264882-03-3Relevant articles and documents
B(C6F5)3-catalyzed O-H insertion reactions of diazoalkanes with phosphinic acids
Jiang, Jun,Zhang, Xinzhi,Zhang, Yangyang,Zhao, Jincheng
, p. 5772 - 5776 (2021/07/12)
A highly efficient base-, metal-, and oxidant-free catalytic O-H insertion reaction of diazoalkanes and phosphinic acids in the presence of B(C6F5)3has been developed. This powerful methodology provides a green approach towards the synthesis of a broad spectrum of α-phosphoryloxy carbonyl compounds with good to excellent yields (up to 99% yield). The protocol features the advantages of operational simplicity, high atom economy, practicality, easy scalability and environmental friendliness.
B(C6F5)3-Catalyzed site-selective N1-alkylation of benzotriazoles with diazoalkanes
Guo, Jing,Mandal, Dipendu,Stephan, Douglas W.,Wu, Yile,Zhao, Yunbo
, p. 7758 - 7761 (2021/08/13)
Alkylation of benzotriazoles is synthetically challenging, often leading to mixtures of N1 and N2 alkylation. Herein, metal-free catalytic site-selective N1-alkylation of benzotriazoles with diazoalkanes is described in the presence of 10 mol% of B(C6F5)3. These reactions provide N1-alkylated benzotriazoles in good to excellent yields and this protocol is successfully adapted to gram-scale syntheses as well as a derivative with antimicrobial activity.
Blue LED-Mediated N-H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study
Maiti, Debajit,Das, Ranajit,Sen, Subhabrata
, p. 2522 - 2533 (2021/02/05)
Mild blue light-mediated N-H insertion of indole and its derivatives into aryldiazoesters has been reported in a batch and flow strategy to afford the corresponding N-alkylated product in moderate-to-excellent yield. Detailed high-performance liquid chromatography-based reaction kinetics measurements, control experiments, and kinetic isotope effect reveal that 3-substituted indoles with electron-withdrawing groups such as -CN and -CHO facilitated the product formation, whereas the electron-donating group retarded the process. The neutral indole performed in between them. Furthermore, Hammett plot and density functional theory-based transition-state optimization studies showed substantial correlation of the electronic nature of the substituents at the C3 position of indoles with the rate of the N-H insertion reaction. The strategy was utilized to synthesize a key intermediate for the natural product (-)-psychotrimine.
Blue Light-Emitting Diode-Mediated in Situ Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine
Guha, Souvik,Maiti, Debajit,Prabakar, Tejas,Sar, Saibal,Sen, Subhabrata
, p. 11736 - 11747 (2021/09/02)
Blue light-emitting diode-mediated environmentally sustainable three component reactions among pyridine/isoquinoline 1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylides from N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes this strategy as the foundation for the photolytic multicomponent reaction.
Blue LED Induced Manganese (I) Catalysed Direct C2?H Activation of Pyrroles with Aryl Diazoesters
Sar, Saibal,Das, Ranajit,Sen, Subhabrata
, p. 3521 - 3531 (2021/06/09)
Herein, we have reported a blue LED mediated manganese pentacarbonyl bromide catalysed incorporation of carbene moieties from aryl diazoesters onto 1H-pyrroles via their selective C2?H activation. A manganese metal-carbene has been identified as the active catalyst to facilitate the reaction. Eighteen mono substituted pyrrole derivatives were isolated in good to excellent yields (67→82%) and the disubstituted products were also formed in minor quantities (5 to 8%). HPLC based kinetics study enabled optimization of the reaction. Control experiments, FT-IR, NMR and GC-MS based characterization elucidated the putative reaction mechanism. (Figure presented.).
