(3S*,4S*,E)-tert-Butyl 3,4-dibromo-5-oxo­cyclo­oct-1-ene­carboxyl­ate

The title compound, C₁₃H₁₈Br₂O₃, was prepared by a bromination reaction of (1E,3Z)-methyl 5-oxocyclo­octa-1,3-diene­carboxyl­ate, which was obtained by an ep­oxy­dation reaction of tert-butyl cyclo­oct-1,3-diene­carboxyl­ate. The crystal structure confirms unequivocally the absolute configuration of both chiral centres to be S. In the crystal, C—H...O inter­actions link the mol­ecules into chains running along the c axis.

(2R,3S,4R)-3,4-Isopropyl­idenedi­oxy-2-(phenyl­sulfonyl­meth­yl)pyrrolidin-1-ol

The title compound, C₁₄H₁₉NO₅S, was prepared by nucleophilic addition of the lithium derivative of methyl­phenyl­sulfone to (3S,4R)-3,4-isopropyl­idene­dioxy­pyrroline 1-oxide. There are four mol­ecules in the asymmetric unit. The crystal structure determination confirms the configuration of the chiral centres as 2R,3S,4R. In the crystal, pairs of O—H...N hydrogen bonds link the mol­ecules into dimers.