Photooxygenation of allylic alcohols: kinetic comparison of unfunctionalized alkenes with prenol-type allylic alcohols, ethers and acetates
- 9 April 2003
- journal article
- research article
- Published by Springer Science and Business Media LLC in Photochemical & Photobiological Sciences
- Vol. 2 (8), 877-881
- https://doi.org/10.1039/b302255b
Abstract
The kinetics of the chemical and physical quenching of the first excited singlet state of oxygen [1O2 (1Δg)] by unfunctionalized alkenes 1–4, allylic alcohols 5–7 and 9, allylic acetates 8 and 11, and the allylic ether 10 display small solvent-polarity effects on the reactivity. The regioselectivity of the singlet oxygen ene reaction is solvent independent for the unfunctionalized alkenes as well as the prenol-type substrates, the latter showing substantial solvent effects on the diastereoselectivity. Pronounced physical quenching is detected only for the allylic alcohols 5 and 6. These results are interpreted in terms of the interactions between singlet oxygen and the allylic hydroxy groups, conformationally promoted by allylic strain which lead either to chemical activation or to physical quenching. The results for substrate 9 in deuterated vs. non-deuterated methanol are in accord with hydrogen bonding between the allylic alcohol and 1O2, which directs the diastereoselectivity of the ene reaction with chiral allylic alcohols.Keywords
This publication has 26 references indexed in Scilit:
- Photooxygenation of 2,4-Dimethyl-1,3-pentadiene: Solvent Dependence of the Chemical (Ene Reaction and [4 + 2] Cycloaddition) and Physical Quenching of Singlet OxygenEuropean Journal of Organic Chemistry, 1998
- Approaches to Stereoselective Dioxygenation of Alkenes: Chiral Phosphite OzonidesThe Journal of Organic Chemistry, 1997
- Diastereoselective Singlet Oxygen Ene Reaction (Schenck Reaction) and Diastereoselective Epoxidations of Heteroatom-Substituted Acyclic Chiral Olefins: A Mechanistic ComparisonJournal of the American Chemical Society, 1996
- ChemInform Abstract: Hydroxy-Directed Regio- and Diastereoselective Ene Reaction of Singlet Oxygen with Chiral Allylic Alcohols.ChemInform, 1993
- Hydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcoholsJournal of the American Chemical Society, 1993
- Quantum Yields of Singlet‐Oxygen Production by Some Natural Quinoid Fungal Metabolites and DerivativesHelvetica Chimica Acta, 1992
- Quenching of singlet oxygen by haematoporphyrin derivative (and haematoporphyrin) and its consequences on the efficiency of photodynamic cancer therapyJournal of the Chemical Society, Chemical Communications, 1988
- Site specificity in the singlet oxygen-trisubstituted olefin reactionJournal of the American Chemical Society, 1979
- Preference for Syn Ene Additions of 1O2 to Trisubstituted, Acyclic OlefinsHelvetica Chimica Acta, 1978
- Photochemische Reaktionen III. Über die Bildung von Hydroperoxyden bei photosensibilisierten Reaktionen von O2 mit geeigneten Akzeptoren, insbesondere mit α‐ und β‐PinenEuropean Journal of Organic Chemistry, 1953