions of zirconacyclopentenes with aldehydes affording homoallyl ketones via oppenauer-type oxidation

Three different components involving alkynes, ethylene, and aldehydes were selectively integrated in a one-pot procedure to afford homoallyl ketones in good yields, via an effective combination of zirconocene-mediated C-C bond forming reactions and Lewis acid mediated organic transformation. Mechanistic studies revealed that a formal Oppenauer oxidation of seven-membered oxazirconacycles, generated in situ from the reactions of zirconacyclopentenes and aldehydes, was promoted by Lewis acid-aldehyde adducts. As a whole, the first aldehyde was incorporated into the product and the second aldehyde was reduced to an alcohol. Multiply deuterated homoallyl ketones could be readily prepared in high yields with more than 98% deuterium incorporation by using this method.     

One-pot synthesis of N-protected α-amino aldehyde acetals from three-component reaction of fluoroalkanesulfonyl azide, vinyl ether and alcohol

A facile one-step method has been developed for the synthesis of N-protected α-amino aldehyde acetals in moderate to good yields by three-component reaction of fluoroalkanesulfonyl azides, vinyl ethers and alcohol at 0 °C within 10 min. This practical synthetic method provides a convenient and expeditious access to N-per(poly)fluoroalkanesulfonyl α-amino aldehyde acetals.     

Indium-mediated one-pot, three-component synthesis of homoallyl alcohol esters without catalysts and dehydrants

Indium-mediated one-pot esterification reaction of acyl chlorides or anhydride by using in situ-prepared homoallyl alcohols from aromatic aldehydes and allyl bromide proceeded smoothly to afford the corresponding homoallyl alcohol esters in high yields within about 1 h, which provided a simple and efficient protocol for the simultaneous allylation and esterification of aldehydes without other catalysts and dehydrants.