Synthesis and downstream reactions of 2-(triphenylphosphino)-4,5-dicarbomethoxy-1,3-diselenole tetrafluoroborate: X-ray crystal structure of a nitroso derivative of a 2-ylidene-1,3-diselenole stabilized by an intramolecular O...Se interaction

Article abstract of DOI:10.1021/jo951979n

The title 1,3-diselenole Wittig reagent 9 has been synthesised by a new, efficient route from readily-available starting materials and reacted with a variety of functionalized aldehydes to form the corresponding 2-ylidene-1,3-diselenones 12 in respectable yields. X-ray analysis of a nitrosated derivative 14e, prepared by the reaction of 12e with isoamyl nitrite, has provided the first direct evidence for the stabilization of such systems by intramolecular oxygen-selenium interactions.

Full text of DOI:10.1021/jo951979n

J . Org. Chem. 1996, 61, 2877-2881
2877
Syn th esis a n d Dow n str ea m Rea ction s of
2
-(Tr ip h en ylp h osp h in o)-4,5-d ica r bom eth oxy-1,3-d iselen ole
Tetr a flu or obor a te: X-r a y Cr ysta l Str u ctu r e of a Nitr oso Der iva tive
of a 2-Ylid en e-1,3-d iselen ole Sta bilized by a n In tr a m olecu la r
O‚‚‚Se In ter a ction
Antony Chesney, Martin R. Bryce,* Michael A. Chalton, Andrei S. Batsanov, and
J udith A. K. Howard
Department of Chemistry, University of Durham, Durham DH1 3LE, UK
J ean-Marc Fabre, Laurent Binet, and Sa ¨ı d Chakroune
Laboratoire de chimie organique structurale, Universit e´ Montpellier II (MSTL) 340695 Montpellier
Cedex 5, France
Received November 7, 1995X
The title 1,3-diselenole Wittig reagent 9 has been synthesised by a new, efficient route from readily-
available starting materials and reacted with a variety of functionalized aldehydes to form the
corresponding 2-ylidene-1,3-diselenones 12 in respectable yields. X-ray analysis of a nitrosated
derivative 14e, prepared by the reaction of 12e with isoamyl nitrite, has provided the first direct
evidence for the stabilization of such systems by intramolecular oxygen-selenium interactions.
The chemistry of the 1,3-dithiole ring system has been
extensively studied primarily due to the many important
properties which make it an attractive building block for
syntheses.8 We recently investigated the application of
1,3-dithiole Wittig reagents including 1b in the synthesis
9
of highly functionalized 1,3-dithiole-2-ylidene systems 2
1
the synthesis of new materials. Some of these features
which were subsequently transformed into nitroso-alkene
are as follows: (i) the ring system is readily accessible
from simple starting materials, and a large number of
functionalities (including fused rings) can be incorporated
into the 4- and 5-positions; (ii) the system is readily
oxidized to the stable 6π 1,3-dithiolium cation; (iii) the
presence of sulfur atoms and the planarity of the 1,3-
dithiolium cation aids the formation of close intermo-
lecular interactions in the solid state due to increased
π-π overlaps. These factors have resulted in the 1,3-
dithiole-2-ylidene unit acting as a key building block in
species 3 (Scheme 1) following the precedent of Cava et
1
0
al. The effect of five-membered S‚‚‚O interactions in
stabilizing nitrosoalkenes 3 was proved by X-ray analysis
of three derivatives.9
,11
With a view to extending our
knowledge of such interactions, we sought to prepare 1,3-
diselenole-2-ylidene systems via reactions of a 1,3-dis-
elenole Wittig reagent. The synthetic sequence to re-
agent 4 from carbon diselenide, tributylphosphine, and
dimethyl acetylenedicarboxylate has previously been
reported (Scheme 2).12 However, due to the extreme
2
areas as widespead as conducting polymers, new π-elec-
tron donors,3 Langmuir-Blodgett films,4 and possible
(4) (a) Dhindsa, A. S.; Song, Y. P.; Badyal, J . P.; Bryce, M. R.; Lvov,
Y. M.; Petty, M. C.; Yarwood, J . Chem. Mater. 1992, 4, 724. (b)
Goldenberg, L. M.; Andreu, R.; Savir o´ n, M.; Moore, A. J .; Gar ´ı n, J .;
Bryce, M. R.; Petty, M. C. J . Mater. Chem. 1995, 5, 1539. (c) Morrison,
V.; Mingotaud, C.; Agricole, B.; Sall e´ , M.; Gorgues, A.; Garrigou-
Lagrange, C.; Delhaes, P. J . Mater. Chem. 1995, 5, 1617.
5
6
ferromagnetic and nonlinear optical materials. A prin-
cipal source of many substituted 1,3-dithiole units are
the substituted Wittig reagents typified by 1.
