CHCl CH CH3 hv△ F f C1(0-or p-)
CH2Cl CH 3 Cl 2 hv Fe CH3 C l ( o - o r p-) Cl 2
Addition reaction of alkene with hX or X ive markovnikov product anti addition of bromine or chlorine H CHe CHo H CH. X=Cl or B X=CL Br. or I tHomson· Brooks Cole
• give Markovnikov product • anti addition of bromine or chlorine Addition reaction of alkene with HX or X2
Allylic bromination of Alkenes HH Br N一Br(NBS) Allylic positions + N一H hu ccl HH 0 Cyclohexene 3-Bromocyclohexene (85%) Thomson· Brooks cole
Allylic Bromination of Alkenes p.114
Allylic stabilization Allyl radical is delocalized p1i Allylic radical is more stable than tertiary alkyl radical H H R R CH—C.R-C R-C. R一C C H H H R Vinylic Methyl Primary Secondary Tertiary< Allylic (1Y (2 Le Stability More Thomson-Brooks Cole able stable
Allylic Stabilization • Allyl radical is delocalized • Allylic radical is more stable than tertiary alkyl radical p.115
Stability of the allyl radical Resonance revisited Three electrons are delocalized over three carbons C H2C CH2 H2CCH2
Stability of the Allyl Radical: Resonance Revisited Three electrons are delocalized over three carbons: