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Doubly Metalated Thiobenzyl AlcoholЧThiobenzaldehyde Dianion.

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are apparently not registered owing to the low solubility of
(3).
In addition to HV(C0)3(n-C6H3(CH3)3)151
we now have
another defined hydrido complex of vanadium in HV(PF,),.
Whether the above synthetic route is suitable for the preparation of hexakis(trifluorophosphane)metal hydrides of higher
homologs of vanadium which may also be capable of existence
is currently under study.
Experimental:
All operations are performed under nitrogen; the solvents
are purified in the usual way and saturated with nitrogen.
Bis (diglyme) sodium hexakis (trifluorophosphane) vanadate(1)
(2)
A solution of ( 1 ) (7.00 g, 13.7 mmol) in diglyme (150 ml) is
cooled to -45°C and saturated with PF, in an irradiation
apparatus (Duran 50) with internal cooling and an external
vacuum jacket. The vigorously stirred reaction mixture is
irradiated for 24 h with an external high-pressure mercury
arc lamp (Q 600 Hanau) until evolution of CO is no longer
observed. The solution must be resaturated several times with
PF3 during the reaction. The solvent is then removed in
a high vacuum and the residue washed twice with light petroleum. The product thus obtained is sufficiently pure for the
synthesis of (3). Analytically pure samples are obtained by
recrystallizing from diglyme with light petroleum. Yield :
11.64g (98%).
Dianions of this kind have hitherto been generated exclusively
by reaction of carbonyl derivatives with alkali metals"]. We
.I
I
I/
131
14)
now report the first preparation of such a reagent with X = S
by double metalation of the corresponding hydrogenated precursor.
Reaction of a solution of lithium benzyl sulfide (3) with
n-butyllithium, in the presence (2.5 h) or absence (4.0h) of
tetramethylethylenediamine (TMEDA), at - 5 "C in THF/pentane (1 : 1) leads to an orange-colored suspension of the dilithium salt ( 4 ) . The presence of the dianion is deduced from
its reactions with various electrophiles, which we generally
add at - 78 "C. The products listed in Table 1 can be divided
into three different types ( 5 ) , ( 6 ) , and (7).
Hexakis(trifluorophosphane)vanadiwn hydride ( 3 )
Compound (2) (5.00g, 5.7 mmol) and crystalline orthophosphoric acid (50g, 510mmol) are heated to 60°C in a flask
fitted with a cold trap. The resulting hydrido complex is
immediately drawn off into the cold trap (- 196°C) by a
high vacuum and then sublimed at 50"C/10-z torr over P4010
in order to remove residual traces of water. Yield 2.26 g (68 YO)
of ( 3 ) .
Received: October 23, 1973 [Z 957 IE]
German version: Angew. Chem. 86, 233 (1974)
Publication delayed at authors' request
[11 Trifluorophosphanemetal Complexes, Part 46. This work was supported
by the Deutsche Forschungsgemeinschaft.-Part 45: Th. Kruck, H. Jung,
M. Hofler, and H . Blume, Chem. Ber., in press.
[2] Tk.Kruck, Angew. Chem. 79, 27 (1967); Angew. Chem. internat. Edit.
6, 53 ( I 967).
[ 3 ] R. P. M. Werner and H. E . Podall, Chem. Ind. [London) 1961, 144.
[4] We are grateful to Dr. G.SyIuesterand Mrs. C. Breitkopffor the magnetic
measurements, Dip1.-Chem. W Molls, for recording the mass spectra, Prof.
Dr. H. Gunrher and DipLChem. H. Schmickler, for recording the NMR
spectra, and to BASF, Ludwigshafen, for the C, H analyses.
[ 5 ] A. Dauison and D. L. Reger, J. Organometal. Chem. 23,491 (1970).
Doubly Metalated Thiobenzyl AlcoholThiobenzaldehyde Dianion[**l
By Dieter Seebach and Karl-Heinz Geiss"]
Carbonyl compounds and their analogs always react with
nucleophiles ( N ) ( 1 ) at the C atom. The polarity of this
reaction can be reversed in favor of electrophiles (E) in the
case of dianions (2).
