10201-59-9Relevant academic research and scientific papers
Organocatalytic epoxidation and allylic oxidation of alkenes by molecular oxygen
Orfanidou, Maria,Petsi, Marina,Zografos, Alexandros L.
supporting information, p. 9172 - 9178 (2021/11/30)
Pyrrole-proline diketopiperazine (DKP) acts as an efficient mediator for the reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols was achieved by adding a catalytic amount of selenium dioxide as an additive, revealing a superior method to the classical application of t-BuOOH as a selenium dioxide oxidant.
Metal-Catalyzed Remote Functionalization of ω-Ene Unsaturated Ethers: Towards Functionalized Vinyl Species
Ho, Guo-Ming,Judkele, Lina,Bruffaerts, Jeffrey,Marek, Ilan
supporting information, p. 8012 - 8016 (2018/06/29)
The combined ruthenium-catalyzed chain walking with the nickel-catalyzed cross-coupling reaction of ω-alkenyl ethers provide a unique entry to functionalized vinyl species. This transformation illustrates the power and flexibility of remote functionalization by demonstrating the compatibility of two independent reactions involving unrelated sites.
Active Ruthenium (0) Nanoparticles Catalyzed Wittig-Type Olefination Reaction
Srivastava, Vivek
, p. 693 - 703 (2017/03/08)
Abstract: Five different Ru metal precursors were reduced in imidazolium based ionic liquids under hydrogen atmosphere (4?bar) at 50 °C to obtain well-dispersed and stable Ru nanoparticles. Transmission electron microscopy (TEM) analysis confirmed size of well dispersed ionic liquid mediated Ru particles (Ru NPs) of 5?nm (±0.5) in diameter. These ruthenium nanoparticles (in ionic liquids) were used for Wittig type olefination reaction under mild reaction environment (70 °C and 1?h). The corresponding stilbenes were obtained in good yield with low-average selectivity. The proposed methodology is especially efficient for the synthesis of stilbenes as they were synthesized in the absence of any additive (as a hydrogen acceptor). The new catalytic system was also successfully applied for the synthesis of polymethoxylated and polyhydroxylated stilbenes, including resveratrol and DMU-212. Graphical Abstract: [Figure not available: see fulltext.]
Hydroalkylation of terminal aryl alkynes with alkyl diacyl peroxides
Li, Yougui,Ge, Liang,Qian, Bo,Babu, Kaki Raveendra,Bao, Hongli
supporting information, p. 5677 - 5680 (2016/11/28)
A photo and nickel co-catalyzed hydroalkylation of terminal aryl alkynes enabled Z-preferred olefin synthesis has been developed under mild conditions. Alkyl diacyl peroxides were utilized as a new type of alkylation reagents and afforded Z-olefins as the major products in moderate to good yields.
Nickel-catalyzed alkylative cross-coupling of anisoles with grignard reagents via C-O bond activation
Tobisu, Mamoru,Takahira, Tsuyoshi,Morioka, Toshifumi,Chatani, Naoto
supporting information, p. 6711 - 6714 (2016/06/14)
We report nickel-catalyzed cross-coupling of methoxyarenes with alkylmagnesium halides, in which a methoxy group is eliminated. A wide range of alkyl groups, including those bearing β-hydrogens, can be introduced directly at the ipso position of anisole derivatives. We demonstrate that the robustness of a methoxy group allows this alkylation protocol to be used to synthesize elaborate molecules by combining it with traditional cross-coupling reactions or oxidative transformation. The success of this method is dependent on the use of alkylmagnesium iodides, but not chlorides or bromides, which highlights the importance of the halide used in developing catalytic reactions using Grignard reagents.
Reactivity of mixed organozinc and mixed organocopper reagents: 14. Phosphine-nickel catalyzed aryl-allyl coupling of (n-butyl)(aryl)zincs. Ligand and substrate control on the group selectivity and regioselectivity
Kalkan, Melike,Erdik, Ender
, p. 28 - 36 (2016/06/09)
The group selectivity and regioselectivity in the allylation of mixed (n-butyl)(aryl)zinc reagents in THF depends on the nickel catalyst type and also on nature of the allylic substrate. Allylation of (n-butyl)(phenyl)zinc reagent with alkyl substituted primary allylic chlorides and acetates in the presence of NiCl2(dppf) catalysis affords the phenyl coupling product with γ-selectivity. However, allylation with aryl substituted primary allylic substrates results in both phenyl- and alkyl-coupling products with medium α-selectivity in the presence of NiCl2(dppf) catalysis whereas phenyl coupling product is formed with α-selectivity in the presence of NiCl2(Ph3P)2 catalysis. This new NiCl2(dppf) catalyzed protocol for γ-selective aryl allylation of (n-butyl)(aryl)zinc reagents with alkyl substituted primary allylic chlorides in THF at room temperature provides an atom economic alternative to allylation of (aryl)2Zn reagents. A mechanism for the dependence of group selectivity and regioselectivity of Ni catalyzed allylation of (n-butyl)(aryl)zinc reagents on the catalyst ligand and the substrate was proposed.
Wittig Reactions of Trialkylphosphine-derived Ylides: New Directions and Applications in Organic Synthesis
McNulty, James,McLeod, David,Das, Priyabrata,Zepeda-Velázquez, Carlos
, p. 619 - 632 (2016/01/15)
The development of semi-stabilized, stabilized, and functionalized ylides derived from short-chain trialkylphosphines in the Wittig-type olefination reactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy separation of water-soluble phosphine oxides. The development of a mild organocatalytic process for the Wittig reaction and extension toward the preparation of reporter stilbenes under biological conditions are also described. Applications toward the preparation of biologically active natural products and derivatives are discussed.
Catalyst-controlled reverse selectivity in C-C bond formation: NHC-Cu-catalyzed α-selective allylic alkylation with organolithium reagents
Pizzolato, Stefano F.,Giannerini, Massimo,Bos, Pieter H.,Fa?anás-Mastral, Martín,Feringa, Ben L.
supporting information, p. 8142 - 8145 (2015/05/20)
An efficient and highly α-selective copper-catalyzed allylic alkylation of allylic halides with organolithium reagents is presented. The use of N-heterocyclic carbenes as ligands is key to reverse the common γ-selectivity of this transformation and gives rise to the corresponding linear products with high levels of regioselectivity.
Catalytic, oxidant-free, direct olefination of alcohols using Wittig reagents
Khaskin,Milstein
, p. 9002 - 9005 (2015/05/27)
Reported here is the catalytic, acceptorless coupling of alcohols with in situ generated, non-stabilized phosphonium ylides to form olefins as major products. The reaction uses low catalyst loadings and does not require added oxidants. Hydrogenation of the product is minimized and the reaction leads to Z (aliphatic) or E (benzylic) stereospecificity.
Improvements and Applications of the Transition Metal-Free Asymmetric Allylic Alkylation using Grignard Reagents and Magnesium Alanates
Grassi, David,Alexakis, Alexandre
supporting information, p. 3171 - 3186 (2015/11/03)
Two new N-heterocyclic carbene (NHC) ligands have been synthesized and employed in the transition metal-free asymmetric allylic alkylation (AAA) mediated by Grignard reagents and magnesium alanates. The employment of these ligands showed high yields and improved regio- and enantioselectivity in the formation of tertiary and quaternary stereocenters. Moreover, the low catalyst loading (up to 0.3 mol%) and high scalability (up to 10 mmol) of this improved methodology provide a convenient access to biologically active compounds and synthetically valuable intermediates.