(
5) (a) Yoshida, Z.; Sugimoto, T. Angew. Chem., Int. Ed. Engl. 1988,
2
7, 1573. (b) Schumaker, R. R.; Rajeswari, S.; J oshi, M. V.; Cava, M.
P.; Takasi, M.; Metzger, R. M. J . Am. Chem. Soc. 1989, 111, 30. (c)
Coffin, M. A.; Bryce, M. R.; Clegg, W. J . Chem. Soc., Chem. Commun.
1
992, 40.
6) (a) Blanchard-Desce, M.; Ledoux, I.; Lehn, J .-M.; Malherte, S.;
(
Zyss, J . J . Chem. Soc., Chem. Commun. 1988, 733. (b) Schuberl, U.;
Salbeck, J .; Daub, J . Adv. Mater. 1992, 4, 41. (c) J en, A. K.-Y.; Rao, V.
P.; Drost, K. J .; Wong, K. Y.; Cava, M. P. J . Chem. Soc., Chem.
Commun. 1994, 2057.
(7) Hansen, T. K.; Bryce, M. R.; Howard, J . A. K.; Yufit, D. S. J .
Org. Chem. 1994, 59, 5324.
Reagent 1a has previously been employed in the
synthesis of unsymmetrical tetrathiafulvalenes (TTF)
7
and 1,3-dithiole-2-ylidene systems, while compound 1b
is widely documented as a basic component in many TTF
(8) (a) Sato, M.; Gonnella, N. C.; Cava, M. P.; J . Org. Chem. 1979,
4
4, 930. (b) Review: Schukat, G.; Richter, A. M.; Fangh a¨ nel, E. Sulfur
X
Abstract published in Advance ACS Abstracts, March 15, 1996.
Rep. 1987, 7, 155.
(
1) Hansen, T. K.; Becher, J . Adv. Mater. 1993, 5, 288.
(9) Bryce, M. R.; Chalton, M. A.; Batsanov, A. S.; Lehmann, C. W.;
Howard, J . A. K. J . Chem. Soc., Perkin Trans. 2, manuscript in
preparation.
(10) (a) Lakshmikantham, M. V.; Cava, M. P. J . Org. Chem. 1981,
46, 3246. (b) Lakshmikantham, M. V.; J ackson, Y.; Cava, M. P. J . Org.
Chem. 1988, 53, 3529. (c) Gowenlock, B. G.; Orrell, K. G.; Sik, V.;
Vasapallo, G.; Lakshmikantham, M. V.; Cava, M. P. Polyhedron 1994,
13, 675.
(11) For other examples of the stabilisation of reactive organosulfur
compounds by nonbonded S‚‚‚O interactions see: (a) Bryce, M. R.;
Chesney, A.; Heaton, J . N.; McKelvey, G. N.; Anderson, M. Tetrahedron
Lett. 1994, 35, 5275, and references therein. (b) Oae, S. Organic Sulfur
Chemistry: Structure and Mechanism, CRC Press: London, 1991; pp
21-26.
(2) (a) Kozaki, M.; Tanaka, S.; Yamashita, Y. J . Chem. Soc., Chem.
Commun, 1992, 1137. (b) Roncali, J .; Gifford, M.; Frere, P.; J ubault,
M.; Gorgues, A. J . Chem. Soc., Chem. Commun. 1993, 689.
(
3) (a) Bryce, M. R.; Moore, A. J .; Hasan, M.; Ashwell, G. J .; Fraser,
A. T.; Hursthouse, M. B.; Karaulov, A. I. Angew. Chem., Int. Ed. Engl.
990, 29, 1450. (b) Hansen, T. K.; Lakshmikantham, M. V.; Cava, M.
1
P.; Metzger, R. M.; Becher, J . J . Am. Chem. Soc. 1991, 113, 2720. (c)
Benhamed-Gasmi, A. S.; Frere, P.; Garrigues, B.; J ubault, M.; Texier,
F.; Gorgues, A. Tetrahedron Lett. 1992, 33, 6457. (d) Fabre, J .-M.;
Chakroune, S.; J avidan, A.; Zanik, L.; Ouahab, L.; Golhen, S.; Delhaes,
P. Synth. Met. 1995, 70, 1127. (e) Misaki, Y.; Ohta, T.; Higuchi, N.;
Fujiwara, H.; Yamabe, T.; Mori, T.; Mori, H.; Tanaka, S. J . Mater.
Chem. 1995, 5, 1571.
0
022-3263/96/1961-2877$12.00/0 © 1996 American Chemical Society

2
878 J . Org. Chem., Vol. 61, No. 8, 1996
Chesney et al.
