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7 – Alkenes & Alkynes Alkenes Nomenclature -ene suffix -E/Z Electrophilic Addition Reactions to Alkenes Reagents What’s Regioselectivity Stereo Intermediate Rearrange Added...

7 – Alkenes & Alkynes Alkenes Nomenclature -ene suffix -E/Z Electrophilic Addition Reactions to Alkenes Reagents What’s Regioselectivity Stereo Intermediate Rearrange Added selectivity ments HBr (or HCl, HI) H+ and Br- Markovnikov - carbocation Possible H3O+ H+ and OH- Markovnikov - carbocation Possible + H , ROH H+ and OR- Markovnikov - carbocation Possible Br2/CCl4 Br+ and Br- - Anti bromonium No (or Cl2) ion Br2/H2O Br+ and OH- Markovnikov Anti bromonium No Cl2/H2O Cl+ and OH- ion Br2/ROH Br+ and OR- Markovnikov Anti bromonium No Cl2/ROH Cl+ and OR- ion (1) Hg(OAc)2, H2O H+ and OH- Markovnikov Anti mercurinium No (2) NaBH4 ion (1) Hg(OAc)2, ROH H+ and OR- Markovnikov Anti mercurinium No (2) NaBH4 ion (1) BH3.THF H+ and OH- Anti-Markovnikov Syn - No - (2) H2O2, OH , H2O H2/catalyst H and H - Syn - No (Catalyst = Pd/C, Pt/C, or Ni) HBr/ROOR (peroxide) H. and Br. Anti-Markovnikov - radical No RCO3H (MCPBA) O - Syn - No (1) RCO3H (MCPBA) OH and OH - Anti - No (2) H3O+ (1) OsO4 OH and OH - Syn - No (2) H2O2 KMnO4 (cold, dilute)/ OH- OH and OH - Syn - No Chiral Usual # Centers of products Formed 0 1 1 2 2 Syn = 2 Oxidative Cleavage of Alkenes Anti = 2 Reducing Conditions None = 4 (1) O3, -78C (2) (CH3)2S or Zn/H2O Oxidizing Conditions (1) O3 (2) H2O2 KMnO4 (hot, concentrated)/OH- (or with H3O+) ChadsPrep.com 19