由卤化物合成醛酮
由二卤甲基或二卤亚甲基合成醛酮
将二卤甲基或二卤亚甲基化合物在酸性或碱性条件下水解，则生成相应的醛酮。比如9，9-二溴芴在醋酸中，于醋酸钠存在下加热回流即可以良好的收率生成芴酮。
由二卤甲基合成醛反应示例：
p-Clorobenzalcloridewasaddedtoa4-l.wide-mouthedbottlecontainingcc.ofconcentratedsulfuricacid,andstirredvigorously(Hood)forfivehours.Theviscousmixtureisthentransferredtoaseparatoryfunnelandallowedtostandovernight,afterwhichthelowerlayerisrunslowly,withstirring,intoa3-l.beakerthree-quartersfilledwithcrackedice.Thecream-coloredsolidobtainedwhentheicehasmeltedisfilteredbysuction,washedwithwater,presseddryonthefunnel,anddividedintothreeequalparts.Eachportionisdissolvedinaminimumofether,andtheethersolutionisrepeatedlyshakenwith2percentsodiumhydroxidesolutionuntilacidificationofthewashingsgivesnoprecipitateofp-chlorobenzoicacid.Afterremovaloftheetherbydistillationonasteambath,theresidueisdistilledunderdiminishedpressurefromaClaisenflask.Theyieldofp-chlorobenzaldehydedistillingat–°/25mm.andmeltingat46–47°is76–84g.(54–60percentofthetheoreticalamount).
Reference:OrganicSyntheses,Coll.Vol.2,p.;Vol.12,p.12
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