Organophosphorus compounds, 145 - Synthesis and reactivity of a polycyclic, oxa-bridged phosphaalkene

Article abstract of DOI:10.1002/1099-0690(200006)2000:12<2219::aid-ejoc2219>3.0.co;2-z

Thermolysis of 2,3-diphenylindenone 2,3-epoxide (1) in the presence of tert-butylphosphaalkyne (3) proceeds through a regiospecific 1,3-dipolar cycloaddition of the phosphaalkyne to the carbonyl ylide intermediate to furnish the polycyclic phosphaalkene derivative 4. Compound 4 exhibits a remarkable - and for phosphaalkenes unusual - stability: thus, it can be stored for several days and no decomposition can be observed even in the absence of inert gas protection. The phosphaalkene 4 reacts with 1,3-dipoles such as ethyl diazoacetate (8) by formal transfer of its phosphaalkene unit to afford the 1,2,4-diazaphosphole 10. Addition of lithium alkoxides to the phosphaalkene unit of the polycyclic compound 4 occurs diastereoselectively to give the novel phosphinites 13 and 14. In this context it should be mentioned that the choice of the lithium alkoxide has a decisive influence on the preferred formation of one diastereomer of the phosphinite.

Full text of DOI:10.1002/1099-0690(200006)2000:12<2219::aid-ejoc2219>3.0.co;2-z

FULL PAPER
Organophosphorus Compounds, 145[°]
Synthesis and Reactivity of a Polycyclic, Oxa-Bridged Phosphaalkene
Sven G. Ruf,[a] Uwe Bergsträßer,[a] and Manfred Regitz*[a]
Dedicated to Professor A. Schmidpeter on the occasion of his 70th birthday
Keywords: Ylides / Phosphaalkynes / Cycloaddition reactions / Phosphinites / Heterocycles
Thermolysis of 2,3-diphenylindenone 2,3-epoxide (1) in the
presence of tert-butylphosphaalkyne (3) proceeds through a
regiospecific 1,3-dipolar cycloaddition of the phosphaalkyne
to the carbonyl ylide intermediate to furnish the polycyclic
acetate (8) by formal transfer of its phosphaalkene unit to
afford the 1,2,4-diazaphosphole 10. Addition of lithium al-
koxides to the phosphaalkene unit of the polycyclic com-
pound 4 occurs diastereoselectively to give the novel phos-
phosphaalkene derivative 4. Compound 4 exhibits a remark- phinites 13 and 14. In this context it should be mentioned
able −− and for phosphaalkenes unusual −− stability: thus, it
can be stored for several days and no decomposition can be
observed even in the absence of inert gas protection. The
phosphaalkene 4 reacts with 1,3-dipoles such as ethyl diazo-
that the choice of the lithium alkoxide has a decisive influ-
ence on the preferred formation of one diastereomer of the
phosphinite.
Introduction
Carbonyl ylide dipoles have proved to be important
building blocks for the preparation of oxygen-containing
heterocyclic systems.[1Ϫ4] The reactive carbonyl ylide is usu-
ally generated in situ in the presence of a suitable di-
polarophile.[5] The elimination of nitrogen from suitable di-
azocarbonyl precursors with transition metal, especially
rhodium, catalysis is a useful method for the generation of
the carbonyl ylides.[6] The incorporation of the carbonyl yl-
ide structure in a delocalized six π-electron system provides
sufficient stabilization so that isolation of the dipolar spe-
cies becomes possible.[7] The resultant mesoionic com-
pounds are known as the isomünchnones. It was recently
demonstrated that various isomünchnone derivatives also
react readily with phosphaalkynes.[8] This provided a simple
access to the poorly investigated class of the 1,3-oxaphos-
pholes.[9] On the basis of this work, further investigations
on the cycloaddition behavior of carbonyl ylides with phos-
phaalkynes have been performed in our laboratories.
Scheme 1. Cycloaddition of carbonyl ylide 2 with phosphaalkyne 3
2,3-diphenylindenone epoxide 1 leads to the pyrylium 4-ol-
ate intermediate 2 with a carbonyl ylide structure.[11] When
oxirane 1 is heated in dichloromethane solution in the pres-
ence of the phosphaalkyne 3, the intermediate 2 reacts re-
giospecifically with 3 to furnish a novel, oxa-bridged phos-
phaalkene derivative 4 (Scheme 1). Product 4 is easily puri-
fied by flash chromatography,[12] and is thus obtained as
pale yellow crystals that are stable for several days even in
the absence of inert gas protection. This high stability to
atmospheric moisture and oxygen is most unusual for a
phosphaalkene derivative[13] and can be rationalized in
terms of a high steric shielding of the reactive phosphaalk-
ene moiety by the tert-butyl and the two phenyl substitu-
ents.
Results and Discussion
Synthesis of the Oxo-Bridged Phosphaalkene 4
On warming, many acceptor-substituted oxiranes un-
dergo cleavage of their CϪC single bonds to generate car-
bonyl ylide intermediates.[10] For example, warming of the
[°]
Part 144: S. G. Ruf, U. Bergsträßer, M. Regitz,
Tetrahedron 2000, 56, 63Ϫ70.
[a]
Fachbereich der Universität Kaiserslautern,
Erwin-Schrödinger-Straße, D-67663 Kaiserslautern, Germany
Fax: (internat.) ϩ 49-631/205-3921
E-mail: regitz@rhrk.uni-kl.de
Eur. J. Org. Chem. 2000, 2219Ϫ2225
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
1434Ϫ193X/00/0612Ϫ2219 $ 17.50ϩ.50/0
2219

S. G. Ruf, U. Bergsträßer, M. Regitz
FULL PAPER
When the charge distribution in the carbonyl ylide 2 is complex 7.[16] The phosphorus atom in 7 experiences a typ-
1
considered together with the polarity of the PϪC triple ical JP-W coupling of 262.7 Hz. An η2-coordination can be
bond, which is characterized by a positively polarized phos- discounted since, according to the available literature data,
phorus atom, the experimentally observed regiochemistry this would have led to an appreciably larger shift to higher
of this 1,3-dipolar cycloaddition reaction is somewhat sur- field.[17] The constitution of complex 7 is also supported by
prising. However, the direction of addition of the phos- its mass spectrum and the IR absorptions for the CO li-
phaalkyne to the carbonyl ylide dipole 2 is in complete har- gands at ν˜ ϭ 1950 and 2078 cmϪ1
mony with that observed in the reactions of isomünchnones
.
with phosphaalkynes.[8] The addition of the phosphaalkyne
Reactivity Towards Diazo Compounds
3 to carbonyl ylides is not charge controlled and can appar-
ently be interpreted as a characteristic property of this class
of dipoles. In order to achieve a better understanding of
the regioselectivity of this cycloaddition ab initio studies are
currently being performed.
When the phosphaalkene derivative 4 is allowed to react
with ethyl diazoacetate at 0 °C a rapid change in the color
of the reaction solution from light yellow to violet is ob-
served. However, instead of the expected cycloaddition
product 9, workup of the reaction finally affords the 1,2,4-
diazaphosphole 10 as well as 1 (Scheme 3).
The constitution of compound 4 can be derived unequi-
vocally from its NMR and mass spectroscopic data. Thus,
the 31P NMR chemical shift value of δ ϭ 261.4 is character-
istic of an isolated PϪC double bond.[13] The 13C NMR
spectrum provides further diagnostic information. Accord-
ingly, the signal for the carbon atom of the PϪC double
1
bond appears at δ ϭ 212.5 as a doublet split by a JC-P
coupling of 45.0 Hz. The signals for the two bridgehead
carbon atoms C-1 and C-3 observed at δ ϭ 94.4 and δ ϭ
98.0, respectively, are also relevant for the structure elucida-
tion. As a consequence of the neighboring carbonyl group
the signal shifted more to low field is assigned to the carbon
atom C-3. This interpretation is supported by the observed
1
C-P coupling constants: C-1 experiences a JC-P coupling
2
of 37.8 Hz, while the JC-P coupling of C-3 is appreciably
smaller (8.9 Hz). The proposed structure of 4 was also con-
firmed by an X-ray crystallographic analysis.[8,14] It should
also be mentioned that the two bridgehead atoms C-1 and
C-3 of the phosphaalkene 4 are chiral centers. However,
since the two chiral carbon atoms cannot change their con-
figurations independently on account of the oxygen bridge,
compound 4 occurs only as a racemic mixture.
Scheme 3. Reactivity of 4 towards diazo compounds
Formation of the compound 10 can only be explained
in terms of a rapid decomposition of the spectroscopically
undetectable intermediate 9 with concomitant formation of
the oxirane 1. A geometry optimization of the intermediate
9 at the PM3 level of theory reveals a highly stretched bond
between the phosphorus atom and the neighboring bridge-
head carbon atom.[8] The resultant weakness of this highly
relevant bond for the structure 9 may explain the decom-
position of the latter into the diazaphosphole 10 and the
oxirane 1. The constitution of product 10 has been unam-
biguously confirmed by a comparison of its NMR spectro-
scopic data with those of the methyl ester derivative synthe-
sized by Regitz.[18]
Complexation of the Phosphaalkene 4
The free electron-pair of a low-coordinated phosphorus
atom can often be complexed by a group 6 metal pentacar-
bonyl fragment.[15] As expected, treatment of the phos-
phaalkene 4 with the pentacarbonyltungsten fragment 6
generated from 5 leads to formation of the tungsten com-
plex 7 (Scheme 2).
Reactivity Towards Lithium Alkoxides
H-acidic compounds like alcohols undergo addition to
phosphaalkene moieties due to the difference in electrone-
gativity between the phosphorus and carbon atoms.[19]
When the reactivity of a phosphaalkene unit is not suffi-
cient for the addition of an alcohol molecule, the use of
the respective alkoxide often renders the desired reaction
Scheme 2. Complexation of phosphaalkene 4
The η1-coordination of the phosphorus atom is demon- possible.[20] Since the newly synthesized phosphaalkene de-
strated by the shift to higher field of the 31P NMR signal rivative 4 did not react with equimolar amounts of any al-
from δ ϭ 261.4 in compound 4 to δ ϭ 235.7 in the metal cohol tested, it was treated with solutions of the lithium
2220
Eur. J. Org. Chem. 2000, 2219Ϫ2225

Organophosphorus Compounds, 145
FULL PAPER
The novel phosphinites 13 and 14 were isolated as the prod-
ucts of these reactions (Scheme 4).
Addition of an alcohol molecule to the phosphaalkene
unit of compound 4 generates two new stereocenters so that
the newly prepared phosphinites possess a total of four cen-
ters of chirality. Since the chiral bridgehead carbon atoms
C1 and C3 cannot change their configurations independ-
ently, four different stereoisomeric phosphinites 13؊16 are
feasible as reaction products. Figure 1 shows these four dif-
ferent diastereomers together with their enthalpies of
formation ∆Hf as calculated at the PM3 level of theory.
As is readily apparent from purely steric considerations, the
diastereomer 15, in which the newly introduced substituents
exist in the same spatial directions as the two phenyl sub-
stituents, is the energetically most unfavorable form. And
structure 16, the most favorable one according to PM3 cal-
culations, is not generated in this experiment because the
formation of 16 would involve an attack of the alkoxide
from the sterically most hindered site of 4.
When the formation of the phosphinites 13 and 14 is
monitored by 31P NMR spectroscopy diastereoselective re-
action pathways are observed in all cases. After workup of
the reaction mixture by flash chromatography on silica gel
60, the compounds 13 and 14 are obtained as pure diastere-
omers. The clear differences in the 31P NMR spectroscopic
data of the phosphinites 13a؊f and 14g؊i, however, indic-
ate that two different diastereomers have been formed. The
change from the simple primary or secondary alcohols
12a؊f to the α-hydroxy ketones 12g؊i apparently has a de-
Scheme 4. Reactivity of 4 towards lithium alkoxides
alkoxides 11a؊i in THF instead. The solutions of the al- cisive effect on the preferred diastereomeric form of the
koxides 11a؊i were always freshly prepared and also con- phosphinites. Assuming that the alkoxides 11g؊i form a
tained equimolar amounts of the respective alcohols 12a؊i. chelated structure with the lithium cation, which strongly
Figure 1. The four possible diastereomeric forms 13؊16 of the phosphinites and the corresponding enthalpies of formation (∆Hf)
Eur. J. Org. Chem. 2000, 2219Ϫ2225
2221

S. G. Ruf, U. Bergsträßer, M. Regitz
FULL PAPER
the internal standard; the chemical shifts for 31P are expressed relat-
ive to external 85% orthophosphoric acid. Elemental analyses were
performed with a PerkinϪElmer-Analyser 2400. IR spectra were
measured with a PerkinϪElmer 16 PC FT-IR spectrophotometer
and mass spectra were recorded with a Finnigan MAT90 spectro-
meter. Compounds 1[23] and 3[24] were prepared according to pub-
lished methods.
favors the observed syn addition, gives a possible explana-
tion of this experimental observation.
