24731-39-3Relevant academic research and scientific papers
Metal-free visible-light-promoted C(sp3)-H functionalization of aliphatic cyclic ethers using trace O2
Blackburn, Bryan G.,Cooke, Maria Victoria,Laulhé, Sébastien,Niu, Ben,Sachidanandan, Krishnakumar
supporting information, p. 9454 - 9459 (2021/12/09)
Presented is a light-promoted C-C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidation mechanism which is maintained through the leaching of trace amounts of O2 as sole green oxidant. This journal is
Photochemical generation of acyl and carbamoyl radicals using a nucleophilic organic catalyst: Applications and mechanism thereof
Balletti, Matteo,De Pedro Beato, Eduardo,Mazzarella, Daniele,Melchiorre, Paolo
, p. 6312 - 6324 (2020/08/24)
We detail a strategy that uses a commercially available nucleophilic organic catalyst to generate acyl and carbamoyl radicals upon activation of the corresponding chlorides and anhydrides via a nucleophilic acyl substitution path. The resulting nucleophilic radicals are then intercepted by a variety of electron-poor olefins in a Giese-type addition process. The chemistry requires low-energy photons (blue LEDs) to activate acyl and carbamoyl radical precursors, which, due to their high reduction potential, are not readily prone to redox-based activation mechanisms. To elucidate the key mechanistic aspects of this catalytic photochemical radical generation strategy, we used a combination of transient absorption spectroscopy investigations, electrochemical studies, quantum yield measurements, and the characterization of key intermediates. We identified a variety of off-the-cycle intermediates that engage in a light-regulated equilibrium with reactive radicals. These regulated equilibriums cooperate to control the overall concentrations of the radicals, contributing to the efficiency of the overall catalytic process and facilitating the turnover of the catalyst. This journal is
Efficiency and Selectivity Aspects in the C-H Functionalization of Aliphatic Oxygen Heterocycles by Photocatalytic Hydrogen Atom Transfer
Raviola, Carlotta,Ravelli, Davide
supporting information, p. 803 - 809 (2019/04/25)
The C-H to C-C conversion in aliphatic oxygen heterocycles (dioxolanes, 1,3-dioxane, or cyclic carbonates) by photocatalytic hydrogen atom transfer and subsequent trapping of the resulting radical with phenyl vinyl sulfone was investigated. The performanc
Visible-Light-Promoted Remote C-H Functionalization of o-Diazoniaphenyl Alkyl Sulfones
Du, Shaofu,Kimball, Elizabeth Ann,Ragains, Justin R.
supporting information, p. 5553 - 5556 (2017/10/25)
Visible-light irradiation of ortho-diazoniaphenyl alkyl sulfones in the presence of Ru(bpy)32+ results in remote Csp3-H functionalization. Key mechanistic steps in these processes involve intramolecular hydrogen atom transfer from Csp3-H bonds to aryl radicals to generate alkyl/benzyl radicals. Subsequent polar crossover occurs by single-electron oxidation of the alkyl/benzyl radicals to carbenium ions that then intercept nucleophiles. We have developed remote hydroxylations, etherifications, an amidation, and C-C bond formation processes using this strategy.
Deep Eutectic Solvents as Reaction Media for the Palladium-Catalysed C?S Bond Formation: Scope and Mechanistic Studies
Marset, Xavier,Guillena, Gabriela,Ramón, Diego J.
supporting information, p. 10522 - 10526 (2017/08/10)
A unique jigsaw catalytic system based on deep eutectic solvents and palladium nanoparticles where C?S bonds are formed from aryl boronic acids and sodium metabisulfite, is introduced. The functionalization step is compatible with a broad spectrum of reagents such as nucleophiles, electrophiles or radical scavengers. This versatile approach allows the formation of different types of products in an environmentally friendly medium by selecting the components of the reaction, which engage one with another as pieces in a jigsaw. This simple procedure avoids the use of toxic volatile organic solvents allowing the formation of complex molecules in a one-pot reaction under mild conditions. Despite the fact that only 1 mol % of metal loading is used, the recyclability of the catalytic system is possible. Kinetic experiments were performed and the reaction order for all reagents, catalyst and ligand was determined. The obtained results were compared to palladium nanocrystals of different known shapes in order to shed some light on the properties of the catalyst.
