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Novel Reactions of 5-Phosphorins and Their Tricarbonylchromium Complexes.

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tablishes a conformation corresponding to that of (
which accounts for the notable persistence of (3a) (tl,z = 1
h a t +40"C).
The coupling constant of the methylene protons in (2)
(ca. 0.4 mT) is considerably smaller than in (34 (ca. 1.0
mT).This is consistent with the structure of a radical anion: coupling constants of b-protons are always much
smaller in radical anions than in the corresponding radical
The "B coupling constant of 0.08 mT is surprisingly
small[81.Splittings of this magnitude can remain undiscovered in broad lines of incompletely resolved ESR spectra.
Attempts to reduce persistent tetraalkyldiboranes(4) to radical anions were previously interpreted as unsuccessful[91,
because the ESR spectra showed no splitting from the two
boron atoms. The results found with (2). however, indicate
that this could be accounted for by the linewidth of 0.36
mT. The persistence of the radical observed on reduction
of 1,2-di-tert-butyl- 1,2-dineopentyldiborane(4) is comparable to that of (2), indicating that another species with a
B-B one electron z-bond is involved.
from the I3C-NMR signals of C-2/6 and C-4, and the I3C31Pcoupling constants[*I,as well as from the ESR spectra
of free radicals formed by the oxidation of (I)[31. We describe the first chemical evidence for the ylide character of
( I ) using a strong base to remove a proton from the a-position of suitable P-substituents (primary or secondary alkyl
groups). A "double" ylide (3) is obtained which adds electrophiles (E), such as D+, CH:, or PhCH:, to give (4).
(46). E = Me, can be deprotonated again, and yields the
I-isopropyl derivative (4d) with MeI. Benzaldehyde reacts
with (3) to give the $-hydroxy compound (S), which forms
the olefin (6) with alcoholic solutions of sodium hydroxide. No Wittig olefination is observed.
Received: March 13, 1981 [Z 869 IE]
German version: Angew. Chem. 93, 903 (1981)
CAS Registry numbers:
(la). 79057-63-9; (Za), 79044-42-1;(3a). 79044-43-2
By Karl Dimroth and Hans Kaletsch"]
Dedicated to Professor Sisfried Hiinig on the occasion
of his 60th birthday
2,4,6-Trisubstituted h5-phosphorins of type (I)[11are not
"non-classical" 6n-heteroarenes, but cyclic phosphorus
ylides whose negative charge is delocalized over the pentadienyl moiety and whose positive charge, depending on
the substituents R',R" is, to a greater or lesser extent, localized on the phosphorus atom''"'. This can be established
Prof. Dr. I(. Dimroth, H. Kaletsch
Fachbereich Chemie der Universitxt
Hans-Meenvein-Strasse, D-3550Marburg (Germany)
No. 10
Novel Reactions of k'-Phosphorins
and Their Tricarbonylchromium Complexes
Angew. Chem Int. Ed Engl. 20 (1981)
+ BuLi
Ill Boron-boron n-bonds also accur in two C2B,H:--heterocycles which are
isoelectronic with CsH3. These, however, are only known as the central
ligands of tripledecker sandwich complexes [2].
121 W. T. Robinson. R. N. Grimes. Inorg. Chem. 24, 3056 (1975), and references cited therein.
[3] The structure [ary12B-BarylZ]:, aryl=p-(CH&N-C6H4, with E-B xbond contribution has been suggested by Leffrer et al. 141 for a radical
formed reversibly from Ar3B and Na/K, and which shows a
1:2:3:4:3:2:1 multiplet with 0.31 mT intervals in the ESR spectrum.
This structure, however, is not consistent with the absence of a splitting
from the 8 o-protons which should be ca. half the magnitude of that in
(C6Hs),B: (aH=0.199 mT [4]).
[4] J. E. Leffler, G. B. Watts. T. Tanigaki. E. Dolan. D. S. Miller, J. Am.
Chem. SOC. 92, 6825 (1970).
IS] The combination "B-"B
occurs with 65.9% probability. The lines expected for the Combination "B-'OB (30.6%) (a'"=0.08 and aioE=0.027
mT) are not resolved due to an experimental linewidth of 0.025 mT.
161 Calculated with oH=B.cos2(60k@),@=torsion angle.
(71 Review: K. Scfiejjler. H. B. Sfegmann:Elektronenspinresonanz, SpringerVerlag, Berlin 1970, p. 461 pp.
