نتایج جستجو برای: grignard reagents
تعداد نتایج: 29282 فیلتر نتایج به سال:
The mechanism of the TEMPO mediated oxidative homo-coupling of aryl Grignard reagents is investigated in detail by experimental and computational studies. Experimental data reveal that the nitroxide-mediated homocoupling reaction of aryl Grignard reagents does not occur via free aryl radicals. Evidence for the presence of biaryl radical anions as intermediates in the coupling reaction is provid...
The formation of carbon-nitrogen (C-N) bonds via an umpolung substitution reaction has been achieved at -78 °C without the need for catalysts, ligands, or additives. The scope is limited to aryl Grignard reagents with N-chloroamines. The findings in this manuscript serve as a reference point for all C-N bond formation involving N-chloroamines and organometallic reagents. Knowing the yields of u...
A novel amide synthesis methodology is described using amines, CO2 and Grignard reagents and Mitsunobu reagents. The method was applied to carbon-11 radiochemistry to label amides using cyclotron-produced [11C]CO2. The synthetic utility of the one-pot labelling methodology was demonstrated by producing [11C]melatonin. The incorporation of [11C]CO2 into [11C]melatonin was 36% - determined by rad...
Addition of allylmagnesium reagents to an aliphatic aldehyde bearing a radical clock gave only addition products and no evidence of ring-opened products that would suggest single-electron-transfer reactions. The analogous Barbier reaction also did not provide evidence for a single-electron-transfer mechanism in the addition step. Other Grignard reagents (methyl-, vinyl-, t-Bu-, and triphenylmet...
The development of an efficient catalytic system for enantioselective carbon-carbon bond formation by 1,4-addition of organometallic reagents (organolithium, Grignard, and organozinc reagents) to enones is a major challenge in organic synthesis. This Account presents the breakthrough realized in this field using chiral phosphoramidite ligands for copper-catalyzed dialkylzinc additions. Applicat...
Abstract An efficient stereocontrolled preparation of 2-substituted pyrrolidines and 5-substituted indolizidin-7-ones, by using chiral N-tert-butanesulfinyl imines derived from 4-halobutanal as starting materials, is detailed. Addition Grignard reagents a decarboxylative Mannich reaction with β-keto acids involving these proceeded high diastereoselectivity. The synthesis the pyrrolidinic alkal...
Fatty acid esters have been synthesized in good yield by reaction between copper(I) ate complexes formed from methylcopper(I) and primary or secondary Grignard reagents and esters of primary iodoalkylcarboxylic acids. The synthetic method is i l lustrated with proced.ures for CHr:gH(CHz)rgCO2C2H5, CeHsCHzO(CH2)16COzCzHs, CH3(CH2)25CO2C2H5, CH3O2C(CH)I2CO2CHI, CzHsOzC(CHz)szCO2C2H5, and CHg(CH2)...
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