A facile, six-step process for the synthesis of (3S,5S)-3-isopropyl-5-((2S,4S)-4-isopropyl-5-oxotetrahydro- furan-2-yl)-2-oxopyrrolidine-1-carboxylic acid tert-butyl ester from (S)-4-benzyloxazolidin-2-one 2 in an overall 50% yield is reported. The key transformations include: a highly efficient diastereoselective epoxidation, Lewis acid-catalyzed ring-opening with bromide, an SN2 reaction using NaN3, and a tandem reduction–cyclization reaction.

Sitagliptin phosphate, a novel DPP-IV inhibitor of T2DM, has been synthesized via 12 linear steps, in an overall yield of 26%. The key step is the coupling reaction of 2,4,5-trifluorophenylmagnesium bromide with a chiral aziridine derivative, which was prepared from l-homo-serine by simple steps.

An efficient synthesis of prasugrel, a novel P2Y12 receptor inhibitor, is described. The cyclopropyl-phenylethanone intermediate was prepared by cyanide substitution, bromination, N-substitution, and the Grignard reaction. After acid hydrolyzation of the methyl ether and subsequent acetylation, the title product was obtained with a total yield of 21% after 10 linear steps from simple and commercially available raw materials.