有机化学 Chapter 14 organometal.ppt

Chapter 14Organometallic CompoundsWhat is organometallic compound? Organometallic compounds are compounds that have a carbon-metal bond.Organometallic compounds are powerful sources of nucleophiles.§14.1 §14.1 OrganometallicOrganometallic nomenclaturenomenclature Organometallic compounds are named as substituted derivatives of metals : The metal is the base name, and the attached alkyl groups are indentified by the appropriate prefix.Example:二乙基镁环丙基锂When the metal bears a substituent other than carbon, the substituent is treated as if it were an anion and named separately:?碘化甲基镁氯化二乙基铝§14.2 Carbon-Metal bonds §14.2 Carbon-Metal bonds in in organometallicorganometallic compoundscompoundsØIonic carbon-metal bond:Organosodium, organopotassium, …ØCovalent carbon-metal bond:Organolithium, organomagnesium, …ØIt is the carbanionic character of covalent organo- metallic compounds (referred to as a carbanion) that is responsible for their usefulness as synthetic reagents.Carbanion- Nucleophile (碳负离子－亲核试剂）§14.3 Preparation of §14.3 Preparation of organometallicorganometallic compounds compoundsA, Organolithium compoundsB, Organomagnesium compounds(Grignard reagent)Aryl and vinyl chlorides don’t form Grignard reagents in diethyl ether. However, when THF is used as the solvent, they are okay.§14.4 §14.4 OrganolithiumOrganolithium & & organomagnesiumorganomagnesium compounds as compounds as BrBrø ønstednsted bases basesu Organolithium and organomagnesium compounds are stable speciesu They are strongly basic, and react instantly with proton donors even alcohol and water§14.5 Synthesis of alcohol using §14.5 Synthesis of alcohol using Grignard reagents Grignard reagentsExample:酸水解注意事项：p使用稀或弱酸水溶液，如稀硫酸，稀盐酸，饱 和氯化铵水溶液等。

p水解条件宜温和（通常在室温下），防止产物 醇发生脱水副反应A, Preparation of primary alcoholsB, Preparation of secondary alcoholsC, Preparation of tertiary alcoholsExample§14.6 Synthesis of §14.6 Synthesis of acetylenicacetylenic alcohols alcoholsu Preparation of sodium alkynide炔钠是一种好的亲核试剂，可以和羰基化合物发 生反应，生产相应的加成产物u Preparation of alkynyl alcohols（炔基醇 ）u Acetylenic alcohols can be also prepared by using acetylenic Grignard reagents:§14.6 §14.6 Organocopper reagents in organic synthesis1. Preparation of the lithium dialkylcuprates2. Alkane synthesis ØPrimary alkyl halides, especially iodides, are the best substratesØSecondary and tertiary halides encounter elimination side reactionUnreactive vinyl and aryl halides react with lithium dialyklcuprates in good yield:3. Lithium dialkylcoprates in conjugate addition Where there is no steric interference, and an alkyl Grigand reagent is used, 1,2-addition is predominated.However, conjugate addition(1,4-adddition) is principal in the presence of a copper(I) salt: Also, Lithium dialkylcoprates undergo conjugate addition to 1,4-unsaturated carbonyl compounds.Examples:。