Asymmetric aza-Morita-Baylis-Hillman reactions of alkyl vinyl ketones with N-protected imines or in situ generated N-protected imines
Guan, Xiao-Yang,Wei, Yin,Shi, Min
scheme or table, p. 4098 - 4105 (2010/10/02)
DABCO-catalyzed aza-MBH reactions of N-Boc imines with MVK and EVK have been thoroughly investigated in the paper. The asymmetric version of this aza-MBH reaction was also systematically investigated by using a chiral amine or a chiral phosphane catalyst. It was found that most of the JVprotected imines are suitable substrates under the mild reaction conditions and are able to give the corresponding adducts in moderate yields with high ee values. The TQO- or LB1-catalyzed aza-MBH reactions of N-protected a-amidoalkyl phenyl sulfones or a-amidoalkyl p-tolyl sulfones with MVK could be well conducted, which provides a facile and direct route to obtain highly enantioselective aza-MBH adducts. The Boc protecting group of the aza-MBH product could be easily removed under acidic conditions to give the corresponding α-methylene-α-amino ketone or α-methyleneβ-amino alcohol derivatives in good yields.
Synthesis of substituted tetrahydrofurans via intermolecular reactions of γ-chlorocarbanions of 3-substituted 3-chloro-propylphenyl sulfones with aldehydes
Brandt, Agnieszka,Wojtasiewicz, Anna,?niezek, Marcin,Makosza, Mieczys?aw
scheme or table, p. 3378 - 3385 (2010/06/20)
Carbanions of 3-substituted-3-chloropropyl phenyl sulfones add to carbonyl groups of aldehydes to produce aldol type adducts that undergo 1,5-intramolecular substitution giving 2,3,5-trisubstituted tetrahydrofurans. The effect of substituents in the 3-pos
Radical alkylation of bis(silyloxy)enamine derivatives of organic nitro compounds
Jin, Young Lee,Hong, Young-Taek,Kim, Sunggak
, p. 6182 - 6186 (2007/10/03)
(Chemical Equation Presented) Alkylation β to a nitro group by radical chemistry is made possible by initial conversion of the organic nitro compound into a bis(silyloxy)enamine (see scheme; TBSOTf=tert-butyldimethylsilyl trifluoromethanesulfonate). An advantage of the method is the simultaneous conversion of the nitro group into a synthetically useful oxime ether group.
Synthesis of deuterated isotopomers of 7α- and (25R,S)-26- hydroxycholesterol, internal standards for in vivo determination of the two biosynthetic pathways of bile acids
Ciuffreda, Pierangela,Casati, Silvana,Alessandrini, Laura,Terraneo, Giancarlo,Santaniello, Enzo
, p. 733 - 738 (2007/10/03)
Deuterated isotopomers of 7α- and (25R,S)-26-hydroxycholesterol, internal standards for in vivo determination of the two biosynthetic pathways of bile acids formation from cholesterol, were prepared from [2,2,3,4,4,6- 2H6]-cholestero
Synthesis and reactivity of iron carbonyl complexes of β-silyl substituted α,β-unsaturated ketones
Gibson, Susan E.,Tustin, Gary J.
, p. 2427 - 2432 (2007/10/02)
β-Silyl α,β-unsaturated ketones, R3SiCH=CHC(O)Me (R3Si = Me3Si, ButMe2Si, PhMe2Si), react with at 35 deg C in diethyl ether to give tetracarbonyliron(0) complexes and at 55 deg C in toluene to give tricarbonyliron(0) complexes.Tricarbonyliron(0) and tricarbonyltMe2SiCH=CHC(O)Me>iron(0) react with methyllithium under a nitrogen atmosphere to give hexane-2,5-dione and 3-(tert-butyldimethylsilyl)hexane-2,5-dione, respectively, and with methyllithium under a carbon monoxide atmosphere to give the vinylketene complexes tricarbonyl(3-methyl-5-trimethylsilyl-1-oxa-1,2,4-triene)iron(0) and tricarbonyl(5-tert-butyldimethylsilyl-3-methyl-1-oxapenta-1,2,4-triene)iron(0) respectively.