Sch em e 1
Ta ble 1. P r od u cts Obta in ed fr om th e Rea ction of Wittig
Rea gen t 9 w ith a Va r iety of Ald eh yd es 11
1
1, R )
% yield of 12a
% yield of 13a
a 2-CF3-C6H4
b 2-pyridyl
c 2,4-di-NO2-C6H4
d C(O)Me
31
21
30
34
36
24
42
20
16
32
b
b
e CHO
a
Yields quoted are of isolated products after purification by
column chromatography. b Yields are based on 1H NMR analysis
of the crude reaction mixture.
tetrafluoroboric acid and triphenylphosphine; the Wittig
reagent 9 thereby formed was used without isolation
(
attempts were made to isolate 9 without success).
The transient phosphorus ylide 10 was conveniently
Sch em e 2
prepared from 9 by treatment of the reaction mixture
with an excess of triethylamine at room temperature.
Trapping the ylide 10 with a variety of aldehydes 11 led
to the desired 2-ylidene-1,3-diselenones 12 in moderate
yields, along with a significant amount of the dihydro
compound 13 which in some cases was isolated cleanly.
The yields of the respective products from each aldehyde
are recorded in Table 1.
The substitution of tributylphosphine for triphenylphos-
phine in the reactions to form 12a and 12d , however, led
to neither of these products, and an increased yield of
13 was obtained (greater than 50% in one case). The
purity of the tetrafluoroboric acid also appears to effect
the amount of 13 produced, since older samples of the
acid produced more of this unwanted product. The use
of trifluoromethanesulfonic acid did not lead to any
improvement in the yields of alkenes 12.
The appearance of 1,3-diselenole derivative 13 along-
side 12 is surprising, since no trace of 13 was observed
in the 1H NMR spectra of seleno ether 8. Analogous
2-hydro-1,3-dithiole derivatives have been prepared by
hydride reduction of the corresponding 1,3-dithiole cat-
ions similar to those obtained from 8 on treatment with
tetrafluoroboric acid.16 A possible source of hydride for
the formation of 13 was thought to be that employed to
transform diselenolium cation salt 7 to seleno ether 8;
however, the use of only a slight excess of sodium
cyanoborohydride and the high yields of the reduction
toxicity of carbon diselenide, its lack of commercial
availability, and difficulty of preparation,1 a new route
to this versatile synthetic reagent was sought which
involved a more readily accessible source of selenium.
The chosen route, which we have successfully executed,
is outlined in Scheme 3. The known compound ethylene-
triselenocarbonate, 5, was prepared as reported in the
literature14 in high yield from commercially available
hydrogen selenide (which can be safely handled from a
cylinder) in five steps using 1,2-dibromoethane as the
alkylating reagent and converted to the diester 615 in
excellent yield (89%). Methylation of selone 6 proceeded
smoothly with a slight excess of methyl trifluoromethane-
sulfonate in dry dichloromethane, to afford the disele-
nolium cation salt 7 (93%) which is stable for several days
at 0 °C. Reduction of 7 with sodium cyanoborohydride
in anhydrous propan-2-ol afforded the seleno ether 8
3a,b
1
3c
(91%) with no reduction of the ester functionalities.
Seleno ether 8 was obtained as an orange oil which
decomposed on standing and was, therefore, immediately
dissolved in acetonitrile and treated sequentially with
Sch em e 3

Nitroso Derivative of a 2-Ylidene-1,3-diselenole
J . Org. Chem., Vol. 61, No. 8, 1996 2879
Sch em e 4
step to form 8, coupled with an exhaustive aqueous
workup, make this scenario improbable. A definitive
explanation for the production of 13 has not yet been
found. However, investigations into possible reaction
pathways with a view to optimizing the yields of the
desired adducts 12 are in progress. In preliminary
experiments the analogous reaction sequence to that in
Scheme 3 using a 1,3-dithiole system yielded a large
amount of a dihydro derivative, and the use of hydro-
quinone as a radical trap during the conversion of 8 to 9
did not reduce the amount of 13 present. To test the
possibility (suggested by a referee) that fluoride ion was
inducing the deselenomethylation of 8, a solution of
compound 8 in acetonitrile was stirred for 3 days in the
presence of caesium fluoride, followed by addition of
hydrochloric acid. However, no evidence for the forma-
tion of compound 13 was obtained (TLC analysis);
gradual decomposition of compound 8 into unidentified
products took place.
F igu r e 1. Molecular structure of 14e. Bond distances (Å):
Se(1)-C(1) 1.857(10), Se(2)-C(1) 1.852(10), Se(1)-C(2)
1
1
1
1
.886(10), Se(2)-C(3) 1.887(10), C(2)-C(3) 1.33(2), C(1)-C(6)
.39(1), C(6)-N(1) 1.37(1), N(1)-O(1) 1.244(13), C(6)-C(7)
.44(2), C(7)-O(2) 1.21(2); bond angles (deg): C(2)Se(1)O(1)
65.7(4), C(6)N(1)O(1) 116(1), N(1)O(1)Se(1) 107.2(6).
