Absolute Configuration Determination of Two Optically Active Cyclopropyl-Ketoacids: (1′S, 3S) 3-(2′,2′-Dichloro-1′-methyl-cyclopropyl)-6-oxo-heptanoic acid and (1′S, 3S) 3-(2′,2′-Dibromo-1′-methyl-cyclopropyl)-6-oxo-heptanoic acid

Abstract

The title compounds C11H16Cl2O3 (III) and C11H16Br2O3 (IV) have been prepared from (S)-Limonen. Their crystal structure and absolute configuration have been determined by X-ray analysis which confirmed the 1′S absolute configuration at the cyclopropyl moiety, in agreement with the known absolute configuration of the starting material. Both (III) and (IV) are orthorhombic, space group P212121 with a = 7.2558(4) A (for III) 7.4058(6) A (for IV), b = 9.7885(5) A (for III) 9.7459(7) A (for IV), c = 17.7551(10) A (for III) 18.0354(14) A (for IV), α = 90°, β = 90°, γ = 90° and Z = 4. Absolute configuration determination, via an X-ray crystallographic study, of two optically active cyclopropyl-ketoacids.