Preparation and reactions of 1,3-diphosphacyclobutane-2,4-diyls that feature an amino substituent and/or a carbonyl group

Article abstract of DOI:10.1002/chem.200306069

The preparation and properties of a 1-amino-1,3-diphosphacyclobutane-2,4- diyl and a 1-benzoyl-1,3-diphosphacyclobutane-2,4-diyl, which can be regarded as functionalized cyclic biradical derivatives, were investigated. Hydrolysis of 1-diisopropylamino-3-m

Full text of DOI:10.1002/chem.200306069

FULL PAPER
Preparation and Reactions of 1,3-Diphosphacyclobutane-2,4-diyls That
Feature an Amino Substituent and/or a Carbonyl Group
Hiroki Sugiyama, Shigekazu Ito, and Masaaki Yoshifuji*[a]
Abstract: The preparation and proper-
ties of a 1-amino-1,3-diphosphacyclo-
butane-2,4-diyl and a 1-benzoyl-1,3-di-
phosphacyclobutane-2,4-diyl, which can
be regarded as functionalized cyclic bi-
radical derivatives, were investigated.
Hydrolysis of 1-diisopropylamino-3-
methyl-2,4-bis(2,4,6-tri-tert-butylphen-
yl)-1,3-diphosphacyclobutane-2,4-diyl
(7), which is formed by reaction of
Mes*CꢀP (4; Mes*=2,4,6-tBu3C6H2)
with lithium diisopropylamide and io-
domethane, resulted in ring-opening of
the 1,3-diphosphacyclobutane-2,4-diyl
skeleton, as well as de-aromatization of
one of the Mes* rings. 3-Oxo-1,3-di-
phosphapropene 8 and 7-phosphabicy-
clo[4.2.0]octa-1(8),2,4-triene 9 were the
resultant products, and these were sub-
sequently characterized. Isomerization
and oxidation of 7 occurred in the pres-
ence of TEMPO (2,2,6,6-tetramethyl-1-
piperidinoxy) to give the first example
1,3-diphosphacyclobutane-2,4-diyl (12)
was isolated and characterized from
the reaction of 4 with tert-butyllithium
and benzoyl chloride. Compound 12
was subsequently heated and under-
went rearrangement of the benzoyl
group and ring-expansion to afford 1-
oxo-1H-[1,3]diphosphole 13. Reaction
of 4 with lithium diisopropylamide and
benzoyl chloride afforded the 2H-
[1,2,4]oxadiphosphinine 15, which was
probably formed through the 1,3-di-
phosphacyclobutane-2,4-diyl intermedi-
ate 14. Thermolysis of 15 afforded 1-
oxo-1H-[1,3]diphosphole 16 in an Ar-
buzov-type rearrangement.
of
a cyclic dimethylenephosphorane
derivative, namely 3-oxo-1,3-diphos-
pha-1,4-diene 10. 1-Benzoyl-3-tert-
butyl-2,4-bis(2,4,6-tri-tert-butylphenyl)-
Keywords: heterocycles
¥
phos-
phaalkenes ¥ phosphaalkynes ¥ pro-
tecting groups ¥ radicals
Introduction
ple, ring-opening of the 1,3-diphosphacyclobutane-2,4-diyl
and formation of a diphosphabicylo[1.1.0]butane were re-
ported,[2,3,5] and very recently, the aniomesolytic cleavage of
In recent years, the general character of radicals, which are
described as highly reactive and short-lived, has not been
found to apply to several biradicals, in particular, the heavi-
er main group elements such as phosphorus.[1] Niecke and
co-workers described the synthesis of an isolable, phospho-
rus-containing, four-membered cyclic biradical species, 2,4-
dichloro-1,3-diphosphacyclobutane-2,4-diyl 1, and its reac-
À
a P C(aryl) bond to afford the 1,3-diphosphacyclobutadi-
enediide was described.[6] On the other hand, Bertrand and
co-workers reported the synthesis of a boron-centered birad-
ical 2,[7,8] and recently, interest has been shown with regard
to the latest results of its radical-type reactivity[9] and the
structural conversion of the B2P2 biradical.[10] These attempts
to obtain stable biradicals have had an impact on both main
group chemistry, as well as the chemistry of reaction inter-
mediates.
tions to afford several intriguing compounds.[2 For exam-
4]
Very recently, we reported the formation of 1,3-diphos-
phacyclobutane-2,4-diyl 3 in the reaction of a bulky phos-
phaalkyne (Mes*CꢀP (4)) with tert-butyllithium and iodo-
methane. Compound 3 was stable at room temperature and
did not decompose up to a few days even in air.[11] More-
over, our method enables various kinds of nucleophiles and
electrophiles to be employed in the reaction of 4. Therefore,
we thought that it might be possible to prepare a number of
1,3-diphosphacyclobutane-2,4-diyl derivatives.
Herein we report the preparation and reactions of some
functionalized 1,3-diphosphacyclobutane-2,4-diyls prepared
from 4. We chose lithium diisopropylamide (LDA) and tert-
butyllithium as nucleophiles, while iodomethane and benzo-
[a] H. Sugiyama, Dr. S. Ito, Prof. M. Yoshifuji
Department of Chemistry, Graduate School of Science
Tohoku University
Aoba, Sendai 980-8578 (Japan)
Fax : (+81)22-217-6562
E-mail: yoshifj@mail.tains.tohoku.ac.jp
2700
¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/chem.200306069
Chem. Eur. J. 2004, 10, 2700 2706

2700 2706
yl chloride were employed as electrophiles. Benzoyl chloride
was used in the hope that the carbonyl moiety would act as
an electron-withdrawing group that would interact with the
P2C2 biradical skeleton. Moreover, we anticipated that the
amino group on the phosphorus might affect the 1,3-diphos-
phacyclobutane-2,4-diyl moiety in such a way that it would
undergo a number of novel reactions. We found that 1,3-di-
phosphacyclobutane-2,4-diyls that bear an amino group un-
dergo isomerization and ring-opening, while the 1,3-diphos-
phacyclobutane skeleton that bears a benzoyl group under-
goes ring-expansion.
observed for 3.[11] This might indicate that a considerable in-
teraction arises between the phosphorus atoms and the
amino group as a result of a p-donating effect.
