2,3-Butanediol: What are its properties and applications? 2,3-Butanediol, also known as 2,3-butanediol, is a colorless liquid with a molecular formula of C4H10O2 and a molecular weight of 90.12. It has a boiling point of 179-182 oC and a density of 0.99 g/cm3. It is slightly soluble in water, ethanol, ether, and acetone. When handling 2,3-butanediol, it is important to avoid inhalation and contact with eyes, skin, and clothing. It is hygroscopic and sensitive to air. It should be stored in a dry and cool place under nitrogen protection. What are the applications of 2,3-butanediol? Chiral Separation Pure tartaric acid derivatives of 2,3-butanediol exhibit optical activity and are widely used in asymmetric synthesis. Non-racemic mixtures of aldehydes derived from (2R,3R)-(-)-2,3-butanediol can be easily separated [1]. The reaction of di-ketones with (2R,3R)-(-)-2,3-butanediol under acid-catalyzed mono-aldehyde formation produces a separable non-racemic mixture of aldehydes (Equation 1) [2]. Reaction of Asymmetric Butenolides Under the action of tin(IV) chloride, aldehydes derived from (2R,3R)-(-)-2,3-butanediol react with α-silyl carbonyl compounds to generate the corresponding butenolides with high enantiomeric excess (Equation 2) [3]. The products can be converted to optically active β-hydroxy ketones with a total yield of 70% through Swern or pyridinium chlorochromate oxidation, Baeyer-Villager oxidation, and methanol hydrolysis. The reaction of asymmetric butenolides can also be catalyzed by boron trifluoride. Non-racemic nucleophilic addition (2R,3R)-(-)-2,3-butanediol exhibits poor stereoselectivity in the reaction with Grignard reagents, but it shows good enantiomeric excess when reacted with lithium aluminum hydride (Equation 3) [4]. Asymmetric Diels-Alder Reaction The chiral diol aluminum complex prepared from ethylaluminum dichloride and 2,3-butanediol catalyzes the Diels-Alder reaction between isobutene aldehyde and cyclopentadiene with good yield but low enantiomeric excess. The catalyst prepared from (S)-1,1-diphenyl-1,2-dihydroxypropane shows better results with an enantiomeric excess of 74% [4]. The non-racemic stereoselectivity of 2,3-butanediol in the Simmons-Smith cyclopropanation reaction with 2-cyclohexen-1-one is good, resulting in a high enantiomeric excess (Equation 4) [5]. Synthesis of Sulfonic Esters Reaction of diols with SOCl2 produces cyclic sulfonic esters (Equation 5), which can be used in the synthesis of anthracene derivatives [6]. Protection of Carbonyl Groups (2R,3R)-2,3-butanediol can be used for the protection of carbonyl groups (Equations 6 and 7) [7]. References 1. Zibuck, R.; Liverton, N. J.; Smith, A. B. J. Am. Chem. Soc.,1986, 108, 2451. 2. Duthaler, R. O. L.; Maienfisch, P. Helv. Chim. Acta., 1982, 65,635. 3. (a) Yanagiya, M.; Matsuda, F.; Hasegawa, K.; Matsumoto, T.Tetrahedron Lett., 1982, 23, 4039. (b) Matsumoto, T.;Matsuda, F.; Hasegawa, K.; Yanagiya, M. Tetrahedron, 1984,40, 2337. 4. Rebiere, G.; Riant, O.; Kagna, H. B. Tetrahedron: Asymmetry,1990, 1, 199. 5. Schurig, V.; Hintzer, K.; Leyrer, U.; Mark, C.; Pitchen, P.;Kagan, H. B. J. Organomet. Chem., 1989, 81. 6. Nakagawa, H.; Sei, Y.; Yamaguchi, K.; Nagano, T.; Higuchi,T. J. Med. Chem., 2004, 219, 221. 7. Bernard, A. M.; Floris, C.; Frongia, A.; Piras, P. P.; Secci, F.Tetrahedron, 2004, 60, 449. 查看更多
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