title: Synthesis of novel adamantyl and homoadamantyl-substituted β-hydroxybutyric acids.
abstract: Several new adamantyl and homoadamantyl-substituted [Formula: see text]-hydroxybutyric acids, 2-[2-(1-adamantyl)ethyl]-3-hydroxybutyric acid (2), 2-(3-homoadamantyl)-3-hydroxybutyric acid (3), and 2-(1-homoadamantyl)-3-hydroxybutyric acid (4), analogues of the 2-(1-adamantyl)-3-hydroxybutyric acid (1), have been prepared as mixtures of diastereoisomers using selective reduction of corresponding [Formula: see text]-keto esters or aldol condensation of the corresponding carboxylic acid and acetaldehyde. The rearrangement of adamantylmethyl and 3-homoadamantyl groups provided entry to both 3-homoadamantyl and 1-homoadamantyl-substituted hydroxy acids 3 and 4, respectively. The relative configurations of diastereoisomers 3 and 4 have been determined by NMR spectroscopy comparing the values of coupling constants. Adamantyl-substituted [Formula: see text]-hydroxybutyric acid 2 has also been prepared in enantiomerically pure form by Evan's asymmetric synthesis and the absolute configuration has been determined by X-ray crystallography. Contrary to the long-chain acid 2, the attempt to prepare short-chain hydroxy acids 1 and 4 by the same method failed indicating pronounced sensitivity of the used method to the vicinity of the bulky cage group.
authors.affiliation: Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 , Zagreb, Croatia.
authors.forename: Marija
authors.initials: M
authors.lastname: Matković
authors.forename: Stella
authors.initials: S
authors.lastname: Vukelić
authors.forename: Ružica
authors.initials: R
authors.lastname: Cirimotić
authors.forename: Goran
authors.initials: G
authors.lastname: Kragol
authors.forename: Krešimir
authors.initials: K
authors.lastname: Molčanov
authors.forename: Kata
authors.initials: K
authors.lastname: Mlinarić-Majerski
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000138:chemical synthesis* / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism
chemical_list: D020155:3-Hydroxybutyric Acid
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