Orgo Exam 3 Reagents (Purpose)

Question 1

NaBr/NaCl

Answer 1

Cl- and Br- can act as nucleophiles when NaCl/Br is dissolved in solution

Question 2

TsCl

Answer 2

Make -OH a good leaving group

Question 3

NaOEt/NaOMe

Answer 3

• Strong bases and strong nucleophiles: Can remove H (elimination rxns) or act as nucleophiles (substitution rxns).
• Involved in Claisen condensation (remove alpha hydrogens to form enolates)

Question 4

KOtBu

Answer 4

• Sterically hindered base, elimination reactions on the less sterically hindered carbon (usually beta hydrogens), poor nucleophile

Question 5

1) Dilute H2SO4
2)H2O

Answer 5

Hydration of alkenes using H3O+ and H2O to protonate and deprotonate the molecule, H2O can act as a nucleophile

Question 6

1) Hg(OAc)2, H2O
2) NaBH4

Answer 6

Adds OH group to more sub. carbon
- Hydrate alkenes without CC rearrangement. Adds OH and mercury across double bond, removes mercury and adds H (H and OH are added at end).

Question 7

1) BH3
2) H2O2, NaOH

Answer 7

Adds OH group to less sub. carbon

Question 8

HBr

Answer 8

Breaks double bond, adds Br to more sub. carbon

Question 9

HBr, ROOR

Answer 9

Breaks double bond, adds Br to less sub. carbon

Question 10

H2 and Pt

Answer 10

Adds hydrogens to both C in a double bond (breaks double bond)

Question 11

Jones reagent

Answer 11

Strong oxidizer:
- Primary OH –> Carboxylic acid
- Secondary OH –> Ketone
- Tertiary OH –> NR
Alcohol attacks electrophilic center (Cr=O bond)

Question 12

PCC (CrO₃ + HCl + pyridine)

Answer 12

Weaker oxidizer:
- Primary OH –> aldehyde
- Secondary OH –> ketone
- tertiary OH –> NR
Alcohol attacks electrophilic center (Cr=O bond)

Question 13

NaBH4

Answer 13

Mild reducing agent:
- Aldehydes –> primary OH
- Ketones –> secondary OH
- acyl chlorides –> primary OH
- esters –> primary OH

Question 14

1) LiAlH4
2) H3O+ or H2O

Answer 14

Strong reducing agent
- aldehydes –> primary OH
- ketones –> secondary OH
- C. acids –> primary OH
- esters –> primary OH
- amides –> amines

Question 15

Grignard reagent
1) R-Mg-X, X=Cl, Br
2) H3O+ or H2O

Answer 15

Forms C-C bonds
- C-Mg bond is polar (C is nucleophilic), attacks carbonyl carbon, forms tetrahedral intermediate, forms an alcohol from double bonded O

Question 16

Gilman reagent
R2CuLi

Answer 16

Used to convert acyl chlorides to ketones, forms C-C bonds with carbonyl carbons.

Question 17

Wittig reagent

Answer 17

Forms alkenes from aldehydes/ketones, PPh3 has a nucleophilic C that attacks electrophilic center of C=O bond

Question 18

TMS-Cl, Et3N

Answer 18

Protects OH during oxidation reactions

Question 19

TBAF

Answer 19

Removes TMS-Cl from OH after oxidation reaction is over

Question 20

SOCl2

Answer 20

Converts alcohols to alkyl chlorides

Question 21

ROH, pyridine

Answer 21

helps SOCl2 reaction occur

Question 22

R2NH

Answer 22

formation of imines, reduction reactions

Question 23

NaH

Answer 23

Strong base, remove H and create enolates
- claisen rxns
- aldol rxns
- michael additions

Question 24

LDA

Answer 24

Strong base, forms enolates, good at forming kinetic enolates

Question 25

NaOH, Br2

Answer 25

NaOH deprotonates alpha hydrogen and Br2 adds bromines to alpha carbons. Will happen to all alpha hydrogens if available.