- A scalable chemoenzymatic preparation of (R)-tetrahydrofuran-2-carboxylic acid
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To develop a practical scalable approach to (R)-tetrahydrofuran-2-carboxylic acid (THFC) 1, a chiral building block for furopenem 2, enantioselective hydrolysis of its esters is explored: When ethyl (±)-tetrahydrofuran-2-carboxylate 3d (2 M, 288 g/L) is digested by an Aspergillus melleus protease {0.2% (w/v)} in a 1.5 M potassium phosphate buffer (pH 8) for 20 h, enantioselective hydrolysis proceeds with E=60 to give (R)-THFC 1 in 94.4% ee. On separation from the left-over antipodal ester (S)-3d by partition, (R)-THFC 1 is treated with N,N-dicyclohexylamine (DCHA) in methyl ethyl ketone/methanol (5:1) to precipitate the crystalline salt 4 that contains (R)-THFC 1 of >99% ee in 22% overall yield from (±)-3d.
- Fujima, Yoshito,Hirayama, Yoshihiro,Ikunaka, Masaya,Nishimoto, Yukifumi
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p. 1385 - 1391
(2007/10/03)
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- Syntheses of optically active 2-tetrahydrofuran derivatives
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The resolution of 2-tetrahydrofuran-carboxylic acid and assignment of configuration to the enantiomers are reported.New syntheses of the enantiomers of 2-tetrahydofurancarboxaldehyde are also described.
- Belanger, Patrice C.,Williams, Haydn W. R.
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p. 1383 - 1386
(2007/10/02)
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