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Eastwood Olefination

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr204

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Eastwood Olefination. Comprehensive Organic Name Reactions and Reagents. 204:949–951.

Publication History

  1. Published Online: 15 SEP 2010

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Abstract

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References

Eastwood olefination reaction was initially reported by Grank and Eastwood in 1964. It is the stereospecific preparation of olefin from vicinal diol by means of the thermal decomposition of a five-membered cyclic orthoformate of the diol in the presence of a catalytic amount of acid (e.g., acetic acid). Therefore, this reaction is known as the Eastwood procedure or Eastwood deoxygenation procedure but is called Eastwood olefination in this work. It has been reported that using acetic anhydride as a solvent, the cyclic orthoformate can be converted into olefin in a high yield. This improvement is referred to as Ando's modification. The Eastwood olefination is especially helpful in the preparation of dideoxy nucleosides and nucleotides. Because acetic anhydride might cause the cleavage of the N-glycosyl bond, dideoxy thymidine has been prepared using hydrous zirconium oxide as the catalyst and tributylamine as the stabilizer.

1 General Description of the Reaction

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References

This reaction was initially reported by Grank and Eastwood in 1964. 1 It is the stereospecific preparation of olefin from vicinal diol by means of the thermal decomposition of a five-membered cyclic orthoformate of the diol in the presence of a catalytic amount of acid (e.g., acetic acid). Therefore, this reaction is known as the Eastwood procedure 2 or Eastwood deoxygenation procedure, 2, 3 but is called Eastwood Olefination in this book. It has been reported that using acetic anhydride as a solvent, the cyclic orthoformate can be converted into olefin in a high yield. 4 This improvement is referred to as Ando's modification. 3b The Eastwood olefination is especially good in the preparation of dideoxy nucleosides and nucleotides. 5 Because acetic anhydride might cause the cleavage of the N-glycosyl bond, 5 dideoxy thymidine has been prepared using hydrous zirconium oxide as the catalyst and tributylamine as the stabilizer. 3b

4 Modification

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References

The decomposition of cyclic orthoformate of vicinal diol has been carried out in acetic anhydride. 4

5 Applications

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References

This reaction has been applied in the preparation of olefin, dideoxy nucleosides, and nucleotides.

7 Cited Experimental Examples

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References
original image

Reference 5.

To a solution of 100 g uridine (410 mmol) in 250 mL trimethyl orthoformate was added 3.0 g p-toluenesulfonic acid monohydrate (15.8 mmol). The solution was stirred at room temperature for l6 h and then cooled to 10°C. Sodium methoxide in methanol (28%, 3.39 g, 17.6 mmol) and 100 mL toluene was added, and the resulting mixture was stirred for 1 h at 10°C. The reaction mixture was filtered, and the separated crystal was washed with 100 mL toluene and dried to yield 113.6 g 2′,3′-O-(methoxymethylene) uridine as a white crystal, in a yield of 96%. inline image (CHCl3/MeOH = 10/1).

A solution of 5.0 g 2′,3′-O-(methoxymethylene) uridine (17.5 mmol) in 50 mL acetic anhydride was stirred for 3 h at 132°C. The reaction mixture was cooled to room temperature and evaporated. Chloroform (50 mL) was added, and the mixture was washed with 50 mL aqueous NaHCO3. Aqueous layer was extracted with 50 mL CHCl3, and the combined organic layers were dried over Na2SO4, concentrated, and purified by silica gel column chromatography (CHCl3/MeOH, 10:1) to give 1.87 g 1-(5-O-acetyl-2′,3′-dideoxy)-β-d-glycero-pent-2-enofuranosyl)uracil, in a yield of 42%, m.p. 128–128.5°C (recrystallized from EtOH).

Other references related to the Eastwood olefination are cited in the literature. 6

References

  1. Top of page
  2. General Description of the Reaction
  3. General Reaction Scheme
  4. Proposed Mechanisms
  5. Modification
  6. Applications
  7. Related Reactions
  8. Cited Experimental Examples
  9. References