With a range of 1,3-diselenole-2-ylidene systems 12a -e
in hand, the formation of nitroso-alkene species derived
from 12a ,d ,e was investigated (Scheme 4). Nitroso
alkenes are normally unstable;1 however, compounds 14
could be isolated in moderate yields by reaction of the
alkenes 12 with isoamyl nitrite in dichloromethane at
room temperature and were assumed to be stable due to
an interaction between the selenium atoms and the
nitroso-oxygen as depicted by the resonance stabilised
structure 14′. Such an intramolecular interaction, where
π-delocalization and additional heteroaromatic stability
can result, has previously been reported for related sulfur
systems.9 The involvement of a selenium atom in such
7
rations of the nitroso and carbonyl groups result in short
intramolecular contacts Se(1)‚‚‚O(1) 2.513(8) and Se-
(
2)‚‚‚O(2) 2.733(8) Å, well below the sum of their Van der
19
Waals radii (3.4 Å).
These distances exceed similar
S‚‚‚O distances in 3 (2.35-2.43 Å for the nitroso group
and 2.61 Å for the carbonyl one) in proportion to the
difference in the chalcogen atom size, both the covalent
and the Van der Waals radii of Se exceeding those of S
,18
19
by 0.15 Å. Thus the structure of 14e implies substan-
a stabilization is, however, less well documented.
A
tial interactions between the nitroso oxygen and the
selenium atom. Such interactions, similar to the hyper-
solitary example of a nitroso group attatched to a
1
0b,c
2
-ylidene-1,3-diselenone 15 has been reported,
and
20
valent or donor-acceptor S‚‚‚O interactions, are much
resonance form 15′ was proposed on the basis of NMR
spectra; no crystallographic data were presented. Ni-
troso-alkene 14e was obtained as bright green crystals
which were characterized by an X-ray single crystal
diffraction study.
The molecule of 14e (Figure 1) comprises a planar
diselenole ring with three planar substituents at C(1),
C(2), and C(3), inclined to the ring plane by 3.5°, 2°, and
less studied for selenium than for sulfur. A few known
examples include four supposedly hypervalent Se-O
21
22
23
bonds with carbonyl, carboxyl, and nitro groups,
ranging from 2.30 to 2.38 Å, and two much shorter
24
interactions in compounds 16 (2.04 Å) and 17a (2.08
Å) which are closer to a single covalent Se-O bond
25
(17) Gilchrist, T. L. Chem. Soc. Rev. 1983, 12, 53.
8
3°, respectively. Such conformation and cisoid configu-
(18) For representative examples of heteropentalenes see: (a)
Abazid, M.; Bertrand, H. O.; Christen, M. O.; Burgot, J . L. J . Chem.
Soc., Chem. Commun. 1994, 131. (b) Dingwall, J . G.; Dunn, A. R.; Reid,
D. H.; Wade, K. O. J . Chem. Soc., Perkin Trans. 1 1981, 131. (c) Beer,
R. J . S.; Cartwright, D.; Gait, R. J .; Harris, D. J . Chem. Soc. (C) 1971,
963. (d) Review: Pedersen, C. T. Sulfur Rep. 1980, 1, 1.
(19) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
Univ. Press: Ithaca, 1960.
(
12) Sugimoto, T.; Awaji, H.; Sugimoto, I.; Misaki, Y.; Kawase, T.;
Yoneda, S.; Yoshida, Z.; Kobayashi, T.; Anzai, H. Chem. Mater. 1989,
, 535.
13) (a) Hendriksen, L. S.; Kristiansen, E. S. S. Int. J . Sulfur Chem.
A] 1972, 2, 133. (b) Pan, W.-H.; Fackler, J . P.; Chen, H.-W. Inorg.
Chem. 1981, 20, 856. (c) Henriksen, L. Acta. Chem. Scand. 1967, 21,
1
(
[
(20) Kucsman, A.; Kapovits, I. In Organic Sulphur Chemistry;
Bernardi, F., Csizmadia, I. G., Mangini, A., Eds; Elsevier: Amsterdam,
1985; p 191.
1
981.
(14) (a) Wudl, F.; Aharon-Shalom, E.; Bertz, S. H. J . Org. Chem.
1
1
981, 46, 4612. (b) Chakroune, S. Thesis, Universit e´ Montpellier II,
(21) (a) Baiwir, M.; Llabres, G.; Didenberg, O.; Dupont, L.; Piette,
J . L. Acta Crystallogr. Sect. B 1975, 31, 2188. (b) Busetti, V.; Valle,
G.; Bardi, R. Acta Crystallogr. Sect. B 1978, 34, 691.
