Lecture 20Outline of Last Lecture I. Addition to AlkenesII. Regioselective Addition of HX (#1)III. Acid Catalyzed Hydration (#2)IV. Addition of Cl2 or Br2 (#3)Outline of Current LectureCHEM 333 1st EditionI. Br2 or Cl2 addition in the presence of H2O or R-OH (#4)II. Oxymercuration-Reduction (#5)III. Hydroboration/Oxidation (#6)IV. Oxidation (#7)V. OzonolysisCurrent LectureI. Br2 or Cl2 addition in the presence of H2O or R-OH (#4)a. Example:i. Mechanism:b. Regioselective reaction: X- adds to less substituted side of doube bond. OH adds to more substituted side of double bond. X and OH are anti to each other.i. Example:c. Can substitute H2O with an alcohol (R-OH)i. Example:d. Can have internal attack of an alcohol onto a brominium/chlorinium ion to make a 5 or 6 membered ringi. Example:II. Oxymercuration-Reduction (#5): hydration of an alkenea. Example:b. Example:c. Example: goes through carbocation. Look for rearrangements.d. Example: no carbocation, so no rearrangementIII. Hydroboration/Oxidation (#6): anti-Markovnikov addition of OH across a double bonda. Example:b. Example:c. Example:IV. Oxidation (#7)a. OsO4 - osmium tetroxide - oxidation of an alkene to a 1,2-diolb. Example:V. Ozonolysis: cleavage of a cdouble bond to 2 carbonylsa. Example:b.
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