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Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding four hydrogens. In 2013, its preferred IUPAC name was established as oxane.[1] The compound is a colourless volatile liquid, but is obscure. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and 3,4-dihydropyran are commonly used as protecting groups in organic synthesis.[2] Furthermore, a tetrahydropyran ring system, i.e., five carbon atoms and an oxygen, is the core of pyranose sugars, such as glucose. In gas phase, the THP exists in its lowest energy Cs symmetry chair conformation.[3]

Tetrahydropyran
Tetrahydropyran
THP
Names
IUPAC name
Oxane
Other names
Tetrahydropyran,
Oxacyclohexane
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
DrugBank
ECHA InfoCard 100.005.048
KEGG
UNII
Properties
C5H10O
Molar mass 86.13 g·mol−1
Density 0.880 g/cm3
Melting point −45 °C (−49 °F; 228 K)
Boiling point 88 °C (190 °F; 361 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Contents

PreparationEdit

One classic procedure for the organic synthesis of tetrahydropyran is by hydrogenation of the 3,4-isomer of dihydropyran with Raney nickel.[4]

ReactionsEdit

In organic synthesis, the 2-tetrahydropyranyl group is used as a protecting group for alcohols.[5][6] Reaction of the alcohol with 3,4-dihydropyran forms a 2-tetrahydropyranyl ether, protecting the alcohol from a variety of reactions. The alcohol can later be restored readily by acidic hydrolysis with formation of 5-hydroxypentanal.[2]

 

Alcohol protectionEdit

In organic synthesis, 2-tetrahydropyranyl group (THP) is used as a protecting group for alcohols by the formation of THP ethers.

Most common protection methodsEdit

 
THP protection used in the total synthesis of solandelactone E[7]

Most common deprotection methodsEdit

See alsoEdit

  • Pyran
  • Dioxane and Trioxane, which have two and three oxygen atoms as part of their six-membered rings respectively

ReferencesEdit

  1. ^ "New IUPAC Organic Nomenclature - Chemical Information BULLETIN" (PDF).
  2. ^ a b c Wuts, Peter G. M.; Greene, Theodora W. (2006). "Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols". Greene's Protective Groups in Organic Synthesis (4th ed.). pp. 16–366. doi:10.1002/9780470053485.ch2. ISBN 9780470053485.
  3. ^ Builth-Williams, J. D.; Bellm, S. M.; Chiari, L.; Thorn, P. A.; Jones, D. B.; Chaluvadi, H.; Madison, D. H.; Ning, C. G.; Lohmann, B. (2013). "A dynamical (e,2e) investigation of the structurally related cyclic ethers tetrahydrofuran, tetrahydropyran, and 1,4-dioxane" (PDF). Journal of Chemical Physics. 139 (3): 034306. doi:10.1063/1.4813237.
  4. ^ Andrus, D. W.; Johnson, John R. (1943). "Tetrahydropyran". Organic Syntheses. 23: 90. doi:10.15227/orgsyn.023.0090.; Collective Volume, 3, p. 794
  5. ^ Earl, R. A.; Townsend, L. B. (1981). "Methyl 4-Hydroxy-2-butynoate". Organic Syntheses. 60: 81. doi:10.15227/orgsyn.060.0081.; Collective Volume, 7, p. 334
  6. ^ Kluge, Arthur F. (1986). "Diethyl [(2-Tetrahydropyranyloxy)methyl]phosphonate". Organic Syntheses. 64: 80. doi:10.15227/orgsyn.064.0080.; Collective Volume, 7, p. 160
  7. ^ Robinson, Anna; Aggarwal, Varinder K. (2010). "Asymmetric Total Synthesis of Solandelactone E: Stereocontrolled Synthesis of the 2-ene-1,4-diol Core through a Lithiation–Borylation–Allylation Sequence". Angewandte Chemie International Edition. 49 (37): 6673–6675. doi:10.1002/anie.201003236.