(22) Dahlen, B. Acta Crystallogr. Sect. B 1973, 29, 595.
(23) Sbit, M.; Dupont, L.; Didenberg, O.; Lambert, C. Acta Crystal-
logr. Sect. C 1988, 44, 340.
993.
(15) Lakshmikantham, M. V.; Cava, M. P. J . Org. Chem. 1976, 41,
8
1
976, 49, 3567.

2
880 J . Org. Chem., Vol. 61, No. 8, 1996
Chesney et al.
length of 1.91 Å. In all these cases the hypervalent
bonding is strongly aided by the formation of a five-
membered pseudoaromatic ring and by the presence of
a heteroatom (especially electronegative) linked to the
Se atom in a trans-position to the oxygen. Selenium-
oxygen interactions in a trans-position to a Se-C bond
are much weaker (as is also the case for sulfur), the
Exp er im en ta l Section
Gen er a l Deta ils. Solvents and reagents employed were
standard reagent grade and were used as received unless
otherwise stated. Anhydrous propan-2-ol was purchased from
Aldrich; all other anhydrous solvents were obtained by stan-
dard techniques. Yields for compound 12a -e are based on
the initial amount of 6 employed when intermediates 8 and 9
were not isolated.
1,2-Dica r bom eth oxyvin ylen e Tr iselen oca r bon a te (6).
To a solution of 1,2-ethanediyltriselenocarbonate (5) (1.81 g,
.5 mmol) in dry toluene (125 mL) was added dimethyl
acetylenedicarboxylate (0.96 g, 6.8 mmol). The resulting
solution was refluxed under argon for 1 h and the solvent
removed in vacuo to afford 6 (2.26 g, 89%) as red needles (from
methanol): mp 126-127 °C (lit.15 127-129 °C).
2-(Tr ip h en ylp h osp h in o)-4,5-d ica r b om et h oxy-1,3-d is-
elen ole Tetr a flu or obor a te (9). To a stirred solution of 1,2-
dicarbomethoxyvinylene triselenocarbonate (6) (250 mg, 0.63
mmol) in dry dichloromethane (5 mL) was added methyl
trifluoromethanesulfonate (110 mg, 0.66 mmol). The resultant
mixture was stirred under an argon atmosphere for 2 h.
Addition of a large excess of anhydrous ether led to the
precipitation of a solid, which was filtered, washed with ether,
and dried to give the salmon pink salt 7 (320 mg, 93%): mp
2
6
Se‚‚‚O distance in 17b being 2.48 Å. For this molecule,
ab initio calculations26 indicated clearly the donation of
1
4
an oxygen lone pair onto the Se atom, whose lone pairs
are arranged perpendicular to the O‚‚‚Se-C axis, in a
trigonal-bipyramidal fashion. A similar picture can be
expected in 14e, where the Se‚‚‚O distance is essentially
the same, though no electronegative atom is bonded to
Se. The interactions with chalcogens should affect the
electron structure of a nitroso group by shifting it toward
the oxime form (as in 15′). In fact, the geometry of the
CNO moieties in 14e, 3, and 16 is in reasonably good
agreement with the structural correlation curve of ni-
troso-isonitroso-oxime transition27 and corresponds to
contributions of the CsNdO and CdNsO forms in ca.
6
0
.6:0.4 (14e), 0.5:0.5 (3, i.e. close to the isonitroso
structure) and 0.6:0.4 (16) ratios.
H 3
109-112 °C dec; δ (CDCl : 200 MHz) 4.05 (6H, s), 3.05 (3H,
s). The salt was dissolved in anhydrous propan-2-ol (5 mL),
and sodium cyanoborohydride (40 mg, 0.63 mmol) was added
in one portion. Within 10 min the solution turned orange
whereupon it was diluted with ether (100 mL) and washed
Although molecules of 14e in the crystal are packed
in parallel layers, the out-of-plane conformation of one
methoxycarbonyl group prevents efficient overlap of the
molecules. Each selenium atom participates in two short
intermolecular contacts of Se(1)‚‚‚Se(2) type, nearly
perpendicular to the ring plane, of 3.72 and 3.77 Å, which
with water (6 × 50 mL) and brine (50 mL). Drying (MgSO
4
)
and removal of the solvent in vacuo afforded the seleno ether
8 (235 mg, 91%) as an unstable orange oil [δH (CDCl : 200
3
MHz) 6.24 (1H, s), 3.78 (6H, s), 2.31 (3H, s)]. The essentially
pure seleno ether was immediately dissolved in dry acetonitrile
is slightly less than twice the Van der Waals radius (4
Å).19
(15 mL) and cooled to 0 °C under argon, and tetrafluoroboric
acid (0.5 mL of a 54% ethereal solution, 5 equiv) was added
slowly with stirring. The mixture rapidly turned deep red and
was maintained at 0 °C for 1 h, and then triphenylphosphine
(180 mg, 0.68 mmol, 1.2 equiv) was added and the solution
stirred at 20 °C overnight. The resultant solution containing
Wittig reagent 9 was used in the subsequent reactions, without
purification.
