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
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.
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.
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.).
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.
