Advices For Studying Organic Chemistry

addition.

CH 3 CH 2 C CCH 2 CH 3 Hsyn addi^2 /Ni tion

H H

2 B (P-2) CC

H 3 CH 2 C CH 2 CH 3

3-Hexyne (Z)-3-Hexene

(cis-3-hexene)

(97%)

2. Lindlar’s catalyst: metallic palladium deposited on calcium carbonate and is
   poisoned with lead acetate and quinoline.

H 2 ,P

CC quinoline

(syn addition)

d/CaCO 3

R R (Lindlar's catalyst) RCCR

H H

7.15B ANTI ADDITION OF HYDROGEN: SYNTHESIS OF TRANS-ALKENES

1. An anti addition of hydrogen atoms to the triple bond occurs when alkynes are
   reduced with lithium or sodium metal in ammonia or ethylamine at low
   temperatures.

1. This reaction, called a dissolving metal reduction, produces an (E)- or
   trans-alkene.

CH 3 (CH 2 ) 2 CC(CH 2 ) 2 CH 3 1. Li, C^2 H^5 NH^2 , −^78

oC

2. NH 4 Cl CC
   (CH 2 ) 2 CH 3

H

H

CH 3 (CH 2 ) 2

4-Octyne (E)-4-Octyne

(trans-4-Octyne)

(52%)