1
-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)-1-[2-
tr iflu or om eth yl)p h en yl]m eth a n e (12a ). To a solution of
in acetonitrile was added 2-(trifluoromethyl)benzaldehyde
120 mg, 0.69 mmol) and triethylamine (1 mL, excess). The
(
9
(
mixture was stirred at room temperature for 3 h whereupon
removal of the solvent in vacuo gave a dark brown oil. The
residue was purified by column chromatography on silica gel
using dichloromethane/hexane as eluant (1:1 v/v) to afford
compound 12a (92 mg, 31%) as orange crystals: mp 125.5-
In conclusion, we have outlined an expedient route to
the 1,3-diselenole Wittig reagent 9 avoiding the use of
1
26.5 °C; δ
7.40 (2H, m), 7.10 (1H, q, J HF ) 3.8 Hz), 3.83 (3H, s), 3.79
(3H, s). Anal. Calcd for C15 Se : C, 38.32; H, 2.36.
Found: C, 38.43; H, 2.33. νmax (KBr)/cm 1727, 1584, 1433,
H 3
(CDCl : 200 MHz) 7.70 (1H, m), 7.58 (1H, m),
the noxious and fetid reagent CSe
2
. Wittig reactions of
with a variety of aldehydes form the corresponding
-ylidene-1,3-diselenoles 12, three of which have been
9
2
H
11
F
3
O
4
2
-
1
8
0
+
1
(
310, 1244, 1168, 1120; m/ z ( Se, CI) (rel int) 473 (M + 1)
100).
-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)-1-(2-
converted to the corresponding nitroso derivatives 14. An
X-ray crystallographic analysis of derivative 14e has
demonstrated that the stability of these compounds is
due, at least in part, to an interaction between the nitroso
oxygen and a selenium atom. An interaction of this type
has rarely been confirmed by structural analysis. The
availability of reagent 9 now paves the way for the
synthesis of new 2-ylidene-1,3-diselenole derivatives,
1
p yr id yl)m eth a n e (12b). To a solution of 9 in acetonitrile
was added pyridine-2-carboxaldehyde (73 mg, 0.69 mmol) and
triethylamine (1 mL, excess). The mixture was stirred at room
temperature for 2 h and the product isolated as described for
12a using dichloromethane/hexane as eluant (3:1 v/v) to afford
1
2b (50 mg, 21%) a pale yellow solid: mp 127-129 °C; δ
(CDCl : 200 MHz) 8.67 (1H, m), 7.65 (1H, td, J ) 4.5, 1.6 Hz),
.18 (1H, s), 7.05 (2H, m), 3.89 (3H, s), 3.84 (3H, s). Anal.
Calcd for C13 Se : C, 38.73; H, 2.75; N, 3.47. Found:
H
8
b,28
3
including tetraselenafulvalene systems.
7
H
11NO
4
2
(
24) Allen, C.; Boeyens, J . C. A.; Briggs, A. G.; Denner, L.; Markwell,
A. J .; Reid, D. H.; Rose, B. G. J . Chem. Soc., Chem. Commun. 1987,
67.
25) Roesky, H. W.; Weber, K. L.; Seseke, U.; Pinkert, W.; Nolten-
meyer, M.; Clegg, W.; Sheldrick, G. M., J . Chem. Soc., Dalton Trans.
985, 565.
26) Barton, D. H. R.; Hall, M. B.; Lin, Z.; Parekh, S. I.; Reibenspies,
J . J . Am. Chem. Soc. 1993, 115, 5056.
27) Gilli, G.; Bertolasi, V.; Veronese, A. C. Acta Crystallogr. Sect.
B. 1983, 39, 450.
8
0
+
C, 38.45; H, 2.66; N, 3.23; m/ z ( Se, CI) 406 (M + 1) 100),
3
17 (15).
9
(
1-(4,5-Dica r bom eth oxy-1,3-d iselen ol-2-ylid en e)-1-(2,4-
d in itr op h en yl)m eth a n e (12c). To a solution of 9 in aceto-
1
(
(28) Review: Cowan, D.; Kini, A. in The Chemistry of Organic
Selenium and Tellurium Compounds; Patai, S. J ., Ed.; Wiley, Chich-
ester, 1987; Vol. 2, 463.
