Modified Hydroborate Agent: (2,2′-Bipyridyl)(tetrahydroborato)zinc Complex, [Zn(BH<sub>4</sub>)<sub>2</sub>(bpy)], as a New, Stable, Efficient Ligand-Metal Hydroborate and Chemoselective Reducing Agent
作者:Behzad Zeynizadeh
DOI:10.1246/bcsj.76.317
日期:2003.2
rato)zinc complex, [Zn(BH4)2(bpy)], is a new white stable compound which has been used for efficient reduction of variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds (1,2-reduction) to their corresponding alcohols in acetonitrile at room temperature. Excellent chemoselectivity was also observed for the reduction of aldehydes over ketones
EFFICIENT REDUCTION OF ORGANIC COMPOUNDS WITH SULFURATED CALCIUM BOROHYDRIDE [Ca(S<sub>3</sub>BH<sub>2</sub>)<sub>2</sub>], A NEW AND STABLE MODIFIED BOROHYDRIDE REAGENT
Calcium, magnesium, and berelium borohydrides are prepared by metathetical reaction between NaBH2S3 and Ca, Mg, and Be chlorides in dry THF and the effect of metal cation exchange on their stability and reactivity has been presented. In this study we have shown that Ca(BH2S3)2 is much more stable and more reactive than its Mg, Be, and Na analogues. Ca(BH2S3)2 can easily reduce carbonylcompounds such as
It was firstly found that the Rieke Ni generated in situ was able to promote the pinacol coupling of various carbonyls efficiently. Based on this information, another catalytically effective, cheaper and more convenient NiCl2(Cat.)/Mg/TMSCl system was designed and developed further successfully. The interesting single-electron transfer (SET) mechanisms for the coupling reactions were proposed. Additionally
Mg/Triethylammonium Formate: A Useful System for Reductive Dimerization of Araldehydes into Pinacols; Nitroarenes into Azoarenes and Azoarenes into Hydrazoarenes
作者:M. GEETA PAMAR、P. GOVENDER、K. MUTHUSAMY、RUI W. M. KRAUSE、H.M. NANJUNDASWAMY
DOI:10.13005/ojc/290316
日期:2013.9.30
of triethylammoniumformate in the presence of magnesium for the efficient intermolecular pinacol coupling using MeOH as solvent. Various aromatic carbonyls underwent smooth reductive coupling to give the corresponding 1,2-diols. A series of azo compounds were obtained by the reductive coupling of nitroaromatics while azo compounds were reduced to the corresponding hydrazoarenes by this system. There
Magnesium-Mediated Carbon−Carbon Bond Formation in Aqueous Media: Barbier−Grignard Allylation and Pinacol Coupling of Aldehydes
作者:Wen-Chun Zhang、Chao-Jun Li
DOI:10.1021/jo982497p
日期:1999.4.1
alkylation of aldehydes with alkyl halides was studied in aqueousmedia. The reaction of aromatic aldehydes with allyl halides is highly effective with either THF or water as the reaction solvent but poor in a mixture of THF/water. It was found that the magnesium-mediated allylation of aldehydes with allyl bromide and iodide proceeds effectively in aqueous 0.1 N HCl or 0.1 N NH(4)Cl. Aromatic aldehydes reacted
在含水介质中研究了镁介导的Barbier-Grignard型醛与烷基卤化物的烷基化反应。用THF或水作为反应溶剂,芳族醛与烯丙基卤的反应非常有效,但是在THF /水的混合物中效果较差。已经发现,镁与烯丙基溴和碘的醛介导的烯丙基化在0.1 N HCl或0.1 N NH(4)Cl水溶液中有效进行。芳族醛在脂肪族醛的存在下发生化学选择性反应。当脂族和芳族醛官能团同时存在于同一分子中时,也观察到排他选择性。在不存在烯丙基卤的情况下,醛和酮与镁在0.1 N NH(4)Cl水溶液中反应形成高产率的相应频哪醇偶联产物。频哪醇反应的有效性受到羰基周围空间环境的强烈影响。脂肪醛和简单的烷基卤化物在用于烷基化或频哪醇偶联反应的反应条件下呈惰性。