中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
4,5,5-三甲基-环己烷-1,3-二酮 | 5,5,6-Trimethyl-cyclohexan-1,3-dion | 18456-85-4 | C9H14O2 | 154.209 |
Treatment of the 3-halo-2-cyclohexen-1-ones 11–15 and 17 with an excess of lithium dimethylcuprate provided good to excellent yields of the corresponding 3,3-dimethylcyclohexanones 21–24. Similar reactions involving the β-bromo cyclopentenones 19 and 20 stopped at the monoaddition stage, producing the cyclopentenones 40 and 43. Reaction of the β-bromo cyclohexenones 12 and 15 with 1.1 equiv. of lithium dimethylcuprate did not effect clean conversion of these substrates into the corresponding 3-methyl-2-cyclohexen-1-ones. When a series of β-bromo enones 12, 14–19 were allowed to react with the lithium (phenylthio)(alkyl)cuprates 44–47, the corresponding β-alkyl enones were, in general, produced cleanly and efficiently. However, reaction of 3-bromo-2-methyl-2-cyclopenten-1-one (19) with the cuprate reagent 44 gave mainly the β-phenylthio enone 49. This undesired result could be avoided by employing, in the place of 19, the β-iodo cyclopentenone 50, which reacted smoothly with 44 to give a high yield of 2,3-dimefhyl-2-cyclopenten-1-one (40). Reaction of 3-bromo-2-cyclohexen-1-one (14) with 3 equiv. of the mixed vinylcuprate reagent 48 gave 3-(3-butenyl)-2-cyclohexen-1-one (32). Alkylation of 1,3-cyclopentanedione with (Z)-1-chloro-2-pentene afforded compound 51, which was converted into the β-bromo enone 52. Treatment of the latter substance with lithium dimethylcuprate provided (Z)-jasmone (53).