Attempts to isolate 7 for X-ray crystallographic studies
were unsuccessful. However, in the course of these studies
several derivatives of 7 were isolated and characterized. In
particular, when compound 7 was kept for 0.5 h in a ben-
zene/water mixture, the subsequent 31P NMR spectrum dis-
played eight major peaks that corresponded to new prod-
ucts, some of which were not able to be identified. The two
major products 8 and 9 were isolated by chromatographic
purification, each as a mixture of two diastereomers, and
these were then recrystallized and analyzed by X-ray crys-
tallography. Figure 1 shows an ORTEP drawing of the mo-
Results and Discussion
Preparation of phosphaalkyne[12] 4 and its precursor: Phos-
phaalkyne 4 was prepared by a Fritsch Buttenberg Wie-
chell-type [1,2] rearrangement using 2,2-dibromo-1-(2,4,6-
=
tri-tert-butylphenyl)-1-phosphaethene (Mes*P CBr2 (5))
and nickel catalyst in the manner previously de-
scribed,[11,13] while dibromophosphaethene 5[14] was prepared
a
from
(2,4,6-tri-tert-butylphenyl)phosphonous
dichloride
(Mes*PCl2)[15] and bromoform in the presence of LDA.[16]
Formation and reactions of 1-diisopropylamino-3-methyl-
1,3-diphosphacyclobutane-2,4-diyl (7): Phosphaalkyne 4 was
allowed to react with 0.5 equivalents of LDA to give the re-
sultant intermediate 6, the structure of which was deter-
mined by 31P NMR spectroscopy (dP =258, 56 ppm;
2J(P,P)=102 Hz) (Scheme 1).[11,17] The reaction mixture was
Figure 1. Molecular structure of 8. All hydrogen atoms except for H1 and
H2, and those found in the solvent (dichloromethane), are omitted for
À
À
clarity. Selected bond lengths [ä] and angles [8]: P1 N 1.646(4), P1 C1
À
À
À
À
1.670(5), P2 O 1.486(3), P2 C1 1.820(4), P2 C2 1.798(4), P2 Me
À
À
À
À
1.804(5), C1 Mes* 1.508(6), C2 C3 1.357(6), C3 C41.521(6), C4 C5
À
À
À
À
1.500(6), C5 C6 1.338(6), C6 C7 1.470(6), C7 C8 1.346(6), C3 C8
1.487(6); N-P1-C1 115.5(2), O-P2-C1 114.9(2), O-P2-C2 116.2(2), O-P2-
Me 109.8(2), C1-P2-C2 108.0(2), C1-P2-Me 105.6(2), C2-P2-Me 101.0(2),
P1-C1-P2 110.3(2), P1-C1-Mes* 138.2(3), P2-C1-Mes* 111.3(3), P2-C2-C3
130.9(4), C2-C3-C4 122.2(4), C2-C3-C8 122.0(4), C4-C3-C8 115.6(4), C3-
C4-C5 109.6(4), C3-C4-tBu 115.2(4), C5-C4-tBu 110.4(4), C4-C5-C6
123.0(4), C5-C6-C7 117.4(4), C6-C7-C8 124.1(4), C3-C8-C7 116.1(4).
lecular structure of 8, which corresponds to the product of a
ring-opening reaction of the 1,3-diphosphacyclobutane skel-
eton followed by addition of water. The six-membered ring
(C3 C8) is not aromatic. It contains two double bonds at
=
=
C5 C6 and C7 C8 and an exo double bond at C3, two
À
À
single bonds at C3 C4and C4 C5, and two additional
À
À
single bonds at C6 C7 and C3 C8 whose bond lengths are
À
characteristic of the central C C diene bond. The nitrogen
Scheme 1.
À
À
À
atom is planar (S(angles)=3608) and the N P1 C1 P2
skeleton is coplanar (V=2.2(5)8). Figure 2 displays an
ORTEP drawing of 9. Although the structure of 9 suggests
that it is also the product from the ring-opening of 7, in con-
trast to 8, the P(NiPr2) phosphorus is bonded to C3 to form
a bicyclic structure.[18] As in compound 8, the six-membered
ring (C2 C7) is not aromatic. Three asymmetric centers are
present in 9, and the diisopropylamino group is trans to the
C3 tBu group so that steric congestion is minimized. It is
likely that compounds 8 and 9 are formed by ring-opening
then treated with iodomethane to afford 7 as a deep blue
compound in almost quantitative yield. In contrast to 3,
compound 7 was found to decompose in air probably be-
À
cause of the instability of the P N bond. In addition, 7 un-
derwent slow decomposition in solution even at À208C. In
31
À
the P NMR spectrum, the P N(iPr2)2 phosphorus atom dis-
played a higher chemical shift than that of the PMe moiety
and a larger coupling constant (2J(P,P)=433.7 Hz) than that
Chem. Eur. J. 2004, 10, 2700 2706
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¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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M. Yoshifuji et al.
FULL PAPER
residue obtained upon removal of the solvent afforded cy-
clodimethylenephosphorane 10 as a red solid (Scheme 1).
The 31P and 13C NMR data were similar to those of a previ-
À
ously reported aminodimethylenephosphorane (Me2N
=
P( CTMS2)2:
TMS=SiMe3:
dP =167 ppm;
dC(P
=
=
C)
55.6 ppm, 1J(P,C)=71.3 Hz).[19] The molecular structure of
10 (Figure 3) reveals that the four-membered ring is almost
Figure 2. Molecular structure of 9. All hydrogen atoms except for those
in the methylene group (C20) and the solvent (dichloromethane) are
À
omitted for clarity. Selected bond lengths [ä] and angles [8]: P1 O
À
À
À
À
1.482(3), P1 N 1.646(4), P1 C1 1.790(5), P1 C3 1.877(5), P2 C1
À
À
À
À
1.828(5), P2 C20 1.860(5), P2 Me 1.847(6), C20 Mes* 1.521(6), C1 C2
À
À
À
À
1.375(6), C2 C3 1.531(6), C2 C7 1.464(6), C3 C41.501(7), C4 C5
À
À
1.347(5), C5 C6 1.465(7), C6 C7 1.354(7); O-P1-N 109.8(2), O-P1-C1
121.0(2), O-P1-C3 118.8(2), N-P1-C1 111.5(2), N-P1-C3 114.9(2), C1-P1-
C3 77.7(2), C1-P2-C20 100.1(2), C1-P2-Me 99.3(2), C20-P2-Me 98.8(2),
P1-C1-P2 133.1(3), P1-C1-C2 92.1(3), P2-C1-C2 134.6(4), C1-C2-C3
104.6(4), C1-C2-C7 137.3(4), C3-C2-C7 117.5(4), P1-C3-C2 84.1(3), P1-
Figure 3. Molecular structure of 10. All hydrogen atoms are omitted for
C3-C4120.7()4, P1-C3-
tBu 113.0(3), C2-C3-C4111.6()4, C2-C3-
tBu
À
À
clarity. Selected bond lengths [ä] and angles [8]: P1 O 1.479(3), P1 C1
115.4(4), C4-C3-tBu 110.0(4), C3-C4-C5 119.8(4), C4-C5-C6 119.1(4), C5-
C6-C7 125.9(5), C6-C7-C2 113.7(4).
À
À
À
À
1.837(4), P1 C2 1.822(4), P1 Me 1.814(4), P2 N 1.612(4), P2 C1
À
À
À
1.656(4), P2 C2 1.669(4), C1 Mes* 1.497(5), C2 Mes* 1.499(5); C1-P1-
C2 88.3(2), C1-P2-C2 100.1(2), P1-C1-P2 85.7(2), P1-C2-P2 85.8(2), P1-
C1-Mes* 125.3(3), P2-C1-Mes* 146.5(3), P1-C2-Mes* 143.9(3), P2-C2-
Mes* 128.8(3).
of a 1,3-diphosphacyclobutene intermediate upon hydrolysis
of 7 in the manner displayed in Scheme 2. Hydrolysis of the
C2P2 four-membered ring might occur to generate the corre-
sponding intermediary 1-hydroxy-1l5,3l3-diphosphacyclobu-
planar (V(C1-P1-C2-P2)=1.6(2)8), and the nitrogen atom
also has an almost planar coordination (S(angles)=359.98).