The exact structure elucidation of the isolated phosphin-
2
ites 13 and 14 is only possible by consideration of the JC-
P coupling constants in their 13C NMR spectra. It is known
2
that the magnitudes of the JC-P coupling constants are
strongly dependent on the position of the corresponding
carbon atom with respect to the free electron pair on the
phosphorus atom,[21] as has been demonstrated by appro-
priate measurements on the cyclic phosphane derivatives 17
and 18 (Figure 2).[22]
9-tert-Butyl-1,3-diphenyl-10-phospha-1,3-etheno-1H-benzopyran-
4(3H)-one (4): A solution of oxirane 1 (2.0 g, 6.7 mmol) and phos-
phaalkyne 2 (670 mg, 6.7 mmol) in 15 mL of CH2Cl2 was heated
for 18 h at 150 °C under 5 bar Ar overpressure. After evaporation
of the solvent the residue was dissolved in 5 mL of CH2Cl2 and
subjected to flash chromatography[12] on silica gel 60 with an n-
pentane/diethyl ether mixture (80:1) to furnish the product as a
pale yellow solid. Yield: 2.0 g (75%); m.p. 96 °C. Ϫ 1H NMR
4
(CDCl3): δ ϭ 1.04 [d, JH-P ϭ 1.2 Hz, 9 H, C(CH3)3], 6.81Ϫ8.09
3
(m, 9 H, aryl-H). Ϫ 13C NMR (CDCl3): δ ϭ 32.9 [d, JC-P
ϭ
2
12.8 Hz, C(CH3)3], 39.4 [d, JC-P ϭ 12.1 Hz, C(CH3)3], 94.4 (d,
1JC-P ϭ 37.8 Hz, C-1), 98.0 (d, 2JC-P ϭ 8.9 Hz, C-3), 122.8 (s), 127.7
(s), 127.9 (s), 128.00 (s), 128.03 (s), 128.1 (s), 128.3 (s), 128.6 (s),
129.0 (s), 132.4 (s), aryl-C, 126.7 (s), 148.3 (s), C-4a, C-8a, 138.5
(d, 3JC-P ϭ 4 Hz, C-1Ј), 139.9 (d, 2JC-P ϭ 10.4 Hz, C-1ЈЈ), 189.6 (d,
3JC-P ϭ 10.4 Hz, C-4), 212.5 (d, 1JC-P ϭ 45.0 Hz, C-9). Ϫ 31P NMR
(CDCl3): δ ϭ 261.4 (s). Ϫ IR (CCl4): ν˜ ϭ 2962 (s, CH), 1698 (vs,
CϭO), 1594 (s), 1492 (m), 1448 (w), 1446 (s), 1364 (m), 1280 (s),
1200 (s), 1184 (m), 1060 (m), 1027 (s), 836 (s) cmϪ1. Ϫ MS (70 eV,
EI): m/z (%) ϭ 398 (5.6) [M]ϩ, 342 (2.8) [M Ϫ C4H8]ϩ, 326 (31.8)
[M Ϫ tBuCP Ϫ O]ϩ, 105 (37.6) [Ph Ϫ CO]ϩ, 77 (16.6) [C6H5]ϩ, 57
(47.0) [C4H9]ϩ. Ϫ C26H23O2P (398.43): calcd. C 78.39, H 5.78;
found C 77.50, H 5.75.
Figure 2. Influence of the syn- and anti-positions on the magnitude
2
of the JC-P coupling constant
In the case of a syn-arrangement, large coupling con-
stants are observed whereas in the case of an anti-arrange-
2
ment the JC-P couplings can disappear completely. When
the 13C NMR signals of the quaternary carbon atoms of
the tert-butyl substituents of the phosphinites 13a؊f are
viewed no doublet splittings are observed. This indicates
that the tert-butyl substituent and the alkoxy group on the
phosphorus atom must have the same spatial direction. This
immediately precludes the diastereomeric forms 14 and 16.
The differentiation between the diastereomers 13 and 15 is
now possible by consideration of the signal of the ipso-car-
bon atom C-1ЈЈ in the aromatic substituent at C-1. In the
10-η1-[9-tert-Butyl-1,3-diphenyl-10-phospha-1,3-etheno-1H-
benzopyran-4(3H)-9-one]pentacarbonyltungsten (7): Phosphaalkene
4 (102 mg, 0.3 mmol) in THF (5 mL) was added to a solution of
W(CO)5thf (6), freshly prepared by irradiation of W(CO)6 (5)
(108 mg, 0.3 mmol) in THF (50 mL). After 14 h the solvent was
removed at 25 °C/0.001 mbar and the residue was subjected to flash
chromatography on silica gel 60 (n-pentane/diethyl ether ϭ 25:1) to
furnish the product 7 as an orange-red solid. Yield: 68 mg (30%);
m.p. 165 °C. Ϫ 1H NMR (CDCl3): δ ϭ 1.22 [s, 9 H, C(CH3)3],
7.30Ϫ8.31 (m, 14 H, aryl-H ). Ϫ 13C NMR (CDCl3): δ ϭ 34.3 [d,
2
phosphinites 13a؊f this exhibits an average JC-P coupling
of 16.4 Hz. Thus, the structure shown for the phosphinites
13a؊f may be considered to be confirmed.
The 13C NMR spectra of the phosphinites 14g؊i are in-
dicative of a completely different situation. In these cases
the signals for the quaternary carbon atoms of the tert-butyl
2
3JC-P ϭ 10.9 Hz, C(CH3)3], 38.7 [d, JC-P ϭ 3.6 Hz, C(CH3)3], 95.4
2
2
(d, 1JC-P ϭ 17.4 Hz, C-1), 100.0 (d, JC-P ϭ 3.6 Hz, C-3), 122.5 (s),
substituents exhibit an average JC-P coupling constant of
12.3 Hz; these experimental observations exclude the dias-
tereomeric forms 13 and 15. Since a JC-P coupling to the
ipso-carbon atom C-1ЈЈ is observed at the same time, the
products must be the phosphinites 14g؊i.
