CHEM 33332 1st Edition Lecture 18Outline of Last Lecture I. Halogentation of Side Chains-Benzylic position is similar to allylic position-abstraction of hydrogen on benzylic position gives resonance stabilized radicalChlorination vs. bromination:Caution:1.2.III. Nucleophilic Substitution of Benzylic Halides- Sn1 or Sn2 readily ovvurs-which one?-depends on the reaction conditionsSubstitution of benzylic halides, continuedReactions of Phenols-some similarities to previously studied reactions of aliphatic alcohols/some differencesI.II.III.I. Oxidation of Phenols of QuinonesII. Electrophilic Aromatic Substitution of Phenol-readily undergoes halogenation, nitration, sulfonation and Friedel-Crafts rections-need less reactive catalyst for Friedel-Crafts reactions:VI. Electrophilic Aromatic Substitution of Phenoxide anionStrongly activated- can use weak electrophiles like CO2These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Chapter 18: Keytones and AldehydesCarbonyl compounds: reagents/solvents/and constituents of fabrics/flavorings/plastics/drugs/proteins/carbohydrates/nucleic acids I. StructureII. Physical PropertiesA. Boiling PointB. SolubilityIII. Reactivity:A. AcidityB. Reactivity of Aldehyde vs. KeytoneIV: Aldehyde and Keytone NomenclatureA. As parent: (priority over alcohols, amines, alkanes, alkynes, ethers)1. Aldehydes – drop “e” from alkane and add “al”For cyclic aldehydes add “carbaldehyde”2. Ketones- drop “e” from alkane name, add “one”For cyclic keytones: since carbonyl is part of ring, same as acyclic keytones; carbonylis always #1As substituents:IV. Spectroscopy of Aldehydes and Ketones (Summary)A. IR – look for carbonyl stretch Conjugation lowers frequency:Ring strain raises frequency:B. hNMRC. C13NMRD. UVOutline of Current Lecture VI Aldehyde and Keytone SynthesisA. Oxidation of AlcoholsB. Cleavage of Alekens by OnzolysisC. Friedel-Crafts AcylationD. Hydrogenation of AlkynesE. 1,3-Dithiane Synthesis of Aldehydes and KetonesA multi-step synthesis:Example: F. Ketones from Carboxylic Acids1.2.3.Ex:G. Ketones from NitrilesEx:H. Aldehydes and Keytones from Acid Chlorides1. Reduction to aldehydesMechanisma) A milder reagent: lithium aluminum tri(t-butoxy)hydrideb) The rosenmunf ReductionEx:2. Conversion to ketones with litium dialkylcuprates (Gilman reagent)Ex:A reminder: use grilman reagent in the corey-House reaction:VII. Reactions of Aldehydes and KeytonesA. Alpha-Carbon reactions – covered in Ch 22B. Nucleophilic Addition Reactions1. Grignard Reaction:2. Addition of Acetylide3. Addition of Hydride4. Catalytic hydrogenation:similar to hydrogenation of alkenes, but aldehydes and keytones are less reactiveCurrent
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