Photolytic amino etherification reactions of aryl diazoacetates with N-heterocycles and a stoichiometric amount of dioxane/tetrahydropyran in aqueous medium: Synthesis of 1,4-dioxepane/1,4,7-dioxazonan-6-one systems
Das, Ranajit,Maiti, Debajit,Sen, Subhabrata
, p. 8533 - 8544 (2021/11/17)
Herein we have reported a blue LED mediated reaction of aryl diazoacetate with a stoichiometric amount of 1,4-dioxane/tetrahydropyran (THP) and various heterocycles like indoles, pyrroles, phthalimides, thiazolidinediones and hydantoins in water. During the reaction, various aryl diazoacetates were converted to oxonium ylides by reacting with 1,4-dioxane and THP. These ylides generated in aqueous medium (under metal- and base-free conditions) were then used for the amino etherification of the aforementioned heterocycles in excellent yield. The ylides underwent a [1,2] shift to afford substituted 1,4-dioxepanes. Phthalimide products were also converted to 1,4,7-dioxazonan-6-ones. Reaction kinetics, Hammett's plot and DFT calculations (solvent phase) rationalize the ylide formation and subsequent reactions with the nucleophiles. The reaction was also demonstrated at the multigram scale. This amino etherification reaction of aryl diazoacetates in aqueous medium demonstrated a sustainable process of converting toxic 1,4-dioxane in functionalizing heterocycles. This journal is
Dirhodium(II)/Xantphos-Catalyzed Relay Carbene Insertion and Allylic Alkylation Process: Reaction Development and Mechanistic Insights
Liang, Xinyi,Lu, Bin,Peng, Qian,Wang, Xiaoming,Wang, Zijian,Zhang, Jinyu
supporting information, p. 11799 - 11810 (2021/08/16)
Although dirhodium-catalyzed multicomponent reactions of diazo compounds, nucleophiles and electrophiles have achieved great advance in organic synthesis, the introduction of allylic moiety as the third component via allylic metal intermediate remains a formidable challenge in this area. Herein, an attractive three-component reaction of readily accessible amines, diazo compounds, and allylic compounds enabled by a novel dirhodium(II)/Xantphos catalysis is disclosed, affording various architecturally complex and functionally diverse α-quaternary α-amino acid derivatives in good yields with high atom and step economy. Mechanistic studies indicate that the transformation is achieved through a relay dirhodium(II)-catalyzed carbene insertion and allylic alkylation process, in which the catalytic properties of dirhodium are effectively modified by the coordination with Xantphos, leading to good activity in the catalytic allylic alkylation process.
Catalytic Enantio- And Diastereoselective Cyclopropanation of 2-Azadienes for the Synthesis of Aminocyclopropanes Bearing Quaternary Carbon Stereogenic Centers
Shao, Xinxin,Malcolmson, Steven J.
supporting information, p. 7380 - 7385 (2019/10/02)
We report the catalytic enantio- and diastereoselective preparation of aminocyclopropanes by the cyclopropanation of terminal and (Z)-internal 2-azadienes with donor/acceptor carbenes derived from α-diazoesters. The resulting cyclopropanes bear quaternary carbon stereogenic centers vicinal to the amino-substituted carbon and are formed as a single diastereomer in up to 99:1 er and 97% yield with 0.5 mol % of Rh2(DOSP)4 and only 1.5 equiv of the diazo reagent. Transformations with internal azadienes afford cyclopropanes with three contiguous stereogenic centers.
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
Shi, Taoda,Teng, Shenghan,Gopi Krishna Reddy, Alavala,Guo, Xin,Zhang, Yueteng,Moore, Kohlson T.,Buckley, Thomas,Mason, Damian J.,Wang, Wei,Chapman, Eli,Hu, Wenhao
supporting information, p. 8737 - 8744 (2019/10/16)
We report a bifunctional Ag catalyst promoted intramolecular capture of oxonium ylides with alkynes for the enantioselective synthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with respect to 9, suggesting that two molecules of 9 are involved in the intramolecular trapping of a Ag-associated oxonium ylide with a Ag-activated alkyne. Based on our mechanistic hypothesis, we further optimized the reaction, rendering a facile approach to 2,5-dihydrofurans in good to excellent yields in a highly chemo- and enantioselective fashion.
A sustainable catalytic enantioselective synthesis of norstatine derivatives
Shi, Taoda,Jing, Changcheng,Qian, Yu,Xu, Xinfang,Alavala, Gopi Krishna Reddy,Lv, Xinxin,Hu, Wenhao
supporting information, p. 9792 - 9798 (2019/12/02)
Norstatine derivatives are of important value in pharmaceutical science. However, their catalytic asymmetric synthesis is rare. We developed a sustainable method via chiral phosphoric acid (CPA)-[Rh(OAc)2]2 co-catalyzed multi-component reactions (MCR) of diazoacetates with alcohol/water and imines. This method allows us to synthesize a library of 45 norstatines with excellent enanotioselectivites and broad substrate scope which includes anti-α-aryl-norstatines 11-1, anti-α-alkyl-norstatines 11-2, syn-α-hydro-norstatines 11-3 and syn-α-aryl-norstatines 11-4. The sustainability of this method lies in the reliable scalability, improved safety, and reusable [Rh(OAc)2]2 catalyst. The synthetic value of norstatine derivatives was demonstrated by preparing oxazolinone 14, ezetimibe analogue 15, and Taxol C-13 chain 16. Mechanistic study reveals that the synergetic catalysis of CPA and [Rh(OAc)2]2 is essential to maintain chemo- and enantioselectivity. Control experiments support the mechanism where the reactions proceed through the trapping of hyper-reactive oxonium ylides with imines. Shortly, we report herein the sustainable catalytic enantioselective synthesis of both syn- and anti-norstatine derivatives. We believe that this method might shed light on the sustainable synthesis of norstatine derivative-based drug candidates.
