Heterogeneous Light-Mediated Reductive Dehalogenations and Cyclizations Utilizing Platinum Nanoparticles on Titania (PtNP@TiO<sub>2</sub>)
作者:Christopher D. McTiernan、Spencer P. Pitre、Hossein Ismaili、Juan C. Scaiano
DOI:10.1002/adsc.201400547
日期:2014.9.15
The utility of platinumnanoparticles on titania (PtNP@TiO2) as a heterogeneous photoredox catalyst is evaluated using a series of reductive transformations. In comparison to TiO2 alone, TiO2 decorated with 0.2% PtNP shows enhanced efficiency, attributed to the NPs ability to both enhance light absorption and inhibit electron‐hole pair recombination. Herein, we demonstrate that under an inert atmosphere
使用一系列还原转化,评估了纳米二氧化钛上的铂纳米颗粒(PtNP @ TiO 2)作为非均相光氧化还原催化剂的效用。与单独的TiO 2相比,用0.2%PtNP装饰的TiO 2显示出更高的效率,这归因于NPs既增强了光吸收又抑制了电子-空穴对重组。本文中,我们证明了在惰性气氛和UVA /可见光照射下,由PtNP @ TiO 2催化剂与牺牲电子给体[二异丙基乙胺((i- Pr)2NEt]可以促进多种不同的还原性脱卤和环化反应,并具有中等至极好的收率。另外,该催化体系具有许多不同的功能,并且由于其非均相性质,具有易于去除催化剂的优点。
Nickel-Catalyzed Organozinc-Promoted Carbocyclizations of Electron-Deficient Alkenes with Tethered Unsaturation
作者:John Montgomery、Eric Oblinger、Alexey V. Savchenko
DOI:10.1021/ja9702125
日期:1997.5.1
A nickel-catalyzed method for cyclizations of electron-deficient alkenes with tethered unsaturation in the presence of organozincs was developed. Considerable flexibility in the structure of each reactive component was observed. Enones, alkylidene malonates, unsaturated β-ketoesters, and nitroalkenes participated as the electron-deficient alkene; alkynes, enones, 1,3-dienes, and aldehydes participated
开发了一种镍催化的方法,用于在有机锌存在下对具有束缚不饱和度的缺电子烯烃进行环化。观察到每个反应组件的结构具有相当大的灵活性。烯酮、亚烷基丙二酸酯、不饱和β-酮酯和硝基烯烃作为缺电子烯烃参与;炔烃、烯酮、1,3-二烯和醛作为系链不饱和键参与;以及各种 sp2 和 sp3 杂化的有机锌,包括那些具有 β-氢的有机锌,作为亲核组分参与其中。底物结构、有机锌结构和配体结构都在决定产物选择性方面发挥了重要作用。具有特殊合成意义的是从普通炔烃制备 E 或 Z 三或四取代烯烃的机会。
Ferrocene-based bifunctional organocatalyst for highly enantioselective intramolecular Rauhut–Currier reaction
showed good performance in enantioselectiveintramolecular Rauhut–Currier reaction of bis(enones), giving the corresponding products in good yield with up to 98% ee. Moreover, with amino acid derived amide-phosphine B3, optically active α-methylene-δ-valerolactone was obtained in 88% yield and > 99.9% ee utilizing the enantioselectiveintramolecular Rauhut-Currier reaction of chalcone derivative.
Stereoselective Synthesis of Cyclohexane Derivatives: Tandem Lithium Iodide Mediated Intramolecular Conjugate Addition of Thiols to α,β-Bisenones
作者:SungYong Seo、Minseok Jeon、Chaeyoung Yun
DOI:10.1055/a-1754-7424
日期:2022.6
A tandem intramolecular conjugateaddition reaction was conducted with α,β-bisenones as selected Michael acceptors which were converted into 1,2,3-trisubstituted six-membered rings in the presence of activated sulfur nucleophiles. The products were obtained in good to excellent yields (maximum yield: 99%). Various substituted α,β-bisenones and sulfur nucleophiles were examined to understand the substrate
Synthesis of carbocycles by enone-selective reduction using organoiodotin hydride
作者:Toshihiro Suwa、Keita Nishino、Masato Miyatake、Ikuya Shibata、Akio Baba
DOI:10.1016/s0040-4039(00)00388-9
日期:2000.4
By using di-n-butyliodotin hydride (n-Bu2SnIH), carbocycles were prepared from substrates bearing both enone and formyl moieties, where the enone-selective reduction was followed by a diastereoselective intramolecular aldol reaction.