À
À
The P2 C1 and P2 C2 distances indicate that these are
phosphorus carbon double bonds, while the sum of the
angles around P2 (359.88) suggests that it has a l5s3 coordi-
nating mode.[12,19] Although the mechanism of formation for
compound 10 is still uncertain, irradiation may induce the
1,3-diphosphacyclobutane-2,4-diyl moiety in 7 to undergo
=
valence isomerization, while the P O group generated by
subsequent TEMPO oxidation stabilizes the dimethylene-
phosphorane[12b] structure. Indeed, compound 10 was not
formed when a mixture of 7 and TEMPO were stirred in
the dark or when a solution of 7 was irradiated in the ab-
sence of TEMPO.[20] Theoretical calculations predicted that
the cyclic phosphorane compound 11B, which is a possible
Scheme 2.
tenes, and then these subsequently undergo rearrangement
and de-aromatization of the Mes* ring to give 8 and 9. Al-
though the reason for this facile hydrolysis and ring-opening
is unclear, the increased reactivity of the aromatic ring
might arise as a result of steric hindrance caused by distor-
tion. Under similar conditions, compound 3 did not undergo
this kind of hydrolysis; this suggests that the electronic
effect of a diisopropylamino group in the C2P2 system facili-
tates these ring-opening reactions.
valence isomer of 1,3-diphosphacyclobutane-2,4-diyl, is
slightly less stable than structure 11A, but is much more
stable than bicyclo[1.1.0]butane 11C or the planar isomer
11D.[4] In contrast to what was observed for 7, compound 3
did not react in the presence of TEMPO upon irradiation,
and only 3 was recovered.
Reaction of
7 with 2,2,6,6-tetramethyl-1-piperidinoxy
(TEMPO) gave rise to markedly different results than those
mentioned above. When a solution of 7 and TEMPO in
THF was irradiated with light, the color of the solution
turned from blue to red. Subsequent recrystallization of the
2702
¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Chem. Eur. J. 2004, 10, 2700 2706

Preparation and Reactions of 1,3-Diphosphacyclobutane-2,4-diyls
2700 2706
Preparation and reactions of 1-benzoyl-1,3-diphosphacyclo-
butane-2,4-diyls: We allowed 4 to react with 0.5 equivalents
of tert-butyllithium and benzoyl chloride, in a manner simi-
lar to that employed for 3, to afford the corresponding 1-
Compound
4
was also allowed to react first with
0.5 equivalents of LDA and then benzoyl chloride at À788C
to give 2H-[1,2,4]oxadiphosphinine 15. Although the color
of the reaction mixture turned deep blue when LDA was al-
lowed to react with 4, and indicates that compound 14 is
being generated, the biradical 14 was not observed in the
spectra (Scheme 3). Furthermore, upon addition of benzoyl
chloride to the reaction, the mixture turned deep red in sev-
eral seconds. The isolated product was subsequently recrys-
tallized and suitable crystals were used for X-ray crystallo-
graphic studies. Figure 5 displays the molecular structure of
benzoyl-1,3-diphosphacyclobutane-2,4-diyl 12 as
a dark-
green solid (Scheme 3). Compound 12 did not decompose
Scheme 3.
below 208C and could be handled in air for several minutes.
The structure of 12 was determined from spectroscopic data.
In the 13C NMR spectrum, a peak for the ring carbon atom
was observed at dC =97.7 ppm. In the UV/Vis spectrum, 12
displayed an absorption at 664nm; this constitutes a batho-
chromic shift, and indicates that the HOMO LUMO gap is
smaller than that for 3.[11]
When 12 was heated at 1008C for 10 min, 1-oxo-1H-
[1,3]diphosphole 13 was obtained in 39% yield as a yellow
solid. The structure of 13 (Figure 4) reveals that the C3P2
Figure 5. Molecular structure of 15. Hydrogen atoms and the solvents (di-
chloromethane) are omitted for clarity. As the p-tBu groups are disor-
À
dered, only the atoms with predominant occupancy factors (0.58 for C1
À
Mes*, 0.52 for C2 Mes*) are displayed. Selected bond lengths [ä] and
À
À
À
À
angles [8]: P1 O 1.724(8), P1 N 1.639(9), P1 C1 1.85(1), P2 C1
1.708(10), P2 C2 1.81(1), O C3 1.36(1), C2 C3 1.38(2), C1 Mes*
À
À
À
À
À
À
1.53(1), C2 Mes* 1.51(1), C3 Ph 1.51(2); O-P1-N 100.7(5), O-P1-C1
96.3(5), N-P1-C1 110.2(5), C1-P2-C2 107.0(5), P1-O-C3 113.4(7), P1-C1-
P2 110.4(6), P1-C1-Mes* 125.4(7), P2-C1-Mes* 124.0(8), P2-C2-C3
121.4(8), P2-C2-Mes* 113.7(9), C3-C2-Mes* 122.8(9), O-C3-C2 121.1(9),
O-C3-Ph 109.7(10), C2-C3-Ph 129.1(9).
15, and reveals a six-membered ring, namely the 2H-
[1,2,4]oxadiphosphinine skeleton. The six-membered ring
displays a boat-type conformation in which the P1 atom is
À
À À
located at the ™bow∫ position (V(C1 P1 O C3)=76.0(7)8).
The sum of the angles around the nitrogen atom is 356.68.
The sp2 phosphorus atom, the phosphino group, and the sp2
carbon atom were identified by NMR spectroscopy.
Figure 4. Molecular structure of 13. All hydrogen atoms are omitted for
Upon being heated, 15 underwent an Arbuzov-type rear-
rangement to afford 1-oxo-1H-[1,3]diphosphole 16
(Scheme 3), and indicates that a stability difference arises
between 15 and 16. In contrast, the formation of 1-oxo-1H-
[1,3]diphosphole 13 from 12 was probably the result of a
tBu group substituent effect. The structure of 16 was unam-
biguously determined by X-ray crystallography (Figure 6).
Although several mechanisms for the reactions described
in Scheme 4are feasible, it is plausible that the isomeriza-
tions that afford compounds 13, 15, and 16 include a [1,2] re-
arrangement of the benzoyl group, in a manner similar to
the Fries-type rearrangement.[23] Subsequently, the carbonyl
group might play a role in the 1,3-diphosphacyclobutane
skeleton undergoing expansion to afford a five- or six-mem-
À
À
clarity. Selected bond lengths [ä] and angles [8]: P1 C1 1.680(2), P1 C2
À
À
À
À
1.856(3), P2 O 1.486(2), P2 C1 1.836(3), P2 C3 1.838(2), P2 tBu
À
À
À
À
1.862(3), C2 C3 1.346(3), C1 Mes* 1.510(3), C2 Mes* 1.517(3), C3 Ph
1.488(3); C1-P1-C2 99.5(1), O-P2-C1 111.6(1), O-P2-C3 113.2(1), O-P2-
tBu 109.2(1), C1-P2-C3 98.0(1), P1-C1-P2 111.5(1), P1-C2-C3 116.2(2),
P2-C3-C2 113.7(2), P1-C1-Mes* 129.5(2), P2-C1-Mes* 118.4(2), P1-C2-
Mes* 119.7(2), C3-C2-Mes* 123.7(2), P2-C3-Ph 119.6(2), C2-C3-Ph
126.3(2), C1-P2-tBu 115.0(1), C3-P2-tBu 109.5(1).
five-membered ring is almost planar, the largest deviation
À
being 0.132 ä, and the P1 C1 distance indicates the pres-
ence of a phosphorus carbon double bond.[12] The structure
of 13 is similar to the calculated structure of 1,3-diphos-
phole,[21] which has not as yet been synthesized experimen-
tally.[22]
Chem. Eur. J. 2004, 10, 2700 2706
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M. Yoshifuji et al.
