Stereochemistry of Chiral Sulfoxides used for the Synthesis of Antitumor Antibiotic Analogues of Sparsomycin

The structures of {[(S)-(4,5-dihydro-2-phenyloxazol-4-yl)methyl]-(S)-sulfinyl}octane, C₁₈H₂₇NO₂S, (2), {[(S)-(4,5-dihydro-2-phenyloxazol-4yl) methyl]-(R)-sulfinyl}octane, C₁₈H₂₇NO₂S, (3) and 4-{[(S)-(4,5-dihydro- 2-phenyloxazol-4yl)methyl]-(S)-sulfinyl}phenol, C₁₆H₁₅NO₃S, (5), have been determined. The known chirality (S) at the C10 atom in all three compounds enabled assignment of the absolute configuration at the S13 atom. The C10 chirality was subsequently confirmed by refinement of the Flack parameter. The absolute configuration at S13 for compounds (2), (3) and (5) is R, S and S, respectively. Comparison with the stereochemistry of sparsomycin enables proper choice of diastereomers for analogue development.

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