Solketal is a protected form of

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids know ...

with an isopropylidene acetal group joining two neighboring

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydrox ...

groups. Solketal contains a chiral center on the center carbon of the glycerol backbone, and so can be purchased as either the

racemate In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

or as one of the two

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

s. Solketal has been used extensively in the synthesis of mono-, di- and tri

glyceride Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids, and are generally very hydrophobic. Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids ...

s by ester bond formation. The free hydroxyl groups of solketal can be

esterified In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...

with a carboxylic acid to form the protected monoglyceride, where the isopropylene group can then be removed using an acid catalyst in aqueous or alcoholic medium. The unprotected

diol A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. The most common industrial diol is ...

can then be esterified further to form either the di- or triglyceride.

References

* * * * {{cite journal , journal = Tetrahedron , volume = 52 , pages = 9387 , year = 1996 , doi = 10.1016/0040-4020(96)00501-7 , title = Selective cleavage of ethers using silica-alumina gel catalysts prepared by the sol-gel method , last1 = Matsumoto , first1 = Yoshihiko , last2 = Mita , first2 = Keisuke , last3 = Hashimoto , first3 = Keiji , last4 = Iio , first4 = Hideo , last5 = Tokoroyama , first5 = Takashi , issue = 28 Ketals Primary alcohols