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Novel Application of Sulfonyl Chloride Fluoride in the Synthesis of Organophosphorus Fluorine Compounds Direct Conversion of and Groups into Groups.

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phane rapid exchange between two equivalent syn-conformations occurs, the carbenium ion 3 has a rigidly fixed
syn-conformation: in the 'H-NMR spectrum (CD2C12) a
singlet for the C H proton occurs at 6=7.71, the bridging
CH2 group appears as two sharp doublets (6=2.05 and
2.49, J = 2 2 Hz) and all eight different ferrocene protons
can be distinguished.
From the twelve signals in the I3C-NMR spectrum only
those of the carbenium C atom (6= 162.3) and the adjacent
C atoms (6= 108.1) show a significant downfield shift (remaining signals: 6= 70-90).
This conformational rigidity of cation 3 must be attributed to conjugation between the positively charged C atom
and both ferrocene units. Nevertheless, the Mossbauer
spectra of these two carbenium ions show that 3 has no
more positive charge residing on the Fe atoms than its
non-bridged counterpart 2 ; each ferrocene has accepted
one-third of the charge. This reduction in charge on the
C H group also can explain the absence of hydride transfer
in 3, whose structure would appear to predestine it to such
an exchange. In the corresponding carbanion, rapid proton transfer is known to occur["I.
The X-ray structure of the tetrafluoroborate of 3 shows
that: I ) the cation is in a fixed syn-conformation; 2) all cyclopentadienyl rings are planar within 1 pm; 3 ) in the two
ferrocene units, the rings are not coplanar but tilted by 6.6
and 7.5", respectively, opening towards the center of the
cation; 4) the Fe-C distances average 206 f 2 pm and indicate that the Fe atoms are located essentially symmetrically with respect to their ligands; 5) the positively charged
C atom is noticeably displaced towards the center of the
molecule, lying ca. 20 pm below the intersection of the two
adjacent cyclopentadienyl rings, with Fe-C' distances of
296 and 301 + 2 pm. In this way, any overlap between the
2p, orbital of the carbenium C atom and the d orbitals at
the iron atoms tends to be maximized, but the rigidity of
the cation allows this to happen only to a very limited degree. In contrast to the earlier crystallographic work, we
may be confident that, because of the cyclic structure, crystal packing forces cannot contribute significantly to the
structural deformation in3. The displacement of the carbenium C atom towards the Fe atoms must therefore be associated with the stabilization effect alone.
The three main factors in a-ferrocenyl carbenium ions
are therefore: charge distribution from the carbenium C
atom to ferrocene, conjugative interaction between the carbenium C atom and the adjacent n-system, and direct
Fe-Ce bonding. The first two stabilizing factors d o not
require geometrical changes as in l b and l c ; since the
third type of stabilization is significant in 3 (with deformation), we assume that carbenium ions of type 1 can, on the
whole, be described by lc.
Received: October 16, 1981 [Z 54 IE]
German version: Angew. Chem. 94 (1982) 313
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982. 686-695
Novel Application of Sulfonyl Chloride Fluoride
in the Synthesis of Organophosphorus Fluorine
Compounds: Direct Conversion of >P(O)H and
>P(O)OH Groups into >P(O)F Groups
By Andrzej Lopusinski and Jan Michalski*
The readily available"] sulfonyl chloride fluoride 2 has
found extensive use as solvent in the spectroscopic investigation of carbocations[21and is occasionally used in organic synthesis[31.Recently the organophosphorus fluorine
compounds RR'P(0)F and R3PF2 have been prepared
from sulfides and selenides >P=X141.
Compounds containing the >P(O)H and >P(O)OH
part structures such as 1 and 4, respectively, show the
ability to act as proton donors. We now describe a novel
method for their conversion into acid fluorides >P(O)F 3
by the action of 2 under extremely mild conditions.
