厦门大学化学化工学院：《有机化学》课程教学资源（课件讲稿，双语版）Chapter 8 Alkenes and Alkynes II：（8.5-8.8）Halohydrin formation

ORGANIC CHEMISTRY Chapter 8 8.5 Addition of water to alkenes Acid-Catalyzed Hydration 烯烃与水的加成:酸催化水合反应 Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 8.5 Addition of Water to Alkenes: Acid-Catalyzed Hydration 烯烃与水的加成 酸催化水合反应

ORGANIC CHEMISTRY Chapter 8 OH HO C=C、+H-OH H H3 PO4 CH2=CH2+ H2O CH3,OH 300,70atm H3O (CH3)2C=CH2 H2O 25°C(CH3)2COH Mechanism H2O (CH3h2C=CH2 (CH3)3C20 (CH3)3C-OH HO CH33C-OH H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 C C + H OH H3O C C H OH CH2 CH2 + H2O 300 , 70 atm CH3CH2OH H3PO4 (CH3)2C CH2 + H2O H3O 25°C (CH3)3COH Mechanism (CH3)2C CH2 H3O (CH3)3C H2O (CH3)3C OH2 H2O H (CH3)3C OH

ORGANIC CHEMISTRY Chapter 8 One complication associated with alkene hydration is the occurrence of arrangements CH HoSO OH CH3 CH3-C-CH=CH H0 CH3-C-CH-CH3 CH CH The carbocation formed initially invariably rearrangement to a more stable one if such a rearrangement is possible CH3 CH3 Y H CH3-C-CH-CH CH -C-CH-Ch-Q CH CH H Y CH OH CH H2O CH3-C-CH-CH2 CH3C—CH-CH H CH3 H CH Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 One complication associated with alkene hydration is the occurrence of arrangements C CH CH2 CH3 CH3 CH3 H2SO4 H2O C CH CH3 CH3 OH CH3 CH3 The carbocation formed initially invariably rearrangement to a more stable one if such a rearrangement is possible. C CH CH2 CH3 CH3 CH3 C CH CH2 CH3 CH3 CH3 H C CH CH2 CH3 CH3 H CH3 H+ H2O C CH CH3 CH3 OH CH3 CH3 H

ORGANIC CHEMISTRY Chapter 8 Oxymercuration- demercuration(羟汞化-脱汞反应) 1)Hg(OAc)2, H2O CH CH (2)NabH4 OH92% OAc OAc Hg-oac Hg-oac HoO CH3 CH H Aco H Hg-oac CH3 NabH4 CH3 OH OH AcOH Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 Oxymercuration-demercuration(羟汞化-脱汞反应) CH3 (1) Hg(OAc)2, H2O (2) NaBH4 CH3 OH 92% CH3 CH3 OH Hg OAc OAc CH3 Hg H2O CH3 Hg OAc O H H CH3 Hg OAc OH AcO AcOH NaBH4 OAc

ORGANIC CHEMISTRY Chapter 8 Hydroboration- oxidation(硼氢化一氧化反应) BRCH=CH2 B2H6 (RCH2CH2)3B Hydroboration H,O2 (RCH2 CH2)3B BRCHCHOH OH Oxidation B(OH)3 2BH B2H6 B B Borane Diborane H 甲硼烷 乙硼烷 H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 Hydroboration–oxidation (硼氢化 氧化反应) 3RCH CH2 + B2H6 3RCH2CH2OH + B(OH)3 (RCH2CH2)3B (RCH2CH2)3B H2O2 OH Oxidation Hydroboration H B H H H B H H 甲硼烷 乙硼烷 2BH3 B2H6 Borane Diborane

ORGANIC CHEMISTRY Chapter 8 HI. B-h H,δ H H hEB--H H-B H CH H CH3 H CH H≈ B H HO H OH H H3C H HrC HH RCO,H H H3C Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 H H H H CH3 B H HH H CH3 B δ− δ+ δ+ H B H H CH3 H B H H H H H3C H2O2 OH HO H H H3C H H H H3C RCO2H

ORGANIC CHEMISTRY Chapter 8 (1)B2H6 CH2CHCH CH3 CH, CH,OH (2)H2O2/OH (1)B2H6 CH3 CH=CHCH,CH CH3CH-CH2 CH2CH (2)H2O2/OH OH CH3CH2CHCH2 CH3 OH (1)B2H6 (2)H202/OH HOT H H CH HO H (1)B2H6 H CH (2)H2O2/OH (±) Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 CH3CH CH2 (1) B2H6 (2) H2O2 / OH− CH3CH2CH2OH CH3CH CHCH2CH3 (1) B2H6 CH3CH CH2CH2CH3 CH3CH2 CHCH2CH3 OH OH + (+) (2) H2O2 / OH− (1) B2H6 (2) H2O2 / OH− H HO H CH3 (1) B2H6 (2) H2O2 / OH− H CH3 HO H (+)

ORGANIC CHEMISTRY Chapter 8 8.6 Addition of bromine and chlorine to Alkenes Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 8.6 Addition of Bromine and Chlorine to Alkenes

ORGANIC CHEMISTRY Chapter 8 CCI CI CI 4 ( CH3)3 CCH=CH2 Cl2 (CH3)3CCH—CH Br Br CCI ( CH3) CHCH=CHCH3 Br (CH3)2CHCH—CH2 Relative rate of bromination Compounds CH2-CH2 CH3CH=CH2(CH3)2C=CH2 Relative rate 2 10.4 (CH3h2C=C(CH3 PhCH=CH 14 3.4 Brch=cH CHo-CHCOH <0.04 <0.03 Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 (CH3)3CCH CH2 + Cl2 CCl4 5 (CH3)3CCH CH2 Cl Cl (CH3)2CHCH CHCH3 + Br2 CCl4 0 (CH3)2CHCH CH2 Br Br Relative rate of bromination CH2 CH2 CH3CH CH2 (CH3)2C CH2 (CH3)2C C(CH3)2 PhCH CH2 BrCH CH2 CH2 CHCO2H 1 2 10.4 14 3.4 < 0.04 < 0.03 Relative rate Compounds

ORGANIC CHEMISTRY Chapter 8 8.6A Mechanism of halogen Addition HoO CH2-CH2+ NaCl No reaction BrCHo Cho Br NaCl CH2-CH2 br2 BrChoChcl H,O BrCH CH2oH HoO CH2-CH2 Br2 2 BrCh CHOH Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 8 8.6A Mechanism of Halogen Addition CH2 CH2 + NaCl No reaction CH2 CH2 + Br2 CH2 CH2 + Br2 BrCH2CH2Br BrCH2CH2Cl BrCH2CH2OH BrCH2CH2OH H2O H2O NaCl H2O