Chemistry Reference
In-Depth Information
Tab. 4.49.
Triphosgene-mediated transformation of tertiary benzylamines 1759 into carbamoyl
chlorides 170 [135].
Entry
Starting compound 1759
Reaction
time (h)
Yield of
170 (%)
Ph
1
7
90
O
N
EtO
Ph
2
7
70
N
O
Et
O
Ph
3
6
86
N
Ph
Ph
4
23
36
a
N
Et
5
5
0
N
Ph
Ph
6
24
74
N
N
Ph
Ph
7
24
77
N
N
a
low yield due to the product instability
ingly, the same order of reactivity between benzyl and alkyl groups as with chloro-
formates is observed: benzyl reacts much more rapidly than an ethyl or methyl
group, thus leading to regioselective N-debenzylation.
(CCl
3
O)
2
CO
or
COCl
2
R
2
N
R
2
N
R
2
N
COCl
Cl
+
Ph
Ph
Cl
R
1
R
1
R
1
COCl
Ph
1759
170
1764
General procedure. Carbamoyl chlorides 170 from tertiary benzylamines 1759 [135]: A
solution of the benzylamine 1759 (1 equiv.) in dichloromethane (0.3 m) is added to
a solution of triphosgene (0.33 equiv.) in dichloromethane (0.1 m)at0
C under
inert atmosphere. The mixture is then allowed to warm to room temperature and
is stirred until no further change is seen by TLC. The reaction mixture is then
concentrated under reduced pressure and purified by flash chromatography.
