9.2 Addition of Hydrogen Halides to alkenes Markovnikoy' s rule(马氏规则) What is it Mar's Rule?-----The addition of hx to an alkenes, the hydrogen atom adds to the carbon atom of the double bond that already has the greater number of hydrogen atoms
9.2 Addition of Hydrogen Halides to Alkenes: Markovnikov’s Rule (马氏规则） What is it Mar’s Rule?-----The addition of HX to an alkenes, the hydrogen atom adds to the carbon atom of the double bond that already has the greater number of hydrogen atoms
Markovnikov's rule(马氏规则) H2C=CHCH3 HX CH2CHCH3 H X Carbon atom with the Markovnikov addition product greater number of hydrogen atoms
H2C CHCH3 + H + X - CH2CHCH3 H X Markovnikov addition product Carbon atom with the greater number of hydrogen atoms Markovnikov’s Rule (马氏规则）
H2c CC +HCI一 CH2C(CH3)2(not CICH, CH(CH3)2 CH H C 2-Methylpropene tert-Butyl chloride Cl CH CH hcl H Methy cyclohexene I-Chloro-1-Methylcyclohexane
H2C CCH3 + HCl CH2C(CH3 ) 2 H Cl (not ClCH2CH(CH3 ) 2 CH3 2-Methylpropene tert-Butyl chloride CH3 + HCl Cl CH3 H Methylcyclohexene 1-Chloro-1-Methylcyclohexane
a mechanism for addition of a hydrogen halide to an alkene (two steps Slow Step l HX rate-determining rep fast Step 2 H X
A mechanism for addition of a hydrogen halide to an alkene (two steps;) Step 1 + HX Slow H + rate-determining step Step 2 H + + X - fast H X
9.2A Theoretical explanation of markovnikov's rule 1. Electronic effects(电子效应 H3C→c=CH2+H-Br CH3CHCH2H (not BrCH2 CHCH3) Br Methyl push electron Markovnikov addition product
9.2A Theoretical explanation of Markovnikov’s Rule C H CH2 + H-Br CH3CHCH2H Br Markovnikov addition product (not BrCH2CHCH3 H ) 3C − + − + H Methyl push electron 1. Electronic Effects (电子效应）