作者:Yoshito Fujima、Yoshihiro Hirayama、Masaya Ikunaka、Yukifumi Nishimoto
DOI:10.1016/s0957-4166(03)00249-0
日期:2003.5
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. (C) 2003 Elsevier Science Ltd. All rights reserved.