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

AbstractThe title compounds C 11 H 16 Cl 2 O 3 (III) and C 11 H 16 Br 2 O 3 (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 P2 1 2 1 2 1 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.Graphical AbstractAbsolute configuration determination, via an X-ray crystallographic study, of two optically active cyclopropyl-ketoacids.[IMAGE]