[*] Prof. Dr. D. Seebach and Dip].-Chem. K.-H. Geiss
Institut fur Organische Chemie, Fachbereich 14 der Universitat
63 Giessen, Ludwigstrasse 21 [Germany)
[**I This work was supported by the Fonds der Chemischen Industrie
and the Deutsche Forschungsgemeinschaft. We thank G. Protschuk for his
assistance in a number of experiments.
202
1) Thiols of type (5) are formed with an aldehyde, a ketone,
or trimethylchlorosilane (molar ratio 1 : I).
2) Derivatives of type (6) are produced with halides, epoxides,
or trimethylchlorosilane (molar ratio 1 :2).
3) Compounds of type (7) formed by addition of two different
electrophiles to C and S are obtained by consecutive treatment
with (i) aldehyde, ketone, or trimethylchlorosilane and (ii)
methyl iodide (molar ratio 1 : 1 in each case).
Special mention should also be made of the tetrahydrothiophenes (8) and (9) obtainable with 1,3-dibromopropane and
epichlorohydrin, respectively, and the mixed dithioacetal ( 1 1)
resulting on benzylation of the primary adduct ( 1 0 ) generated
with dimethyl disulfide, which is apparently stable under the
reaction conditions. Yields (not optimized) and physical data
of the derivatives ( 5 ) - ( 9 ) and (11) are given in Table 1.
All the IR and NMR spectra and the results of elemental
analysis are in accordance with the structures given. Products
having more than one center of asymmetry were isolated
as mixtures of diastereoisomers.
Doubly metalated thiobenzyl alcohol is remarkably
After storage for two weeks at +S"C about 30% of the
dianion remains undecomposed. The decomposition products
have not yet been studied in detail.
Angew. Chem. internal. Edit. 1 Vol. 13 (1974) 1 No. 3
( 4 ) is a readily available, strongly nucleophilic, heterosubstituted carbanion whose reaction products with electrophiles
The Pseudogeminal "Quinhydrone" of the [2.2] Paracyclophane Series[']
By Walter Rebafka and Heinz A . StaabL.1
Table 1. Yields [a] and physical data of the compounds ( 5 ) - ( 9 ) and ( 1 1 ) .
Product
E'
Yield [a]
["/.I
73
[.I
145/0.02
70
[lit. [d]
150-1 55/0.04]
(1.6096)
65/25
(1.5495: lit.
[el 1.5497
72
93
70
4310.1
( 1.5413)
cfl
-
17010.4
1.5402)
non-distillable
oil
80/0.2
(1.5313)
I I0/0.05
(1.5358)
130/0.9
(1.5651)
f
80
91
90
76
O<,H
34 [gl
140/0.03
61 [hl
130/0.08
CH 3
82
CH3
48
160/0.05
(1.6025)
m. p.
100.4-101.6 "C
100/1.3
(1.5839;
lit. [i] 1.5839)
13010.5
[ 1.6004)
l40/0.03
[ I .6195)
CH3
67
44
13
[a] Based on distilled or recrystallized product using lOmmol amounts of
starting materials.
[b] Oil bath temperature o n molecular distillation.
[c] NMR data identical with those reported in the literature: A. W i g h t et
a/., J. Amer. Chem. SOC.94, 4784 (1972).
[d] C . Djrrassi et a/., J. Amer. Chem. SOC.77, 568 (1955).
[e] W. E . Bacon and W M . Le Suer, J. Amer. Chem. SOC.76, 670 (1954).
[q Determined by spectroscopy; the product very readily loses the S-silyl
group.
[g] In addition, 45 YOof a 1 : 1 mixture of the enolization products (camphor
and benzyl methyl sulfide) are obtained.
[h] In addition 14% of the 1,4 adduct are present.
[i] R . D. Obolentseu and V. G. Bukharou, Chem. Abstr. 5 5 , 25908b (1961).
are open to a variety of transformations. Preliminary experiments show that other thiols can also be doubly metalated.