125.3 (s), 128.2 (s), 128.4 (s), 128.9 (s), 129.1 (s), 129.7 (s), 130.1
(s), 131.0 (s), 132.5 (s), aryl-C, 127.5 (s), 142.9 (s), C8a, C4a, 135.4
2
3
2
(d, JC-P ϭ 7.3 Hz, C-1Ј), 138.4 (d, JC-P ϭ 8.0 Hz, C-1ЈЈ), 187.3
3
2
(d, JC-P ϭ 13.8 Hz, C-4), 194.3 (d, JC-P ϭ 8.7 Hz, CO-cis), 195.9
2
1
(d, JC-P ϭ 40.7 Hz, CO-trans), 197.7 (d, JC-P ϭ 32.7 Hz, C-9). Ϫ
31P NMR (CDCl3): δ ϭ 235.7 (s, JP-W ϭ 262.7 Hz). Ϫ IR (CCl4):
1
ν˜ ϭ 2078 [vs, W(CO)], 1950 [vs, W(CO)], 1698 (s, CϭO) cmϪ1. Ϫ
MS (70 eV, EI): m/z (%) ϭ 722 (6.9) [M]ϩ, 694 (6.3) [M Ϫ CO]ϩ,
638 (57.6) [M Ϫ 3CO]ϩ, 582 (24.5) [M Ϫ 5CO]ϩ, 398 (53.5) [M Ϫ
W(CO)5]ϩ, 342 (38.1) [M Ϫ W(CO)5 Ϫ C4H8]ϩ, 265 (26.0) [M Ϫ
W(CO)5 Ϫ C4H8 Ϫ C6H5]ϩ, 105 (100.0) [Ph Ϫ CO]ϩ, 77 (43.7)
[C6H5]ϩ, 57 (43.7) [C4H9]ϩ.
Experimental Section
General Remarks: All experiments were carried out under argon
(purity Ͼ 99.998%) in previously evacuated and heated Schlenk
vessels. When the reaction mixture had to be heated to temper-
atures above the boiling point of the solvent, special pressure
Schlenk tubes (glass tubes, 3 ϫ 5 cm, wall thickness 2 mm) with Ethyl 5-tert-Butyl-[1,2,4]-diazaphosphole-3-carboxylate (10): The
screw-threaded, Teflon stoppers and Teflon stopcocks were used.
The solvents were dried by standard procedures, distilled, and
stored under argon until used. Melting points were determined
with a Mettler FP61 apparatus (heating rate 2 °C minϪ1) and are
uncorrected. NMR spectra were recorded with Bruker WP200 and
Bruker AMX 400 instruments. Chemical shifts for 1H and 13C
NMR spectra are reported in ppm relative to tetramethylsilane as
phosphaalkene 4 (300 mg, 0.75 mmol) was dissolved in 15 mL of
CH2Cl2 and cooled to 0 °C. To this solution was added an equimo-
lar amount of the diazo compound 8 (86 mg, 0.75 mmol). The mix-
ture was allowed to warm to room temp. during 24 h. After the
evaporation of the solvent the residue was extracted three times
with n-pentane (20 mL each). The combined pentane extracts were
filtered through a pad of Celite and, after removal of the solvent,
2222
Eur. J. Org. Chem. 2000, 2219Ϫ2225

Organophosphorus Compounds, 145
FULL PAPER
the product 10 was isolated as a pale yellow solid. The insoluble
residue consisted mainly of the oxirane 1 (IR comparison with an
(CDCl3): δ ϭ 16.7 (d, 3JC-P ϭ 6.7 Hz, C-b), 31.7 [d, 3JC-P ϭ 7.3 Hz,
1
C(CH3)3], 34.9 [s, C(CH3)3], 63.7 (d, JC-P ϭ 30.5 Hz, C-9), 66.9
2
1
authentic sample[23]). Yield: 72 mg (45%); m.p. 142 °C. Ϫ 1H NMR (d, JC-P ϭ 19.3 Hz, C-a), 86.9 (s, C-3), 93.3 (d, JC-P ϭ 25.3 Hz,
3
(CDCl3): δ ϭ 0.95 (t, JH-H ϭ 7.1 Hz, 3 H, CO2CH2CH3), 1.43 [s, C-1), 125.5 (d, JC-P ϭ 2.5 Hz), 126.8 (s), 127.3 (s), 127.6 (s), 127.7
3
9 H, C(CH3)], 4.03 (q, JH-H ϭ 7.1 Hz, 2 H, CO2CH2CH3), 12.52
(s), 128.2 (s), 128.3 (s), 128.6 130.3 (s), 132.6 (s), aryl-C, 129.2 (d,
