Chem 239 MT 1

Structure of: Formyl Group, Acetyl Group, Propionyl Group, Benzoyl Group

Formyl: formaldehyde, aldehyde-like group
Acetyl: acetone, ketone-like group
Propionyl: 3 total carbons, so propionyl
Benzoyl: attaching a benzene

How do you form acetals from ketones

Need 2 equivalents of alcohol and a catalytic acid.

Mechanism not on exam

What is the product and what is the mechanism

What are 3 reducing reagents, what does it mean to reduce a carboxylic acid, and what are their relative strengths?

LAH > NaBH₄ > H₂.

LAH will reduce C.A., ketone, aldehyde

NaBH₄ will reduce ketone, aldehyde

H₂ will reduce just aldehydes

Aldehyde Nomenclature: suffix, carbon numbering, multiple aldehydes, ring

Ketone Nomenclature:

• Aldehyde / Ketone + HCN = add -C—N & -H to the central carbon

• Aldehyde / Ketone + H2O = geminal hydrate (twin alcohols)

  • Ketones equilibrium lies mostly to the left, less reactive. Formaldehyde lies mostly to the right as a geminal hydrate

And what are examples of strong nucleophiles

The strong nucleophile here is CN-, attacking the basic carbonyl carbon and then getting protonated in an acid workup step

And what’s an example of a weak nucleophile

Sodium Borohydride Mechanism

LAH Mechanism

Regular strong nucleophile mechanism,

1. Lithium cation bonds to O

2. H- attacks carbonyl carbon

3. Acidic workup protonates O and gets rid of Li

Grignard synthesis

What are Acetals & Ketals (normal and Hemi)

• Acetals & Ketals - a carbon bonded to two O-R groups. If its bonded to a hydrogen too its an acetal, two C groups is a ketal

  • Hemi means one O-R & one O-H

What is an Imine functional group

N=O

What is an Enamine

R’-N-C=R the N-C=C

Four ways to synthesize carboxylic acids

You oxidize primary alcohols, alkyl benzenes, and aldehydes. For CO2 you use a grignard reagent to attack the partially positive middle carbon

Friedel Crafts Acylation

Ester Nomenclature

Reactions of Carboxylic Acids: at the C, O, and decarboxylyation

Fisher Esterification

CH₂N₂ Reagent Reaction

Reducing Agents & what they do to Ketones & Carboxylic Acids & Relative Strengths

LAH, reduces aldehydes to primary alcohols, ketones to secondary alcohols, C.A.s to alcohols to primary alcohols

What carboxylic acids can be de-carboxylated & how do you do it

1. Beta Ketoic Acid (double carbonyl with carboyl at Beta carbon)

2. Maleic acid (double carbonyl with C.A. carbonyl at Beta carbon)

3. Y-COOH where Y = OR, OH, NH₂

You decarboxylate by reacting with heat & acid. Chops off the right CO₂ and the H adds to the alpha carbon.

Decarboxylation of Beta-Keto acids mechanism

Forms the cyclohexane looking intermediate by rotating central carbon

Have an idea of the general reactivity of C.A. derivatives

Steps of C.A. Derivative Nucleophilic Acyl Substitution

1. Nucleophile attacks carbonyl carbon, pi-bond electrons kick up to oxygen.

2. Tetrahedral intermediate is formed, strongest leaving group leaves