由于分子光敏剂和有机金属催化剂的发展,可见光驱动的C–C键的形成近来引起了越来越多的关注。然而,这些均质方法学通常需要使用基于贵金属的(例如,Ir,Ru等)光敏剂。相比之下,固态半导体代表了一种有吸引力的替代方法,但对于由可见光照射驱动的C–C键形成反应的探索仍然较少。在此,我们报道在二维ZnIn 2 S 4上可以实现苯甲醛与氢安息香的光催化频哪醇C–C偶联。在牺牲电子供体(例如三乙胺)存在下在可见光照射下形成纳米片。我们进一步证明,在激发的ZnIn 2 S 4中同时利用激发电子和空穴是可行的如果使用苄醇作为起始底物,则在不使用任何牺牲试剂的情况下进行C-C偶联反应,可最大程度地提高光催化的能量效率并避免任何副产物。在这种情况下,形成工业上重要的安息香和脱氧安息香作为最终产物。更重要的是,通过明智地调整光催化条件,我们能够以前所未有的高选择性生产苯偶姻或脱氧苯偶姻。用各种清除剂系统地研究了
Chemoselective Photoredox Synthesis of Unprotected Primary Amines Using Ammonia
作者:Jiawei Rong、Peter H. Seeberger、Kerry Gilmore
DOI:10.1021/acs.orglett.8b01637
日期:2018.7.6
radicals are produced as novel intermediates via a transformation that merges acid-promoted N–H imine generation and chemoselective photocatalytic single-electron reduction. Coupling ammonia and aldehydes/ketones allows the generation of primaryamines under mild conditions without the need for protecting groups. The key intermediate can be efficiently transformed into primary (di)amines by a formal dimerization
Heterogeneous carbon nitride photocatalyst for C–C bond oxidative cleavage of vicinal diols in aerobic micellar medium
作者:Tengfei Niu、Shengjun Chen、Mei Hong、Tianhao Zhang、Jiayang Chen、Xinyu Dong、Bangqing Ni
DOI:10.1039/d0gc01727b
日期:——
A green and efficient visible-light promoted aerobic oxidative C–C bond cleavage of vicinal diols in micellarmedium has been developed. This protocol used graphitic carbon nitride with nitrogen vacancies (CN620) as a metal-free recyclable photocatalyst and CTAB as surfactant in water. Control experiments and the ESR results indicated that superoxide radicals and valence band holes played an important
NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols
作者:Jitender M. Khurana、Anshika Lumb、Ankita Chaudhary
DOI:10.1007/s00706-016-1749-z
日期:2017.2
found to be an excellent oxidizing agent in aqueousmedium. NaBrO3:bmim[HSO4] oxidized 1,2-diols, α-hydroxyketones, and alcohols to the corresponding carbonylcompounds in excellent yields. This method offers advantages such as low cost reagents, aqueousreaction conditions, moderate temperatures and short reaction times and hence environmentally benign reaction. Moreover, the ionic liquid bmim[HSO4] could
Organic Photoredox Catalyst with Substrate-capture Ability: A Perylene Derivative Bearing Urethane Moiety for Reductive Coupling of Ketones and Aldehydes under Visible Light
作者:Shusuke Okamoto、Hiroki Tsujioka、Atsushi Sudo
DOI:10.1246/cl.171160
日期:2018.3.5
A perylene derivative bearing a urethane moiety served as an efficient photoredox catalyst for the reductivecoupling of ketones and aldehydes under visiblelight, implicating the urethane moiety captured substrates through hydrogen bonds to lower the LUMO levels of the captured substrates, thus promoting single electron transfer from the reductant anion radical of the perylene moiety to the substrates
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。