A new route to arsonium, stibonium, and bismuthonium 2,2-dimethyl-4,6-dioxo-1,3-dioxanides - The crystal structures of Ph 3E-C6H6O4 (E = As, Sb, Bi) [1]

Article abstract of DOI:10.1002/zaac.200300049

The ylides Ph₃E-C₆H₆O₄ [3; E = As (a), Sb (b), Bi (c)] have been prepared through the reaction of Ph ₃E and 5-bromo-2,2-dimethyl-4,6-dioxo-1,3-dioxin (4) followed by addition of triethylamine in good yields. The crystal structures of 3 are reported.

Full text of DOI:10.1002/zaac.200300049

A New Route to Arsonium, Stibonium, and Bismuthonium 2,2-Dimethyl-4,6-
dioxo-1,3-dioxanides ؊ The Crystal Structures of Ph3E-C6H6O4
(E ؍ As, Sb, Bi) [1]
Norbert Kuhn,* Ahmed Al Sheikh, Simon Schwarz, and Manfred Steimann
Tübingen, Institut für Anorganische Chemie der Universität
Received February 18th, 2003.
Dedicated to Professor Heinrich Nöth on the Occasion of his 75th Birthday
Abstract. The ylides Ph3E-C6H6O4 [3; E ϭ As (a), Sb (b), Bi (c)]
have been prepared through the reaction of Ph3E and 5-bromo-2,2-
dimethyl-4,6-dioxo-1,3-dioxin (4) followed by addition of triethyl-
amine in good yields. The crystal structures of 3 are reported.
Keywords: Arsenic; Antimony; Bismuth; Ylides; Crystal structure
Ein neuer Weg zu Arsonium- Stibonium- und Bismutonium-2,2-Dimethyl-4,6-dioxo-
1,3-dioxamiden ؊ die Kristallstrukturen von Ph3E-C6H6O4 (E ؍ As, Sb, Bi) [1]
Inhaltsübersicht. Die Ylide Ph3E-C6H6O4 [3; E ϭ As (a), Sb (b), Bi
(c)] wurden durch Reaktion von Ph3E und 5-Bromo-2,2-dimethyl-
4,6-dioxo-1,3-dioxin (4) und anschließende Zugabe von Triethyl-
amin in guter Ausbeute hergestellt. Die Kristallstrukturen von 3
werden mitgeteilt.
Introduction
investigated the reaction of diazomethane derivatives with
triorganopnictides [2Ϫ4, 9, 11], additional reports deal with
the ylide synthesis starting from CH-acidic organyls and
R3EX type compounds (X ϭ CO3, O, Cl2 [5Ϫ7, 10]).
In fact, the reactions of 4 with Ph3E (E ϭ As, Sb, Bi)
followed by addition of triethylamine give the title com-
pounds as stable crystalline solids in good yields. On com-
parison with other Meldrum’s acid derivatives, the spectro-
scopic data (see experimental part) are in the expected
range.
There has been increasing attention for the chemistry of the
heavier group 15 element ylides starting with the pioneering
discovery of their cyclopentadienides 1 (E ϭ As [2], Sb [3],
Bi [4]) by Lloyd. In the past years, the investigation of bis-
muth ylides by Barton [5] and Suzuki [6, 7] opens up new
routes in organic synthesis. As well known from phos-
phorus ylide chemistry [8], methylene fragments containing
π-acceptor substituents cause an excellent stabilization thus
dimedone and Meldrum’s acid derivatives (2, 3) being ex-
pected to be their most stable representatives.
Recently, we reported on a new route to Meldrum’s acid
derivatives starting from 5-bromo-2,2-dimethyl-4,6-dioxo-
1,3-dioxin (4) and nucleophiles in the presence of bases [1].
In the following part, we describe a new synthesis for the
ylides 3 and their structural characterization. 3a [9] and 3c
[6, 10] have been prepared by other procedures formerly.
To get more insight into their bonding, we have deter-
mined the crystal structures of 3 (Tables 1Ϫ5, Figures 1Ϫ3).