(

Nitroso Derivative of a 2-Ylidene-1,3-diselenole
J . Org. Chem., Vol. 61, No. 8, 1996 2881
nitrile, was added 2,4-dinitrobenzaldehyde (124 mg, 0.69
mmol) and triethylamine (1 mL, excess). The mixture was
stirred at room temperature for 30 min and the product
isolated as described for 12a with dichloromethane/hexane as
eluant (1:1 v/v) to give 12c (93 mg, 30%) as orange crystals:
1-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)-1-n i-
tr osoeth a n a l (14e): green crystals (18 mg, 34%) (from hexane/
dichloromethane) mp 132-133 °C; δ
H 3
(CDCl : 200 MHz) 11.12
(1H, s), 3.99 (3H, s), 3.90 (3H, s). Anal. Calcd for C H NO -
9
7
6
Se : C, 28.22; H, 1.84; N, 3.66. Found: C, 28.35; H, 2.00; N,
2
-1
mp 142 °C; δ
.45 (1H, dd, J ) 10, 3.0 Hz), 7.7 (1H, d, J ) 10 Hz), 7.2 (1H,
s), 3.85 (3H, s), 3.81 (3H, s). Anal. Calcd for C14 Se
C, 34.17; H, 2.05; N, 5.69. Found: C, 34.36; H, 2.03; N, 5.66.
H
(CDCl
3
: 200 MHz) 8.82 (1H, d, J ) 3.0 Hz),
3.45. ν (neat)/cm 1734, 1653, 1396, 1281, 1247, 1211; m/ z
max
8
(
(
80Se, CI) (rel int) 386 (M
+
+ 1) (100), 372 (90), 357 (30), 303
H
10
N
2
O
8
2
:
50).
1
-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)-1-n i-
tr osop r op a n -2-on e (14d ): green crystals (29 mg, 55%) (from
hexane/dichloromethane) mp 119-120 °C; δ (CDCl : 200
MHz) 4.00 (3H, s), 3.99 (3H, s), 3.10 (3H, s). Anal. Calcd for
NO Se : C, 30.25; H, 2.28; N, 3.53. Found: C, 30.38;
H, 2.39; N, 3.31. νmax (neat)/cm 2958, 2926, 2854, 1741, 1703,
-
1
80
ν
max (KBr)/cm 1740, 1718, 1624, 1533, 1434, 1245. m/ z ( Se,
+
CI) (rel int) 494 (M +1) (15), 303 (60), 163 (100), 149 (80).
-(4,5-Dica r bom eth oxy-1,3-diselen ol-2-yliden e)pr opa n -
-on e (12d ). To a solution of 9 in acetonitrile, was added
H
3
1
2
C
10
H
9
6
2
methylglyoxal (1 mL of an aqueous solution, excess) and
triethylamine (1 mL, excess). The mixture was stirred at room
temperature for 1 h, diluted with water (50 mL), and extracted
with dichloromethane (2 × 50 mL), the organic portions were
-1
8
0
+
1
(
641, 1400, 1283, 1223; m/ z ( Se, CI) (rel int) 400 (M + 1)
20), 386 (80), 145 (45), 86 (100).
Cr ysta l Str u ctu r e Deter m in a tion . The X-ray single
crystal diffraction experiment was performed at room tem-
perature on a Siemens SMART CCD detector. Crystal data
4
combined and dried (MgSO ), and the solvent was removed in
vacuo. The residue was purified by column chromatography
on silica gel with dichloromethane/hexane as eluant (1:1 v/v),
followed by dichloromethane, to afford 12d (80 mg, 34%) as a
for 14e: C
Pna2 (No.33), a ) 9.270(1), b ) 24.337(3), c ) 5.3406(6) Å, V
) 1204.9(4) Å (from 424 reflections with 12 < θ < 21°), Z )
9 7 6 2
H NO Se , M ) 383.08, orthorhombic, space group
yellow solid: mp 117-119 °C; δ
1H, s), 3.73 (3H, s), 3.72 (3H, s), 2.10 (3H, s). Anal. Calcd
for C10 Se : C, 32.63; H, 2.74. Found: C, 32.64; H, 3.01.
max (KBr)/cm 1734, 1701, 1625, 1577, 1475, 1431, 1231. m/ z
H
[(CD
3
)
2
CO: 200 MHz] 7.46
1
3
(
-
3
H
10
O
5
2
1
4, D
c
) 2.11 g cm , F(000) ) 736, graphite-monochromated
R
-
-1
ν
Mo K radiation, λ ) 0.71073 Å, µ ) 61.6 cm , dark green
8
0
+
(
Se, CI) (rel int) 371 (M + 1) (100).
