rac-2-tert-Butyl-2,4,5,6,6-penta-chloro-cyclo-hex-3-en-1-one.

The title compound, C(10)H(11)Cl(5)O, is a chiral mol-ecule with two stereogenic centres. However, it crystallizes as a racemate. One of enanti-omers reveals the relative configuration (2S*,5R*). The cyclo-hexene ring adopts a half-chair conformation.