Results 31 to 40 of about 30,808 (260)

Tunable Endo/Exo Selectivity in Direct Catalytic Asymmetric 1,3-Dipolar Cycloadditions with Polyfunctional Lewis Acid / Azolium-Aryloxide Catalysts. [PDF]

Angew Chem Int Ed Engl
A novel concept for catalytic asymmetric 1,3‐dipolar cycloadditions with iminoesters employs modular polyfunctional Lewis acid/azolium‐aryloxide betaine catalysts, controlling endo‐ and exo‐selectivity through adjustments of metal center, azolium, and sterics.
Bürstner A, Becker PM, Allgaier A, Pfitzer L, Wanner DM, Dollinger J, Willig F, Herrmann J, Miskov-Pajic V, Hans AC, Frey W, van Slageren J, Kästner J, Peters R.   +13 more
europepmc   +2 more sources

Construction of the 5,10b‐Phenanthridine Skeleton Using [3+2]‐Cycloaddition of a Non‐Stabilized Azomethine Ylide: Total Synthesis of (±)‐Maritidine and (±)‐Crinine Alkaloids [PDF]

, 2010
Ganesh Pandey, Nishant R. Gupta, Smita R. Gadre   +2 more
openalex   +2 more sources

Fused Nitrogen Bridgehead N,O-Acetals as Versatile Scaffolds: Synthetic Strategies, Mechanism and Applications. [PDF]

Chemistry
Fused nitrogen‐bridgehead N,O‐acetals receive specific emphasis as pivotal scaffolds due to their significant role in the bioactivity of medicinally relevant molecules. Significant approaches have been reported on their role as key synthetic building blocks/motifs in the construction of complex organic molecules and their utility as chiral auxiliaries ...
Kouvelas AD, Kallitsakis MG, Lykakis IN.
europepmc   +2 more sources

K₂CO₃-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

Molecules, 2023
The synthesis of dicyclic spiropyridazine oxoindole derivatives by using [3+3]-cycloaddition of N-unsubstituted isatin N,N′-cyclic azomethine imine 1,3-dipoles was reported.
Guosheng Yang, Sicheng Li, Qiumi Wang, Huabao Chen, Chunping Yang, Zhongqiong Yin, Xu Song, Li Zhang, Cuifen Lu, Guizhou Yue   +9 more
doaj   +1 more source

Exploring Regio- and Stereoselectivity in [3+2] Cycloaddition: Molecular Electron Density Theory Approach for Novel Spirooxindole-Based Benzimidazole with Pyridine Spacer

Crystals, 2023
A new ethylene derivative was synthesized as a precursor for the [3+2] cycloaddition (32CA) reaction to access a novel spirooxindole embodied with benzimidazole with a pyridine spacer.
Saeed Alshahrani, Abdullah Mohammed Al-Majid, Abdullah Saleh Alamary, Mar Ríos-Gutiérrez, Assem Barakat   +4 more
doaj   +1 more source

Kinetic Resolution of Alkylidene Norcamphors via a Ligand-Controlled Umpolung-Type 1,3-Dipolar Cycloaddition

iScience, 2019
Summary: Development of a general catalytic and highly efficient method utilizing readily available precursors for the regio- and stereoselective construction of bioactive natural-product-inspired spiro architectures remains a formidable challenge in ...
Chong Shen, Yuhong Yang, Liang Wei, Wu-Wei Dong, Lung Wa Chung, Chun-Jiang Wang   +5 more
doaj   +1 more source

[Bmim]Br Accelerated One-Pot Three-Component Cascade Protocol for the Construction of Spirooxindole–Pyrrolidine Heterocyclic Hybrids

Molecules, 2020
Our synthetic approach for the assembly of structurally complex spirooxindole heterocyclic hybrids was based on an ionic liquid, [bmim]Br mediated one-pot three-component cascade reaction strategy involving 1,3-dipolar cycloaddition reaction of N-1-(2 ...
Raju Suresh Kumar, Dhaifallah M. Al-thamili, Abdulrahman I. Almansour, Natarajan Arumugam, Necmi Dege   +4 more
doaj   +1 more source

Cationic Pyrrolidine/Pyrroline-Substituted Porphyrins as Efficient Photosensitizers against E. coli

Molecules, 2021
New porphyrin–pyrrolidine/pyrroline conjugates were prepared by revisiting 1,3-dipolar cycloaddition reactions between a porphyrinic azomethine ylide and a series of dipolarophiles.
Bruno M. F. Ladeira, Cristina J. Dias, Ana T. P. C. Gomes, Augusto C. Tomé, Maria G. P. M. S. Neves, Nuno M. M. Moura, Adelaide Almeida, M. Amparo F. Faustino   +7 more
doaj   +1 more source

Chemo-/Regio-Selective Synthesis of Novel Functionalized Spiro[pyrrolidine-2,3′-oxindoles] under Microwave Irradiation and Their Anticancer Activity

Molecules, 2023
A novel series of nitrostyrene-based spirooxindoles were synthesized via the reaction of substituted isatins 1a–b, a number of α-amino acids 2a–e and (E)-2-aryl-1-nitroethenes 3a–e in a chemo/regio-selective manner using [3+2] cycloaddition (Huisgen ...
Richa Sharma, Lalit Yadav, Ali Adnan Nasim, Ravi Kant Yadav, Rui Hong Chen, Neha Kumari, Fan Ruiqi, Ashoke Sharon, Nawal Kishore Sahu, Sirish Kumar Ippagunta, Paolo Coghi, Vincent Kam Wai Wong, Sandeep Chaudhary   +12 more
doaj   +1 more source

An Expedient Regio- and Diastereoselective Synthesis of Hybrid Frameworks with Embedded Spiro[9,10]dihydroanthracene [9,3′]-pyrrolidine and Spiro[oxindole-3,2′-pyrrolidine] Motifs via an Ionic Liquid-Mediated Multicomponent Reaction

Molecules, 2015
A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10 ...
Natarajan Arumugam, Abdulrahman I. Almansour, Raju Suresh Kumar, J. Carlos Menéndez, Mujeeb A. Sultan, Usama Karama, Hazem A. Ghabbour, Hoong-Kun Fun   +7 more
doaj   +1 more source