Organic Chem - Exam #4

Acid Catalyzed Tautomerization

H3O+ (converts keto into enol)

Base Catalyzed Tautomerization

OH- (converts keto into enol)

Thermodynamic Enolate

• double bond goes to more crowded side

• more stable

Kinetic Enolate

• double bond goes to less crowded side

• less stable

NaOH rxn

• NaOH

• creates a thermodynamic enolate

• double bond on more crowded side

LDA rxn

• 1) 1.1 EQ LDA

• 2) /\Br

• creates a kinetic enolate

• double bond on less crowded side

Isotopic Labeling

• NaOD, D2O (xs)

• replaces all H @ alpha carbons with D

• can be added at sp2 ONLY IF there’s resonance

• mix of sterochem

Alpha Halogenation - Acidic Catalysis

1 EQ Br2, CH3COOH (adds 1 Br to alpha carbon)

• goes to more crowded side

Alpha Halogenation - Basic Catalysis

Br2 (xs), NaOH (xs) (adds as many Br to alpha carbon)

• goes to less crowded side

Haloform Reaction

Br2 (xs), NaOH (xs), H2O (converts to carbonyl)

Aldol

NaOH, /\OH

• stop at beta hydroxy if there ARENT 2 hydrogens available

• trans is major product

• larger ring # is MORE favorable

• catch H2O

Claisen Condensation

1) NaO-LG, HO-LG

2) H3O+ WKP

• enolate (nuc) + 3rd ox state ester (elec)

• remove LG and attach ester to enolate

Alkylation

1) 1.1 EQ LDA

2) R—I

• adds R to less crowded side

• adds sp3 C-C bonds

Enamine Alkylation

1) H-N-R2, HCl (cat)

2) Br—R

3) H2O, HCl (cat)

• adds R to more crowded side

Malonic Esters

1) Na-ESTER, H-ESTER

2) R—I

• adds R to alpha carbon

Basic Carboxylation

1) NaOH, H2O

2) H3O+ WKP

• converts esters to carboxylic acids

Acidic Carboxylation

H2O, H2SO4 (cat)

• converts esters to carboxylic acids

Decarboxylation

Heat

• removes carboxylic acid that has a 1:3 carbon ratio to a carbonyl

Synthesis of Amines

Br—R, NaO—KETONE

• converts imine to enamine by adding R to nitrogen

• makes 2* amines

Gabriel Synthesis

1) R—Br, KOH

2) NaOH (xs), H2O

• adds R and H to nitrogen

• makes 1* amines

NaCN rxn

1) NaCN

2) LiAlH4

3) H3O+ WKP

• adds carbon AND NH2 where LG was

Azide rxn

1) NaN3

2) LiAlH4

3) H3O+ WKP

• adds only NH2 where LG was

Reductive Amination

R—NH, HCl (cat), NaBH3CN

• converts 2nd ox carbonyl to an amine

• takes away one H from amine and one bond from carbonyl

Hoffman Rearrangement

Br2, NaOH, H2O

• removes carbonyl and bond next to it

• CAN’T have any other alpha positions with a hydrogen

Mannich rxn

1) =N< + Cl - , H2O, HCl

2) NaOH, I—CH3 (xs)

• adds double bond to an alpha carbon position