(s, 1 H, NH). Ϫ 13C NMR (CDCl3): δ ϭ 14.1 (s, CO2CH2CH3),
JC-P ϭ 2.6 Hz), 137.2 (s), C-4a, C-8a, 139.6 (d, JC-P ϭ 6.0 Hz, C-
3
2
31.7 [d, 3JC-P ϭ 7.2 Hz, C(CH3)3], 31.7 [d, 2JC-P ϭ 14 Hz, C(CH3)3], 1Ј), 143.5 (d, JC-P ϭ 15.9 Hz, C-1ЈЈ), 192.7 (s, C-4). Ϫ 31P NMR
2
61.4 (s, CO2CH2CH3), 163.2 (d, JC-P ϭ 21.7 Hz, CO2CH2CH3), (CDCl3): δ ϭ 133.2 (s). Ϫ IR (CCl4): ν˜ ϭ 2955 (m, CϪH), 1706
164.0 (d, 1JC-P ϭ 57.0 Hz, C-3), 192.9 (d, 1JC-P ϭ 62.2 Hz, C-5). Ϫ
31P NMR (CDCl3): δ ϭ 96.3 (s). Ϫ IR (pentane): ν˜ ϭ 3261 (w,
(vs, CϭO), 1595 (m), 1493 (m), 1447 (w), 1223 (m), 1219 (m), 1046
(s), 926 (m), 837 (w) cmϪ1. Ϫ MS (70 eV, EI): m/z (%) ϭ 444 (2.4)
NH), 1759 (vs, CϭO) cmϪ1. Ϫ MS (70 eV, EI): m/z (%) ϭ 214 [M]ϩ, 387 (42.5) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ CH3CH2OP Ϫ H
(35.0) [M]ϩ, 199 (65.7) [M Ϫ CH3]ϩ, 185 (14.2) [M Ϫ C2H5]ϩ, Ϫ CH3]ϩ, 337 (44.2) [M Ϫ CH3CH2OPH Ϫ 2CH3]ϩ, 298 (93.8)
169.1 (11.8) [M Ϫ C2H5O]ϩ, 158 (19.5) [M Ϫ C4H9]ϩ, 153 (100.0)
[C21H14O2]ϩ, 270 (15.4) [C21H14O2 Ϫ CO]ϩ, 221 (17.2) [C21H14O2
[M Ϫ CH3 Ϫ C2H5]ϩ, 130 (32.5) [M Ϫ C4H9 Ϫ C2H5]ϩ; Ϫ Ph]ϩ, 193 (12.0) [C21H14O2 Ϫ PhCO]ϩ, 165 (29.9) [C21H14O2 Ϫ
C9H15N2O2P (214.20).
PhCO Ϫ CO]ϩ, 105 (54.9) [Ph Ϫ CO]ϩ, 77 (27.7) [C6H5]ϩ, 57 (22.1)
[C4H9]ϩ. Ϫ C28H29O3P (444.50): calcd. C 75.59, H 6.58; found C
74.89, H 6.51.
10-Alkoxy-9-tert-butyl-1,3-diphenyl-10-phospha-1,3-ethano-1H-
benzopyran-4(3H)-one (13, 14). ؊ General Procedure: The phos-
phaalkene 4 was dissolved in 15 mL of THF and cooled to Ϫ78
°C. Then, an equimolar amount of a freshly prepared solution of
the appropriate lithium alkoxide in THF was added and the reac-
tion mixture allowed to warm to room temp. during 16 h. After
removal of the solvent the residue was subjected to flash chromato-
graphy on silica gel 60 (n-pentane/diethyl ether ϭ 50:1 for 13a-f
and n-pentane/diethyl ether ϭ 20:1 for 14g؊i) to furnish the phos-
phinites 13 and 14 as white solids.
9-tert-Butyl-1,3-diphenyl-10-propoxy-10-phospha-1,3-ethano-1H-
benzopyran-4(3H)-one (13c): Yield: 130 mg (46%); m.p. 107 °C. Ϫ
3
1H NMR (CDCl3): δ ϭ 0.66 (dd, JH-H ϭ 7.4 Hz, 7.3 Hz, 3 H,
4
OCH2CH2CH3), 0.87 [d, JH-P ϭ 1.5 Hz, 9 H, C(CH3)3], 1.26 (m,
2
2 H, OCH2CH2CH3), 2.47 (d, JH-P ϭ 12.6 Hz, 1 H, H at C-9),
3
3
2
3.35 (dq, JH-H ϭ JH-P ϭ 6.9 Hz, JH-H ϭ 9.6 Hz, 1 H) and 3.64
(dq, 3JHH ϭ 3JH-P ϭ 6.4 Hz, 2JH-H ϭ 9.6 Hz, 1 H, OCH2CH2CH3),
7.31Ϫ7.40 (m, 7 H), 7.45Ϫ7.49 (m, 2 H), 7.82Ϫ7.84 (m, 2 H),
8.17Ϫ8.19 (m, 1 H), 8.51 (bd, 2 H) aryl-H. Ϫ 13C NMR (CDCl3):
Preparation of the Lithium Alkoxides ؊ General Procedure: The
appropriate alcohol (16 mmol) was dissolved in 10 mL of THF and
the resulting mixture was cooled to 0 °C in an ice bath. To this
mixture was added dropwise 5 mL of a 1.6  nBuLi solution in n-
hexane. The resulting mixture was stirred for 15 min at 0 °C and
then used in the preparation of the phosphinites 13 and 14.