Surprisingly, the ylides do not form isotypic crystals as a
consequence both from different orientations of the Ph3E
fragments with respect to the heterocyclic ring [3a 179.2(3);
3b 176.4(3); 3c 166.1(2)°] and from the relative orientation
of the phenyl rings. The ylidic E-C bond lengths are in the
range of short single bonds [3a 1.859(2), 3b 2.044(2), 3c
Syntheses and Structures of the Ylides
Ph3E-C6H6O4 (3)
In general, there are two well known routes to give stabil-
ized ylides of the heavier group 15 elements. While Lloyd
˚
2.139(7) A] on comparison with the corresponding E-Ph
distances. There are only minor differences in the structural
parameters of the dioxin fragments (for details see table 5)
including the folding angle along the axis of the endocyclic
oxygen atoms [3a 42.6(2), 3b 43.4(3), 3c 41.9(4)°]. The enol-
ate nature of the heterocyclic ring apparently causes a
marked oxygen basicity which is revealed by short contacts
between the pnictogen atoms and one of the exocyclic oxy-
* Prof. Dr. N. Kuhn
Institut für Anorganische Chemie der Universität Tübingen
Auf der Morgenstelle 18
D-72076 Tübingen
Fax: ϩ(49 7071) 295306
˚
gen atoms [3a 2.926, 3b 3.010, 3c 3.162 A]. Apparently, the
C-O and C-C bond lengths of the dioxin fragment are not
influenced by these interactions.
E-mail: norbert.kuhn@uni-tuebingen.de
Z. Anorg. Allg. Chem. 2003, 629, 1245Ϫ1248
DOI: 10.1002/zaac.200300049
 2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
1245

N. Kuhn, A. Al Sheikh, S. Schwarz, M. Steimann
Fig. 2 The structure of Ph3Sb-C6H6O4 (3b) in the crystal.
Scheme 1
Fig. 3 The structure of Ph3Bi-C6H6O4 (3c) in the crystal.
Fig. 1 The structure of Ph3As-C6H6O4 (3a) in the crystal.
A comparison of 3 with the structures of the dimedone
derivatives 2 [12] reveals only minor differences in the
ability of the heterocyclic framents to stabilize charge separ-
ation. In fact, the central E-C bond lengths are a little bit
shorter for 3.
Surprisingly, triphenylphosphane does not give an ylide
of the type 3 on the reaction with 4 under the conditions
mentioned below, triphenylphosphane oxide being the only
phosphorus containing product detected. We are investiga-
Concluding Remarks
As expected, the crystal structures demonstrate 3 to be stab-
ilized ylides, and no marked differences are observed going
from arsenic to its heavier neighbours. Small deviations may
be influenced by packing effects. The structure of their di-
oxin fragments are very close to that of its pyridine adduct
5 [1] which underlines the betaine nature of 3.
1246
 2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2003, 629, 1245Ϫ1248

The Crystal Structures of Ph3E-C6H6O4 (E ϭ As, Sb, Bi) [1]
Table 1 Crystal data of the compounds Ph3E-C6H6O4 (3)
Table 3 Atomic coordinates (x 104) and equivalent isotropic dis-
2
3
˚
placement parameters (A x 10 ) for Ph3Sb-C6H6O4 (3b). U(eq) is
defined as one third of the trace of the orthogonalized Uij tensor.
