CHEM 30B REACTIONS SUMMARY. STUDY GUIDE FOR
FALL 2024. REVISED WITH ANSWERS PROVIDED
1. Tertiary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
Carbocation intermediate
2. Secondary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
Some rearrangement possible
Carbocation intermediate
3. Primary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
SN2 Reaction
4. Primary -01 with (I-branching + HX: Methyl shift after
carbocation is formed to create a higher degree CC. Then HX
attack
5. -Ols + PBr3: Primarily used for 1 0 and 20 -Ols Replaces -OH
with -Br
Less rearrangement than using HX
6. 1 -01 + SOC12/SOBr2: conditions: pyridine necessary
0
replaces OH with Cl
7. 20 -01 + SOC12/SOBr2: conditions: pyridine necessary replaces OH
with Cl and inverts stereocenter
8. -01 + TsCI or MsCI: conditions: pyridine necessary replace -OH with -
OTs/-OMs keep stereocenter needs a polar protic solvent for future
reaction
9. how does TsCI interact with rings: It needs to react with -OH in axial
NOT equatorial position show a chair conformation
10. Acid Catalyzed Dehydration of 1 0 -01: Conditions: must be
heated at high temp + acid catalyst ß elimination
1 1 . Acid Catalyzed Dehydration of 2 0 -01: Conditions: must be
heated at less temp than 1 0 + acid catalyst ß elimination
FALL 2024. REVISED WITH ANSWERS PROVIDED
1. Tertiary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
Carbocation intermediate
2. Secondary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
Some rearrangement possible
Carbocation intermediate
3. Primary -01 + HX: Conditions: 250 C
Result: Replace -OH with X
SN2 Reaction
4. Primary -01 with (I-branching + HX: Methyl shift after
carbocation is formed to create a higher degree CC. Then HX
attack
5. -Ols + PBr3: Primarily used for 1 0 and 20 -Ols Replaces -OH
with -Br
Less rearrangement than using HX
6. 1 -01 + SOC12/SOBr2: conditions: pyridine necessary
0
replaces OH with Cl
7. 20 -01 + SOC12/SOBr2: conditions: pyridine necessary replaces OH
with Cl and inverts stereocenter
8. -01 + TsCI or MsCI: conditions: pyridine necessary replace -OH with -
OTs/-OMs keep stereocenter needs a polar protic solvent for future
reaction
9. how does TsCI interact with rings: It needs to react with -OH in axial
NOT equatorial position show a chair conformation
10. Acid Catalyzed Dehydration of 1 0 -01: Conditions: must be
heated at high temp + acid catalyst ß elimination
1 1 . Acid Catalyzed Dehydration of 2 0 -01: Conditions: must be
heated at less temp than 1 0 + acid catalyst ß elimination