FULL PAPER
ring-opening, valence isomerization, and ring-expansion re-
actions to afford novel organophosphorus compounds. In-
corporation of functional groups in the 1,3-diphosphacyclo-
butane-2,4-diyl moiety is a useful manner by which to tune
the properties of the C2P2 ring, as well as to construct novel
heterocyclic structures.
Experimental Section
General: All the experiments described here were carried out under an
atmosphere of argon using dry solvents, unless otherwise specified. Melt-
ing points were determined with a Yanagimoto micro melting-point appa-
ratus MP-J3, and are not corrected. Microanalyses were performed at the
Instrumental Analysis Center of Chemistry, Graduate School of Science,
Tohoku University. 1H and 13C NMR spectra were recorded on a Bruker
AVANCE400 spectrometer and 31P NMR spectra were obtained with a
Bruker AC200P or AVANCE400 spectrometer using 85% H3PO4 as an
external standard. NMR spectra were recorded at 258C unless otherwise
noted. MS spectra were taken on a JEOL HX-110 or a Hitachi M-2500S
spectrometer. FT-IR and UV/Vis spectra were taken on a Horiba FT-300
and a Hitachi U-3210 spectrometer, respectively.
Figure 6. Molecular structure of 16. Hydrogen atoms and the solvents
(benzene) are omitted for clarity. Selected bond lengths [ä] and angles
À
À
À
À
À
[8]: P1 O 1.482(3), P1 N 1.658(3), P1 C1 1.839(3), P1 C3 1.843(4), P2
À
À
À
À
C1 1.679(3), P2 C2 1.875(3), C2 C3 1.353(5), C1 Mes* 1.514(4), C2
À
Mes* 1.512(4), C3 Ph 1.491(5); O-P1-N 110.8(1), O-P1-C1 109.9(2), O-
P1-C3 112.7(2), N-P1-C1 116.2(2), N-P1-C3 109.0(2), C1-P1-C3 97.8(2),
C1-P2-C2 99.5(2), P1-C1-P2 111.5(2), P1-C1-Mes* 118.0(2), P2-C1-Mes*
130.1(3), P2-C2-C3 115.6(3), P2-C2-Mes* 118.8(2), C3-C2-Mes* 125.3(3),
P1-C3-C2 113.8(3), P1-C3-Ph 119.0(2), C2-C3-Ph 126.7(3).
Compound 5: LDA (ca. 36 mmol, prepared from diisopropylamine and
butyllithium in THF at 08C) was added to a stirred solution of Mes*PCl2
(5.2 g, 15 mmol) and bromoform (17 mmol) in THF (60 mL) at À788C.
The reaction mixture was stirred at À788C for 15 min and was then al-
lowed to warm to room temperature. The solvent was removed under
vacuum, the residue was dissolved in hexane (200 mL), and the organic
layer was washed with water. The solution was dried with MgSO4 and
concentrated. The residual solid was recrystallized from ethanol to afford
5 (4.6 g, 67%). The spectroscopic data were identical to those from the
literature.[14]
Compound 7: LDA (ca. 0.56 mmol) was added to a solution of 4 (300 mg,
1.04mmol) in THF (6 mL) at À788C. The reaction mixture was stirred at
À788C for 15 min and was then stirred for 1 h at room temperature. Io-
domethane (0.64mmol) was added to the mixture and the solvent was re-
moved under vacuum. The residue was extracted with hexane and the
solution was concentrated to afford almost pure 7 as a deep blue solid in
almost quantitative yield (0.36 g). Attempts to crystallize 7 were not suc-
cessful because of its slight instability. The sp2 radical center could not be
identified in the 13C NMR spectrum as a result of slow decomposition.
31P{1H} NMR (162 MHz, CDCl3): d=15.1 (d, 2J(P,P)=433.7 Hz; PMe),
À18.4ppm (d, 2J(P,P)=433.7 Hz; PNiPr2); 1H NMR (400 MHz, CDCl3):
d=7.54(s, 2H; m-Mes*), 7.36 (s, 2H; m-Mes*), 3.11 (sept, 3J(H,H)=
6.6 Hz, 2H; CHMe2), 1.84(d, 2J(P,H)=10.0 Hz, 3H; PMe), 1.73 (s, 18H;
Scheme 4.
3
o-tBu), 1.72 (s, 18H; o-tBu), 1.40 (s, 18H; p-tBu), 0.68 ppm (d, J(H,H)=
6.6 Hz, 12H; CHMe2).
bered heterocyclic system. Alternatively, as is the case for 1,
ring-opening of the four-membered ring in compound 12 or
Reaction of 7 with water: A solution of 7 (0.36 g, 0.52 mmol) in wet ben-
zene (10 mL) was stirred in air at room temperature for 0.5 h. The sol-
vent was then removed under vacuum and the residue was purified by
silica-gel column chromatography (hexane/EtOAc) to afford 8 (177 mg,
48%) and 9 (156 mg, 42%), respectively, each as a mixture of two iso-
mers. Recrystallization of each isolated compound from dichloromethane
at 08C afforded single isomers of 8 and 9.
À
14 by cleavage of the P C bond might occur to generate a
nucleophilic phosphinocarbene intermediate.[2] Migration of
the benzoyl group then takes place, and allows the residual
À
=
5-oxo-1,3-diphosphapropene derivatives that bear a P C
À
=
=
P C C O skeleton to undergo cyclization to give a 2H-
[1,2,4]oxadiphosphinine ring. Studies are in progress to clari-
fy the reaction mechanism for the ring-expansion of 12 and
intermediary 14.
Compound 8: (Isomer A): Colorless plates, m.p. 127 1298C (decomp);
31P{1H} NMR (162 MHz, CDCl3): d=282.3 (d, J(P,P)=174.4 Hz; P C),
2
=
2
31.6 ppm (d, J(P,P)=174.4 Hz; P O); 1H NMR (400 MHz, CDCl3): d=
=
7.48 (d, 4J(H,H)=2.0 Hz, 1H; m-Mes*), 7.39 (d, 4J(H,H)=2.0 Hz, 1H;
m-Mes*), 6.06 (dd, 2J(P,H)=21.7 and 5J(H,H)=1.2 Hz, 1H; P(O)CH),
6.04(pseudo-t, [ 5J(H,H)
+
5J(H,H)]/2=2.6 Hz, 1H; CH), 5.78 (dd,
=
3
5
J(H,H)=5.8 and J(H,H)=2.6 Hz, 1H; CH), 4.58 (d, 3J(H,H)=5.8 Hz,
=
1H; CH), 4.45 (sept, 3J(H,H)=6.3 Hz, 1H; NCH), 3.56 (sept, 3J(H,H)=
7.0 Hz, 1H; CHMe2), 1.65 (s, 9H; o-tBu), 1.54(s, 9H; o-tBu), 1.37 (d,
3J(H,H)=7.0 Hz, 6H; CHMe2), 1.32 (s, 9H; tBu), 1.31 (s, 9H; p-tBu),
1.13 (d, 2J(P,H)=12.6 Hz, 3H; PMe), 1.07 (s, 9H; tBu), 1.07 (m, 6H;
CHMe2), 0.99 ppm (s, 9H; tBu); 13C{1H} NMR (101 MHz, CDCl3): d=
Conclusion
In summary, we have prepared some functionalized 1,3-di-
phosphacyclobutane-2,4-diyls that bear a diisopropylamino
and benzoyl group on the four-membered biradical skeleton,
and showed the first examples of these diyls undergoing
3
3
160.2 (d, J(P,C)=4.6 Hz; C C), 149.7 (pseudo-t, [ J(P,C) + 4J(P,C)]/2=
=
4.9 Hz; o-Mes*), 147.5 (pseudo-t, [3J(P,C) + 4J(P,C)]/2=4.9 Hz; o-Mes*),
2704
¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2004, 10, 2700 2706

Preparation and Reactions of 1,3-Diphosphacyclobutane-2,4-diyls
2700 2706
4
2
(101 MHz, CDCl3, selected data): d=207.1 (dd, 1J(P,C)=94.2 and
=
=
147.1 (d, J(P,C)=2.8 Hz; C C), 145.1 (d, J(P,C)=16.7 Hz; C C), 144.0
1
3
(s; p-Mes*), 132.4(dd, J(P,C)=81.7 and 53.8 Hz; P C), 130.2 (s; C C),
J(P,C)=31.1 Hz; C O), 97.7 ppm (dd, 1J(P,C)=25.0 and 16.7 Hz; CP2);
=
=
=
130.1 (s; C C), 126.2 (dd, 2J(P,C)=39.0 and 2.7 Hz; ipso-Mes*), 125.3
IR (KBr): n˜ =1637 cmÀ1 (C O); UV/Vis (hexanes) lmax(e)=664(1500),
=
=
(dd, 1J(P,C)=101.2 and J(P,C)=5.6 Hz; P(O)C C), 123.1 (s; m-Mes*),
370 (13200), 329 nm (17600).