[8] Assuming that the Karplus-Fraenkel relationship a x =(Q: -QZ) .p is
valid for X = B, the 5-nparameters Q: and QT,whose values are considerably different (ca. 4.0 and 1.4 mT) when X = C, must be approximately
equal (QY-Q;=O.I6 mT) when X=B.
191 K. Scfiliiter. A . Berndt, Angew. Chem. 92, 64 (1980); Angew. Chem. Int.
Ed. Engl. 19, 57 (1980).
(//, R = P h , rB,
R', R"= M e , E t , P h ,
NK;, O M e , SEt, C1, B r . 1 , etc.
In the nonplanar'", highly stablers1P,P-substituted tricar-
bony1(~'-2,4,6-triphenyl-h5-phosphorin)chromium derivative (7), the ylide character is strengthened by the electronic buffer-effect of the Cr(CO)3 moietyf6]which leads to
increased delocalization of the negative charge. Compounds of type (7) are obtained either from reaction of h5phosphorins with Cr(CO)6, whereby the larger residue R"
assumes the exo-po~ition~~'~,
or from tricarbonyl(2,4,6-triphenyl-h3-phosphorin)chromium[71via em-addition of nucleophiles and subsequent reaction with electrophiles (at
the endo-position)"]. If R' and/or R" are primary or secondary alkyl groups, the same sequence of deprotonation
and addition of electrophiles as in the h5-phosphorins can
be performed. However, with the bulky base Ph,C- only
the exo-rnethyl group of the 1,l-dimethyl complex (8) is deprotonated and subsequently deuterated to (9) with D20,
(8). R
R"= CH3
while with BuLi both the exo- and endo-CH3 groups are
deprotonated to almost an equal extent. With DzO, therefore, a mixture of (9) and its endo-CHzD isomer is obtained. The I-endo-methyl-1-exo-phenylcomplex, which
0 Verlag Chemie CmbH. 6940 Weinherm. 1981
0570-0833/81/1010-0871 S 02.50/0
87 1
produced the “double” ylide complex with BuLi [cf.
(2)- (3)],was thoroughly investigated. D and CH: give
(IOU-b), and benzaldehyde (11) from which (12) is obtained.
171 a ) J . Deberilz. H. Noth. Chem. Ber. 103, 2541 (1970); b) Tricarbonyl(2,4,6tri-terr-butyl-b’-phosphorin)chromium(m. p. 135- 137“C) can readily be
obtained (in 7009 yield) as a crystalline compound from the reaction of
2,4,6-tri-lerr-butyl-~’-phosphorin with Cr(CH,CN),(CO),, and reacted
with nucleophiles and electrophiles.
IS] K . Dirnrorh. H. Kaletsch. Pol. J. Chem. in press.
[9] H. F. Semrnelhack, H. T.Hall, R. Farina, M . Yashijiuji. G. Clark, T. Barger, K. Hirotsu, J. Clardy, J. Am. Chem. SOC.101, 3535 (1979).
Bis(trimethylgermyl)magnesium, the First
Organogermylmagnesium Compound Isolated[**’
Careful oxidation of the Cr(CO), complex resulted in
cleavage of the tricarbonylchromium moiety, by analogy to
carbocyclic $-tricarbonylchromium benzene complexes191,
whereby h5-phosphorins having the novel substituents R’
and R“ at phosphorus are produced.
1.2 Stoichiometric amounts of nBuLi are added to a solution of (2), or its tricarbonylchromium complex, in anhydrous tetrahydrofuran (THF) under argon, and the mixture
stirred for 30 min. D20, CH31, PhCH,Br, or PhCHO are
then added, and the mixture stirred for a further 30 min,
allowed to warm up to room temperature, the solvent removed by evaporation, and the residue chromatographed
on A1203(neutral) using benzene, or in the case of (IOU, b)
on S O 2 using CH,Cl,/petroleum ether (70--80°C) 1 : 1 ;
(12) is purified by HPLC.
By Lutz Rosch“’
Dedicated to Professor Ferdinand Bohlmann on the
occasion of his 60th birthday
Organogermylmagnesium compounds have frequently
been postulated as intermediates“’. We now wish to report
the successful isolation of bis(trimethy1germyl)magnesium.2 DME (= dimethoxyethane) ( I ) and hence establish
the ability of organogermylmagnesium to exist.
