A 4-step synthesis of an optically active synthetic intermediate [(1R, 2S)-2-(4′- fluorobenzylamino) cyclopentanecarboxylic acid ethyl ester complex with (S)-(+)-mandelic acid; compound 12,> 99% de] required for the preparation of a promising HCV NS5B polymerase inhibitor is reported. This process utilizes mandelic acid as a resolving agent, which can be recovered in good yield by a simple extraction. An optimized version of the ...