3a (EϭAs)
3b (EϭSb)
3c (EϭBi)
Unit cell dimension:
x
y
z
U(eq)
˚
a/A
9.728(3)
10.334(3)
11.654(4)
64.69(2)
80.70(2)
78.02(2)
1032.5(6)
2
9.586(5)
9.743(6)
12.287(6)
73.63(4)
69.37(2)
84.13(4)
1030(1)
2
12.013(2)
12.943(3)
14.555(3)
˚
b/A
Sb(1)
O(1)
O(2)
O(3)
O(4)
C(1)
C(3)
C(2)
C(4)
C(5)
C(6)
C(7)
C(8)
6650(1)
8512(2)
8975(2)
7064(2)
8121(2)
7521(2)
7503(2)
8325(3)
8285(2)
6786(3)
9366(3)
5311(2)
5722(3)
4748(3)
3383(3)
2978(3)
3941(3)
8230(2)
8143(2)
9136(3)
10223(3)
10322(3)
9332(3)
5091(2)
4054(3)
2897(3)
2781(3)
3822(3)
4981(3)
7575(1)
4957(2)
4011(2)
7263(2)
5126(2)
6127(2)
6264(3)
5040(2)
3796(3)
3077(3)
2906(3)
9174(2)
9912(3)
10909(3)
11179(3)
10457(3)
9455(3)
8676(2)
10164(2)
10948(3)
10246(3)
8764(3)
7959(3)
6595(2)
5643(3)
5150(3)
5597(3)
6520(3)
7037(3)
6696(1)
6317(2)
8037(2)
9425(2)
9629(2)
7855(2)
8984(2)
7338(2)
9318(2)
9745(3)
9887(3)
7438(2)
8101(3)
8594(3)
8432(2)
7773(3)
7272(2)
5058(2)
4733(2)
3658(2)
2906(2)
3249(2)
4319(2)
6296(2)
7218(2)
6991(3)
5845(3)
4928(3)
5147(2)
21(1)
37(1)
28(1)
39(1)
28(1)
24(1)
25(1)
25(1)
25(1)
36(1)
35(1)
22(1)
33(1)
36(1)
29(1)
32(1)
29(1)
21(1)
23(1)
26(1)
27(1)
27(1)
24(1)
23(1)
31(1)
39(1)
38(1)
35(1)
28(1)
˚
c/A
α/°
β/°
γ/°
105.62(3)
3
˚
Cell volume / A
Z
2179.6(8)
4
1.775
monoclinic
P21/n
CAD-4
1.54184
Ϫ60
density [calc.]/g/cmϪ3
crystal system
Space group
measurement device
wave length
1.442
1.596
triclinic
triclinic
¯
¯
P1
P1
Siemens P4
0.71073
Ϫ100
2.15Ϫ29.50
0.71073
Ϫ100
2.18Ϫ27.50
C(9)
temperature/°C
theta range/θ
reflections:
collected
observed [F0>4σ(F0)] 5538
refinement
parameter
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
2.36Ϫ24.69
7930
9430
4723
4677
3692
full matrix least-squares method on F2
347
347
347
solution and refinement
R1-Value [I>2σ(I)]
wR2-Value [I>2σ(I)]
1R-Value [all data]
wR2-Value [all data]
largest difference peak and
ShelXTL V5.1 (NT)
0.0294
0.0733
0.0300
0.0762
0.0295
0.0776
0.0300
0.0782
0.0342
0.0818
0.0495
0.0876
3
˚
hole/e·A
ϩ0.88, Ϫ1.11 ϩ1.40, Ϫ1.68 ϩ1.15, Ϫ1.02
Table 2 Atomic coordinates (x 104) and equivalent isotropic dis-
Table 4 Atomic coordinates (x 104) and equivalent isotropic dis-
2
3
˚
placement parameters (A x 10 ) for Ph3As-C6H6O4 (3a). U(eq) is
2
3
˚
defined as one third of the trace of the orthogonalized Uij tensor.
placement parameters (A x 10 ) for Ph3Bi-C6H6O4 (3c). U(eq) is
defined as one third of the trace of the orthogonalized Uij tensor.
x
y
z
U(eq)
x
y
z
U(eq)
As(1)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
3821(1)
874(1)
855(1)
1879(1)
1725(1)
Ϫ648(1)
Ϫ1563(1)
Ϫ2284(1)
203(2)
1751(1)
2757(1)
3661(1)
2373(1)
3442(1)
2660(1)
3011(1)
2791(1)
4290(2)
5475(2)
4574(2)
1238(1)
Ϫ36(2)
Ϫ357(2)
592(3)
1863(3)
2193(2)
271(1)
Ϫ517(2)
Ϫ1554(2)
Ϫ1794(2)
Ϫ1028(2)
18(2)
20(1)
33(1)
31(1)
32(1)
30(1)
22(1)
25(1)
23(1)
27(1)
34(1)
43(1)
23(1)
33(1)
45(1)
47(1)
47(1)
37(1)
25(1)
35(1)
46(1)
45(1)
44(1)
34(1)
25(1)
32(1)
38(1)
38(1)
37(1)
31(1)
Bi(1)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
8710(1)
7727(5)
9102(5)
11339(5)
10902(5)
