Strong Asymmetry in the Perepoxide Bifurcation Mechanism: The Large-Group Effect in the Singlet Oxygen Ene Reaction with Allylic Alcohols

ChemPhotoChem ◽  
2017 ◽  
Vol 1 (5) ◽  
pp. 213-221 ◽  
Author(s):  
Axel G. Griesbeck ◽  
Bernd Goldfuss ◽  
Christina Jäger ◽  
Eric Brüllingen ◽  
Tim Lippold ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Allylic Alcohols ◽  
Group Effect ◽  
Ene Reaction ◽  
Bifurcation Mechanism ◽  
Large Group ◽  
Strong Asymmetry

Photooxygenation in polymer matrices: En route to highly active antimalarial peroxides

2005 ◽  
Vol 77 (6) ◽  
pp. 1059-1074 ◽  
Author(s):  
Axel G. Griesbeck ◽  
Tamer T. El-Idreesy ◽  
Anna Bartoschek
Keyword(s):  
Singlet Oxygen ◽  
Protoporphyrin Ix ◽  
Polymer Matrices ◽  
Allylic Alcohols ◽  
Ene Reaction ◽  
Highly Active ◽  
Determining Factors ◽  
Broad Variety ◽  
Covalently Linked

Photooxygenation involving the first excited singlet state of molecular oxygen is a versatile method for the generation of a multitude of oxy-functionalized target molecules often with high regio- and stereoselectivities. The efficiency of singlet-oxygen reactions is largely dependent on the nonradiative deactivation paths, mainly induced by the solvent and the substrate intrinsically. The intrinsic (physical) quenching properties as well as the selectivity-determining factors of the (chemical) quenching can be modified by adjusting the microenvironment of the reactive substrate. Tetraarylporphyrins or protoporphyrin IX were embedded in polystyrene (PS) beads and in polymer films or covalently linked into PS during emulsion polymerization. These polymer matrices are suitable for a broad variety of (solvent-free) photooxygenation reactions. One specific example discussed in detail is the ene reaction of singlet oxygen with chiral allylic alcohols yielding unsaturated β-hydroperoxy alcohols in (threo) diastereoselectivities, which depended on the polarity and hydrogen-bonding capacity of the polymer matrix. These products were applied for the synthesis of mono- and spirobicyclic 1,2,4-trioxanes, molecules that showed moderate to high antimalarial properties. Subsequent structure optimization resulted in in vitro activities that surpassed that of the naturally occurring sesquiterpene-peroxide artemisinin.

Geminal selectivity of singlet oxygen ene reactions. The nonbonding large group effect

1990 ◽  
Vol 112 (17) ◽  
pp. 6417-6419 ◽  
Author(s):  
Michael Orfanopoulos ◽  
Manolis Stratakis ◽  
Yiannis Elemes
Keyword(s):  
Singlet Oxygen ◽  
Group Effect ◽  
Ene Reactions ◽  
Large Group

scholarly journals Synthesis of spiroannulated and 3-arylated 1,2,4-trioxanes from mesitylol and methyl 4-hydroxytiglate by photooxygenation and peroxyacetalization

2010 ◽  
Vol 6 ◽  
Author(s):  
Axel G Griesbeck ◽  
Lars-Oliver Höinck ◽  
Jörg M Neudörfl
Keyword(s):  
Singlet Oxygen ◽  
Lewis Acid ◽  
Allylic Alcohols ◽  
Ene Reaction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Homoallylic Alcohols ◽  
Acid Catalyzed ◽  
Benzaldehyde Derivatives

Cycloalkanones were utilized in the Lewis acid catalyzed peroxyacetalization of ß-hydroperoxy homoallylic alcohols (prepared by the ene reaction of the allylic alcohols mesitylol and methyl 4-hydroxytiglate, respectively, with singlet oxygen) to give spiroannulated 1,2,4-trioxanes 5a–5e and 9a–9e, respectively. A second series of 3-arylated trioxanes 10a–10h, that are available from the hydroperoxy alcohol 4 and benzaldehyde derivatives, was investigated by X-ray crystallography.

Diastereoselective schenck ene reaction of singlet oxygen with chiral allylic alcohols; access to enantiomerically enriched 1,2,4-trioxanes

Tetrahedron ◽  
2009 ◽  
Vol 65 (41) ◽  
pp. 8531-8537 ◽  
Author(s):  
Sunil Sabbani ◽  
Louise La Pensée ◽  
John Bacsa ◽  
Erik Hedenström ◽  
Paul M. O'Neill
Keyword(s):  
Singlet Oxygen ◽  
Allylic Alcohols ◽  
Ene Reaction
Sign in / Sign up

Export Citation Format

Share Document