6327-79-3Relevant articles and documents
Synthesis of Highly Substituted Biaryls by the Construction of a Benzene Ring via in Situ Formed Acetals
Balamurugan, Rengarajan,Manojveer, Seetharaman,Tarigopula, Chandrahas
, p. 11871 - 11883 (2021/09/13)
Herein, we present an interesting method for the construction of a benzene ring using propargylic alcohols and 1,3-dicarbonyls, which involves three new C-C bond formations via cascade alkylation, formylation, annulation, and aromatization to make substituted biaryls. This one-pot Br?nsted acid-promoted protocol utilizes the unique reactivity of the acetal formed under the reaction conditions. Alkynyl methyl ketones could be employed instead of 1,3-dicarbonyls as they are converted to 1,3-dicarbonyls by hydration under the reaction conditions.
Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils
Zhu, Jia-Liang,Tsai, Yi-Ting
, p. 813 - 828 (2020/12/22)
The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.
Non-metal catalytic method for preparing 1,3-diketone compounds based on acetyenic ketone
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Paragraph 0052-0055, (2020/02/19)
The invention discloses a non-metal catalytic method for preparing 1,3-diketone compounds based on acetyenic ketone. The preparation method is a stepwise method or a one-pot method. The stepwise method comprises the following steps: mixing an acetyenic ketone compound I, a nitrogen-containing aromatic compound II and a No.1 base for a reaction, performing separation and purification to obtain an intermediate product, mixing the intermediate product and a No.2 base for a reaction, and performing separation and purification to obtain the product; and the one-pot method comprises the following steps: firstly mixing an acetyenic ketone compound I and a nitrogen-containing aromatic compound II, adding a No.1 base, performing a reaction for a period of time, adding a No.2 base, continuing a reaction for a period of time, and finally performing separation and purification to obtain the product. The method provided by the invention has mild reaction conditions, simple operation and a higher yield, wherein the yield is generally 80% or more, and the method has greater practical application value in drug synthesis.
Novel Bifunctionalization of Activated Methylene: Base-Promoted Trifluoromethylthiolation of β-Diketones with Trifluoromethanesulfinyl Chloride
Sun, Dong-Wei,Jiang, Min,Liu, Jin-Tao
supporting information, p. 10797 - 10802 (2019/07/03)
A novel bifunctionalization of activated methylene was achieved successfully through the base-promoted trifluoromethylthiolation of β-diketones or β-ketoesters with trifluoromethanesulfinyl chloride. A series of α-trifluoromethylthiolated α-chloro-β-diketones and α-chloro-β-ketoesters were obtained in moderate to good yields under mild conditions. When β-diketones containing a phenyl group with a hydroxyl or amino substituent at the ortho position were used as substrates, intramolecular trifluoromethylthiolation/cyclization reaction took place to give the corresponding cyclic products. Furthermore, the protocol could be extended to perfluoroalkylthiolation with the sodium perfluoroalkanesulfinate/POCl3 system. On the basis of experimental results, plausible mechanisms are proposed.
Method of preparing 1,3-diketone compound by acetyenic ketone
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Paragraph 0194-0200, (2019/06/12)
The invention relates to a preparation method of preparing a 1,3-diketone compound by acetyenic ketone. The preparation method comprises the following steps: S1, putting alpha-alkynyl ketone compound,water, gold salt and silver salt in a reaction solvent to obtain a precursor mixture, wherein the molar ratio of the alpha-alkynyl ketone compound, water, gold salt and silver salt is 1: (1-50): (0.001-0.10): (0.002-0.15); and S2, putting the precursor mixture obtained in the S1 to react at a reaction temperature of 0-50 DEG C to obtain the 1,3-diketone compound, wherein the reaction time is 5 min to 48 h. The method is simple in reaction condition, free of acid or alkaline additives and high in yield, and can be applied to modern production on a large scale.
1,2-Diazacyclopentane-3,5-diyl Diradicals: Electronic Structure and Reactivity
Yoshidomi, Shohei,Abe, Manabu
supporting information, p. 3920 - 3933 (2019/03/07)
Localized singlet diradicals are key intermediates in bond homolysis. A thorough study of the reactive species is needed to clarify the mechanisms of the homolytic bond cleavage and formation processes. In general, the singlet diradicals are quite short-lived because of the fast radical-radical coupling reactions. The short-lived characteristic has retarded the thorough study on bond homolysis. In this study, a new series of long-lived singlet diradicals, viz., 1,2-diazacyclopentane-3,5-diyl, were identified, and their electronic structures and novel reactivities were thoroughly studied using laser-flash photolysis (LFP), product analysis, and computational studies. A direct observation of the thermal equilibration (fast process) between the singlet diradicals and the corresponding ring-closing compounds was undertaken on the submicrosecond time scale. The solvent and substituent effects on the equilibration constant and rate constants for the ring-closing reaction and ring-opening reaction clarify the novel nitrogen-atom effect on the localized singlet 1,3-diyl diradicals. Two types of alkoxy-migrated compounds, 9 and 10, were isolated with high yields as the final products. Crossover, spin-trapping, and LFP experiments for the formation of alkoxy-group migration products (i.e., 9 versus 10) revealed the unique temperature effect on the product ratio of the two types of alkoxy-migration products. The temperature-insensitive intersystem crossing process (slow process, millisecond time scale) was found to be a key step in the formation of 9, which is an entropy-controlled pathway. An intramolecular migration process was identified for the formation of 10 that was accelerated by a polar solvent in an enthalpy-controlled process. This unique heteroatom effect has opened up a new series of localized singlet diradicals that are crucial intermediates in bond homolysis.
