Use of radical ring opening for introduction of alkyl and substituted alkyl groups with stereochemical control: a synthetic application of cyclopropylcarbinyl radicals

1991 ◽  
Vol 56 (12) ◽  
pp. 3801-3814 ◽  
Author(s):  
Derrick L. J. Clive ◽  
Sylvain Daigneault
Keyword(s):  
Ring Opening ◽  
Radical Ring ◽  
Stereochemical Control ◽  
Alkyl Groups ◽  
Synthetic Application

Kinetics of the Imidazolium Ring-Opening of mRNA 5'-cap Analogs in Aqueous Alkali

2006 ◽  
Vol 71 (4) ◽  
pp. 567-578 ◽  
Author(s):  
Alicja Stachelska ◽  
Zbigniew J. Wieczorek ◽  
Janusz Stępiński ◽  
Marzena Jankowska-Anyszka ◽  
Harri Lönnberg ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Ring Opening ◽  
Nucleophilic Attack ◽  
Amino Groups ◽  
Hydroxide Ion ◽  
Methyl Group ◽  
Structural Modifications ◽  
Alkyl Groups ◽  
Imidazolium Ring ◽  
Kinetics Of

Second-order rate constants for the hydroxide-ion-catalyzed imidazolium ring-opening of several mono- and dinucleosidic analogs of mRNA 5'-cap have been determined. Intramolecular stacking of the two nucleobases in the dinucleosidic analogs, m7GpppN (m7G = 7-methylguanosine, N = 5'-linked nucleoside), and electrostatic interaction between the N-alkylated imidazolium ring and phosphate moiety have been shown to shield the m7G moiety against the nucleophilic attack of hydroxide ion. In addition, the effect of methylation of the nucleobase amino groups and replacement of the 7-methyl group with other alkyl groups have been studied. The influence of all the structural modifications studied turned out to be modest, the cleavage rates of the most and least reactive analogs (with the exception of non-phosphorylated nucleosides) differing only by a factor of 5.

TiCp2Cl-Catalyzed Living Radical and Ring Opening Polymerizations Initiated from Epoxides and Aldehydes in the Synthesis of Linear, Graft and Branched Polymers

2004 ◽  
Vol 856 ◽  
Author(s):  
Alexandru D. Asandei ◽  
Isaac W. Moran ◽  
Gobinda Saha ◽  
Yanhui Chen
Keyword(s):  
Electron Transfer ◽  
Ring Opening ◽  
Glycidyl Methacrylate ◽  
Ring Opening Polymerization ◽  
Branched Polymers ◽  
Single Electron Transfer ◽  
Radical Ring ◽  
Polymer Architectures ◽  
Complex Polymer

ABSTRACTTi(III)Cp2Cl-catalyzed radical ring opening (RRO) of epoxides or single electron transfer (SET) reduction of aldehydes generates Ti alkoxides and carbon centered radicals which add to styrene, initiating a radical polymerization. This polymerization is mediate in a living fashion by the reversible termination of growing chains with the TiCp2Cl metalloradical. In addition, polymers or monomers containing pendant epoxide groups (glycidyl methacrylate) can be used as substrates for radical grafting or branching reactions by self condensing vinyl polymerization. In addition, Ti alkoxides generated in situ by both epoxide RRO and aldehyde SET initiate the living ring opening polymerization of ε-caprolactone. Thus, new initiators and catalysts are introduced for the synthesis of complex polymer architectures.

Radical Ring-Opening Copolymerization of 2-Methylene 1,3-Dioxepane and Methyl Methacrylate:  Experiments Originally Designed To Probe the Origin of the Penultimate Unit Effect

1999 ◽  
Vol 32 (5) ◽  
pp. 1332-1340 ◽  
Author(s):  
G. Evan Roberts ◽  
Michelle L. Coote ◽  
Johan P. A. Heuts ◽  
Leesa M. Morris ◽  
Thomas P. Davis
Keyword(s):  
Methyl Methacrylate ◽  
Ring Opening ◽  
Radical Ring

Scope and limitations of the nitroxide-mediated radical ring-opening polymerization of cyclic ketene acetals

2013 ◽  
Vol 4 (17) ◽  
pp. 4776 ◽  
Author(s):  
Antoine Tardy ◽  
Vianney Delplace ◽  
Didier Siri ◽  
Catherine Lefay ◽  
Simon Harrisson ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Radical Ring ◽  
Cyclic Ketene Acetals ◽  
Ketene Acetals

Copper-mediated controlled radical ring-opening polymerization (RROP) of a vinylcycloalkane

2008 ◽  
pp. 3049 ◽  
Author(s):  
Nikhil Kumar Singha ◽  
Amalin Kavitha ◽  
Prodip Sarker ◽  
Stephen Rimmer
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Radical Ring

Free-radical ring-opening polymerization of 2-(o-chlorophenyl)-4-methylene-1,3-dioxolane

1993 ◽  
Vol 30 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Simona Morariu ◽  
Emil C. Buruiana ◽  
Bogdan C. Simionescu
Keyword(s):  
Free Radical ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Radical Ring
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