Abstract: The invention comprises a multi-step synthesis of l(-) prostaglandin E.sub.2. The special features of the synthesis include: (1) a triply-convergent conjugate-addition and alkylation reaction involving the 1,4-addition of a chiral vinyl lithium reagent to a chiral vinylsulfone to produce a sulfone-stabilized anion. This anion is alkylated in situ to produce the basic prostaglandin skeleton structure, which is then subjected to (2) an efficient peracid oxidation of a secondary amine to a .beta.-silyloxy oxime; and (3) an alkali-catalyzed 1,4-elimination of an .alpha.-sulfonyl oxime to produce a vinyl nitroso intermediate. This intermediate is treated with borohydride to give a stereospecific 1,4-reduction which yields the bis-silyloxy oxime of l(-)PGE.sub.2. Hydrolysis of the oxime, with concurrent cleavage of the silyloxy protecting groups, affords l(-)PGE.sub.2.