Received: October 25, 1973 [Z 958 IE]
German version: Angew. Chem. 86,202 (1974)
[ l ] Examples of (CeHs)*C=X are
X = 0: P . J. Hamrick and C. R. Hauser, J. Amer. Chem. SOC.81, 493 (1959);
X = N-C6Hs: J . G . Smith and R . A. Turk, J. Org. Chem. 37, 126 (1972);
X = S : !l Minoura and S . Tsuboi, J . Org. Chem. 37, 2064 (1972). There
is an otherwise unconfirmed report in the patent literature [ D . 0. De Pree
and J . D. Johnston, US-Pat. 3239568, Chem. Abstr. 64, 15921 (1966)] that
disodium derivatives can be obtained from aliphatic alcohols and alkylated
at carbon.
[2] The formation of 2 % of stilbene from thiobenzyl alcohol and potassium
tert-butoxide in dimethyl sulfoxide at +8O"C was explained in terms of
an a elimination of the postulated thiobenzyl alcohol dianion: 7: J . Wallace,
H . Pobiner, J . E . Hofmann, and A. Schriesheim, J Chem. SOC.1965, 1271.
Angrw. Chem. internal.
Edit. / Vol. 13 ( 1 9 7 4 ) / No. 3
For the investigation of intramolecular donor-acceptor interactions a comparison of the two stereoisomeric "quinhydrones" ( I a) and ( I b ) of the [2.2]paracyclophane seriesrz1
was thought to be promising: although the total electron
affinity of the acceptor and the total ionization energy of
the donor are the same in (I a) and ( I b) the sterical conditions
for n-electron overlap and the differences of charge densities
on opposite carbon atoms are characteristically different in the
two systems.Therefore some information about the importance
of sterical factors and of local conditions to donor-acceptor
interactions was to be expected.
@
(la)
/
' ,
OH
o@
'OH
(lb)
0
Synthesis and properties of the pseudoortho compound ( I a )
have been reported recently"]. The pseudogeminal stereoisomer ( I b ) was not obtainable in an analogous reaction
sequence since ring contraction of both diastereomeric
5,8,14,17-tetramethoxy-2,11
-dithia[3.3]paracyclophanes using
three different methods yielded only the chiral 4,7,12,15-tetramethoxy[2.2]paracyclophane (Za)"] but not the achiral pseudogeminal (Zb). The exclusive formation of ( 2 a ) with the
sterically more favored arrangement of the four methoxy
groups is explained on the assumption that a two-step radical
mechanism of the three ring-contraction methods allows formation of the thermodynamically more stable stereoisomer
by the rotation of an aryl unit through 180°[3J.On the basis
of this assumption the following synthesis of (Zb) was developed.
Treatment of 1,4-dibromo-2,5-dimethoxy-3,6-dimethylbenzenel'] (prepared from 1,4-dimetho~y-2,5-dimethylbenzene[~~
by electrophilic bromination, 80 %, m. p. 125-1 26 "C) with
N-bromosuccinimide/carbon tetrachloride yielded 1,4-dibromo-2,5-dimethoxy-3,6-bis(bromomethyl)benzene~41
(85%,
m.p. 194-195 "C) which was cyclized with 1,4-bis(mercaptomethyl)-2,5-dimethoxybenzene to give 5,8-dibromo-6,9,14,17tetramethoxy-2,11-dithia[3.3]paracyclophane~41 (conditions
cf.['], 7-15%, m. p. 235-237 oC)[61.By irradiation in triethyl
phosphite (450-W Hg high-pressure lamp, 16 h) a mixture of both stereoisomeric 4,7-dibromo-5,8,12,15-tetra-
[*] DiplLChem. W. Rebafka and Prof. Dr. H. A. Staab
Institut fur Organische Chemie der Universitat
69 Heidelberg, Im Neuenheimer Feld 7 (Germany)
203
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thiobenzyl, alcoholчthiobenzaldehyde, double, dianion, metalated
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