An effective preparation of both 1,3-diketones and nitriles from alkynones with oximes as hydroxide sources
Chen, Pei,Zhang, Qian-Qian,Guo, Jia,Chen, Lu-Lu,Wang, Yan-Bo,Zhang, Xiao
, p. 6958 - 6966 (2018/10/02)
An effective phosphine-catalyzed protocol has been established for the syntheses of 1,3-diketones and nitriles from alkynones with oximes as hydroxide surrogates. This method features the use of a phosphine catalyst, compatibility with various functional groups and ambient temperature, which makes this approach very practical. A plausible mechanism was proposed.
Controlling reactivity through liquid assisted grinding: The curious case of mechanochemical fluorination
Howard, Joseph L.,Sagatov, Yerbol,Repusseau, Laura,Schotten, Christiane,Browne, Duncan L.
supporting information, p. 2798 - 2802 (2017/07/24)
We have identified an example of a mechanochemically milled organic reaction where liquid-assisted grinding controls the selectivity, such a phenomenon has not been reported/observed before. It was found that upon milling dibenzoylmethane with Selectfluor in the absence of any solvent, a 3:1 ratio of monofluorinated:difluorinated product was observed. Whereas, addition of 0.125 mL of acetonitrile (～10% of the total volume of materials present) to the ground reaction mixture afforded 50:1 selectivity. Furthermore, this phenomenon is applicable to a small range of diketone substrates thus far explored. Additionally, we have demonstrated that difluorination can be achieved by simply switching from adding acetonitrile to addition of sodium carbonate. Most notable, in the latter case, is the reduced reaction time compared to a conventional solvent approach, 2 hours in the mill and 24 hours in the flask.
Room-Temperature Coupling/Decarboxylation Reaction of α-Oxocarboxylates with α-Bromoketones: Solvent-Controlled Regioselectivity for 1,2- and 1,3-Diketones
He, Zhen,Qi, Xiaotian,She, Zhijie,Zhao, Yinsong,Li, Shiqing,Tang, Junbin,Gao, Ge,Lan, Yu,You, Jingsong
supporting information, p. 1403 - 1411 (2017/02/10)
A transition-metal-free and room-temperature coupling/decarboxylation reaction between α-oxocarboxylates and α-bromoketones is reported herein. It represents the first mild and regioselective synthesis of either 1,2- or 1,3-diketones from the same starting materials. Notably, the regioselectivity is simply controlled by solvents. The preliminary experimental data and DFT calculations suggest sequential Darzens-type coupling, alkaline hydrolysis, KOH-promoted oxirane opening and decarboxylation in one pot. This method is efficient for the synthesis of α,β-epoxy-γ-butyrolactone and curcuminoids.
Structure-dependent selective O- or C-trifluoroethylation of 1,3-dicarbonyls by mesityl(2,2,2-trifluoroethyl)iodonium triflate
Zhao, Cheng-Long,Yang, Jing,Han, Zhou-Zhou,Zhang, Cheng-Pan
supporting information, p. 23 - 30 (2017/10/30)
Reaction of [ArICH2CF3][OTf] with structurally diversified 1,3-dicarbonyls and an appropriate base at room temperature gave O-trifluoroethylated products, C-trifluoroethylated products, or a mixture of O- and C-trifluoroethylated products in good yields. The product type was dramatically dependent upon the structure of the starting 1,3-dicarbonyls in this reaction. The cyclic 1,3-diketones exclusively afforded the O-trifluoroethylated products, whereas the acyclic 1,3-diketones, β-keto esters, and malonates selectively or specifically formed the C-trifluoroethylated products. Li2CO3 facilitated the C-trifluoroethylation of acyclic 1,3-diketones and β-keto esters. The reaction proceeded under mild conditions, without pre-activation of 1,3-dicarbonyls and use of strong base, and demonstrated a catalyst-free structure-dependent regioselective trifluoroethylation of 1,3-dicarbonyls by mesityl(2,2,2-trifluoroethyl)iodonium triflate.
