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Aldehydes
- AL ending
- Always on the C-1
- R-CH=O
- Bond is polar
- soluble in water
- BP increases by 20=
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Synthesis of Aldehydes
RAMP
- Reimer-Tieman Synthesis of Phenolic Aldehydes
- Acid Chloride Reduction
- Methyl Benzene Oxidation
- Primary Alcohol Oxidation
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Reimer Tieman Synthes of Phenolic Aldehydes
- A chlorine is going to leave and take electrons with it.
- Aldahyde on a benzene ring with OH
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Enols and Gemdiols are
unstable
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Acid Chloride Reduction
- RAMP
- R-C(Cl)=O
or benzene- C(Cl)=O in LiAlH4 -------> R-CH=O + ClLi+ AlH3 or Benzene-CH=O + ClLi + AlH3 - Chlorine Leaves
- The H- from the LiAlH4 attacks the group and the Cl leaves
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LiAlH4
- Lithium Aluminum Hydride
- Suplies the H-
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Methyl Benzene Oxidation
- RAMP
- Creates Major and Minor
- Involves a Benzene Ring
- Major---> Cl2 and heat, Minor---> CrO3
- In Major- Cl jump onto the C then react in water where OH jump on and Cl jump off. The 2 OH react together creating R-CH=O +H2O
- In Minor- O jump on the C then react in water. creating R-CH=O
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Primary Alcohol Oxidation
- RAMP
- Is only a synthesis of aldeyhide with CrO3Cl- (Pyridinium Chlorochromate)
- DOES NOT proceed to Carboxylic Acid
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Synthesis of Ketones
SOFA
- Secondary Alcohol Oxidation
- Organo Copper Compound of Acid Chloride (Corey House)
- Friedel Craft Acylation
- Aceto Acetic Ester Synthesis
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Secondary Alcohol Oxidation
- SOFA
- Reacts in CrO3 or K2Cr2O7
- Hydrogens from OH and CH are removed by reagent
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Organo Copper Compound of Acid Chloride
- SOFA
- Like a Corey House---> supplies two R-
- R- is attacking species
- R-C(Cl)=O --------> R-C(R-)=O
- Cl leaves and R- jumps on
- CH3CH2-CuLi + CH3CH2CH2CH2-C(Cl)=O --------> CH3CH2CH2CH2-C=O-CH3CH2 + CuLi
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Friedel Craft Acylation
- SOFA
- R+ is attacking species
- R-C(Cl)=O + AlCl3------> R-C(R)=O + Cl-
- Cl hangs out with AlCl3 for a little bit then jumps off
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Aceto Acetic Ester Synthesis
- SOFA
- 1) Aceto acetate ester---> 2) Add Haloalkane to Alpha Carbon----> 3) Creates Carbocylic Acid---> 4) Add Acid for carboxylic acid to dissociate----> 5) add heat and creates Ketone
- Methly group never ever changes
- To add a second R group- Do it all again! New haloalkane will attach to Alpha Carbon
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Widdig the ROACH pushes the SOFA with the OXO up the RAMP
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OXO Process
- Synthesis of Aldehyde
- -C=C- + C=O + H2 ------> (Cobalt) -----> -C-C-CH=O
- Creates an OctaCarbonylDiCobalt (2 Cobalts and 8 Carbonyl Carbons)
- 1) H2 breaks the the Cobalt-Cobalt Bond
- 2) One C=O leaves and is replaced by an Alkene
- 3) A C=O is added to the Alkene and double bond flips out to accomodate
- 4) Add H2 again: H- to C=O and H+ to other end. The Aldehyde seperates from catalyst
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ROACH
- Reactions of Ketones and Aldehydes
- Reduction of Aldehydes to 1o alcohols, Ketones to 2o alcohols.
