Dioxolane is a heterocyclic acetal with the chemical formula (CH2)2O2CH2. It is related to tetrahydrofuran by interchange of one oxygen for a CH2 group. The corresponding saturated 6-membered C4O2 rings are called dioxanes. The isomeric 1,2-dioxolane (wherein the two oxygen centers are adjacent) is a peroxide. 1,3-Dioxolane is used as a solvent and as a comonomer in polyacetals.
1,3-dioxolane, formal glycol
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||74.08 g/mol|
|Melting point||−95 °C (−139 °F; 178 K)|
|Boiling point||75 °C (167 °F; 348 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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As a class of compoundsEdit
Organic compounds containing carbonyl groups sometimes need protection so that they do not undergo reactions during transformations of other functional groups that may be present. A variety of approaches to protection and deprotection of carbonyls including as dioxolanes are known. For example, consider the compound methyl cyclohexanone-4-carboxylate, where lithium aluminium hydride reduction will produce 4-hydroxymethylcyclohexanol. The ester functional group can be reduced without affecting the ketone by protecting the ketone as a ketal. The ketal is produced by acid catalysed reaction with ethylene glycol, the reduction reaction carried out, and the protecting group removed by hydrolysis to produce 4-hydroxymethylcyclohexanone.
NaBArF4 can also be used for deprotection of acetal or ketal-protected carbonyl compounds. For example, deprotection of 2-phenyl-1,3-dioxolane to benzaldehyde can be achieved in water in five minutes at 30 °C.
Neosporol is a natural product that includes a 1,3-dioxolane moiety, and is an isomer of sporol which has a 1,3-dioxane ring. The total synthesis of both compounds has been reported, and each includes a step in which a dioxolane system is formed using trifluoroperacetic acid (TFPAA), prepared by the hydrogen peroxide – urea method. This method involves no water, so it gives a completely anhydrous peracid, necessary in this case as the presence of water would lead to unwanted side reactions.
In the case of neosporol, a Prilezhaev reaction with trifluoroperacetic acid is used to convert a suitable allyl alcohol precursor to an epoxide, which then undergoes a ring-expansion reaction with a proximate carbonyl functional group to form the dioxolane ring.
A similar approach is used in the total synthesis of sporol, with the dioxolane ring later expanded to a dioxane system.
- 1,3-Dioxolane at Sigma-Aldrich
- formal glycol - PubChem Public Chemical Database
- R. A. Daignault, E. L. Eliel (1973). "2-Cyclohexyloxyethanol (involves acetalisation of cyclohexanone)". Organic Syntheses.; Collective Volume, 5, p. 303
- Greene, Theodora W.; Wuts, Peter G. M. (1999). "Dimethyl acetals". Greene's Protective Groups in Organic Synthesis (3rd ed.). Wiley-Interscience. pp. 297–304, 724–727. ISBN 9780471160199. Archived from the original on December 3, 2016. Retrieved June 20, 2017.
- Greene, Theodora W.; Wuts, Peter G. M. (1999). "1,3-Dioxanes, 1,3-Dioxolanes". Greene's Protective Groups in Organic Synthesis (3rd ed.). Wiley-Interscience. pp. 308–322, 724–727. ISBN 9780471160199. Archived from the original on December 7, 2016. Retrieved June 20, 2017.
- Chang, Chih-Ching; Liao, Bei-Sih; Liu, Shiuh-Tzung (2007). "Deprotection of Acetals and Ketals in a Colloidal Suspension Generated by Sodium Tetrakis(3,5-trifluoromethylphenyl)borate in Water". Synlett. 2007 (2): 283–287. doi:10.1055/s-2007-968009.
- Pirrung, Michael C.; Morehead, Andrew T.; Young, Bruce G., eds. (2000). "10. Neosporol, Sporol". Part B: Bicyclic and Tricyclic Sesquiterpenes. The Total Synthesis of Natural Products. 11. John Wiley & Sons. pp. 222–224. ISBN 9780470129630.
- Ziegler, Fredrick E.; Metcalf, Chester A.; Nangia, Ashwini; Schulte, Gayle (1993). "Structure and total synthesis of sporol and neosporol". J. Am. Chem. Soc. 115 (7): 2581–2589. doi:10.1021/ja00060a006.
- Caster, Kenneth C.; Rao, A. Somasekar; Mohan, H. Rama; McGrath, Nicholas A.; Brichacek, Matthew (2012). "Trifluoroperacetic Acid". e-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt254.pub2.
- Cooper, Mark S.; Heaney, Harry; Newbold, Amanda J.; Sanderson, William R. (1990). "Oxidation Reactions Using Urea–Hydrogen Peroxide; A Safe Alternative to Anhydrous Hydrogen Peroxide". Synlett. 1990 (9): 533–535. doi:10.1055/s-1990-21156.
- Hagen, Timothy J. (2007). "Prilezhaev reaction". In Li, Jie Jack; Corey, E. J. (eds.). Name Reactions of Functional Group Transformations. John Wiley & Sons. pp. 274–281. ISBN 9780470176504.