Sarkomycin A methyl esters and functionalized cyclopentane blocks for brefeldin A were synthesized starting from diastereoisomeric (1R,2S)-and (1S,2R)-2-hydroxymethyl-N-[(1R)-1-phenylethyl]cyclopent-3-ene-1-carboxamides. III, V, VIII, R = α-OH; IV, VI, VII, R = β-OH. Chiral cyclopentene blocks are key synthons for the preparation of natural cyclopentanoids and their analogs [1-3]. We previously described [4] a practical procedure for the synthesis of individual vicinally functionalized diastereoisomeric cyclopentenes I and II which were used to develop rational synthetic approaches to enantiomeric cyclosarkomycins [5]. Up to now interest in sarkomycin A [6] and brefeldin A [7] as antimicrobial, anticancer, and antiviral antibiotics remains fairly strong. Studies are performed to improve methods of their synthesis [8-12], and new aspects of their application are revealed [13].In the present work we demonstrated the possibility of using compounds I and II as chiral templates by the synthesis of enantiomeric sarkomycin A methyl esters and most important cyclic precursors of brefeldin A. The structures of the target products and the retrosynthetic sequence starting from compounds I and II are shown in Scheme 1.We initially examined functionalization of the double bond in lactone IX which was obtained by acid hydrolysis of compound I in dioxane-9 N H 2 SO 4 [4]. However, seemingly promising approaches to blocks V-VIII directly from compound IX via epoxidationreduction to X, IV, and VI, reduction with BH 3 and oxidation to XI [14], and bromohydroxylation to XII and XIII turned out to be inappropriate; all these reactions led to the formation of isomer mixtures which