- Reduction of Aldehydes & Keytones to Alkanes- Clemmensen REduction and Wolf Kischner
- Oxidation of Aldehydes
- Addtions Reactions- Gringard Reagent, Alcohol-Acetal, Ketal Formation, Derivatives of Ammonia
- Cannizzaro Reaction
- Wittig Reaction
- Halogenation of Ketones
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Reduction of Aldehydes to 1o Alcohols/ Ketones to 2o Alcohols
- ROACH
- (R)/H-C(R)=O -----> H2, Pt or Pd or Ni -----> R/H-CH(R)(OH)
- (R)/H-C(R)=O-----> LiAlH4 or NaBH4-----> R/H-CH(R)(OH)
- The H- and H+ are supplied from the Reagents.
- H+ attaches to O and H- attaches to the C
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Reduction of Aldehydes & Keytones to Alkanes
Clemmensen Reduction and Wolf-Kishner
- ROACH
- Aldehydes are converted to 1o alcohol then to an Alkane
- Keytones are converted to 2o alcohol then to an Alkane
- Major: Zn(Hg) concentrate HCl
- Minor: HN2-HN2
- Provides 2 H+ and 2 H-
- (R)/H-C(R)=O-----> Reagent----> (R)/H-CH(R)=OH-----> (R)/H-CH2-R + H2O
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Oxidation of Aldehydes
- ROACH
- ONLY Aldehydes- 1o Alcohol
- Reagent: KMnO4 or K2Cr2O7
- R-CH2-OH----> Reagent-----> R-CH=O---> Reagent----> R-C(OH)=O
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Addition Reactions
Grignard Reagent
- ROACH
- (R)/H-C(R)=O + R-MgX----> (R)/H-C(R)(R)-O-MgX+----> H2O-----> (R)/H-C(R)(R)-OH + MGX+OH-
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Addition Reactions
Alcohol-Acetal, Ketal Formation
- ROACH
- (R)/H-C(R)=O + CH3OH---> CH3O-C(R/H)(R)-OH----> CH3-O-C(R/H)(R)+ CH3O---->CH3-O-C(R/H)-CH3O + H2O
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Hemi-Acetal
- Begins as Aldehyde becomes an Acetal (diether)
- H-C(RO)(R)-OH
- Must particiate in an ETHER linkage
- Must have an ALCOHOL group attached to it
- Formed by addtion to the double bond
- CH3O-CH(R)-OCH3
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Hemi-Ketal
- Begins as a Ketone becomes a Ketal (diether)
- R-C(RO)(R)-OH
- Synthesis then Nucleophilic substitution
- CH3O-C(R)(R)-OCH3
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Cannizzaro Reaction
- ROACH
- ALDEHYDE only
- MUST NOT HAVE ALLYLIC HYDROGENS
- Products are: The salt of a Carboxylic Acid and an Alcohol
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Halogenation of Ketones
- ROACH
- Similar to Halogenation of Alkenes
- CH3-C(=O)-CH3 + Cl2 ------> CH2(Cl)-C(=O)-CH3 + HCl
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Wittig Reaction
- ROACH
- Converts or Incorporates Ketones or Aldehydes into ALKENES
- CH3-C(CH3)=O + CH3-C(CH3)=Ylide----> CH3(C)(CH3)=O-Ylide----> CH3-C(CH3)=C(CH3)-CH3 + O=Ylide
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ID Tests for Aldehydes
- Tollen's Test
- Benedicts and Fehlig's Test
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Tollen's Reagent
- Can be aromatic
- R-C(=O)-H + Tollen's Reagent----> Heat----> R-C(=O)-O- + Ag(solid)
- 2Ag+(NH3)2
- 2NO3-
- 3Na+
- 3OH-
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Benedicts and Fehling's Test
- NOT aromatic
- Gives Brown to Red percipitate of Cu2O
- R-CH=O + Benedict's/ Fehling's Reagent---> Heat---> R-C(=O)-O- + Cu2O(solid)
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ID Test for Allylic-Hydroxy Ketones
- Will give the Silver Mirror when reacted with Tollen's Reagent
- -C(=O)-CH(OH)- + Tollen's Reagent ----> Heat----> -C(=O)-C(=O)- + Ag(solid)
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