Diastereoselective Synthesis of Pyrazolines by Metal-Free Rearrangement of Bicyclic Triazolines

Synthesis ◽  
2020 ◽  
Vol 52 (19) ◽  
pp. 2892-2898
Author(s):  
Sara Pellegrino ◽  
Emanuela Erba ◽  
Raffaella Bucci ◽  
Francesca Clerici
Keyword(s):  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
Metal Free ◽  
Synthetic Procedure

The metal-free preparation of diazoalkanes through the ring rearrangement of bicyclic triazolines is reported here. Their use in 1,3-dipolar cycloaddition reactions with electron-withdrawing alkenes was investigated. This synthetic procedure allows differently substituted pyrazolines to be obtained in few steps and with high atom economy.

1,3-Dipolar Cycloaddition of 3-Amino Oxindole-Based Azomethine Ylides and O-Vinylphosphonylated Salicylaldehydes for Diastereoselective Synthesis of Oxindole Spiro-P,N-polycyclic Heterocycles

Synthesis ◽  
2020 ◽  
Vol 52 (09) ◽  
pp. 1387-1397
Author(s):  
Mingshu Wu ◽  
Dulin Kong ◽  
Tiao Huang ◽  
Li Liu ◽  
Qinghe Wang
Keyword(s):  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
Assembly Strategy

An efficient stereoselective assembly strategy for the construction of pyrrolidin-2,3′-oxindole cis-fused phosphadihydrocoumarins was established. The process involves the condensation of O-vinylphosphonylated salicylaldehydes and 3-amino oxindoles followed by intermolecular cycloaddition with high diastereoselectivity and atom economy.

scholarly journals Regio- and Stereoselectivity in the 1,3-Dipolar Cycloaddition Reactions of Isoquinolinium Ylides with Cyclopenta[a]acenaphthylen-8-ones

Synlett ◽  
2020 ◽  
Vol 31 (17) ◽  
pp. 1691-1695
Author(s):  
Issa Yavari ◽  
Parisa Ravaghi ◽  
Maryam Safaei ◽  
Jasmine Kayanian
Keyword(s):  
Dft Calculations ◽  
Cycloaddition Reaction ◽  
Crystallographic Analysis ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Diastereoselective Synthesis ◽  
X Ray

AbstractA convenient regio- and diastereoselective synthesis of functionalized 5a,5b-dihydro-5H,13H-naphtho[1′′,8′′:4′,5′,6′]pentaleno[1′:3,4]pyrrolo[2,1-a]isoquinolin-5-ones via 1,3-dipolar cycloaddition reaction of 8H-cyclopenta[a]acenaphthylen-8-ones with carbonyl-stabilized isoquinolinium N-ylides, is described. Based on DFT calculations at b3lyp/6-311+g(d,p) level of theory, a nonconcerted mechanism is proposed to explain the regioselectivity of this reaction. The structure of a typical product was confirmed by X-ray crystallographic analysis.

Alkenylazaarenes as dipolarophiles in 1,3-dipolar cycloaddition of nitrones: regioselectivity-switchable and highly diastereoselective synthesis of multisubstituted isoxazolidines

2018 ◽  
Vol 5 (20) ◽  
pp. 2945-2949 ◽  
Author(s):  
Mengchao Tong ◽  
Yong Zhang ◽  
Cong Qin ◽  
Yiwei Fu ◽  
Yonghai Liu ◽  
...  
Keyword(s):  
Dipolar Cycloaddition ◽  
Diastereoselective Synthesis ◽  
Metal Free

Metal free 1,3-dipolar cycloaddition between alkenylazaarenes and nitrones has been developed for the synthesis of 4-substituted isoxazolidines and 5-substituted isoxazolidines in good yields and selectivities.

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