The crystal structures of six polybromo carvones

The crystal structures of six polybromo carvones have been determined by si ngle-crystal X-ray diffraction. These are the three previously reported iso meric tetrabromo carvones, (1S,3S,4R,8R)-1,3,8,9-tetrabromo-p-menthan-2-one (4), (1S,3S,4R,8S)-1,3,8,9-tetrabromo-p-menthan-2-one (5) and (1R,3S,4R,8R )-1,3,8,9-tetrabromo-p-menthan-2-one (12), two tribromo derivatives, (1S, 4 R, 8R)-1,8,9-tribromo-p-menthan-2-one (10) and (1S,4R, 8S)-1,8,9-tribromo- p-menthan-2-one (11) [all derived from (R)- carvone (1)], together with a p entabromo derivative, (1S, 3S, 4R, 6R, 8R)- 1,3,6,8,9- pentabromo-p-menthan -2-one (7) [derived from (S)-carvone ent-(1)]. In all examples, the stereoc hemistry agrees with that predicted from the synthetic pathway, while with one [the (1R, 3S, 4R, 8R)- tetrabromide (12)] a distorted twist-chair confo rmation is found.