3
3
δ ϭ 10.4 (s, C-c), 24.6 (d, JC-P ϭ 7.3 Hz, C-b), 32.0 [d, JC-P
ϭ
1
7.3 Hz, C(CH3)3], 35.2 [s, C(CH3)3], 64.2 [d, JC-P ϭ 30.5 Hz, C-9],
73.0 (d, JC-P ϭ 18.1 Hz, C-a), 87.2 (s, C-3), 93.6 (d, JC-P
2
1
ϭ
24.7 Hz, C-1), 125.8 (d, JC-P ϭ 2.9 Hz), 127.2 (s), 127.6 (s), 127.9
(s), 128.1 (s), 128.2 (s), 128.5 (s), 128.6, 129 (s), 132.9 (s) aryl-C,
3
129.6 (d, JC-P ϭ 2.2 Hz), 137.5 (s), C-4a, C-8a, 140.0 (d, JC-P
ϭ
2
7.4 Hz, C-1Ј), 143.9 (d, JC-P ϭ 16.0 Hz, C-1ЈЈ), 193.0 (s, C-4). Ϫ
31P NMR (CDCl3): δ ϭ133.0 (s). Ϫ IR (CCl4): ν˜ ϭ 2957 (m,
CϪH), 1704 (vs, CϭO), 1595 (m), 1447 (s), 1283 (m), 1223 (m),
1206 (m), 1064 (m), 1038 (m) 837 (w) cmϪ1. Ϫ MS (70 eV, EI): m/z
(%) ϭ 458 (0.7) [M]ϩ, 401 (23.5) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ
9-tert-Butyl-10-methoxy-1,3-diphenyl-10-phospha-1,3-ethano-1H-
benzopyran-4(3H)-one (13a): Yield: 101 mg (36%); m.p. 87 °C. Ϫ
4
1H NMR (CDCl3): δ ϭ 0.89 [d, JH-P ϭ 1.4 Hz, 9 H, C(CH3)3],
2.49 (d, 2JH-P ϭ 12.9 Hz, 1 H, H at C-9), 3.43 (d, 3JH-P ϭ 12.7 Hz,
3 H, OCH3), 7.25Ϫ7.42 (m, 7 H), 7.47Ϫ7.53 (m, 2 H), 7.81Ϫ7.83
(m, 2 H), 8.18Ϫ8.19 (m, 1 H), 8.50 (d, 2 H) aryl-H. Ϫ 13C NMR
CH3CH2CH2OP
Ϫ
H
Ϫ
CH3]ϩ, 337 (25.3) [M
Ϫ
CH3CH2CH2OPH Ϫ 2CH3]ϩ, 298 (70.3) [C21H14O2]ϩ, 270 (5.6)
[C21H14O2 Ϫ CO]ϩ, 221 (4.4) [C21H14O2 Ϫ Ph]ϩ, 193 (1.8)
[C21H14O2 Ϫ PhCO]ϩ, 165 (1.0) [C21H14O2 Ϫ PhCO Ϫ CO]ϩ, 105
(11.8) [Ph Ϫ CO]ϩ, 57 (2.0) [C4H9]ϩ. Ϫ C29H31O3P (458.50): calcd.
C 75.29, H 6.77; found C 74.25, H 6.69.
3
(CDCl3): δ ϭ 32.1 [d, JC-P ϭ 7.6 Hz, C(CH3)3], 35.4 [s, C(CH3)3],
58.2 (d, 1JC-P ϭ 21.4 Hz, C-9), 63.9 (d, 2JC-P ϭ 30.6 Hz, C-a), 87.4
2
1
(d, JC-P ϭ 1.5 Hz, C-3), 93.6 (d, JC-P ϭ 23.6 Hz, C-1), 126.0 (d,
JC-P ϭ 3.8 Hz), 127.2 (s), 127.8 (s), 128.0 (s), 128.2 (s), 128.7 (d,
J
C-P ϭ 9.1 Hz), 128.8 (s), 128.9 (s), 129.5 (s), 130.6 (s), aryl-C, 133.0
(s), 137.3 (s), C-4a, C-8a, 139.9 (d, 3JC-P ϭ 6.1 Hz, C-1Ј), 143.8 (d,
2JC-P ϭ 16.7 Hz, C-1ЈЈ), 193.0 (s, C-4). Ϫ 31P NMR (CDCl3): δ ϭ
131.4 (s). Ϫ IR (CCl4): ν˜ ϭ 2956 (m, ϪCH), 1702 (vs, CϭO), 1596
9-tert-Butyl-10-neopentyloxy-1,3-diphenyl-10-phospha-1,3-ethano-
1H-benzopyran-4(3H)-one (13d): Yield: 105 mg (34%); m.p. 107 °C.