(I) is synthesized in an analogous manner to the homologous silyl compound (2)121(see procedure). The wellformed colorless crystals of (1) decompose immediately on
contact with the air, however, without the spontaneous ignition observed with (2)I’l. Apart from the signals from the
coordinated DME, the ‘H-NMR spectrum of (I) in benzene shows only one sharp signal for the trimethylgermyl
protons (in the vicinity of the TMS-signals); the ratio
DME :Me,Ge amounts to 1 :1. Decomposition of (1) with
water or D 2 0 produces trimethylgermane or deuterio(trimethyl)germane, respectively. The results of the elemental
M.p. r C ]
Yield [%I
MS ( M + , [%I)
417 (100)
430 (81)
506 (35)
444 (41)
522 (55)
504 (100)
553 (44)
566 (11)
658 (100)
640 (100)
Mg[Si(CH3),12. C4H,002
analysis were corroborated by the mass spectrum. This
shows a weak signal from the molecular ion with the expected isotopic splitting, as well as signals from the expected cleavage products. (1) melts at 90”C, accompanied
by slight discoloration. A sample which is heated to 100°C
for 10 min with dilute HCI yields, apart from trimethylgermane, a small amount of methane. This indicates that dimethylgermanediyl is produced during the decomposition
and that the latter proceeds relatively slowly at this temperature.
(8) (0.4 g) is treated with the stoichiometric amount of
Ph3CNa in THF and after 30 min, I mL of D 2 0 is added.
(9)ISb1(0.350 g, 90%, m.p. 276-277”C, MS 491 (13%)) is
obtained after chromatography on SiOz.
Received: April 27, 1981 [Z 870 IE]
German version: Angew. Chem. 93, 898 (1981)
CAS Registry numbers:
(2). 13689-25-3; (3), 79044-36-3; (4a). 79044-37-4; (461, 20442-47-1; ( 4 ~ ) .
79044-38-5; (4d). 79044-39-6; (51, 79044-40-9; (6). 79044-41-0; (8), 79101-614; (Y), 79101-62-5; (Ion), 79101-63-6; (lob). 79101-64-7; (lor). 79101-65-8;
(I I). 79101-66-9; ( I 2). 7912 1-00-9
[I1 K . Dirnroth, Fortschr. Chem. Forsch. (Top. Curr. Chem.) 38, 1 (1973).
121 a) K. Dirnroth, Sl. Berger, H . Kalefsch. Phosphorus Sulfur, in press; b) T.
Bundgaard. H . 1.lacobsen, K. Dirnrorh, H. H. Pohl. Tetrahedron Lett.
1974. 3 179.
131 K . Dirnroth. W.Heide, Chem. Ber. 114, 3004, 3019 (1981).
141 T. Debaerdemaeker. Acta Crystallogr. B 35, 1686 (1979).
I51 a) M. Luckoff.K . Dimroth, Angew. Chem. 88. 543 (1976); Angew. Chem.
In!. Ed. Engl. I S . 503 (1976); b) K. Dimroth, M. LuckoH, H . Kaletsch.
Phosphorus Sulfur, in press.
I61 W.M . McFarlane. S. 0.Grim,J. Organomet. Chem. 5, 147 (1966).
0 Verlag Chemie GmbH. 6940 Weinheim. 1981
All reactions were conducted under conditions of rigorous exclusion of air and moisture under argon.
(Me,Ge),Hg (9 g) is dissolved in 70 mL of anhydrous
DME and stirred with Mg (4 g) until the initially formed
red color disappears (ca. 3 d). The dark solution is then filtered through a glass frit; the volatile fraction of the filtrate is removed using an oil vacuum pump. The solid residue is taken up in ca. 40 mL of anhydrous Et20. The solution is allowed to settle and separated from the undissolved material. Approximately 5 g of colorless ( I ) crystallizes out at -2O”C, m.p. ~ 9 0 ° C
Received: March 16, 1981 [Z 872 IE]
German version: Angew. Chem. 93, 894 (1981)
CAS Registry numbers:
(I). 79121-08-7: (Me,Ge)2Hg, 13915-91-8
Priv.-Doz. Dr. L. R6sch
Institut fur Anorganische und Analytische Chemie
der Technischen UniversitPt
Strasse des 17. Juni 135, D-1000 Berlin 12 (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft
OS70-0833/81/1010-0872 $ 02.SO/O
Angew. Chem. Inl. Ed. Engl. 20 (1981) No. 10
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phosphorite, thein, reaction, tricarbonylchromium, novem, complexes
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