3
=
122.8 (s; m-Mes*), 51.7 (d, 4J(P,C)=12.9 Hz; o-CMe3), 47.2 (d, 4J(P,C)=
24.1 Hz; o-CMe3), 46.3 (d, 4J(P,C)=5.6 Hz; CMe3), 40.1 (s; CMe3), 39.6
(s; CMe3), 38.7 (d, 2J(P,C)=4.5 Hz; NCH), 38.7 (d, 2J(P,C)=5.6 Hz;
NCH), 36.0 (s; o-CMe3), 35.8 (s; p-CMe3), 35.6 (s; o-CMe3), 34.4 (s;
CMe3), 32.6 (s; CMe3), 31.6 (s; p-CMe3), 29.7 (s; CMe3), 28.7 (s;
NCHMe2), 28.7 (s; NCHMe2), 27.3 (d, 3J(P,C)=15.8 Hz; CH), 20.1 ppm
Compound 13: A solution of 12 (ca. 1.04mmol) in toluene (8 mL) was
heated at 1008C for 10 min, after which time it was cooled to room tem-
perature and the solvent was removed under vacuum. The residue was
purified by silica-gel column chromatography (hexane/EtOAc) and the
resultant solid was recrystallized from a mixture of hexane and dichloro-
methane at 08C to give 13 (150 mg, 39%) as orange prisms. M.p. 199
2018C; 31P{1H} NMR (162 MHz, CDCl3): d=313.7 (d, 2J(P,P)=36.9 Hz;
1
3
(dd, J(P,C)=80.2 and J(P,C)=9.7 Hz; P(O)Me); IR (KBr): n˜ =1174and
1159 cmÀ1
elemental
analysis
calcd
(%)
for
2
1
=
(P O);
=
=
P C), 75.7 ppm (d, J(P,P)=36.9 Hz; P O); H NMR (400 MHz, CDCl3):
4
C45H77NOP2¥1.5CH2Cl2: C 66.69, H 9.63, N 1.67; found: C 67.08, H 10.25,
d=7.54(brs, 1H; m-Mes*), 7.52 (d, J(H,H)=2.0 Hz, 1H; m-Mes*), 7.44
1.77. (Isomer B): 31P{1H} NMR (162 MHz, CDCl3) d=287.8 (d,
(d, 3J(H,H)=7.1 Hz, 2H; o-Ph), 7.35 (brs, 1H; m-Mes*), 7.24(d,
4J(H,H)=2.0 Hz, 1H; m-Mes*), 7.05 (t, 3J(H,H)=7.1 Hz, 1H; p-Ph),
6.99 (pseudo-t, [3J(H,H) + 3J(H,H)]/2=7.1 Hz, 2H; m-Ph), 1.72 (s, 9H;
o-tBu), 1.71 (s, 9H; o-tBu), 1.60 (s, 9H; o-tBu), 1.34(s, 9H; p-tBu), 1.32
(s, 9H; p-tBu), 1.20 (s, 9H; o-tBu), 0.54ppm (d, 3J(P,H)=15.0 Hz, 9H;
N
2
2
=
=
J(P,P)=156.4Hz; P C), 33.8 ppm (d, J(P,P)=156.4Hz; P O).
Compound 9: (Isomer A): Pale yellow powder, m.p. 164 1658C
(decomp); 31P{1H} NMR (162 MHz, CDCl3): d=35.4(d, 2J(P,P)=5.0 Hz;
P O), À24.6 ppm (d, 2J(P,P)=5.0 Hz; PMe); 1H NMR (400 MHz,
=
PtBu); 13C{1H} NMR (101 MHz, CDCl3): d=179.9 (dd, 1J(P,C)=52.5 and
CDCl3): d=7.31 (s, 1H; m-Mes*), 7.26 (s, 1H; m-Mes*), 6.34(d,
1
J(P,C)=44.5 Hz; P C), 155.1 (dd, 1J(P,C)=46.4 and 3J(P,C)=33.4Hz;
=
5
3
=
=
=
J(P,H)=2.2 Hz, 1H; CH), 6.10 (d, J(P,H)=14.5 Hz, 1H; CH), 4.40
C C), 152.4(dd, 2J(P,C)=10.2 and J(P,C)=5.6 Hz; ipso-Mes*), 149.7 (s;
3
(dd, 2J(P,H)=13.4and 3J(P,H)=7.4Hz, 1H; C HH), 3.78 (pseudo-t,
{2J(P,H) + 3J(P,H)}/2=12.9 Hz, 1H; CHH), 3.27 (sept, 3J(H,H)=6.9 Hz,
2H; CHMe2), 1.58 (s, 9H; o-tBu), 1.42 (m, 12H; CHMe2), 1.38 (s, 9H;
tBu), 1.31 (s, 9H; o-tBu), 1.15 (s, 9H; tBu), 1.07 (s, 9H; tBu), 0.71 ppm
o-Mes*), 149.4 (brs; o-Mes*), 149.3 (s; o-Mes*), 148.3 (d, 3J(P,C)=
2.8 Hz; o-Mes*), 146.9 (pseudo-t, [2J(P,C)
+
2J(P,C)]/2=7.0 Hz; ipso-
Mes*), 143.9 (d, 5J(P,C)=2.7 Hz; p-Mes*), 143.1 (d, 5J(P,C)=2.8 Hz; p-
Mes*), 132.1 (dd, J(P,C)=21.3 and 14.8 Hz; C C), 129.3 (d, 4J(P,C)=
2
(d, J(P,H)=5.7 Hz, 3H; PMe); 13C{1H} NMR (101 MHz, CDCl3, selected
2
=
3
data): d=165.5 (dd, 2J(P,C)=17.6 and 12.1 Hz; C C), 150.1 (dd,
4.6 Hz; o-Ph), 128.7 (d, J(P,C)=13.0 Hz; ipso-Ph), 127.4(s; m-Ph), 125.5
=
(d, 4J(P,C)=1.9 Hz; m-Mes*), 125.5 (s; m-Mes*), 122.2 (s; m-Mes*),
122.1 (d, 4J(P,C)=2.1 Hz; m-Mes*), 41.7 (s; o-CMe3), 39.4(s; o-CMe3),
1
J(P,C)=61.7 and 46.9 Hz; C C), 145.0 (dd, 2J(P,C)=43.6 and 4J(P,C)=
=
2.8 Hz; C C), 144.3 (d, 3J(P,C)=12.0 Hz; C C), 132.3 (d, 4J(P,C)=
=
=
1
7.4Hz; C C), 125.6 (d, J(P,C)=13.0 Hz; C C), 78.3 (dd, 1J(P,C)=64.0
3
38.8 (d, J(P,C)=8.3 Hz; PCMe3), 37.0 (s; o-CMe3), 36.4(s, o-CMe3), 36.0
=
=
and 3J(P,C)=3.7 Hz; PC), 24.0 ppm (m; CH2); IR (KBr): n˜ =1153 and
(s; o-CMe3), 35.6 (s; o-CMe3), 35.5 (s; o-CMe3), 35.3 (s; o-CMe3), 35.1 (s;
p-CMe3), 34.9 (s; p-CMe3), 31.8 (s; p-CMe3), 31.8 (s; p-CMe3), 25.5 ppm
1126 cmÀ1
(P O);
elemental
analysis
calcd
(%)
for
=
(s; PCMe3); IR (KBr): n˜ =1161 cmÀ1 (P O); elemental analysis calcd
=
C45H77NOP2¥0.4CH2Cl2: C 73.29, H 10.53, N 1.88; found: C 73.80, H
10.86, N 1.83. (Isomer B): 31P{1H} NMR (162 MHz, CDCl3): d=33.8 (d,
(%) for C49H72OP2: C 79.63, H 9.82; found: C 79.67, H 9.91.
