1493-51-2Relevant academic research and scientific papers
Br?nsted acid-catalyzed enantioselective addition of 1,3-diones to in situ generated N-acyl ketimines
Sadhu, Milon M.,Ray, Sumit K.,Unhale, Rajshekhar A.,Singh, Vinod K.
supporting information, p. 410 - 414 (2022/01/20)
A Br?nsted acid-catalyzed asymmetric Mannich-type addition of 1,3-diones to cyclic N-acyl ketimines is reported for the synthesis of enantioenriched isoindolinones. Various dicarbonyl-substituted isoindolinones bearing a quaternary carbon stereocenter were synthesized with excellent yields (up to 98%) and moderate to high enantioselectivities (up to 95% ee), and most of them possess a fluorine atom at the reactive center. Furthermore, the synthetic utility of the protocol has been demonstrated by the debenzoylation of the product.
Ag-Catalyzed Insertion of Alkynyl Carbenes into C-C Bonds of β-Ketocarbonyls: A Formal C(sp2) Insertion
Ning, Yongquan,Song, Qingmin,Sivaguru, Paramasivam,Wu, Lizuo,Anderson, Edward A.,Bi, Xihe
supporting information, p. 631 - 636 (2022/01/20)
Here we report a silver-catalyzed alkynyl carbene insertion into β-ketocarbonyls using alkynyl N-nosylhydrazones as alkynyl carbene precursors, which provides access to trisubstituted allenyl ketones. This reaction represents the first example of an alkynyl carbene insertion into a C-C σ bond, affording products homologated with an sp2 carbon center. The products are useful substrates for further transformations. Experimental investigations and theoretical calculations suggest the reaction proceeds through a stepwise enol cyclopropanation/retro-aldol pathway.
I2-Promoted [3+2] Cyclization of 1,3-Diketones with Potassium Thiocyanate: a Route to Thiazol-2(3H)-One Derivatives
An, Zhenyu,Liu, Yafeng,Yan, Rulong,Zhao, Pengbo
supporting information, p. 3240 - 3244 (2021/06/16)
An I2-promoted strategy has been developed for the synthesis of thiazol-2(3H)-one derivatives from 1,3-diketones with potassium thiocyanate. This [3+2] cyclization reaction involves C?S and C?N bond formation and exhibits good functional group tolerance. A series of thiazol-2(3H)-one derivatives are obtained in moderate to good yields. (Figure presented.).
Direct synthesis of 2,3,5-trisubstituted pyrroles: via copper-mediated one-pot multicomponent reaction
He, Jian-Ping,Huang, Guo-Sheng,Luo, Nan,Zhan, Zhen-Zhen,Zhang, Ming-Ming
supporting information, p. 9831 - 9835 (2021/01/05)
We have developed a copper-mediated one-pot synthesis of 2,3,5-trisubstituted pyrroles from 1,3-dicarbonyl compounds and acrylates using ammonium acetate as a nitrogen source. The reaction achieves C-C and C-N bond formation and provides an efficient approach to access highly functionalized pyrroles without further raw material preparation. This method is operationally simple, compatible with a wide range of functional groups, and provides the target products in moderate to good yields. This journal is
Electrochemical oxidative cyclization of olefinic carbonyls with diselenides
Guan, Zhipeng,Wang, Yunkun,Wang, Huamin,Huang, Yange,Wang, Siyuan,Tang, Hongding,Zhang, Heng,Lei, Aiwen
supporting information, p. 4976 - 4980 (2019/09/30)
The tandem cyclization of olefinic carbonyls with easily accessible diselenides facilitated by electrochemical oxidation has been successfully developed, which provides an environmentally friendly method for the construction of C-Se and C-O bonds simultaneously. A series of seleno dihydrofurans and seleno oxazolines, bearing fragile heterocycles, subtle C-I bonds and supernumerary vinyl groups, were forged using this elegant chelation strategy. Neither metal catalysts nor external chemical oxidants are required to promote this transformation.
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.
Method of preparing 1,3-diketone compound by acetyenic ketone
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Paragraph 0208-0214, (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.
Organic base-catalysed solvent-tuned chemoselective carbotrifluoromethylation and oxytrifluoromethylation of unactivated alkenes
Yang, Ning-Yuan,Li, Zhong-Liang,Ye, Liu,Tan, Bin,Liu, Xin-Yuan
supporting information, p. 9052 - 9055 (2016/07/21)
An unprecedented and efficient organic base-catalysed highly chemoselective carbo- and oxytrifluoromethylation of unactivated alkenes with Togni's reagent was developed. The switchable chemoselectivity was tuned by simply changing the organic base catalyst and solvent. Mechanistic studies indicated that a radical cyclization pathway for carbotrifluoromethylation in DMSO and a carbocation pathway for oxytrifluoromethylation in DCE were probably involved.
Regioselective Rhodium-Catalyzed Addition of 1,3-Dicarbonyl Compounds to Terminal Alkynes
Beck, Thorsten M.,Breit, Bernhard
supporting information, p. 124 - 127 (2016/01/15)
A new method for the rhodium-catalyzed regioselective C-C bond formation using terminal alkynes and 1,3-dicarbonyl compounds to achieve valuable branched α-allylated 1,3-dicarbonyl products is reported. With a Rh(I)/DPEphos/p-CF3-benzoic acid as the catalyst system, the desired products can be obtained in good to excellent yields and with perfect regioselectivity. A broad range of functional groups were tolerated, and first experimental insights of a plausible reaction mechanism were obtained.
2,2-Difluoro-1,3-diketones as gem-Difluoroenolate Precusors for Asymmetric Aldol Addition with N-Benzylisatins
Qian, Jinlong,Yi, Wenbin,Huang, Xin,Jasinski, Jerry P.,Zhang, Wei
, p. 2811 - 2816 (2016/09/13)
2,2-Difluoro-1,3-diketones are introduced as gem-difluoroenolate precursors for the first example of an organocatalytic asymmetric aldol addition with N-benzylisatins to form 3-difluoroalkyl-3-hydroxyoxindoles. (Figure presented.).
