Chemistry Reference
In-Depth Information
R
YY
R
O
carbonate, carbamate,
urea, diaryl ketone
Y = O, NR
+ R-YH
O
- HCl
+ R-YH
R
l
Y
l
- HCl
- CO
2
acid chloride
R
RNCO
isocyanate
O
chloroformate,
mixed acid anhydride,
carbamoyl chloride
Y = CO
2
R = alkyl, alkenyl,
alkynyl, aryl,
heteroaryl
Z = H
RCl
chloride
- HCl
- CO
2
Y = O, S, NR, CO
2
RY = aryl
R = H, alkyl, alkenyl, alkynyl,
aryl, heteroaryl
Z = H
Y = NH
R = alkyl, aryl, heteroaryl,
alkenyl, alkynyl
Z = H
- HCl
- 2 HCl
- HCl
- CO
2
Y = O
R = alkyl, alkenyl,
alkynyl
Z = H
CHLOROFORMYLATION
Y
R
Z
nucleophilic
compound
CARBONYLATION
CHLORINATION
Cl
Cl
O
phosgene
DEHYDRATION
- CO
2
- 2 HCl
R = alkyl, aryl,
heteroaryl,
alkenyl, alkynyl
Z = NH
2
Y = CO
Z = CO-Y-R
Y = NH
Z = CHO
Y = NH
R
N
CNR
R-NC
R-CN
isocyanide
cyanide
carbodiimide
Scheme 4.1.
Main phosgenation reactions and functional groups that can be formed.
with idealized molecular fragments, called synthons, and reactions thereof leading
to their synthetic equivalents. When a formal chloroformylation, carbonylation, chlo-
rination,ordehydration is desired, a phosgenation reaction is appropriate. The
reader can then refer to the relevant chapter and choose the best suited phosgene
equivalent or phosgene itself. The various phosgene reactions and the functional
groups that they form are presented in Scheme 4.1.
Looking at Scheme 4.1, one can see that in chloroformylation, carbonylation, and
chlorination reactions, phosgene reacts with nucleophilic groups Y
Z of monovalent
type: Z is always H, and Y is represented by the classical nucleophilic elements; the
reactivity (nucleophilicity) of the nucleophiles increases according to: thiols
a
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