Syntheses of optically active 2-tetrahydrofuran derivatives

Abstract

The resolution of 2-tetrahydrofuran-carboxylic acid and assignment of configuration to the enantiomers are reported. New syntheses of the enantiomers of 2-tetrahydrofurancarboxaldehyde are also described.

Complete Retention of Configuration in a Cobaloxime π-Cation-Mediated Cyclization of an (ω-Hydroxy-β-hydroxyalkyl)cobaloxime

“…In addition to the configuration information reported in refs and , an X-ray crystal structure of the brucine salt used for the resolution of 11 was obtained. The X-ray crystal structure confirmed the configuration shown.…”

“…To determine this it was necessary to obtain an authentic sample of either ( R )- 10 or ( S )- 10 by an independent method (Scheme ). Enantioenriched tetrahydyro-2-furoic acid ( R )- 11 was obtained through a brucine resolution . Borane reduction of ( R )- 11 using BH 3 ·SMe 2 in THF gave ( R )- 12 in moderate yield .…”

Applications of Heterogeneous Catalytic Processes to the Environmentally Friendly Synthesis of Fine Chemicals

“…Chiral tetrahydro-2-furoic acids are used as intermediates for anti-obesity, and anti-hypertensive and proline dehydrogenase drugs [80,81]. (S)-tetrahydro-2-furoic acid (THFA) can be prepared by chemical resolution of racemic THFA using very expensive (+)-ephedrine with the overall yield of 12%.…”

Regeneration of Carbonyl Compounds from the Corresponding Oximes

“…41 (S)-Tetrahydrofurancarboxaldehyde was obtained from the corresponding oxime in good yield by titanium trichloride, citric acid monohydrate and concentrated ammonium hydroxide. 189 The titanium tetrachloride/sodium iodide 190 (TiCl 4 /NaI) system generating low-valent titanium (LVT) is a mild, efficient and selective reagent, which operates the reductive cleavage of oximes to afford the corresponding carbonyl compounds (Table 39).…”