1. I. Organometallic Reagents = carbon-metal bonds
Nucleophilic Carbon
OH- contains a nucleophilic oxygen that can give a new C—O bond
Formation of new C—C bonds is the key requirement in organic synthesis
Alkylmetal Reagents
Haloalkanes can be transformed into organometallic compounds
Alkyllithium Synthesis (I > Br > Cl reactivity)
Alkylmagnesium Synthesis (Grignard Reagent)

2. Alkylmetals are very basic, very strong Nucleophiles
pKa of CH3—H bond is about 50
Alkylmetal reagent is the conjugate base of a very weak acid H3C:-
Use them as soon as you make them (…made in situ…)
Air and water sensitive, must do reaction under N2 or Ar
True structure involves coordinated solvent—require ether or THF
Very polar bond, metal is electropositive
Opposite of usual situation for carbon, as in Haloalkanes
Treat the molecule like R- = Carbanion
Resonance forms
Hydrolysis :

3. C. Alkylmetal reagents in Alcohol Synthesis
Goal: Formation of new C—C bonds by using C Nucleophile
Nucleophilic attack of Haloalkane by alkylmetal reagent is unsuccessul
Elimination Reactions give side products because of extreme basicity
We will need a more successful carbon electrophile

4. 5) Carbonyl electrophiles (Cd+==Od-) react more cleanly with alkylmetals
Ketones give tertiary alcohol products
Aldehydes give secondary alcohol products
Formaldehyde (CH2O) gives primary alcohol product -

5. II. Oxidation of Alcohols to Carbonyls
Reduction reactions can be reversed to give the aldehydes or ketones
Oxidizing Reagent is Cr(VI)
(Na2Cr2O7 or K2Cr2O7 or CrO3) and H2SO4 and H2O
Primary alcohols can be overoxidized to carboxylic acids

6. Do Primary alcohol oxidation without water
PCC = pyridinium chlorochromate =
Anhydrous conditions and PCC don’t overoxidize primary alcohol
4) Mechanism involves Chromic Ester

7. III. Synthesis of Complex Alcohols Using Alkylmetal Reagents
A. Useful Reaction Sequence
B. Retrosynthetic Analysis = Work Backwards from Target
Complex molecules are made from simple parts
Look for C—C bonds to break (form)