Homework Problem to help with mechanism knowledge.

ORGANIC CHEMISTRY 203
SUMMER QUARTER 2004-2005
PROBLEM SET
NAME:


Lycopodine, isolated in 1881, is the most widely distributed alkaloid from the genus
lycopodium. There have been a number of elegant total syntheses of this compound. One of the
earliest was by Gilbert Stork, using his enamine synthesis as a key reaction.
This is a mostly mechanism Problem Set. Each reaction is divided up into small steps.
Provide either reagents or mechanism as indicated. If it is a mechanism step, all reagents are
provided, do not add any.


mechanism

1. MeO OEt NaOEt, EtOH MeO OEt


O O


2. mechanism
MeO OEt
OEt MeO OEt
+ NaOEt, EtOH
O
O O O
EtO
O O

3. mechamism
MeO OEt
MeO O

O NaOEt, EtOH

EtO
O O EtO
O O

4. mechanism
MeO O MeO O
K2CO3, H2O
+ CO2 + EtOH
heat
EtO
O O OH
5. mechanism

MeO O 1. LiAlH4 MeO O


2. H3O+

OH (Think conjugate addition, then elimination)



6. Mechanism

MeO O 1. CH MgBr, CuCl MeO O
3 2



(Gilman reagent)

2. dilt. H+

7. reagents

MeO O ? MeO N




O NH2

8. mechanism O

NH2
MeO N +
MeO N

MeOH



9. mechanism
9. mechanism
O NH2

O
H
N
+
MeO N MeO NH
+




O
H +
MeO NH
redrawn


+
O N
H

OMe

10. mechanism




a cationic cyclization

+
O N O N
H H
OMe OMe



11. mechanism




LiAlH4


reduces amides to amines
O N N
H H

OMe OMe
12. mechanism




Li/ NH3., EtOH


Birch reduction N
N
H H

OMe OMe



13. mechanism




1. KOtBu

2.
N O N
H
Cl O CCl3
OMe O O OMe
(protects amine)
CCl3

14. reagents




?


N Chapter 6
N CHO

O O OMe CO2Me
O O

CCl3
CCl3
15. mechanism




OH
H2O2 (30%) O
N CHO OH
+
N N C OH
CO2Me O
O O CO2Me CO2Me
O O O O

CCl3
CCl3 CCl3




H
N O
O
CO2Me
O O

CCl3



16. mechanism




NaOMe
H
N O N O
O
CO2Me CO2Me
O O O O

CCl3 CCl3
17. mechanism extra credit




Zn, MeOH

N O deprotects amine N O
H
CO2Me CO2Me
O O

CCl3


18. mechanism




+ MeOH
N O O
H N
CO2Me
O




19. reagents




? ?


N O N OH N O


O