Metal-free synthesis of novel indolizines from chromones and pyridinium salts via 1,3-dipolar cycloaddition, ring-opening and aromatization

2019 ◽  
Vol 60 (29) ◽  
pp. 1871-1874 ◽  
Author(s):  
Kai-Kai Dong ◽  
Qiang Huang
Keyword(s):  
Ring Opening ◽  
Dipolar Cycloaddition ◽  
Pyridinium Salts ◽  
Metal Free

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

Unprecedented access to functionalized pyrrolo[2,1-a]isoquinolines from the domino reaction of isoquinolinium ylides and electrophilic benzannulated heterocycles

2021 ◽  
Author(s):  
Sheba Ann Babu ◽  
Rajalekshmi A. R. ◽  
Nitha P. R. ◽  
Vishnu K. Omanakuttan ◽  
Rahul P. ◽  
...  
Keyword(s):  
Ring Opening ◽  
Domino Reaction ◽  
Dipolar Cycloaddition

The reaction between electrophilic benzannulated heterocycles and isoquinolinium methylides results in a domino dipolar cycloaddition-ring opening transformation, generating functionalized pyrrolo[2,1-a]isoquinolines and S–S-bridged bis-pyrrolo[2,1-a]isoquinolines.

1,3-dipolar cycloaddition in the synthesis of glycoconjugates of natural chlorins and bacteriochlorins

2009 ◽  
Vol 13 (03) ◽  
pp. 336-345 ◽  
Author(s):  
Mikhail A. Grin ◽  
Ivan S. Lonin ◽  
Anna A. Lakhina ◽  
Elena S. Ol'shanskaya ◽  
Alexey I. Makarov ◽  
...  
Keyword(s):  
Triple Bond ◽  
Tautomeric Form ◽  
Click Reaction ◽  
Copper Cation ◽  
Water Soluble ◽  
Dipolar Cycloaddition ◽  
Nmr Studies ◽  
Metal Free ◽  
Cu Complex ◽  
Derivatives Of

Glucose-, galactose- and lactose-containing photosensitizers based on derivatives of chlorophyll a and bacteriochlorophyll a were synthesized with the use of [3+2] cycloaddition between sugar azides and triple bond derivatives of chlorins and bacteriochlorins. Unlike bacteriochlorin cycloimide, chlorin was detected to form a Cu -complex during the click reaction. An approach to the synthesis of metal-free glycosylated chlorins was developed with the use of "protection" by Zn 2+ cation and subsequent demetalation. It is based on the action of alkynyl chlorin e6 derivative Zn -complex, which is resistant to the substitution by copper cation. Bacteriochlorin p cycloimide conjugate with per-acetylated β-D-lactose was obtained and shown to become water-soluble after unblocking of the lactose hydroxy functions. NMR studies allowed for the elucidation of structure, tautomeric form and conformation of the obtained compounds.

Synthesis of metal-free poly(1,4-dioxan-2-one) by enzyme-catalyzed ring-opening polymerization

2000 ◽  
Vol 38 (9) ◽  
pp. 1560-1567 ◽  
Author(s):  
Haruo Nishida ◽  
Mitsuhiro Yamashita ◽  
Masumi Nagashima ◽  
Takeshi Endo ◽  
Yutaka Tokiwa
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Metal Free

Photoinduced, strain-promoted cycloadditions of trans-cycloheptenones and azides

2020 ◽  
Vol 22 (20) ◽  
pp. 7023-7030
Author(s):  
Hongzhi Yang ◽  
Tianying Zeng ◽  
Shuang Xi ◽  
Shengkun Hu ◽  
Yunfei Wu ◽  
...  
Keyword(s):  
Oxidation Reaction ◽  
Aerobic Oxidation ◽  
Dipolar Cycloaddition ◽  
Reaction Sequence ◽  
Metal Free

Metal-free cycloadditions of cycloheptenones with azides have been developed, hinging on a photoisomerization/1,3-dipolar cycloaddition/aerobic oxidation reaction sequence.

scholarly journals Metal-Free Ring-Opening Metathesis Polymerization

2015 ◽  
Vol 137 (4) ◽  
pp. 1400-1403 ◽  
Author(s):  
Kelli A. Ogawa ◽  
Adam E. Goetz ◽  
Andrew J. Boydston
Keyword(s):  
Ring Opening ◽  
Ring Opening Metathesis Polymerization ◽  
Free Ring ◽  
Metathesis Polymerization ◽  
Metal Free

Benzonaphthyridine N-Oxides as 1,3-Dipoles

1996 ◽  
Vol 49 (4) ◽  
pp. 523 ◽  
Author(s):  
T Zujewska ◽  
B Bachowska
Keyword(s):  
Ring Opening ◽  
Room Temperature ◽  
Dipolar Cycloaddition ◽  
Dimethyl Acetylenedicarboxylate ◽  
Ring Contraction

Benzonaphthyridine N-oxides give N-ylides with dimethyl acetylenedicarboxylate at room temperature, most probably by 1,3-dipolar cycloaddition followed by ring contraction to form an aziridine derivative, and ring opening.

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