1. Chemistry 125: Lecture 66 April 9, 2010 Oxidizing/Reducing Reagents Bookeeping & Mechanism This For copyright notice see final page of this file

2. There is no reciprocal 3 Hz quintet for A! Could this 3 Hz doublet be due to long-range splitting by A? Just the 7 Hz triplet from C! Question 8 C C N H H H mirror plane enantiotopic C H H D enantiotopic ?diastereotopic ! same  (unless chiral, resolved solvent) no mirror plane 1:3:3:1 7 Hz 1:2:1 7 Hz different  (> 3 Hz for larger field)

3. Oxidation/Reduction as Bookkeeping (for purposes of reagent selection) (CH 3 ) 3 C C CH 3 O “reduction” (CH 3 ) 3 C C CH 3 OH H +2 C C 0 Need a “reducing agent” Oxidizing:Reducing : Neither : H-Cl +1 H-Cl Br-Br 0 0 CH 4 -4 1 CH 4 Li + AlH 4 - +1 +3 LiAlH 4 NaH +1 NaH K 0 K KCl +1 KCl RS-SR RS-SR CrO 3 +6 -2 CrO 3 ? HOCrO 2 - is a stable ion +4 Not all reducing agents would work satisfactorily, but it is usually futile to try a reagent from the wrong redox class. H 2 C CH 2 Br -2 (oxidizes RS-H H-SR to RS-SR) Certainly reduces O 2, and Fe 2 O 3 at great heat; Br 2 in free-radical halogenation; but not generally reactive. +1-2 H2OH2O H2OH2O But photosynthesis changes H 2 O into O 2 and “H - ” (NAD +  NADH) RSH H 2 C CH 2 H OH -2 -3

4. Alcohol Oxidation (sec. 16.14) Br 2 Mechanism

5. Alcohol Oxidation (sec. 16.14) Cr +6 Mechanism

6. End of Lecture 66 April 9, 2010 Copyright © J. M. McBride 2010. Some rights reserved. Except for cited third-party materials, and those used by visiting speakers, all content is licensed under a Creative Commons License (Attribution-NonCommercial-ShareAlike 3.0).Creative Commons License (Attribution-NonCommercial-ShareAlike 3.0) Use of this content constitutes your acceptance of the noted license and the terms and conditions of use. Materials from Wikimedia Commons are denoted by the symbol. Third party materials may be subject to additional intellectual property notices, information, or restrictions. The following attribution may be used when reusing material that is not identified as third-party content: J. M. McBride, Chem 125. License: Creative Commons BY-NC-SA 3.0