- Palladium-Catalyzed Carbonylative Coupling of Aryl Iodides with Alkenylaluminum Reagents
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A highly reactive catalytic system for the carbonylative coupling of aryl iodides with alkenylaluminum reagents has been developed. Various β-substituted γ,δ-unsaturated ketones were produced under mild conditions in good to excellent yields even under ppm level of palladium catalyst. Notably, this also represents the first example on carbonylative transformation of alkenylaluminum compounds. Additionally, by the addition of zinc salt, the selectivity of the product can be modified.
- Chen, Bo,Wu, Xiao-Feng
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supporting information
p. 7624 - 7629
(2019/10/02)
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- Chiral Hydroxytetraphenylene-Catalyzed Asymmetric Conjugate Addition of Boronic Acids to Enones
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(S)-2,15-Br2-DHTP-catalyzed asymmetric conjugate addition of boronic acids to β-trifluoromethyl α,β-unsaturated ketones and enones was studied. The reaction afforded the corresponding Michael addition products in moderate to high yields with excellent enantioselectivities (up to 99:1 er). This catalytic system features mild reaction conditions, high efficiency, and tolerance to heteroarylboronic acids.
- Chai, Guo-Li,Sun, A-Qiang,Zhai, Dong,Wang, Juan,Deng, Wei-Qiao,Wong, Henry N.C.,Chang, Junbiao
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supporting information
p. 5040 - 5045
(2019/07/03)
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- Rhenium-catalyzed α-alkylation of enol acetates with alcohols or ethers
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When benzylic and allylic alcohols were treated with enol acetate in the presence of a catalytic amount of a rhenium complex, ReBr(CO)5, the carbon-carbon bond formation of the alcohols and enol acetate smoothly proceeded to give the corresponding ketones and aldehyde in moderate to good yields. For the reaction of allylic alcohols, γ,δ-unsaturated carbonyl compounds were obtained in good yields. When ethers were used instead of alcohols as the alkylated agent, two alkyl moieties on the ethers were utilized on the reaction.
- Umeda, Rui,Takahashi, Yuuki,Yamamoto, Takaaki,Iseki, Hideki,Osaka, Issey,Nishiyama, Yutaka
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supporting information
p. 92 - 101
(2018/11/01)
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- Asymmetric Conjugate Addition of Organoboron Reagents to Common Enones Using Copper Catalysts
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Copper complexes of phosphoramidites efficiently catalyzed asymmetric addition of arylboron reagents to acyclic enones. Importantly, rare 1,4-insertion of arylcopper(I) was identified which led directly to O-bound copper enolates. The new mechanism is fundamentally different from classical oxidative addition/reductive elimination of organocopper(I) on enones.
- Wu, Chunlin,Yue, Guizhou,Nielsen, Christian Duc-Trieu,Xu, Kai,Hirao, Hajime,Zhou, Jianrong
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supporting information
p. 742 - 745
(2016/02/05)
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- Triflic acid promoted direct α-alkylation of unactivated ketones using benzylic alcohols via in situ formed acetals
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Direct α-alkylation of unactivated ketones using benzylic alcohols as electrophiles has been achieved at room temperature. This reaction takes place via in situ formed acetal using triflic acid and trimethyl orthoformate. It is believed that methyl vinyl
- Koppolu, Srinivasa Rao,Naveen, Naganaboina,Balamurugan, Rengarajan
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supporting information
p. 6069 - 6078
(2014/07/21)
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- Enone-alkyne reductive coupling: A versatile entry to substituted pyrroles
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The reductive coupling of enones or enals with alkynes, followed by olefin oxidative cleavage and Paal-Knorr cyclization, provides a versatile entry to a variety of pyrrole frameworks. A number of limitations of alternate entries to the requisite 1,4-dica
- Thompson, Benjamin B.,Montgomery, John
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supporting information; experimental part
p. 3289 - 3291
(2011/09/13)
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- Copper(I) iodide dimethyl sulfide catalyzed 1,4-addition of alkenyl groups from alkenyl-alkylzincate reagents
