First example of stereoselective Aza-Perkow reaction

Full text of DOI:10.1023/A:1012310329462

Russian Journal of General Chemistry, Vol. 71, No. 1, 2001, pp. 143 144. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 1, 2001,
pp. 157 158.
Original Russian Text Copyright
2001 by Onys’ko, Kim, Kiseleva, Sinitsa.
LETTERS
TO THE EDITOR
First Example of Stereoselective Aza-Perkow Reaction
P. P. Onys’ko, T. V. Kim, E. I. Kiseleva, and A. D. Sinitsa
Institute of Organic Chemistry, Ukrainian National Academy of Sciences, Kiev, Ukraine
Received April 13, 2000
Reactions of N-benzylpolychloroalkylimidoyl chlo-
rides RHlgCCl=NCH2Ph with trialkyl phosphites pro-
ceed unusually and, depending on the number of -at-
oms of chlorine, yield either C,N-diphosphorylated
vinylamides (RHlg = CCl3) [1] or C-phosphorylated
azadienes (RHlg = Me2CCl) [2]. The behavior of N-
benzyldichloroacetimidoyl chloride I in this reaction
is of particular interest, because it furnishes informa-
tion not only on the direction but also on stereochem-
istry of the process.
Only one geometric isomer of III was detected,
which shows that the reaction of the aza-Perkow type
is highly stereoselective. Large coupling constant
between the phosphorus and the proton at the double
bond (3JHP 30.6 Hz) indicates the trans arrangement
of the proton and phosphoryl group (cf. [4]).
Formation of diphosphorylated product III even at
an excess of imidoyl chloride I shows that interme-
diates A and B exhibit considerably higher reactivity
in relation to phosphite than the starting imidoyl
chloride. For example, the 31P NMR data show that
the final mixture obtained in the reaction of equimolar
amounts of compounds I and II (80 90 C, 1 h) con-
tains bisphosphorylated vinylamide III ( 65 mol %),
azadiene IV (5 10%), and unidentified products
( 25%). At a 1 : 2 ratio of I and II the yield of vi-
nylamide decreases. Phosphorylated azabutadiene IV
is evidently formed by dehydrochlorination of inter-
mediates A and B (cf. [2]). It was prepared indepen-
dently by the reaction of dichloroazadiene V with tri-
ethyl phosphite.
We have found that imidoyl chloride I, irrespective
of the reactant ratio, reacts with 2 mol of triethyl
phosphite to give chlorovinylphosphoroamidate III.
Note that it is the first example of the reaction of
aza-Perkow type involving the CHCl2 group. Analo-
gous transformations were previously known only for
the derivatives containing CCl3 and CF3 groups at
the C=N bond [3].
CHCl2
+ (EtO)3P
N
CH2Ph
Cl
I
II
+
Et3N
(EtO)3P
P(OEt)3
Cl
CHCl2
I
CHCl=C(Cl)N=CHPh
IV
(2)
V
N
CH2Ph
A
It is noteworthy that reactions (1) and (2) yield
the same geometric isomer of phosphonate IV, and
dehydrochlorination of I also yields a single geomet-
ric isomer of chloroazabutadiene V. The coupling con-
stant between the phosphorus atom and the proton in
azadiene IV (3JHP 9.4 Hz) is considerably smaller
than that in vinylamide III and suggests the cis lo-
cation of hydrogen and the phosphoryl group. Thus,
the aza-Perkow reaction as well as phosphorylation of
chloroazadiene V yield sterically less hindered iso-
mers of III and IV.
EtCl
O P(OEt)2
N
B
CHCl2
CH2Ph
P(OEt)2
O
N CH2Ph
H
(EtO)3P
Cl
III
P(OEt)2
(1)
O
Ph
N
N-Benzyldichloracetimidoyl chloride I was pre-
pared by the reaction of N-benzyldichloroacetamide
with phosphorus pentachloride. Yield 72%, bp 98
Cl
H
P(OEt)2
O
HCl
1
IV
99 C/0.09 mm. H NMR spectrum (CDCl3), , ppm:
1070-3632/01/7101-0143$25.00 2001 MAIK Nauka/Interperiodica

