1. Reduction of Aldehydes and Ketones Complete reduction of a carbonyl group to a methylene (-CH 2 -) group is possible by two different methods 1)Wolff-Kishner reduction: Highly basic conditions Extension of imine formation 1 19.12 Reduction of Carbonyl Groups to Methylene Groups

2. Reduction of Aldehydes and Ketones 2 19.12 Reduction of Carbonyl Groups to Methylene Groups

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5. Reduction of Aldehydes and Ketones 2)Clemmensen reduction: Acidic conditions Zinc amalgam + HCl The mechanism is uncertain 5 19.12 Reduction of Carbonyl Groups to Methylene Groups

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7. Problems 1)Draw the products for the following reactions: 7

8. 2)Draw the complete mechanism for the following reaction: 8

9. The Wittig Alkene Synthesis Method of preparing alkenes from aldehydes and ketones 9

10. Regioselective rxn, assuring the location of alkene 10

11. The Wittig Alkene Synthesis Preparation of phosphorous ylide Ylid (or ylide): compound with opposite charges on adjacent, covalently bound atoms 11 19.13 The Wittig Alkene Synthesis

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13. The Wittig Alkene Synthesis Stereochemistry – Both E and Z products Retrosynthetically 13

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15. Problems 1)Draw the product(s) for the following reaction 2)What carbonyl compound and phosphorus ylide might you use to prepare the following compound? 15