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The presence of catalytic quantities of the copper(I) iodide dimethyl sulfide complex {(CuI)4(SMe2)3} with alkenyl-alkylzincate reagents allows for the complete chemoselective 1,4-addition of various alkenyl groups to a nu
- El-Batta, Amer,Bergdahl, Mikael
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p. 1761 - 1765
(2008/02/05)
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- A new reaction of the phenylhydrazones of 1,5-diketones. Synthesis of dihydropyran derivatives
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It was shown that the monophenylhydrazones of 1,5-diketones are converted by reduction with borohydride followed by treatment of the obtained hydrazino alcohols with acidic agents into derivatives of dihydropyran with the elimination of phenylhydrazine as
- Moskovkina
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- Conjugate addition of organosiloxanes to α,β-unsaturated carbonyl compounds catalyzed by a cationic rhodium complex
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A novel, additive-free, and clean conjugate addition reaction of organosiloxanes to α,β-unsaturated carbonyl compounds catalyzed by a cationic rhodium complex in water-containing solvent has been developed. A plausible reaction mechanism involving the add
- Oi, Shuichi,Honma, Yoshio,Inoue, Yoshio
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p. 667 - 669
(2007/10/03)
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- Carbon-carbon bond formation by reactions of allylic alcohol with enoxysilane in the presence of Ir-complex
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Substitution of allylic alcohols to form a carbon-carbon bond is accomplished by a simple reaction of the allylic alcohol itself with an enoxysilane, catalyzed by [Ir(cod)(PPh3)2]X which is activated by H2 molecule. The anion part X of the complexes plays an important role to enhance the rate and product yields of the reactions. The efficacy of the catalyst increases with switching X in the order of PF6-4--.
- Matsuda, Isamu,Wakamatsu, Shogo,Komori, Ken-Ichi,Makino, Tatsuya,Itoh, Kenji
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p. 1043 - 1046
(2007/10/03)
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- Tandem addition β-lithiation - Alkylation sequence on α,β-unsaturated aldehydes
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A tandem reaction between (E)-cinnamaldehyde, 1a, and phenyllithium affording β-substituted dihydrochalcones was recently reported. NMR spectroscopic studies on the reaction mixture, as well as isotopic exchange reactions and trapping of two intermediates, provide clues on the several mechanistic steps of this new reaction. Extended studies revealed that β-alkyl-substituted α,β-unsaturated aldehydes and aliphatic lithium reagents did not afford good yields of the tandem reaction products, while aromatic lithium reagents gave good results. The aggregation features of the aryllithium reagents and the extended charged delocalization effects are considered to promote β-selectivity. This approach provides a convenient route for the synthesis of a wide variety of β-alkyl-substituted dihydrochalcones.
- Nudelman,Garcia
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p. 1387 - 1394
(2007/10/03)
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- Synthetically useful desulfurisation reactions of heteroaryl sulfoxide conjugate adducts
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Efficient desulfurisation reactions of the conjugate addition products derived from 1-methyl-2-imidazolyl and 2-pyridyl sulfoxides have been achieved. Hydrodesulfurisation was effected either by reduction of the sulfoxides to sulfides, followed by treatment with Raney nickel, or more reliably by reaction of either the sulfides or the sulfoxides with nickel boride. Pyrolytic elimination furnished alkenes stereoselectively on heating the sulfoxides to reflux in toluene or chloroform.
- Casey,Gairns,Walker
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p. 1725 - 1728
(2007/10/03)
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- Isolation and characterisation of aromatic substituted olefinic compounds from the starfish Pteraster militaris
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Two series of the polyaromatic coumpound (1-6 and 7-14) have been isolated from the starfish Pteraster militaris after column chromatography over Amberlite XAD-2 resin.Their structures have been established by spectroscopic means and confirmed as 2,4-diph
- Yayli, Nurettin
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p. 556 - 561
(2007/10/03)
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