Detection and the analysis of the factors affecting the competition between ring closure, internal rotation, and cleavage in diradical intermediates formed in allene cycloaddition reactions

1984 ◽  
Vol 106 (1) ◽  
pp. 152-157 ◽  
Author(s):  
Daniel J. Pasto ◽  
Shun Hua Yang
Keyword(s):  
Internal Rotation ◽  
Ring Closure ◽  
Cycloaddition Reactions ◽  
Factors Affecting

scholarly journals α-Halogenoacetamides: versatile and efficient tools for the synthesis of complex aza-heterocycles

2019 ◽  
Vol 17 (37) ◽  
pp. 8467-8485 ◽  
Author(s):  
Abderrahman El Bouakher ◽  
Arnaud Martel ◽  
Sébastien Comesse
Keyword(s):  
Ring Closure ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions

This review presents the use of α-alkyl- and α-alkoxy-halogenoacetamides as powerful partners for domino and 1,3-dipolar cycloaddition reactions resulting in a ring closure.

Organometallic Complexes Containing a Co−N−C Three-Membered Ring:  Factors Affecting the Dynamic of the Ring Closure

2003 ◽  
Vol 22 (12) ◽  
pp. 2486-2491 ◽  
Author(s):  
Renata Dreos ◽  
Alessandro Felluga ◽  
Giorgio Nardin ◽  
Lucio Randaccio ◽  
Giovanni Tauzher
Keyword(s):  
Membered Ring ◽  
Organometallic Complexes ◽  
Ring Closure ◽  
Factors Affecting

scholarly journals Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis

2011 ◽  
Vol 7 ◽  
pp. 1663-1670 ◽  
Author(s):  
Kristina Butković ◽  
Željko Marinić ◽  
Krešimir Molčanov ◽  
Biserka Kojić-Prodić ◽  
Marija Šindler-Kulyk
Keyword(s):  
Acetic Acid ◽  
Photochemical Reactions ◽  
Acid Anhydride ◽  
Ring Closure ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Thermal Reactions

New trans- and cis-o-stilbene-methylene-sydnones 3a,b were synthesized by transforming the trans- and cis-o-aminomethylstilbene derivative, obtained by reduction of corresponding o-cyano derivatives, into glycine ester derivatives (43 and 31% yield) followed by hydrolysis (90 and 96% yield), nitrosation and ring closure with acetic acid anhydride (30 and 40% yield). The products were submitted to photochemical and thermal intramolecular [3 + 2] cycloadditions to afford diverse heteropolycyclic compounds. Photochemical reactions afforded cis-3-(4-methylphenyl)-3a,8-dihydro-3H-pyrazolo[5,1-a]isoindole (11, 12.5% yield) and trans-3-(4-methylphenyl)-3a,8-dihydro-3H-pyrazolo[5,1-a]isoindole (12, 5% yield). Thermal reactions afforded 3-(4-methylphenyl)-3,3a,8,8a-tetrahydroindeno[2,1-c]pyrazole (14, 50% yield) and 11-(4-methylphenyl)-9,10-diazatricyclo[7.2.1.02,7]dodeca-2,4,6,10-tetraene (15, 22% yield).

Catalytic palladium-oxyallyl cycloaddition

Science ◽  
2018 ◽  
Vol 362 (6414) ◽  
pp. 564-568 ◽  
Author(s):  
Barry M. Trost ◽  
Zhongxing Huang ◽  
Ganesh M. Murhade
Keyword(s):  
Organic Synthesis ◽  
Palladium Catalyst ◽  
Subsequent Treatment ◽  
Conjugated Dienes ◽  
Ring Closure ◽  
Cycloaddition Reactions ◽  
Ring Systems ◽  
Oxyallyl Cation

Exploration of intermediates that enable chemoselective cycloaddition reactions and expeditious construction of fused- or bridged-ring systems is a continuous challenge for organic synthesis. As an intermediate of interest, the oxyallyl cation has been harnessed to synthesize architectures containing seven-membered rings via (4+3) cycloaddition. However, its potential to access five-membered skeletons is underdeveloped, largely due to the thermally forbidden (3+2) pathway. Here, the combination of a tailored precursor and a Pd(0) catalyst generates a Pd-oxyallyl intermediate that cyclizes with conjugated dienes to produce a diverse array of tetrahydrofuran skeletons. The cycloaddition overrides conventional (4+3) selectivity by proceeding through a stepwise pathway involving a Pd-allyl transfer and ring closure sequence. Subsequent treatment of the (3+2) adducts with a palladium catalyst converts the heterocycles to the carbocyclic cyclopentanones.

Relative importance of factors affecting activity and upper extremity function in children with Narakas Group 2 brachial plexus birth palsy

2020 ◽  
pp. 175319342096476
Author(s):  
Kıvanç Delioğlu ◽  
Akin Uzumcugil ◽  
Ebru Öztürk ◽  
Mintaze Kerem Gunel
Keyword(s):  
Brachial Plexus ◽  
Internal Rotation ◽  
Upper Limb ◽  
Treatment Strategies ◽  
Shoulder Function ◽  
Outcome Data ◽  
Joint Movement ◽  
Level Of Evidence ◽  
Significance Level ◽  
Factors Affecting

The aim of the study was to determine the differences in upper limb function and activity/participation levels between preschool children with Narakas Groups 2a and 2b obstetric brachial plexus injury; and to determine the significance level of the factors affecting upper limb functions in these patients. Sixty-seven children, aged 3 to 7, who had not had surgical intervention, were evaluated in terms of joint movements, modified Mallet classification, Raimondi hand classification, brachial plexus outcome measure, paediatric outcome data collection instrument and stereognosis. There were significant functional differences between the groups, in favour of Group 2a. The movements affecting total function of the upper limb were: hand to spine ( p < 0.001), global abduction ( p < 0.001) and hand to mouth ( p < 0.001), in descending order of significance. Passive internal rotation was the most important passive joint movement affecting shoulder function ( p < 0.001). The results of this study suggest that more emphasis should be placed on the shoulder internal rotation in treatment strategies. Level of evidence: III

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