9415(7)
8674(7)
10579(7)
10015(8)
9543(13)
10550(15)
9637(7)
10817(8)
11325(10)
10667(9)
9478(9)
8959(8)
8504(6)
8129(8)
7961(9)
8177(8)
8584(8)
8733(7)
6977(7)
6108(8)
5015(10)
4808(12)
5663(14)
6777(11)
4208(1)
6448(5)
7240(4)
4938(4)
6451(4)
5511(6)
6374(6)
5553(6)
7076(7)
6581(12)
8121(10)
2734(6)
2656(8)
1725(8)
882(7)
2333(1)
1738(4)
1253(4)
2096(4)
1400(4)
1781(6)
1599(6)
1778(5)
812(7)
Ϫ158(8)
764(13)
2309(5)
2573(7)
2486(8)
2132(8)
1862(8)
1953(7)
3757(5)
4277(6)
5147(6)
5486(7)
4986(6)
4103(6)
1389(6)
1777(7)
1163(10)
211(11)
Ϫ171(8)
410(7)
45(1)
61(2)
57(1)
59(1)
61(2)
49(2)
51(2)
46(2)
60(2)
81(3)
89(4)
45(2)
62(2)
67(3)
70(3)
72(3)
57(2)
42(2)
51(2)
63(2)
60(2)
60(2)
50(2)
52(2)
65(2)
87(3)
95(4)
90(4)
69(3)
4874(1)
2868(1)
3018(1)
1553(1)
3697(2)
1708(2)
2233(2)
765(2)
5782(1)
6274(2)
7730(2)
8662(2)
8154(2)
6710(2)
2828(1)
2624(2)
1821(2)
1232(2)
1460(2)
2260(2)
3796(2)
3277(2)
3364(2)
3926(2)
4451(2)
4402(2)
514(2)
Ϫ1204(2)
Ϫ2032(2)
Ϫ2102(2)
Ϫ3144(2)
1513(2)
1948(2)
1761(3)
1146(3)
693(3)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
880(2)
951(7)
3095(2)
2455(2)
3270(3)
4698(3)
5332(2)
4534(2)
2847(2)
2218(2)
2859(2)
4134(2)
4759(2)
4111(2)
1890(7)
4573(6)
3828(7)
4085(8)
5071(8)
5801(7)
5566(6)
3899(6)
3585(7)
3409(9)
3523(9)
3807(10)
4009(8)
2840(1)
4111(2)
4929(2)
4466(2)
3202(2)
2382(2)
ting therefore the mechanism of this reaction and will re-
port on our results in due course.
prepared according to a published procedure [13]. Crystallographic
data for the structural analyses have been deposited with the Cam-
bridge Crystallographic Data Centre (3a: CCDC 205373, 3b:
CCDC 205372, 3c: CCDC 205371). Copies of this information may
be obtained free of charge from the Director, CCDC, 12 Union
Experimental Section
All experiments have been performed in purified solvents under
argon. 5-Bromo-2,2-dimethyl-4,6-dioxo-1,3-dioxin (4) has been
Z. Anorg. Allg. Chem. 2003, 629, 1245Ϫ1248
zaac.wiley-vch.de
 2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
1247

N. Kuhn, A. Al Sheikh, S. Schwarz, M. Steimann
MS (FAB): m/z (%) ϭ 449 [6, Mϩ ϩ H], 391 [100, MϩϪMe2CO], 347 [30,
MϩϪMe2CO, CO2] and further fragments.
˚
Table 5 Selected bond lengths /A and angles /° for
Ph3E-C6H6O4 (3).
Ph3Sb-C6H6O4 (3b). 1.59 g (90 %) yield, colourless crystals, m.p.
110-113 °C. Elemental analysis for C24H21O4Sb (495.18 g/mol):
found (calc.) C 58.13 (58.21), H 3.93 (4.27) %.
3a (EϭAs)
3b (EϭSb)
3c (EϭBi)
EϪC(1)
EϪC(7)
EϪC(13)
EϪC(19)
C(2)ϪO(1)
C(2)ϪO(2)
C(3)ϪO(3)
C(3)ϪO(4)
C(4)ϪO(4)
C(4)ϪO(2)
C(1)ϪC(2)
C(1)ϪC(3)
C(4)ϪC(5)
C(4)ϪC(6)
1.859(2)
1.915(2)
1.915(2)
1.917(2)
1.222(2)
1.368(2)
1.219(2)
1.386(2)
1.434(2)
1.442(2)
1.426(2)
1.421(2)
1.512(2)
1.516(2)
2.044(2)
2.116(2)
2.113(2)
2.113(2)
1.228(3)
1.377(3)
1.213(3)
1.381(3)
1.429(3)
1.438(3)
1.410(3)
1.424(3)
1.516(3)
1.516(3)
2.139(7)
2.214(7)
2.205(7)
2.200(8)
1.212(9)
1.384(2)
1.205(9)
1.385(9)
1.425(10)
1.428(10)
1.408(11)
1.401(11)
1.507(15)
1.515(15)
1H-NMR (CDCl3): δ ϭ 1.80 (s, 6 H, Me), 7.38-7.75 (m, 15 H, Ph).
