43108-75-4Relevant academic research and scientific papers
Sc(OTf)3a'Catalyzed Ca'C Bond-Forming Reaction of Cyclic Peroxy Ketals for the Synthesis of Highly Functionalized 1,2-Dioxene Endoperoxides
Feng, Haowei,Zhao, Yukun,Liu, Pengkang,Hu, Lin
supporting information, p. 1632 - 1637 (2021/03/08)
A new and general Sc(OTf)3-catalyzed C-C bond-forming reaction of 3-(2-methoxyethoxy)-endoperoxy ketals with silyl ketene acetals, silyl enol ethers, allyltrimethylsilane, and trimethylsilyl cyanide has been developed via the reactive peroxycarbenium ions, affording a wide range of complicated 3,3,6,6-tetrasubstituted 1,2-dioxenes bearing adjacent quaternary carbons and 3-acetyl/allyl/cyano functional groups in good yields at room temperature. Notably, the resultant 1,2-dioxenes are structurally stable, which can be facially transformed into another important 1,2-dioxane endoperoxide under conventional hydrogenation conditions without deconstructing the weak O-O bond.
Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways to Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
Laserna, Victor,Porter, Michael J.,Sheppard, Tom D.
, p. 11391 - 11406 (2019/09/30)
A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. First, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxyimines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-amino alcohols with high syn selectivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines. A mechanism for the hydroamination has been proposed on the basis of experimental studies and density functional theory calculations.
Method for preparing organoboron compound under catalytic effect of chitosan immobilized copper and application
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, (2017/07/21)
The invention discloses a method for preparing an organoboron compound under a catalytic effect of chitosan immobilized copper and an application. The method comprises the following steps: A) adding a chitosan immobilized copper catalyst and a ligand into a reaction tube and stirring; B) respectively continuously adding an initial raw material I and bisdiboron into a system in turn; C) stirring the whole reaction system and reacting under room temperature; D) after the reaction is ended, filtering the whole reaction system, washing with tetrahydrofuran, performing rotary evaporation and concentration on a filtrate, adopting a mixed solvent of ethyl acetate and petroleum ether at different ratios for performing column chromatography on the residues, separating and purifying, thereby acquiring a target product II. The silica gel is taken as a fixing phase for column chromatography. The invention also relates to the application of the prepared organoboron compound in compounding beta-hydroxy compound and anti-cancer drug molecules. The method is feasible; the operation is simple and convenient; the method is suitable for various substrates and can be used for successfully preparing the corresponding target compounds. The catalyst is low in dosage and is recyclable, is easily separated after the ending of the reaction, is free from metal residue and is suitable for large-scale production.
A green and recyclable chitosan supported catalyst for the borylation of α,β-unsaturated acceptors in water
Xu, Pengyu,Li, Bojie,Wang, Liansheng,Qin, Caiqin,Zhu, Lei
, p. 23 - 26 (2016/08/09)
We herein report a green and recyclable chitosan supported copper catalyst which is capable of catalyzing the borylation of α,β-unsaturated acceptors in water at room temperature. A broad substrate scope including chalcone derivatives, esters and nitriles have been explored. In all the cases, desired products were obtained in good to excellent yields. Remarkably, this chitosan supported catalyst could be recovered and reused for five times without any significant decrease of reactivity.
An Umpolung Approach to Alkene Carboamination: Palladium Catalyzed 1,2-Amino-Acylation, -Carboxylation, -Arylation, -Vinylation, and -Alkynylation
Faulkner, Adele,Scott, James S.,Bower, John F.
supporting information, p. 7224 - 7230 (2015/06/25)
Conventional approaches to Pd-catalyzed alkene 1,2-carboamination rely upon the combination of a nucleophilic nitrogen-based component and an internal C-based or external oxidant. In this study, we outline an umpolung approach, which is triggered by oxidative initiation at an electrophilic N-based component and employs "standard" organometallic nucleophiles to introduce the new carbon-based fragment. Specifically, oxidative addition of a Pd(0)-catalyst into the N-O bond of O-pentafluorobenzoyl oxime esters generates imino-Pd(II) intermediates, which undergo 5-exo cyclization with sterically diverse alkenes. The resultant alkyl-Pd(II) intermediates are intercepted by organometallic nucleophiles or alcohols, under carbonylative or noncarbonylative conditions, to provide 1,2-carboamination products. This approach provides, for the first time, a unified strategy for achieving alkene 1,2-amino-acylation, -carboxylation, -arylation, -vinylation, and -alkynylation. For carbonylative processes, orchestrated protodecarboxylation of the pentafluorobenzoate leaving group underpins reaction efficiency. This process is likely a key feature in related Narasaka-Heck cyclizations and accounts for the efficacy of O-pentafluorobenzoyl oxime esters in aza-Heck reactions of this type. (Chemical Equation Presented).
A study of base-catalyzed aldol reaction of trimethylsilyl enolates
Sutar,Joshi
, p. 1553 - 1560 (2015/02/02)
Mukaiyama-type aldol reaction of trimethylsilyl enolates with aldehydes in the presence of a base is a complicated reaction. It usually results in various products determined by the nature of base and reaction medium. The present study has been undertaken to understand these factors and design new Lewis base catalysts to optimize the yield of desired aldol product. It has been shown that mild Bronsted base with inbuilt hydrogen bonding sites are efficient catalysts for the reactions involving trimethylsilyl enolates. Based on the observed results, a mechanism is proposed to explain the reaction outcome.
Stereoselective direct amine-catalyzed decarboxylative aldol addition
Rohr, Kerstin,Mahrwald, Rainer
supporting information; experimental part, p. 1878 - 1880 (2011/06/20)
A stereoselective decarboxylative aldol addition of β- and α-keto acids in the presence of catalytic amounts of amines is described. By the optional deployment of chiral enolizable aldehydes an access to enantiopure configurative defined ketopentoses, ketohexoses, or ketoheptoses is given.
Structural study-guided development of versatile phase-transfer catalysts for asymmetric conjugate additions of cyanide
Provencher, Brian A.,Bartelson, Keith J.,Liu, Yan,Foxman, Bruce M.,Deng, Li
supporting information; experimental part, p. 10565 - 10569 (2011/12/05)
Unprecedented phase-transfer catalysts for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin are reported (see scheme). Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. The catalysts were developed as a result of key structural insights gained by X-ray analysis. Copyright
Directed reductive amination of β-hydroxy-ketones: Convergent assembly of the ritonavir/lopinavir core
Menche, Dirk,Arikan, Fatih,Li, Jun,Rudolph, Sven
, p. 267 - 270 (2007/10/03)
(Chemical Equation Presented) An efficient procedure for the directed reductive amination of β-hydroxy-ketones (3) for the stereoselective preparation of 1,3-syn-amino alcohols (6) is reported. The operationally simple protocol uses Ti(iOPr)su
Reduction of β-hydroxyketones by Sml2/H2O/ Et3N
Davis, Todd A.,Chopade, Pramod R.,Hilmersson, Goeran,Flowers II, Robert A.
, p. 119 - 122 (2007/10/03)
(Chemical Equation Presented) Reduction of a series of β- hydroxyketones by Sml2/H2O/Et3N provided 1,3-diols in quantitative yields. The reactions were exceedingly clean with no byproduct formation, negating the need for f
