FIELD: organic chemistry. SUBSTANCE: product - stereospecific penem of the formula (I) (image) where R - allyl, (trimethylsilyl)-ethyl; R1 - silyl-protective group; R2 - -C1-C4-alkyl, 2-hydroxyethyl, 2-(p-nitrobenzylcarbonylamino)-ethyl, 1-(p-nitrobenzylhydroxycarbonyl)-3S-pyrrolidinyl, 1R-oxo-3S-thiolanyl or 1,1-dioxo-3R- and 3S-thiolanyl. Reagent 1: compound of the formula (II) (image). Reagent 2: Ag(NO2)2. Reaction conditions: in the presence of pyridine with successive treatment of product with H2S, p-nitrophenylchloroformate, hexamethyldisilylamide lithium, trifluoromethanesulfoacid anhydride, HSR2 where R, R1, R2 as indicated above. EFFECT: improved method of synthesis.