-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)et h a -
n a l 12e. To a solution of 9 in acetonitrile was added glyoxal
crystal of 0.18 × 0.2 × 0.4 mm, ω scan mode, 2θ e 51.5°, 4896
total data, 1667 unique data, Rint ) 0.076, a semiempirical
absorption correction29 based on strongest equivalents (trans-
missions Tmin ) 0.1866, Tmax ) 0.2684) was applied. The
1
(
(
1 mL of a 40% aqueous solution, excess) and triethylamine
1 mL, excess). The solution was then stirred at room
structure was solved by direct methods (SHELXS-86 pro-
temperature for 1 h. Purification as described for 12d afforded
grams30 ) and refined by full-matrix least squares (SHELXL-
1
1
2e (67 mg, 36%) as a pale yellow solid: mp 108-110 °C (lit.12
08-109 °C).
3 software31 ) against F of all data with Chebyshev weighting
2
9
scheme and empirical extinction correction. The refinement
of 169 variables (all non-H atoms with anisotropic displace-
ment parameters, methyl groups as rigid bodies, H(7) riding)
4
,5-Dica r bom eth oxy-1,3-d iselen ole (13). This compound
was isolated as a malodorous orange oil, in the yields stated
in Table 1, as the first product to elute from the column during
2
converged at wR(F ) ) 0.128 and goodness-of-fit 1.104 for all
the purification of 12a -e: δ
H
(CDCl
3
: 200 MHz) 4.52 (2H, s),
data, and R(F) ) 0.046 for 1593 “observed” data with I g 2σ-
3
ν
3
3
.80 (6H, s); δ (CDCl : 100 MHz) 163.7, 134.6, 53.6, 14.0;
C 3
(
I). The absolute structure (direction of the polar axis) was
-1
80
max (neat)/cm 1716, 1567, 1431, 1239; m/ z ( Se, CI) (rel int)
17 (M + 1) (100); HRMS calcd for C H O Se 315.8753; found
7 8 4 2
32
determined by refining the Flack parameter, which con-
+
verged at -0.02(3). Residual electron density features: ∆Fmax
15.8757.
-3 33
)
0.58, ∆Fmin ) -0.71 eÅ .
P r ep a r a t ion of Nit r osa t ed Der iva t ives 14: Gen er a l
P r oced u r e. To a stirred solution of the appropriate 1,3-
diselenol-2-ylidene derivative 12 (50 mg) in dichloromethane
Ackn owledgm en t. This work was funded by EPSRC
(
5 mL) at 0 °C was added isoamyl nitrite (0.5 mL 3.75 mmol,
(grants to A.S.B. and A.C.), Ciba-Geigy (Basel) (stu-
dentship to M.A.C.), and EC Human Capital and
Mobility Programme CHRX-CT93-0271 (to A.C.).
excess). The mixture was maintained at 0 °C for 15 min before
being stirred at room temperature for 12 h. The solvent was
removed in vacuo, and cold methanol (2 mL) was added to the
residue to induce precipitation. The resulting nitroso deriva-
tives were isolated by filtration and further purified by
crystallization from the appropriate solvent where stated.
J O951979N
(29) Sheldrick, G. M.; Orpen, A. G.; Reichert, B. E.; Raithby, P. R.
1
-(4,5-Dica r b om et h oxy-1,3-d iselen ol-2-ylid en e)-1-(2-
tr iflu om eth yl)ph en yl]-1-n itr osom eth an e (14a): green crys-
tals (20 mg, 37%) (from hexane/dichloromethane) mp 148-
Abstracts of the Fourth European Crystallographic Meeting (ECM4),
Oxford, Oxford University Press: Oxford, 1977; p 147.
(30) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, 46, 467.
(31) Sheldrick, G. M., SHELXL-93, Program for the refinement of
crystal structures, University of G o¨ ttingen, Germany, 1993.
[
1
7
1
1
50 °C; δ
.50 (2H, m), 3.99 (3H, s), 3.89 (3H, s); δ
63.27, 162.95, 155.58, 134.63, 133.03, 132.19, 131.59, 129.93,
H
(CDCl
3
: 200 MHz) 8.05 (1H, m), 7.80 (1H, m), 7.60-
C
(CDCl : 100 MHz)
3
(
32) Flack, H. D. Acta Crystallogr. Sect. A 1983, 39, 876.
(33) The author has deposited atomic coordinates for this structure
8
0
29.56, 129.37, 128.71, 127.31, 126.46, 54.71, 53.18; m/ z ( Se,
with the Cambridge Crystallographic Data Centre. The coordinates
can be obtained, on request, from the Director, Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge, CB2 1EZ, U.K.
+
CI) (rel int) 502 (M + 1) (30) 488 (10), 276 (25), 188 (100);
HRMS Calcd for C15 NO Se 500.8841; found 500.8840.
H
10
F
3
5
2