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

摘要

The title compounds C_(11)H_(16)Cl_2O_3 (III) and C_(11)H_(16)Br_2O_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_12_12_1 with a = 7.2558(4) ? (for III) 7.4058(6) ? (for IV), b = 9.7885(5) ? (for III) 9.7459(7) ? (for IV), c = 17.7551(10) ? (for III) 18.0354(14) ? (for IV), α = 90°, β = 90°, γ = 90° and Z = 4.