Singlet Oxygen

Introduction

Like molecular oxygen ( [³] O₂), singlet oxygen ( [¹] O₂) plays an important role in atmospheric and biological processes. It is also a powerful and inexpensive organic reagent whose chemistry has been initiated by Foote and co-workers in the 1960’s (Figure  [¹] ). [¹]

Figure 1 Triplet (³O2) and singlet (¹O2) oxygen

Singlet oxygen can be synthesized by several ways. The oldest and simplest method consists in a mixture of hydrogen peroxide and sodium hypochlorite to form singlet oxygen, water and sodium chloride (Scheme  [¹] ). [²]

Scheme 1 Synthetic ways for the formation of ¹O2

The currently most widely used method is the use of triplet oxygen in the presence of light and a sensitizer (e.g., rose bengal, methylene blue, tetraphenylporphyrin, vide infra).

Storable singlet oxygen sources can also been used. For example, [¹] O₂ can be obtained thanks to a mixture of tri­phenyl phosphite and ozone (O₃) (via the formation of an ozonide intermediate), [³] the use of calcium peroxide diperoxohydrate (CaO₂˙2H₂O₂), [4] or the use of 9,10-diphenyl­anthracene peroxide [5] and its water soluble analogue 1,4-endoperoxide of 3-(4-methyl-1-naphthyl)propionic acid. [6]

The reactions involving singlet oxygen are usually oxidations or addition reactions that afford clean reactions which are consistent with the concept of atom economy. [7] In this spotlight a special emphasis has been made for illustrating different types of organic reactions in the context of the total synthesis of natural products.

References

• 1a Foote CS. Acc. Chem. Res.  1968,  1:  104 
• 1b Wasserman HH. DeSimone RW. Singlet Oxygen In Encyclopedia of Reagents for Organic Synthesis   Parquette LA. John Wiley & Sons Ltd.; New York: 2005.  p.4478-4484  
• 1c For recent advances in singlet oxygen chemistry, see: Clennan EL. Pace A. Tetrahedron  2005,  61:  6665 
• 2 Greer A. Acc. Chem. Res.  2006,  39:  797 
• 3 Schaap AP. Bartlett PD. J. Am. Chem. Soc.  1970,  92:  6055 
• 4 Pierlot C. Nardello V. Schrive J. Mabille C. Sombret B. Aubry J.-M. J. Org. Chem.  2002,  67:  2418 
• 5 Wasserman HH. Scheffer JR. Cooper JL. J. Am. Chem. Soc.  1972,  94:  4991 
• 6 Saito I. Matsuura T. Inoue K. J. Am. Chem. Soc.  1981,  103:  188 
• 7a Trost BM. Science  1991,  254:  1471 
• 7b Trost BM. Angew. Chem. Int. Ed.  1995,  34:  259. 
• 8 Ohkubo K. Nanjo T. Fukuzumi S. Bull. Chem. Soc. Jpn.  2006,  79:  1489 
• 9a Clennan EL. Acc. Chem. Res.  2001,  34:  875 
• 9b Tsuboi T. Takaguchi Y. Tsuboi S. Chem. Commun.  2008,  76: 
• 10For a recent review, see:
• 10 Matsumoto MJ. Photochem. Photobiol., C  2004,  5:  27;  and references therein
• For representative examples, see:
• 11a Bronstein I. Voyta JC. Thorpe GHG. Kricka LJ. Armstrong G. Clin. Chem.  1989,  1441 
• 11b Sabelle S. P Y. Pecorella K. de Suzzoni-Dezard S. Creminon C. Grassi J. Mioskowski C. J. Am. Chem. Soc.  2002,  124:  4874 
• 11c Richard J.-A. Jean L. Romieu A. Massonneau M. Noack-Fraissignes P. Renard PY. Org. Lett.  2007,  9:  4853 
• 12 Nicolaou KC. Gunzner JL. Shi GQ. Agrios KA. Gartner P. Yang Z. Chem. Eur. J.  1999,  5:  646 
• 13For a review, see:
• 13 Leach AG. Houk KN. Chem. Commun.  2002,  1243 
• 14a Vassilikogiannakis G. Stratakis M. Angew. Chem. Int. Ed.  2003,  42:  5465 
• 14b Vassilikogiannakis G. Margaros I. Montagnon T. Org. Lett.  2004,  6:  2039 
• 14c Vassilikogiannakis G. Margaros I. Montagnon T. Stratakis M. Chem. Eur. J.  2005,  11:  5899 
• 14d Montagnon T. Tofi M. Vassilikogiannakis G. Acc. Chem. Res.  2008,  41:  1001 
• 15For a review, see:
• 15 Stratakis M. Orfanopoulos M. Tetrahedron  2000,  56:  1595 
• 16 Baran PS. Guerrero CA. Corey EJ. J. Am. Chem. Soc.  2003,  125:  5628