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.
Similar content being viewed by others
References and notes
G. O. Schenck, H. Eggert and W. Denk, Photochemical reactions. III. The formation of hydroperoxides by the photosensitized reaction of oxygen with appropriate acceptors, especially with α- and β-pinene Liebigs Ann. Chem. 1953 584 177–198.
A. G. Griesbeck, T. T. El-Idreesy, W. Adam and O. Krebs, Ene reactions with singlet oxygen, in CRC Handbook of photochemistry and photobiology, ed. W. M. Horspool and P.-S. Sing, CRC, Boca Raton, FL, in press.
M. Stratakis and M. Orfanopoulos, Regioselectivity in the ene-reaction of singlet oxygen with alkenes Tetrahedron 2000 56 1595–1615.
M. Orfanopoulos, M. B. Grdina and L. M. Stephenson, Site specificity in the singlet oxygen-trisubstituted olefin reaction J. Am. Chem. Soc. 1979 101 275–276.
A. G. Leach and K. N. Houk, Diels-Alder and ene reactions of singlet oxygen, nitroso compounds and triazolinediones: Transition states and mechanisms from contemporary theory Chem. Commun. 2002 1243–1255.
W. Adam and M. Prein, The Schenck ene reaction: Diastereoselective oxyfunctionalization with singlet oxygen in synthetic applications Angew. Chem., Int. Ed. Engl. 1996 35 477–494.
W. Adam and B. Nestler, Hydroxy-directed regio- and diastereoselective ene reaction of singlet oxygen with chiral allylic alcohols J. Am. Chem. Soc. 1993 115 5041–5049.
A. G. Griesbeck, T. T. El-Idreesy, M. Fiege and R. Brun, Synthesis of antimalarial 1,2,4-trioxanes via photooxygenation of a chiral allylic alcohol Org. Lett. 2002 4 4193–4195.
W. Adam, H.-G. Brünker, A. S. Kumar, E.-M. Peters, K. Peters, U. Schneider, H. G. von Schnering, Diastereoselective singlet oxygen-ene reaction (Schenck reaction) and diastereoselective epoxidations of heteroatom-substituted acyclic chiral olefins: A mechanistic comparison J. Am. Chem. Soc. 1996 118 1899–1905.
K. Gollnick and A. Griesbeck, Solvent dependence of singlet oxygen/substrate interactions in ene-reactions, [4 + 2]- and [2 + 2]-cycloaddition reactions Tetrahedron Lett. 1984 25 725–728.
K. Gollnick and A. Griesbeck, Interactions of singlet oxygen with 2,5-dimethyl-2,4-hexadiene in polar and nonpolar solvents. Evidence for a vinylog ene-reaction Tetrahedron 1984 40 3235–3250.
K. Gollnick and A. Griesbeck, Singlet oxygen photooxygenation of furans. Isolation and reactions of (4 + 2)-cycloaddition products (unsaturated sec.-ozonides) Tetrahedron 1985 41 2057–2068.
P. D. Merkel and D. R. Kearns, Radiationless decay of singlet molecular oxygen in solution. Experimental and theoretical study of electronic-to-vibrational energy transfer J. Am. Chem. Soc. 1972 94 7244–7253.
R. Schmidt and E. Afshari, Collisional deactivation of oxygen (1Δg) by solvent molecules. Comparative experiments with 16O2 and 18O2Ber. Bunsenges. Phys. Chem. 1992 96 788–794.
R. Schmidt and H. D. Brauer, Radiationless deactivation of singlet oxygen (1Δg) by solvent molecules J. Am. Chem. Soc. 1987 109 6976–6981.
C. Tanielian, G. Heinrich and A. Entezami, Quenching of singlet oxygen by hematoporphyrin derivative (and hematoporphyrin) and its consequences on the efficiency of photodynamic cancer therapy J. Chem. Soc., Chem. Commun. 1988 1197–1198.
Our values slightly deviate from the literature values that were determined for the allylic alcohols after reduction with NaBH4; see: K. H. Schulte-Elte, B. L. Muller and V. Rautenstrauch, Preference for syn ene additions of 1O2 to trisubstituted, acyclic olefins Helv. Chim. Acta 1978 61 2777–2783.
A. G. Griesbeck, M. Fiege, M. S. Gudipati and R. Wagner, Photooxygenation of 2,4-dimethyl-1,3-pentadiene: Solvent dependence of the chemical (ene reaction and [4 + 2] cycloaddition) and physical quenching of singlet oxygen Eur. J. Org. Chem. 1998 2833–2838.
P. H. Dussault and K. R. Woller, Approaches to stereoselective dioxygenation of alkenes: Chiral phosphite ozonides J. Org. Chem. 1997 62 1556–1559.
The corresponding chiral allylic alcohol (Z)-3-methyl-3-penten-2-ol has been reported as a probe for 1,2- vs. 1,3-allylic strain; see: W. Adam and B. Nestler, Z-3-methyl-3-penten-2-ol as stereochemical probe for 1,2- versus 1,3-allylic strain in the photooxygenation of chiral allylic alcohols Tetrahedron Lett. 1993 34 611–614.
By time-resolved infrared singlet oxygen phosphorescene in acetone solution; see: E. L. Clennan and K. Yang, Remote participation during photooxidation at sulfur. Evidence for sulfurane intermediates J. Org. Chem. 1992 57 4477–4487.
25-Fold lifetime increase from comparison of kd (CH3OH) = 1.1 × 105 s-1 (ref. 14) vs. kd (CD3OD) = 4.2 × 103 s-1: T. Aminian-Saghafi, G. Nasini, T. Caronna, A. M. Braun and E. Oliveros, Quantum yields of singlet oxygen production by some natural quinoid fungal metabolites and derivatives Helv. Chim. Acta 1992 75 531–538.
C. N. R. Rao, Effect of deuteration on hydrogen bonds J. Chem. Soc., Faraday Trans. 1 1975 71 980–983.
R. W. Hoffmann, Allylic 1,3-strain as controlling factor in stereoselective transformations Chem. Rev. 1989 89 1841–1860.
Author information
Authors and Affiliations
Corresponding author
Additional information
Dedicated to the memory of Professor Günther Otto Schenck, discoverer of the singlet oxygen ene reaction, deceased March 25th 2003.
Rights and permissions
About this article
Cite this article
Griesbeck, A.G., Adam, W., Bartoschek, A. et al. Photooxygenation of allylic alcohols: kinetic comparison of unfunctionalized alkenes with prenol-type allylic alcohols, ethers and acetates. Photochem Photobiol Sci 2, 877–881 (2003). https://doi.org/10.1039/b302255b
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1039/b302255b