144
ONYS’KO et al.
4.75 s (2H, CH2), 6.37 s (1H, Cl2CH), 7.4 m (5H,
Ph). Found, %: Cl 45.15; N 6.01. C9H8Cl3N. Calcu-
lated, %: Cl 44.97; N 5.92.
amount of triethylamine was added at 20 C. A day
later the precipitate was filtered off, the filtrate was
evaporated, and the residue was distilled in a vacuum.
Yield 88%, bp 97 100 C/0.09 mm Hg. 1H NMR
spectrum (CDCl3), , ppm: 6.88 s (1H, =CHCl),
7.4 m (3H) and 7.8 m (2H) (Ph), 8.44 (1H, =CHN).
Found, %: Cl 34.82; N 6.79. C9H7Cl2N. Calcu-
lated, %: Cl 35.44, N 7.0.
(Z)-1-Chloro-2,3-bis(diethoxyphosphoryl)-4-phe-
nyl-3-aza-1-butene III. A mixture of equimolar
amounts of imidoyl chloride I and triethyl phosphite
was heated in a Claisen flask at 80 90 C until the gas
evolution ceased ( 1 h) and then was distilled. Yield
1
1
The H and 31P NMR spectra were recorded on
35%, bp 173 179 C/0.05 mm Hg. H NMR spectrum
(CDCl3), , ppm: 1.4 m (12H, Me), 4.2 m (8H,
a Varian VXR-300 spectrometer, working frequencies
299.5 and 121.42 MHz, respectively. The chemical
shifts were measured against internal TMS (1H) and
external 85% phosphoric acid (31P).
OCH2), 4.69 d (2H, CH2N, 3JCH NP 9.6 Hz), 6.45 d.d
2
3
4
(1H, =CH, JHP 30.6, JHP 2.6 Hz), 7.3 m (5H, Ph).
31P NMR spectrum (CDCl3), P, ppm: 5.0 m (1P,
3
NP), 9.7 d.m (1P, =CP, JPC=CH 30.6 Hz). Found, %:
ACKNOWLEDGMENTS
Cl 7.60; N 3.32; P 14.28. C17H18ClNO6P2. Calcu-
lated, %: Cl 8.06; N 3.18; P 14.08.
The work was financially supported by the Ukrain-
ian State Foundation for Basic Research (project
no. 3.4/207).
4-Chloro-3-(diethoxyphosphoryl)-1-phenyl-2-aza-
1,3-butadiene IV was prepared by heating of a 1 : 2
mixture of dichloroazadiene V and (EtO)3P at 90
100 C for 1 h. Yield 35%. The compound was not
isolated analyticaly pure; after distillation it con-
tained about 25 mol % unidentified admixtutes ( P 12,
7.1, and 3.8 ppm). The spectral characteristics of IV
were close to those of the previously synthesized phos-
REFERENCES
1. Sinitsa, A.D., Onys’ko, P.P., Kim, T.V., Kiseleva, E.I.,
and Pirozhenko, V.V., Zh. Obshch. Khim., 1986,
vol. 56, no. 12, pp. 2681 2689.
1
phorylated azadienes [2]. H NMR spectrum (CDCl3),
2. Sinitsa, A.D., Maidanovich, N.K., Onys’ko, P.P., and
Shurubura, A.K., Zh. Obshch. Khim., 1989, vol. 59,
no. 11, pp. 2492 2497.
, ppm: 1.34 t (Me, JHH 7.5 Hz), 4.2 m (OCH2),
3
6.78 d (1H, CHCl, JHP 9.4 Hz), 7.5 m and 7.8 m
4
(Ph), 8.45 d (1H, CH=N, JHP 1.8 Hz). 31P NMR
3. Sinitsya, A.A., Kolotilo, M.V., and Onis’ko, P.P., Ukr.
Khim. Zh., 1998, vol. 64, no. 5, pp. 48 67.
spectrum (CDCl3), P, ppm: 9.8.
1,2-Dichloro-4-phenyl-2-aza-1,3-butadiene V. To
a solution of imidoyl chloride I in ether an equimolar
4. Quian, D.Q., Shi, X.D., Cao, R.Z., and Liu, L.Z.,
Heteroatom Chem., 1999, vol. 10, no. 4, pp. 271 276.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 1 2001