13C-NMR (CDCl3): δ ϭ 26.4 (Me), 58.3 (C5), 103.7 (C2), 128.9, 130.0, 132.8,
135.7 (Ph), 165.8 (C4,6).
IR (KBr): νCO ϭ 1658 cmϪ1
.
MS (FAB): m/z (%) ϭ 504 [100, Mϩ ϩ Na,ϪMe], 437 [28, MϩϪMe2CO],
393 [8, MϩϪMe2CO, CO2] and further fragments.
Ph3Bi-C6H6O4 (3c). 1.60 g (55 %) yield, pale yellow crystals, m.p.
90-91 °C. Elemental analysis for C24H21BiO4 (582.41 g/mol): found
(calc.) C 48.90 (49.50), H 3.25 (3.63) %.
1H-NMR (CDCl3): δ ϭ 1.78 (s, 6 H, Me), 7.48-7.67 (m, 15 H, Ph).
13C-NMR (CDCl3): δ ϭ 26.5 (Me), 57.8 (C5), 103.7 (C2), 126.4, 130.1, 132.8,
133.2 (Ph), 165.8 (C4,6).
IR (KBr): νCO ϭ 1581 cmϪ1
.
C(1)ϪEϪC(7)
113.51(6)
109.83(6)
109.21(7)
109.00(7)
103.42(6)
111.76(7)
116.66(11)
108.00(12)
122.75(13)
124.2010)
112.08(10)
117.82(13)
125.45(14)
116.71(13)
117.02(13)
128.56(14)
114.37(12)
110.66(12)
110.18(14)
110.64(13)
105.25(13)
106.81(15)
113.15(15)
114.13(9)
115.3(1)
111.0(1)
105.83(9)
100.94(9)
108.53(9)
115.55(18)
117.94(18)
122.6(2)
111.55(16)
125.41(17)
118.0(2)
125.4(2)
116.5(2)
116.5(2)
128.4(2)
115.0(2)
110.7(2)
109.8(2)
110.7(2)
106.5(2)
106.3(2)
112.8(2)
115.0(3)
109.9(3)
108.2(3)
112.6(3)
103.2(3)
107.4(3)
116.6(6)
118.1(6)
123.4(7)
113.7(6)
121.9(6)
117.1(7)
127.3(8)
115.6(7)
116.3(7)
128.8(7)
114.8(7)
110.8(7)
106.0(8)
106.1(10)
110.0(9)
110.6(8)
113.2(11)
MS (FAB): m/z (%) ϭ 552 [3, MϩϪ2 Me], 525 [8, MϩϪMe2CO], 363 [36,
C(1)ϪEϪC(13)
C(1)ϪEϪC(19)
C(7)ϪEϪC(13)
C(7)ϪEϪC(19)
C(13)ϪEϪC(19)
C(2)ϪO(2)ϪC(4)
C(3)ϪO(4)ϪC(4)
C(2)ϪC(1)ϪC(3)
C(2)ϪC(1)ϪE
Ph2Biϩ], 286 [66, PhBiϩ], 209 [100, Biϩ] and further fragments.
Financial support of this work by the Deutsche Forschungsgemein-
schaft and the Fonds der Chemischen Imdustrie is gratefully
acknowledged.
References
C(3)ϪC(1)ϪE
O(1)ϪC(2)ϪO(2)
O(1)ϪC(2)ϪC(1)
O(2)ϪC(2)ϪC(1)
O(3)ϪC(3)ϪO(4)
O(3)ϪC(3)ϪC(1)
O(4)ϪC(3)ϪC(1)
O(2)ϪC(4)ϪO(4)
O(2)ϪC(4)ϪC(5)
O(4)ϪC(4)ϪC(5)
O(2)ϪC(4) C(6)
O(4)ϪC(4)ϪC(6)
C(5)ϪC(4)ϪC(6)
[1] Meldrum’s Acid Derivatives, 2. For part 1 see N. Kuhn,
A. Al-Sheikh, M. Steimann, Z. Naturforsch., Part b, in press.
[2] D. Lloyd, M. I. C. Singer, Chem. Ind. 1967, 510.
