3343-45-1Relevant academic research and scientific papers
Reactions of cephalosporin sulphones 1. Rearrangement of the β-lactam ring to a triazole derivative
Gunda, Tamas E.,Tamas, Laszlo,Salyi, Szabolcs
, p. 3061 - 3064 (1998)
The 7β-amino-cephalosporin sulphones, generated in situ from the appropriate 7β-tBoc-amino derivative and diazotized in a one-pot reaction in aq. HClO4 - MeOH - NaNO2, rearrange exclusively to the triazoles 5 in a multistep reaction.
Preparation and Application of α-Imino Ketones through One-Pot Tandem Reactions Based on Heyns Rearrangement
Li, Ling,Zhang, Shiqi,Deng, Xiongfei,Li, Guangxun,Tang, Zhuo,Zhao, Gang
supporting information, p. 6819 - 6824 (2021/09/08)
α-Imino ketone is a useful building block for the preparation of α-amino ketones and α-amino alcohols. However, its preparation has been seldomly seen. Herein, a metal-free and operationally simple strategy has been developed to generate α-imino ketones with high regioselectivity. Meanwhile, the method allowed for the preparation of various N,O-ketals with high regioselectivities and diastereoselectivities through cascade reactions in one pot.
Chiral Bidentate Phosphoramidite-Pd Catalyzed Asymmetric Decarboxylative Dipolar Cycloaddition for Multistereogenic Tetrahydrofurans with Cyclic N-Sulfonyl Ketimine Moieties
Lv, Hao-Peng,Yang, Xiao-Peng,Wang, Bai-Lin,Yang, Hao-Di,Wang, Xing-Wang,Wang, Zheng
supporting information, p. 4715 - 4720 (2021/06/28)
An asymmetric [3 + 2] cycloaddition of vinyl ethylenecarbonates (VECs) and (E)-3-arylvinyl substituted benzo[d] isothiazole 1,1-dioxides has been developed using the Pd complex of a bidentate phosphoramidite (Me-BIPAM) as the catalyst, providing a wide variety of chiral multistereogenic vinyltetrahydrofurans in good yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, 99% ee).
Palladium-Catalyzed (3+3) Annulation of Allenylethylene Carbonates with Nitrile Oxides
Pan, Ting,Gao, Xing,Yang, Sen,Wang, Lan,Hu, Yimin,Liu, Min,Wang, Wei,Wu, Yongjun,Zheng, Bing,Guo, Hongchao
supporting information, p. 5750 - 5754 (2021/08/16)
In this paper, we designed and synthesized a new type of cyclic carbonates, allenylethylene carbonates (AECs). With AECs as reactive precursors, we developed palladium-catalyzed (3+3) annulation of AECs with nitrile oxides. Various AECs worked well in this reaction under mild reaction conditions. A variety of 5,6-dihydro-1,4,2-dioxazine derivatives with allenyl quaternary stereocenters can be accessed in a facile manner in high yields (≤98%).
Aerobic Direct Dioxygenation of Terminal/Internal Alkynes to α-Hydroxyketones by an Fe Porphyrin Catalyst
Kimura, Kento,Kurahashi, Takuya,Matsubara, Seijiro
supporting information, p. 3615 - 3618 (2021/10/01)
We herein report a new synthetic method for the preparation of α-hydroxyketones by the dioxygenation of alkynes. The reaction proceeds at room temperature under the action of Fe porphyrin and pinacolborane under air as a green oxidant to produce α-hydroxyketones. The mild reaction conditions allow chemoselective oxidation with functional group tolerance. Terminal alkynes in addition to internal alkynes are applicable, affording unsymmetrical α-hydroxyketones that are difficult to obtain by any reported dioxygenation of unsaturated C?C bonds.
One-Pot Enzymatic-Chemical Cascade Route for Synthesizing Aromatic α-Hydroxy Ketones
Wang, Lei,Song, Wei,Wang, Binju,Zhang, Yan,Xu, Xin,Wu, Jing,Gao, Cong,Liu, Jia,Chen, Xiulai,Chen, Jinghua,Liu, Liming
, p. 2808 - 2818 (2021/03/15)
2-Hydroxyacetophenone (2-HAP) is an important building block for the production of a series of natural products and pharmaceuticals; however, there is no safe, efficient, and economical method for 2-HAP synthesis. Here, a one-pot enzymatic-chemical cascade route was designed for synthesizing 2-HAP based on retrosynthetic analysis. First, a spontaneous proton-transfer reaction was designed using a computational simulation that enabled 2-HAP synthesis from the isomer 2-hydroxy-2-phenylacetaldehyde. A route for 2-hydroxy-2-phenylacetaldehyde synthesis was then constructed by introducing the unnatural substrate glyoxylic acid into a C-C ligation reaction catalyzed by Candida tropicalis pyruvate decarboxylase. Assembly and optimization of this enzymatic-chemical cascade route resulted in a final yield of 92.7%. Furthermore, stereospecific carbonyl reductases were introduced to construct a synthetic application platform that enabled further transformation of 2-HAP into (S)- and (R)-1-phenyl-1,2-ethanediol. This method of cascading spontaneous chemical and enzymatic reactions to synthesize chemicals offers insight into avenues for synthesizing other valuable chemicals.
Enantioselective Cascade Biocatalysis for Deracemization of Racemic β-Amino Alcohols to Enantiopure (S)-β-Amino Alcohols by Employing Cyclohexylamine Oxidase and ω-Transaminase
Zhang, Jian-Dong,Chang, Ya-Wen,Dong, Rui,Yang, Xiao-Xiao,Gao, Li-Li,Li, Jing,Huang, Shuang-Ping,Guo, Xing-Mei,Zhang, Chao-Feng,Chang, Hong-Hong
, p. 124 - 128 (2020/09/21)
Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg?1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L?1) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.
Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
supporting information, p. 9982 - 9992 (2020/06/27)
The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
Palladium-Catalyzed [5 + 2] Annulation of Vinylethylene Carbonates with Barbiturate-Derived Alkenes
Chen, Yuehua,Deng, Hao,Gao, Xing,Guo, Hongchao,Jiang, Feng,Wang, Wei,Wu, Yongjun,Zhu, Dongyu
supporting information, p. 7158 - 7163 (2020/10/02)
A palladium/XantPhos-catalyzed [5 + 2] annulation of VECs with electron-deficient alkenes having an isolated carbon-carbon double bond has been developed to afford spirobarbiturate-tetrahydrooxepines. This study provides an expedient assembly of biologically interesting spirobarbiturate-tetrahydrooxepines. The easy scalability and versatile transformability of the reaction products were also exhibited.
Palladium-Catalyzed Diastereoselective Formal [5 + 3] Cycloaddition for the Construction of Spirooxindoles Fused with an Eight-Membered Ring
Niu, Ben,Wu, Xiao-Yun,Wei, Yin,Shi, Min
supporting information, p. 4859 - 4863 (2019/06/27)
A Pd-catalyzed formal [5 + 3] intermolecular cycloaddition reaction of isatin-derived α-(trifluoromethyl)imines with aryl substituted vinylethylene carbonates (VECs) has been reported, affording trifluoromethyl-group-containing spirooxindoles fused with an eight-membered ring as a single diastereoisomer in good yields in the presence of a Br?nsted acid in a one-pot manner under mild conditions. The asymmetric version of this reaction has been also realized using a chiral phosphine ligand along with the further transformation of the obtained product to give a spirooxindolo pyrrolidine derivative upon oxidation.