2
2
=
J(P,P)=7.0 Hz; P O), À26.9 ppm (d, J(P,P)=7.0 Hz; PMe).
Compound 10: A mixture of 7 (ca. 0.52 mmol) and TEMPO (0.52 mmol)
in THF (25 mL) was irradiated with medium-pressure Hg lamp
Compound 15: LDA (0.52 mmol) was added to a solution of 4 (300 mg,
1.04mmol) in THF (8 mL) at À788C. The mixture was warmed to room
temperature, benzoyl chloride (0.52 mmol) was added, and the solvent
was removed under vacuum. The residue was extracted with hexane and
the solution was concentrated. The resultant solid was recrystallized from
dichloromethane at 08C to give 15 (253 mg, 62%, based on 4) as orange
crystals. M.p. 102 1048C (decomp); 31P{1H} NMR (162 MHz, CDCl3):
a
(100 W) at À108C for 1 day. The mixture was then warmed to room tem-
perature and the solvent was removed under vacuum. The residue was
purified by silica-gel column chromatography (hexane/EtOAc) to afford
10 (79 mg, 45%). Recrystallization from hexane/dichloromethane at 08C
afforded single crystals of dark orange plates. M.p. 192 1948C; 31P NMR
(162 MHz, CDCl3): d=121.8 (dt, 2J(P,P)=183.2 and 3J(P,H)=12.6 Hz;
PNiPr2), 25.4ppm (dq, 2J(P,P)=183.2 and 3J(P,H)=12.9 Hz; PMe);
1H NMR (400 MHz, CDCl3): d=7.42 (s, 2H; m-Mes*), 7.34(s, 2H; m-
Mes*), 3.22 (sept, 3J(H,H)=6.8 Hz, 2H; CHMe2), 2.00 (d, 2J(P,H)=
12.9 Hz, 3H; PMe), 1.74(s, 18H; o-tBu), 1.60 (s, 18H; o-tBu), 1.32 (s,
18H; p-tBu), 1.11 ppm (d, 3J(H,H)=6.8 Hz, 12H; CHMe2);
d=294.7 (d, 2J(P,P)=46.9 Hz, P C), 122.3 ppm (d, 2J(P,P)=46.9 Hz,
=
PNiPr2); 1H NMR (400 MHz, CDCl3): d=7.62 (brs, 1H; m-Mes*), 7.56
(brs, 1H; m-Mes*), 7.54(brs, 1H; m-Mes*), 7.49 (brs, 1H; m-Mes*),
7.34(d, 3J(H,H)=7.0 Hz, 2H; o-Ph), 7.20 (t, 3J(H,H)=7.0 Hz, 1H; p-
Ph), 7.13 (pseudo-t, [3J(H,H) + 3J(H,H)]/2=7.0 Hz, 2H; m-Ph), 3.48 (m,
2H; CHMe2), 1.72 (s, 9H; o-tBu), 1.61 (s, 9H; o-tBu), 1.52 (s, 9H; o-
tBu), 1.41 (s, 9H; o-tBu), 1.40 (s, 9H; p-tBu), 1.35 (s, 9H; p-tBu),
0.68 ppm (m, 12H; CHMe2); 13C{1H} NMR (101 MHz, CDCl3, selected
3
13C{1H} NMR (101 MHz, CDCl3): d=155.6 (dd, J(P,C)=10.0 and 3.9 Hz;
1
o-Mes*), 152.5 (dd, 3J(P,C)=8.7 and 4.3 Hz; o-Mes*), 147.4 (dd,
5J(P,C)=3.9 and 2.2 Hz; p-Mes*), 126.8 (dd, 2J(P,C)=3.4and 1.7 Hz;
ipso-Mes*), 123.3 (dd, 4J(P,C)=3.4and 1.7 Hz; m-Mes*), 123.2 (dd,
4J(P,C)=3.4and 1.7 Hz; m-Mes*), 56.0 (dd, 1J(P,C)=110.7 and 68.4Hz;
=
=
data): d=179.5 (dd, J(P,C)=77.2 and 53.7 Hz, P C), 153.1 (m, C C),
123.0 ppm (pseudo-t, [1J(P,C) + J(P,C)]/2=25.4Hz, C C).
1
=
Compound 16: A solution of 15 (0.36 mg, 0.52 mmol) in toluene (10 mL)
was heated at 1008C for 12 h, and was then cooled to room temperature
and concentrated. The residue was purified by silica-gel column chroma-
tography (hexane/EtOAc) to give 16 (400 mg, ca. 100%) as an orange
P( C)2), 51.4(s; o-CMe3), 51.4(s; o-CMe3), 39.0 (d, 2J(P,C)=25.0 Hz;
=
CHMe2), 35.0 (s; p-CMe3), 34.8 (s; o-CMe3), 34.5 (s; p-CMe3), 31.7 (s; o-
CMe3), 24.5 (d, 3J(P,C)=3.4Hz; CH Me2), 20.6 ppm (dd, 1J(P,C)=77.4
2
amorphous solid. 31P{1H} NMR (162 MHz, CDCl3): d=281.2 (d, J(P,P)=
and 3J(P,C)=24.7 Hz; PMe); IR (KBr): n˜ =1186 cmÀ1 (P O); elemental
=
36.6 Hz; P C), 56.0 ppm (d, 2J(P,P)=36.6 Hz; PNiPr2); 1H NMR
=
analysis calcd (%) for C45H75NOP2: C 76.34, H 10.68, N 1.98; found: C
76.17, H 10.90, N 1.86.
