Organic Chemistry

prepare the following compounds because vinyl and aryl halides cannot undergo

nucleophilic attack (Section 10.8):

Gilman reagents can even replace halogens in compounds that contain other functional

groups.

PROBLEM 33

Explain why tertiary alkyl halides cannot be used in coupling reactions with Gilman

reagents.

PROBLEM 34

Muscalure is the sex attractant of the common housefly. Flies are lured to traps by filling

them with fly bait containing both muscalure and an insecticide. Eating the bait is fatal.

How could you synthesize muscalure using the following reagents?

Coupling reactions can be carried out that give high yields of products (80–98%)

using a transition-metal catalyst.

In each of the following reactions, the catalyst is palladium(0), ligated to four mole-

cules of phenyl phosphine.

Pd PPh 3 P

transition-metal catalyst

Ph 3 P PPh 3

Ph 3 P PPh 3

triphenyl phosphine

=

CH 3 (CH 2 ) 7 (CH 2 ) 8 Br

H H

CC and CH 3 (CH 2 ) 4 Br

muscalure

CH 3 (CH 2 ) 7 (CH 2 ) 12 CH 3

H H

CC

Section 12.12 Coupling Reactions 471

(CH 3 CH 2 ) 2 CuLi

Br

I

THF

+ CH 3 CH 2 Cu

H CH 2 CH 3

CH 3

C

H

H 3 C H 3 C

CC

CH 3

C + + LiBr

(CH 3 ) 2 CuLi

THF

+

CH 3

+ CH 3 Cu + LiI

Tutorial:

Organometallic compounds

CH 2 CCu

(CH 3 ) 2 CuLi

THF

CH 3 CHCCH 3 + CH 3 Cu

O

Br

O

CH 3

CH 3

CH 22 C CuLi

CH (^3) CCH 2
CH 3
CH 3
Cl
CH 3
CH 3 CHCCH 3
THF

• 
  


• 
  
  
  
  • 
    
    
    
    • LiCl
    
    
    
    
  
  
  
  


• LiBr
  BRUI12-437_480r3 27-03-2003 11:51 AM Page 471