ORGANIC CHEMISTRY Chapter 12 12.5 Organometallic Compounds 有机金属化合物 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.5 Organometallic Compounds 有机金属化合物
ORGANIC CHEMISTRY Chapter 12 o Compounds that contain carbon-metal bond are called organometallic compounds -C: M Primarily ionic Primarily covalent (M=Na or K)(=Mg or Li)(M=Pb, Sn, Hg, or TD) o The reactivity of organometallic compounds increases with the percent ionic character of the carbon-metal bond o Rli and rmgX are of great importance in organic syntheSIs Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 Compounds that contain carbon-metal bond are called organometallic compounds. C M C M δ− δ+ C M Primarily ionic Primarily covalent (M = Na+ or K+ ) (M = Mg or Li) (M = Pb, Sn, Hg, or Tl) The reactivity of organometallic compounds increases with the percent ionic character of the carbon-metal bond. RLi and RMgX are of great importance in organic synthesis
ORGANIC CHEMISTRY Chapter 12 12.6 Preparation of Organolithium and Organomagnesium Compounds 有机锂和有机镁化合物的制备 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.6 Preparation of Organolithium and Organomagnesium Compounds 有机锂和有机镁化合物的制备
ORGANIC CHEMISTRY Chapter 12 12. 6A Organolithium Compounds o Organolithium compounds are often prepared by th reduction of organic halides with lithium metal R-X+2Li Eto RLI LiX or ar-X (or Arli Reactivity: RI>RBr> RcI Et,o CHr CH,CH, CH2 Br 2 Li CH2CHCH CHoLi + LiBr 口10°C Butyl bromide Butyllithium (80~909%) Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.6A Organolithium Compounds Organolithium compounds are often prepared by th reduction of organic halides with lithium metal. R X + 2 Li RLi + LiX (or Ar X ) (or ArLi) Et2O Reactivity: RI > RBr > RCl CH3CH2CH2CH2Br + 2 Li Et2O 10°C CH3CH2CH2CH2Li + LiBr Butyl bromide Butyllithium (80 ~ 90%)
ORGANIC CHEMISTRY Chapter 12 12.6B Grignard Reagents o Grignard reagents are usually prepared by the reaction of an organic halide and magnesium metal in an ether solvent Eto R-X + Mg RMgX G orignal Et,o or thf reagents Ar-X+ Mg ArMeX Et,o CH3-I Mg CH2Mgl 35°C ethylmagnesium iodide THE C6H5-CI+ M g-△ CkHsMeCI Phenylmagnesium chloride Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.6B Grignard Reagents Grignard reagents are usually prepared by the reaction of an organic halide and magnesium metal in an ether solvent. R X Ar X + Mg Et2O RMgX + Mg Et2O or THF ArMgX Grignard reagents CH3 I + Mg Et2O CH3MgI 35°C Methylmagnesium iodide C6H5 Cl + Mg THF C6H5MgCl Phenylmagnesium chloride
ORGANIC CHEMISTRY Chapter 12 12. 7 Reactions of Organolithium and Organomagnesium Compounds Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.7 Reactions of Organolithium and Organomagnesium Compounds
ORGANIC CHEMISTRY Chapter 12 12.7A Reactions with Compounds Containing Acidic hydrogen Atoms o Grignard reagents and organolithium compounds are very strong bases. They react with any compounds that has a hydrogen attached to an electronegative atom such as oxygen, nitrogen, or sulfur HOH RH HO+ Mgt+X ROH RMgX RH+RO Mg+ X R'C≡CH RH+RC≡CMgx δ-8 RLi+RC≡CH—-RH+RC≡CL Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.7A Reactions with Compounds Containing Acidic Hydrogen Atoms Grignard reagents and organolithium compounds are very strong bases. They react with any compounds that has a hydrogen attached to an electronegative atom such as oxygen, nitrogen, or sulfur. RMgX R'C CH HOH R'OH RH RH RH + + + HO + Mg2+ + X R'O + Mg2+ + X R'C C MgX δ− δ+ RLi + R'C CH R'C C Li δ− δ+ RH +
ORGANIC CHEMISTRY Chapter 12 12. 7B Reactions of Grignard Reagents with Oxiranes(epoxides) 0O +_.ht RMgX+H2C—CH2—-RCH2CH2OMgX RCH2 CH2OH (1)Et2O CH5MgBr+HC—CH CkHCHoCHOH 2(2)H2OH (lEtO C6 Hs MgBr+H2C—CH-CH3 CkHsCHoCHCH (2)H2O/H OH Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.7B Reactions of Grignard Reagents with Oxiranes (Epoxides) RMgX + H2C CH2 O RCH2CH2O MgX H+ RCH2CH2OH C6H5MgBr + H2C CH2 O C6H5CH2CH2OH (1) Et2O (2)H2O/H+ C6H5MgBr + H2C CH O CH3 (1) Et2O (2)H2O/H+ C6H5CH2CHCH3 OH
ORGANIC CHEMISTRY Chapter 12 12. 7C Reactions of Grignard Reagents with Carbonyl Compounds (1)Et2O RMgX +C=O R-C-OH Mgx2 (2)H2O/H Mechanism R:MgX+C0→→R-C-0MgX R-C-o MgX +H-o-H R-C-OH +0-H+ MgX H Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.7C Reactions of Grignard Reagents with Carbonyl Compounds RMgX + C O (1) Et2O (2)H2O/H+ R C OH + MgX2 Mechanism Mechanism R MgX+ C O δ− δ+ R C O MgX R C O MgX H O H H + R C OH O H H + + MgX
ORGANIC CHEMISTRY Chapter 12 12.8 Alcohols from Grignard Reagents Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 12 12.8 Alcohols from Grignard Reagents