234 PS1 - Problem set 1 PDF

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Problem set 1...

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PROBLEM SET 1 Lectures 1 & 2

Klein Chapters 12, 13 and part of 14

1. Predict the product for the following transformations.

Br

Mg(0) Et2O

O O

i. Li(0), (2 equiv) Et2O Cl

ii. D3O+

i. MgBr

O H

Et2O ii. H3O+

Me

H2O MgBr

O

Li THF

O

Mg(0), THF

Br

(i) Mg(0), Et2O (ii) I

t-Bu

Me

Me

O H

(iii) H2O

(i) O

THF

O (ii) H3O+

H

O

MgBr

OH

(i) PBr3 (ii) Mg(0), Et2O

2

(i)

H

i-Pr Me

MgBr

THF

(ii) PhCHO (iii) H3O+

O O

(i) NaBH4, MeOH (ii) NaH, DMF Me

O

Br

O O

(i) LiAlH4, Et2O (ii) H3O+ (iii) NaH, DMF

O

Br

Me

Br

(i) KH, 18-c-6, THF Ph

Br

(ii) Mg(0), THF OH

3

O

i. PhMgBr, Et2O H

ii. H3O+

MeO

i.

MgBr Et2O

H ii.

O iii. H3O+

O

MgBr , Et2O

i.

ii. H3O+

i.

MgBr

O Et2O ii. H3O+ Ph

i. BrMg Et2O

OH O Ph

H Me

ii. H3O+

4

Me

(i) 9-BBN, THF (ii) H2O2, NaOH

O

NaBH4, MeOH H

O

(i) LiAlH 4, Et 2O

Me

(ii) H 3O+

O O

NaBH 4, MeOH

O

5

O (i) LiAlH 4, Et 2O

O

(ii) H 3O+

(i) KH, 18-crown-6

OH Me

(ii)

Br

Me

OH

(i) NaH, DMF

(ii) MeI

OH Me

(i) NaH, DMF

(ii)

Br

6

2. Provide a reasonable electron-pushing mechanism to account for the following transformations: Me

Me DMF Br

+

I

NaI

MeO

MeO

Draw the transition state that explains the stereochemistry in the product.

Ph

Ph

H2O H2SO4

7

Ph

Ph OH

O NaBH4, MeOH

HO

H

O

OH Me

(i) LiAlH4, Et2O (ii) H3O+

MeO OMe

Me MeO OMe

8

Li

Cl Li(0), (2 equiv) Et2O

NMe2

NMe2

Mg(0) Br

Et2O

9

MgBr

O i.

MgBr , Et2O

HO

ii. H3O+

OMe O

i. MeMgBr (excess) Et2O ii. H3

O+

OH Me

10

Me

H

OH

i. NaNH2, NH3

Me Me

ii. Me

CHO Me Me

iii. H3O+

OH

O (i) NaH, DMF

(ii)

Br Me

11

Me

O Ph

(i) LiAlH4, THF OMe

Ph

OH

(ii) H2O

(i) EtMgBr, Et2O (ii) O H

O

OH

H O

(iii) H3O+

12

3. Provide the reagents to accomplish the following transformations:

HO

Cl

O

O

O

O

HO

Br

O

O

O

O

OH

Br

Ph

O O

O

O

13

Me Me

HO MeMgBr

OMe

HO

Me Me

Me

OMe

OMe

O

HO

14

Ph

OH

H

Ph

OMe OMe

OH H Ph

H

OMe

O Me t-Bu

t-Bu

15

HO OMe

Ph

HO

Me

OH CO2Me CO2Me OH

H Me

H

O

Me

H Me

OH

H

OH

Me

16

O

H

O

H

MeO

OH

MeO H

O

H

O

H

OH

H

MeO

Ph

MeO H

O

H

O

H

O

Ph

H

MeO

HO O

O

H

Me Me

17

H

O

Ph

Br

MgBr

H O

OEt

Br

MgBr

EtO O

OEt

OH Ph

Br

18

HO H

HO O

H

Ph O

OH

19

4. Perform a retrosynthetic analysis on the following molecules (work backwards). Check your answer by providing the synthesis in the forward direction.

O

Ph HO

HO

Me

Ph

Me

O

H Me

Me

MeO

MeO O

O

OH Ph

O

Ph

Ph

OH Ph

Ph

H

Ph

20

O

OH

H MeO

MeO

Cl MeO

Ph Me

Me

O

Br Me

Me

1.

4.

2.

3.

21

OMe

Me

S

MgBr

1.

4.

2. OH S 3.

O O

Ph

H

O

O

OEt 1.

4.

2.

2. O

3.

22

O

OEt...