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Synthesis

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  1. Synthesis

  2. HC CH HC CNa O C CH HO 1. NH3 + HC CNa 2. H3O+ (65-75%) Remember: Sodium Salts of Acetylenes NaNH2 NH3

  3. Question • What compound will be obtained from the reaction shown below? • A) B) • C) D)

  4. CH3(CH2)3C CH CH3(CH2)3C CMgBr 1. H2C O 2. H3O+ CH3(CH2)3C CCH2OH (82%) Using Acetylenic Grignard Reagents + CH3CH2MgBr diethyl ether + CH3CH3

  5. Protection of Alcohols • Consider the reaction below. Why won’t it work? • The alcohol can act as an acid, especially in the presence of reactive reagents like the Grignard reagent. • The alcohol must be protected to prevent it from reacting.

  6. Protection of Alcohols http://en.wikipedia.org/wiki/Protecting_group • A three-step process is required to achieve synthesis of the targeted diol. There are many different “protecting” groups for each of the various functions. Each must be easily added and easily removed.

  7. Protection of Alcohols (TMS) • The protection step requires the presence of a base.

  8. Protection of Alcohols TMS is removed with H3O+ or with F–, which comes from TBAF. H3O+ or SEE: CONCEPTUAL CHECKPOINT 13.18

  9. Question What is the correct order of reagents needed for the following transformation? g h c, g, a, b c, h, a, b c, I, b

  10. Reactions of Alcohols • Thionyl chloride, SOCl2, has commonly been used to convert alcohols to an alkyl chlorides.

  11. Question What is the product of the following reaction?

  12. Reactions of Alcohols • PBr3 can be used to convert an alcohol to an alkyl bromide. • Note that the last step of the SOCl2 and PBr3 mechanisms are SN2 reactions. • SEE: SKILLBUILDER 13.6

  13. Question What is the product of the following reaction?

  14. Oxidation-Reduction Reactions

  15. SummaryReactions of Alcohols

  16. Reactions Paths:to & from alcohols

  17. Question What is the correct order of reagents needed for the following transformation? A. 1) Hg(OAc)2, THF:H2O 2) NaBH4, OH– 3) TMS-Cl, Et3N 4) Potassium tert-butoxide 5) HBr/H2O2 6) TBAF B. 1) NaBr/DMSO 2) Hg(OAc)2, THF:H2O 3) NaBH4, OH– C. 1) Hg(OAc)2, THF:H2O 2) NaBH4, OH– 3) TMS-Cl, Et3N 4) Potassium tert-butoxide 5) BH3:THF 6) H2O2, OH– 7) PBr3 8) TBAF D. all of the above