(S)-Carvone (C₁₀H₁₄O) - R or S Configuration

Chiral Center Analysis

(S)-Carvone (C₁₀H₁₄O) contains 1 chiral center. The caraway seed enantiomer (R-carvone is spearmint). Like limonene, the chiral center is in a ring, but now C1 is a ketone (C=O). The ring path toward C=O outranks the CH₂ path because oxygen (8) beats carbon (6) at the third atom level.. Each chiral center is analyzed below using CIP (Cahn-Ingold-Prelog) priority rules to determine R or S configuration.

CIP Priority Assignment

The four substituents on the chiral center are ranked by atomic number of the directly attached atom, with ties broken by exploring outward along each branch.

• Priority 1: -C(=CH₂)CH₃ - Isopropenyl: C bonded to C, C, C (=CH₂ gives two phantom C atoms + CH₃) - three carbons at second level
• Priority 2: ring→C=O - Ring path toward C1(=O): at C6 has C,H,H → at C1 reaches O from ketone - oxygen (8) at third level wins
• Priority 3: ring→C=C - Ring path toward C3=C2: at C4 has C,H,H → at C3 reaches C=C - only carbon (6), loses to oxygen path
• Priority 4: H - Hydrogen always lowest (atomic number 1)

R/S Configuration

With the lowest priority group (priority 4) oriented away from the viewer, the remaining three substituents trace a counterclockwise path from priority 1 to 2 to 3. This gives the S configuration.

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