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Prerequisites: 333 CHEM 334 www.chem.sc.edu/faculty/bryson/index.html Linked to course syllabus and “WEB PAGE” synthesis Modified from sides of William Tam & Phillis Chang 29/32
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Due the second recitation: (1) Answer the following question in some detail. (2) Complete review work sheet of 333 reactions. What study activity (activities) helped you the most in CHEM 333? Assignments
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Text Solomons (10 th ed) Schedule of tests and “ projected ” pace Honor code Policy - grading scale Recitation WEB PAGE Homework problems, aids, etc SYLLABUS “ must read ” (linked to the “ Home ” and WEB Page*) *www.chem.sc.edu/faculty/bryson/index.html
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CHAPTER 12 Alcohols from Carbonyl Compounds Oxidation-Reduction Organometallic Compounds Srtucture of the carbonyl group C=O addition/ROH oxidation Hydrogenation of “ double bonds ” olefins and carbonyls LiAlH 4 NaBH 4 Oxidation w/ PCC Oxidation w/ H 2 CrO 4 and KMnO 4 Organometallic compounds R-Li & RMgX Organometallics as bases Organometallics as Nu:(-) with: carbonyls epoxides esters Synthesis Chapter 12 CHEM 334
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Ch. 12 - 5 Structure Carbonyl carbon: sp 2 hybridized Planar structure
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Ch. 12 - 4 Structure of the Carbonyl Group, Carbonyl compounds aldehyde alkanal ketone alkanone Others: Y = OH, OR’, NH 2, X, etc.
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Ch. 12 - 6 Rxs of Carbonyl Compounds with Nucleophiles Rxs of Carbonyl Compounds with Nucleophiles One of the most important reactions: nucleophilic addition to the carbonyl recall:
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Ch. 12 - 7 Two important nucleophiles (bases): Two important reactions: Hydrides (H: (-) from NaBH 4 & LiAlH 4 ) Carbanions (from R: (-)(+) Li & R: (-)(++) Mg (-) X )
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Ch. 12 - 8 Oxidation-Reduction Rxs reduction: increase in hydrogen content or decrease in oxygen content carboxylic acid aldehyde oxygen content decreases hydrogen content decreases oxidation: increase in oxygen content or decrease in hydrogen content
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Ch. 12 - 17 Alcohols by Reduction of Carbonyl Compounds
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Ch. 12 - 18 Alcohols by Reduction of Carbonyl Compounds (1 o alcohol)
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Ch. 12 - 19 Hydrides Nucleophilic and very basic React violently with H 2 O or protic sources Rxs in Et 2 O or THF, reduces all carbonyl groups LiAlH 4 = less reactive & less basic than LiAlH 4 uses protic solvent (e.g. EtOH) reduces only aldehydes and ketones “ LAH ” NaBH 4
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Ch. 12 - 23 Examples skip ether ex
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Ch. 12 - 21 Mechanism (neutralize)
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Ch. 12 - 22 Mechanism Esters (carboxylic acids) are reduced to 1 o alcohols
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Ch. 12 - 24 3C.Summary of LiAlH 4 and NaBH 4 Reactivity ease of reduction reduced by NaBH 4 reduced by LiAlH 4
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Ch. 12 - 25 Oxidation of Alcohols Oxidation of Primary (1 o ) Alcohols special CrO 3 reagents stronger oxidants
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Ch. 12 - 26 Special CrO 3 reagent = PCC Reagent p yridinium c hloro c hromate
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Ch. 12 - 27 PCC oxidation 1o1o 3o3o 2o2o No Reaction
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Ch. 12 - 28 Oxidation of 1 o Alcohols to Carboxylic Acids Jones reagent
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Ch. 12 - 29 Oxidation: CrO 3 + H 2 SO 4 [or H 2 CrO 4 ] [or KMnO 4 /HO (-) / Δ then H + /H 2 O]
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Ch. 12 - 34 Organometallic Compounds organometallic compounds contain carbon-metal bonds
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Ch. 12 - 35 Preparation of Organolithium & Organomagnesium Compounds Order of reactivity of RX RI > RBr > RCl
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Ch. 12 - 36 Examples
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Ch. 12 - 37 Rxs with Compounds Containing Acidic Hydrogens Grignard reagents and organolithium compounds are very strong bases
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Ch. 12 - 38 Examples as base + Mg 2+ + Br −
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As nucleophiles:
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Ch. 12 - 39 React as nucleophiles with epoxides
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Ch. 12 - 41 Rxs of Grignard & Organolithium Reagents with Carbonyls
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Ch. 12 - 44 examples
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Ch. 12 - 45 Reaction with esters 3 o alcohol
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Ch. 12 - 46 Mechanism
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Ch. 12 - 49 Addition-Elimination
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Ch. 12 - 50 Planning a Grignard [or RLi ] Synthesis Synthesis of
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Ch. 12 - 51 Method 1 Retrosynthetic analysis Synthesis
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Ch. 12 - 52 Method 2 Retrosynthetic analysis Synthesis
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Ch. 12 - 53 Method 3 Retrosynthetic analysis Synthesis
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Ch. 12 - 56 RMgX & RLi reagents cannot be prepared in the presence of the following groups because of reactions (acid-base or nucleophilic addition) :
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Ch. 12 - 58 Sodium or Lithium Alkynides (acetylides) Preparation of lithium alkynides Reaction with aldehydes or ketones
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Ch. 12 - 59 Synthesis and Protecting Groups
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Ch. 12 - 60 Retrosynthetic analysis However disconnection
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Ch. 12 - 61 Need to “ protect ” the –OH group first
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Ch. 12 - 62 Synthesis
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