(400 MHz, CDCl3): d=7.62 (brs, 1H; m-Mes*), 7.61 (brs, 1H; m-Mes*),
7.51 (brs, 1H; m-Mes*), 7.42 (brs, 1H; m-Mes*), 7.40 (d, 3J(H,H)=
7.0 Hz, 2H; o-Ph), 7.05 (brs, 1H; p-Ph), 7.04(brs, 2H; m-Ph), 3.14(m,
2H; CHMe2), 1.77 (s, 9H; o-tBu), 1.74(s, 9H; o-tBu), 1.70 (s, 9H; o-
tBu), 1.40 (s, 9H; o-tBu), 1.39 (s, 9H; p-tBu), 1.26 (s, 9H; p-tBu),
0.77 ppm (dd, 3J(P,H)=7.0 and 3J(H,H)=7.0 Hz, 12H; CHMe2);
Compound 12: To a solution of 4 (300 mg, 1.04mmol) in THF (8 mL) at
À788C was added tert-butyllithium (0.52 mmol, 1.6m solution in pen-
tane). The mixture was warmed to room temperature, benzoyl chloride
(0.52 mmol) was added, and after several minutes the solvent was re-
moved under vacuum. The residue was extracted with hexane and the
solution was concentrated. The residual solid was washed with ethanol to
obtain 12 (257 mg, 67%) as deep green crystals. M.p. 134 1368C;
31P{1H} NMR (162 MHz, CDCl3): d=73.2 (d, 2J(P,P)=215.1 Hz; PtBu),
25.2 ppm (d, 2J(P,P)=215.1 Hz; PC(O)Ph); 1H NMR (400 MHz, CDCl3):
d=7.46 (s, 2H; m-Mes*), 7.44 (s, 2H; m-Mes*), 7.42 (m, 2H; o-Ph), 7.31
(t, 3J(H,H)=7.5 Hz, 1H; p-Ph), 7.04(pseudo-t, [ 3J(H,H)+ 3J(H,H)]/2=
7.5 Hz, 2H; m-Ph), 1.70 (brs, 18H; o-tBu), 1.45 (brs, 18H; o-tBu), 1.37
13C{1H} NMR (101 MHz, CDCl3, selected data): d=182.8 (dd, 1J(P,C)=
1
71.2 and 48.5 Hz; P C), 151.5 (pseudo-t, [ J(P,C) + 1J(P,C)]/2=29.3 Hz;
=
=
1
À1
=
C C), 122.1 ppm (d, J(P,C)=28.8 Hz; C C); IR (KBr): n˜ =1159 cm
=
(P O); elemental analysis calcd (%) for C51H77NOP2¥2C6H6: C 80.64, H
9.56, N 1.49; found: C 80.50, H 9.86, N 1.48.
X-ray crystallography: Single crystals were obtained by recrystallization
from a mixture of hexane and dichloromethane at 08C. A Rigaku
RAXIS-IV imaging plate detector (for 8, 9, 10, 15, and 16) or a Rigaku
MSC Mercury CCD detector (for 13) with graphite-monochromated
3
(s, 18H; p-tBu), 1.05 ppm (d, J(P,H)=15.4Hz, 9H; P tBu); 13C{1H} NMR
Chem. Eur. J. 2004, 10, 2700 2706
www.chemeurj.org
¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2705

M. Yoshifuji et al.
FULL PAPER
MoKa radiation (l=0.71070 ä) was used. The structures were solved by
direct methods (SIR92),[24] expanded by using Fourier techniques
(DIRDIF94),[25] and then refined by full-matrix least squares. The data
were corrected for Lorentz polarization effect. Structure solution, refine-
ment, and graphical representation were carried out using the teXsan
package.[26]
E. Niecke, W. W. Schoeller, Angew. Chem. 1998, 110, 995; Angew.
Chem. Int. Ed. 1998, 37, 949.
[3] a) E. Niecke, A. Fuchs, M. Nieger, Angew. Chem. 1999, 111, 3213;
Angew. Chem. Int. Ed. 1999, 38, 3028; b) E. Niecke, A. Fuchs, M.
Nieger, O. Schmidt, W. W. Schoeller, Angew. Chem. 1999, 111, 3216;
Angew. Chem. Int. Ed. 1999, 38, 3031.
[4] W. W. Schoeller, C. Begemann, E. Niecke, D. Gudat, J. Phys. Chem.
A 2001, 105, 10731.
Compound 8: C45H75NOP2¥CH2Cl2, Mr =794.99, pale yellow prisms,
0.15î0.15î0.10 mm , triclinic, P1 (no. 2), a=16.040(2), b=16.570(1), c=
3
≈
[5] a) A. Fuchs, D. Gudat, M. Nieger, O. Schmidt, M. Sebastian, L.
Nyulµszi, E. Niecke, Chem. Eur. J. 2002, 8, 2188; b) A. Fuchs, M.
Nieger, E. Niecke, L. Nyulµszi, O. Schmidt, W. W. Schoeller, M. Se-
bastian, Phosphorus Sulfur Silicon Relat. Elem. 2002, 177, 1605.
[6] M. Sebastian, M. Nieger, D. Szieberth, L. Nyulµszi, E. Niecke,
Angew. Chem. 2004, 116, 64 7;Angew. Chem. Int. Ed. 2004, 43, 637.
[7] D. Scheschkewitz, H. Amii, H. Gornitzka, W. W. Schoeller, D. Bour-
issou, G. Bertrand, Science 2002, 295, 1880.
[8] a) M. Seierstad, C. R. Kinsinger, C. J. Cramer, Angew. Chem. 2002,
114, 4050; Angew. Chem. Int. Ed. 2002, 41, 3894; b) W. W. Schoeller,
A. Rozhenko, D. Bourissou, G. Bertrand, Chem. Eur. J. 2003, 9,
3611.
[9] H. Amii, L. Vranicar, H. Gornitzka, D. Bourrsou, G. Bertrand, J.
Am. Chem. Soc. 2004, 126, 1344.
[10] D. Scheschkewitz, H. Amii, H. Gornitzka, W. W. Schoeller, D. Bour-
issou, G. Bertrand, Angew. Chem. 2004, 116, 595; Angew. Chem. Int.
Ed. 2004, 43, 585.
9.689(1) ä,
2398.1(4) ä3, Z=2, 1calcd =1.101 gcmÀ3, F(000)=868, m=0.234mm À1, T=
150 K, 17793 reflections measured (2qmax =55.08), 9882 observed (Rint
0.041), R1 =0.074[ I>3.0s(I)], Rw =0.095 (all data), S=1.79 (785 parame-
ters).
a=100.729(1),
b=101.232(2),
g=102.225(5)8,
V=
=
Compound 9: C45H75NOP2¥1.5CH2Cl2, Mr =879.92, pale yellow prisms,
3
≈
0.25î0.25î0.20 mm , triclinic, P1 (no. 2), a=12.344(1), b=22.569(2), c=
9.856(1) ä,
2576.9(4) ä3, Z=2, 1calcd =1.134gcm À3, F(000)=952, m=0.324mm À1, T=
150 K, 19257 reflections measured (2qmax =55.08), 10635 observed (Rint
a=101.930(6),
b=92.154(2),
g=105.444(6)8,
V=
=
0.037), R1 =0.089 [I>3.0s(I)], Rw =0.238 (all data), S=1.89 (496 parame-
ters).