Dialkyl phosphites and compounds of type 1 react at
-40°C in dichloromethane with 2 in the presence of tertiary amine to give the corresponding fluorides 3. The
most important discovery was that in dichloromethane 2
reacts smoothly at -60°C with tetracoordinate phosphorus acid salts 4 to give fluorides 3 in very high yield. At
higher temperatures the chlorides RR'P(0)CI are formed
in addition to 3. Presumably the reaction proceeds via the
mixed anhydrides RR'P(0)OS02CI as reactive intermediates.
K\ O0
P + CISOzF
p'
294
0 Verlag Chemie GmbH. 6940 Weinheim, 1982
H
1
-
R\
P
P
R" 'F
2
+
Q
O
Et,NH S0,Cl
3
a, R = R'= OEt
4
b, R = rBu, R'= P h
3
Experimental
3b: 2 (1.5 g, 0.012 mol) was added to a solution of tertbutyl(pheny1)phosphinic acid 4b (1.9 g, 0.01 mol) in 15 mL
of CH2CI, and Et3N (1.0 g, 0.01 mol) at -65°C. The reaction mixture was stirred at -55°C to -60°C for 2 h and
held at 0°C for additional 6 h. The solution was washed
with 15 mL of H 2 0 and the organic layer dried over
MgS04. Distillation gave 1.5 g (75%) of tert-butyl(pheny1)phosphinic acid fluoride 3b, b. p. =68 -70 "CI0.2 torr,
c ~ ( ~ ' P )+58.63,
=
J p F = 1048 Hz, S(I9F)= +98.34 (CFCI,
int.).
3a: Diethylfluorphosphate 3a was obtained in a similar
procedure from l a (1.3 g, 0.01 mol), Et3N (1.0 g, 0.01 mol),
and 2 (1.5 g, 0.012 mol) at -40°C in 85% yield:
b.p.=59-6O0C/12 torr, S(3'P)= -9.4, JpF=964 Hz.
Received: December 15, 1981 [Z 55 IE]
German version: Angew. Chem. 94 (1982) 302
[*I
171 U. Behrens, J. Organomer. Chem. 182 (1979) 89.
181 a) S. Lupan, M. Kapon, M. Cais, F. H. Herbstein, Angew. Chem. 84
(1972) 1106: Angew. Chem. I n t . Ed. Engl. 1 I (1972) 1025: b) R. Gleiter,
R. Seeger, H. Binder, E. Fluck, M. Cais, Angew. Chern. 84 (1972) 1107;
Angew. Chem. Int. Ed. Engl. I 1 (1972) 1028; c) M. Cais, S. Dani, F. H.
Herbstein, M. Kapon, J. Am. Chem. SOC.100 (1978) 5554.
I151 A. Cassens, P. Eilbracht, A. Nazzal, W. Prossdorf, U. T. Mueller-Westerhoff, J. Am. Chem. Sot. 103 (1981) 6367.
[IS] U. T. Mueller-Westerhoff, A. Nazzal, W. Prhssdorf, J. Am. Chem. Soc.
103 (1981) 7678.
\
Prof. Dr. J. Michalski, Dr. A. topusinski
Polish Academy of Sciences,
Centre of Molecular and Macromolecular Studies
Boczna 5, PL-90-362 Lodz (Poland)
[I] C. W. Tullock, D. D. Coffmann, J. Org. Chem. 25 (1960) 2016.
[21 G. A. Olah, D. J. Donovan, J. Am. Chem. Soc. 100 (1978) 5163.
131 G. A. Olah, S. C. Narang, A. Garcia-Luna, Synthesis 1980. 659; 661 ; M.
Hedayatullah, A. Guy, Phosphorus Sulfur 7 ( 1979) 95; G. A. Sokolskii, Zh.
Obshch. Khim. 36 (1966) 860.
141 A. Lopusinski, J. Michalski, J. Am. Chern. SOC.104 (1982) 290.
0570-0833/82/0404-0294 $02.50/0
Angew. Chem. Inl. Ed. Engl. 21 (1982) No. 4
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synthesis, compounds, fluoride, application, group, direct, novem, fluorine, chloride, organophosphorus, sulfonyl, conversion
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