[3] D. Lloyd, M. I. C. Singer, Chem. Ind. 1967, 787.
[4] D. Lloyd, M. I. C. Singer, Chem. Commun. 1967, 1042.
[5] D. H. R. Barton, J.-C. Blazejewski, B. Charpiot, J.-P. Finet,
W. B. Motherwell, M. T. Barros Papoula, S. P. Stanforth,
J. Chem. Soc., Perkin Trans. 1 1985, 2667.
[6] H. Suzuki, T. Murafuji, T. Ogawa, Chem. Lett. 1988, 847.
[7] T. Ogawa, T. Murafuji, H. Suzuki, Chem. Lett. 1988, 849;
T. Ogawa, T. Murafuji, H. Suzuki, J. Chem. Soc., Chem. Com-
mun. 1989, 1749; T. Ogawa, T. Murafuji, K. Iwata, H. Suzuki,
Chem. Lett. 1989, 325; H. Suzuki, T. Murafuji, Bull. Chem.
Soc. Jpn. 1990, 63, 950; H. Suzuki, T. Ikegami, Y. Matano,
Tetrahedron Lett. 1994, 35, 8197; Y. Matano, M. Yoshimune,
H. Suzuki, J. Org. Chem. 1995, 60, 4663; M. M. Rahman,
Y. Matano, H. Suzuki, J. Chem. Soc., Perkin Trans. 1 1999,
1533.
Road, Cambridge, CB2 1EZ, UK, Fax ϩ44-1223-336033; E-mail:
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk.
General procedure for the synthesis of 3. 5 mmols of Ph3E were ad-
ded to a solution of 1.115 g (5 mmol) of 4 in 30 ml of dichlorometh-
ane, and the mixture was stirred at room temp. for 1 h. After ad-
dition of 0.90 ml (6.5 mmol) of triethylamine and stirring for
further 1 h, the solution was extracted with 10 ml of water. The
organic layer was dried over Na2SO4 and evaporated in vacuo to
dryness. The residue was recrystallized from dichloromethane to
give the ylides 3 as stable crystals.
[8] A. W. Johnson, Ylides and Imines of Phosphorus, Wiley-Inter-
sience, New York, 1993; O. I. Kolodiazhnyi, Phosphorus
Ylides, Wiley-VCH, Weinheim, 1999.
[9] I. Gosney, D. Lloyd, Tetrahedron 1973, 29, 1697.
[10] Y. Matano, H. Nomura, Synthesis 2002, 631.
[11] B. H. Freeman, D. Lloyd, Tetrahedron 1974, 30, 2257; C. Gli-
dewell, D. Lloyd, S. Metcalfe, Tatrahedron 1986, 42, 3887;
C. Glidewell, D. Lloyd, S. Metcalfe, Synthesis 1988, 319.
[12] G. Ferguson, C. Glidewell, I. Gosney, D. Lloyd, S. Metcalfe,
H. Lumbroso, J. Chem. Soc., Perkin 2 Trans. 1988, 1829;
M. Yasui, T. Kikuchi, F. Iwasaki, H. Suzuki, T. Murafuji, T.
Ogawa, J. Chem. Soc., Chem. Commun. 1990, 3367.
Ph3As-C6H6O4 (3a). 1.45 g (95 %) yield, colourless crystals, m.p.
215-216 °C. Elemental analysis for C24H21AsO4 (448.35 g/mol):
found (calc.) C 64.16 (64.29), H 4.58 (4.72) %.
1H-NMR (CDCl3): δ ϭ 1.78 (s, 6 H, Me), 7.45-7.65 (m, 15 H, Ph).
13C-NMR (CDCl3): δ ϭ 26.0 (Me), 57.4 (C5), 103.2 (C2), 126.4, 129.5, 132.3,
132.7 (Ph), 165.3 (C4,6).
IR (KBr): νCO ϭ 1648 cmϪ1
.
[13] E. Ott, Liebigs Ann. Chem. 1913, 401, 159.
1248
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