Compound 10: C45H75NOP2, Mr =708.04, red prisms, 0.30î0.20î
0.15 mm3, orthorhombic, P212121 (no. 19), a=9.7452(7), b=17.211(1), c=
25.8268(9) ä, V=4331.8(5) ä3, Z=4, 1calcd =1.086 gcmÀ3, F(000)=1560,
m=0.133 mmÀ1, T=130 K, 36734reflections measured (2 qmax =55.08),
5099 observed (Rint =0.047), R1 =0.051 [I>3.0s(I)], Rw =0.130 (all data),
S=1.35 (443 parameters).
[11] H. Sugiyama, S. Ito, M. Yoshifuji, Angew. Chem. 2003, 115, 3932;
Angew. Chem. Int. Ed. 2003, 42, 3802.
Compound 13: C48H72OP2, Mr =727.04, yellow prisms, 0.20î0.20î
0.05 mm3, monoclinic, P21/n (no. 14), a=18.864(2), b=13.344(4), c=
[12] a) K. B. Dillon, F. Mathey, J. F. Nixon, Phosphorus: The Carbon
Copy, Wiley, Chichester, 1998; b) M. Regitz, O. J. Scherer, Multiple
Bonds and Low Coordination in Phosphorus Chemistry, Thieme,
Stuttgart, 1990.
19.525(6) ä, b=115.370(4)8, V=4440(2) ä3, Z=4, 1calcd =1.087 gcmÀ3
,
F(000)=1592, m=0.130 mmÀ1
, T=173 K, 34457 reflections measured
(2qmax =55.08), 9769 observed (Rint =0.035), R1 =0.038 [I>3.0s(I)], Rw =
0.041 (all data), S=0.81 (469 parameters).
[13] M. Yoshifuji, S. Ito, Top. Curr. Chem. 2003, 223, 67.
[14] a) S. J. Goede, F. Bickelhaupt, Chem. Ber. 1991, 124, 2677; b) S. J.
Goede, M. A. Dam, F. Bickelhaupt, Recl. Trav. Chim. Pays-Bas
1994, 113, 278; c) R. Appel, C. Casser, M. Immenkeppel, Tetrahe-
dron Lett. 1985, 26, 3551.
[15] M. Yoshifuji, I. Shima, N. Inamoto, K. Hirotsu, T. Higuchi, J. Am.
Chem. Soc. 1981, 103, 4587; M. Yoshifuji, I. Shima, N. Inamoto, K.
Hirotsu, T. Higuchi, J. Am. Chem. Soc. 1982, 104, 6167.
[16] a) M. Yoshifuji, S. Ito, K. Toyota, M. Yasunami, Heteroat. Chem.
1996, 7, 23; b) L. T. Scott, M. M. Mashemi, D. T. Meyer, H. B.
Warren, J. Am. Chem. Soc. 1991, 113, 7082; c) A. R. Araujo, D. K.
Ohira, P. M. Iwamura, Synth. Commun. 1992, 22, 1409.
[17] S. Ito, H. Sugiyama, M. Yoshifuji, Chem. Commun. 2002, 1744.
[18] a) H. Jun, V. G. Young, Jr., R. J. Angelici, Organometallics 1994, 13,
2444; b) U. Heim, H. Pritzkow, U. Fleischer, H. Gr¸tzmacher,
Angew. Chem. 1993, 105, 1400; Angew. Chem. Int. Ed. Engl. 1993,
32, 1359.
Compound 15: C51H77NOP2¥2CH2Cl2, Mr =951.99, yellow prisms, 0.25î
0.25î0.20 mm3, monoclinic, P21/n (no. 14), a=9.7433(9), b=18.122(1),
c=30.773(5) ä,
b=94.431(4)8,
V=5417.2(8) ä3,
Z=4,
1calcd =
1.167 gcmÀ3, F(000)=2048, m=0.313 mmÀ1, T=120 K, 39325 reflections
measured (2qmax =55.08), 12276 observed (Rint =0.152), R1 =0.098 [I>
3.0s(I)], Rw =0.137 (all data), S=2.12 (546 parameters).
Compound 16: C51H77NOP2¥2C6H6, Mr =938.35, orange prisms, 0.30î
0.20î0.20 mm3, triclinic, P1 (no. 2), a=14.526(1), b=15.555(1), c=
≈
14.349(1) ä,
a=114.314(4),
b=89.923(4),
g=100.728(6)8,
V=
2892.7(4) ä3, Z=2, 1calcd =1.077 gcmÀ3
,
F(000)=1024, m=0.114mm À1
,
T=223 K, 20616 reflections measured (2qmax =55.08), 11662 observed
(Rint =0.040), R1 =0.071 [I>3.0s(I)], Rw =0.098 (all data), S=1.81 (604
parameters).
CCDC-223665 (8), 223666 (9), 222766 (10), 222765 (13), 222764( 15), and
224391 (16) contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge via www.ccdc.cam.
ac.uk/conts/retrieving.html (or from the Cambridge Crystallographic
Data Centre, 12, Union Road, Cambridge CB21EZ, UK; fax:
(+44)1223-336-033; or deposit@ccdc.cam.ac.uk).
[19] R. Appel, J. Peters, A. Westerhaus, Angew. Chem. 1982, 94, 76;
Angew. Chem. Int. Ed. Engl. 1982, 21, 80.
[20] Photolysis of 7 in the absence of TEMPO gave a number of prod-
ucts, none of which were compound 10. The products are currently
being isolated and characterized.
[21] A. Dransfeld, L. Nyulµszi, P. von R. Schleyer, Inorg. Chem. 1998, 37,
4413.
[22] A diphospholide anion was prepared and used as a metal-complex
ligand: S. S. Al-Juaid, P. B. Hitchcock, R. M. Matos, J. F. Nixon, J.
Chem. Soc. Chem. Commun. 1995, 1661.
[23] a) M. A. Miranda, I. Galindo, Mol. Supramol. Photochem. 2003, 9,
43; b) R. Martin, Bull. Soc. Chim. Fr. 1974, 983.
[24] A. Altomare, M. C. Burla, M. Camalli, M. Cascarano, C. Giacovaz-
zo, A. Guagliardi, G. Polidori, J. Appl. Crystallogr. 1994, 27, 435.
[25] P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, R.
de Gelder, R. Israel, J. M. M. Smits, The DIRDIF94program
system, Technical Report of the Crystallography Laboratory, Uni-
versity of Nijmegen, The Netherlands, 1994.
Acknowledgements
This work was supported in part by Grants-in-Aid for Scientific Research
(No. 13304049 and 14044012) from the Ministry of Education, Culture,
Sports, Science and Technology, Japan. The authors thank Dr. Chizuko
Kabuto, Instrumental Analysis Center of Chemistry, Graduate School of
Science, Tohoku University, for obtaining the X-ray data for 13.
[1] a) H. Gr¸tzmacher, F. Brehler, Angew. Chem. 2002, 114, 4178;
Angew. Chem. Int. Ed. 2002, 41, 4006; b) P. P. Power, Chem. Rev.
2003, 103, 789.
[26] Crystal Structure Analysis Package, Molecular Structure Corpora-
tion, The Woodlands, TX, 1985 and 1999.
[2] a) Niecke, A. Fuchs, F. Baumeister, M. Nieger, W. W. Schoeller,
Angew. Chem. 1995, 107, 64 0;Angew. Chem. Int. Ed. Engl. 1995, 34,
555; b) O. Schmidt, A. Fuchs, D. Gudat, M. Nieger, W. Hoffbauer,
Received: December 27, 2003
Published online: April 14, 2004
2706
¹ 2004Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2004, 10, 2700 2706