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。
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
A Highly Nucleophilic Multifunctional Chiral Phosphane-Catalyzed Asymmetric Intramolecular Rauhut-Currier Reaction
作者:Xiao-Nan Zhang、Min Shi
DOI:10.1002/ejoc.201200940
日期:2012.11
An asymmetric variant of the intramolecularRauhut–Currier (RC) reaction can be achieved using a highlynucleophilicmultifunctionalchiral phosphane; the corresponding cyclopentene and cyclohexene derivatives are produced in moderate to good yields and with good to excellent enantioselectivities.
Titanocene‐Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods
作者:Zhenhua Zhang、Julius B. Stückrath、Stefan Grimme、Andreas Gansäuer
DOI:10.1002/anie.202102739
日期:2021.6.21
Cp2Ti(TFA) is a broadly applicable catalyst for the [2+2] cycloaddition of bisenones by inner-sphere electron transfer. The attractiveness of this mechanism is shown by comparison with outer-sphere ET methods. DFT calculations show that the reaction proceeds through a unique unfavorable 5-exo (the rate-determining step) and a favorable 4-exo cyclization.