Ϫ
1H NMR (CDCl3): δ ϭ 0.46 [s, 9 H, OCH2C(CH3)3], 0.73 [d,
(m), 1493 (w), 1447 (m), 1285 (w), 1223 (m), 1037 (s), 838 (w) cmϪ1
.
2
4JH-P ϭ 1.0 Hz, 9 H, C(CH3)3], 2.36 (d, JH-P ϭ 12.1 Hz, 1 H, H
Ϫ MS (70 eV, EI): m/z (%) ϭ 430 (2.2) [M]ϩ, 398 (52.8) [M Ϫ
MeOH]ϩ, 373 (31.8) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ CH3OP Ϫ H Ϫ
1
3
at C-9), 2.94 (dd, JH-H ϭ 8.6 Hz JH-P ϭ 6.8 Hz, 1 H) and 3.20
1
3
[dd, JH-H ϭ 8.6, JH-P ϭ 2.6 Hz, 1 H, OCH2C(CH3)3], 7.16Ϫ7.32
(m, 9 H), 7.68Ϫ7.70 (m, 2 H), 8.03Ϫ8.05 (m, 1 H), 8.42 (bd, 2 H)
aryl-H. Ϫ 13C NMR (CDCl3): δ ϭ 26.0 [s, OCHA-BC(CH3)3],
31.9 [d, JC-P ϭ 8.0 Hz, C(CH3)3], 32.5 [d, JC-P ϭ 9.6 Hz,
OCHA-BC(CH3)3], 34.9 [s, C(CH3)3], 64.5 (d, JC-P ϭ 32.1 Hz, C-
CH3]ϩ, 337 (38.4) [M
Ϫ CH3OPH Ϫ
2CH3]ϩ, 298 (68.5)
[C21H14O2]ϩ, 270 (10.5) [C21H14O2 Ϫ CO]ϩ, 221 (12.9) [C21H14O2
Ϫ Ph]ϩ, 193 (44.8) [C21H14O2 Ϫ PhCO]ϩ, 165 (55.1) [C21H14O2
Ϫ PhCO Ϫ CO]ϩ, 105 (80.1) [Ph Ϫ CO]ϩ, 77 (37.7) [C6H5]ϩ, 57
(33.9) [C4H9]ϩ.
3
3
1
2
1
9), 80.9 (d, JC-P ϭ 16.0 Hz, C-a), 86.7 (s, C-3), 93.6 (d, JC-P
ϭ
9-tert-Butyl-10-ethoxy-1,3-diphenyl-10-phospha-1,3-ethano-1H- 24.9 Hz, C-1), 125.6 (d, JC-P ϭ 2.4 Hz), 126.9 (s), 127.4 (s), 127.7
benzopyran-4(3H)-one (13b): Yield: 120 mg (42%); m.p. 92 °C. Ϫ (s), 127.8 (s), 128.3 (s), 128.4 (s), 128.7, 130.4 (s), 132.7 (s) aryl-C,
4
3
1H NMR (CDCl3): δ ϭ 0.87 [d, JH-P ϭ 1.0 Hz, 9 H, C(CH3)3], 129.4 (s), 137.3 (s), C-4a, C-8a, 139.7 (d, JC-P ϭ 6.4 Hz, C-1Ј),
0.91 (pt, JH-H ϭ 7.1 Hz, 6.9 Hz, 3 H, OCH2CH3), 2.46 (d, 143.7 (d, JC-P ϭ 16.0 Hz, C-1ЈЈ), 192.7 (s, C-4). Ϫ 31P NMR
3
2
2JH-P ϭ 12.9 Hz, 1 H, H at C-9), 3.44 (m, 3JH-H ϭ 6.9 Hz, 2JH-H ϭ (CDCl3): δ ϭ 130.2 (s). Ϫ IR (CCl4): ν˜ ϭ 2956 (s, CH), 1706 (vs,
3
2
9.9 Hz, 1 H) and 3.73 (m, JH-H ϭ 7.1 Hz, JH-H ϭ 9.9 Hz, 1 H,
CϭO), 1595 (w), 1493 (w), 1447 (m), 1207 (m), 1036 (m), 1012 (s),
OCH2CH3), 7.30Ϫ7.37 (m, 7 H), 7.42Ϫ7.49 (m, 2 H), 7.80Ϫ7.82 837 (m), 817 (w) cmϪ1. Ϫ MS (70 eV, EI): m/z (%) ϭ 486 (0.3)
(m, 2 H), 8.15Ϫ8.17 (m, 1 H), 8.50 (d, 2 H) aryl-H. Ϫ 13C NMR
[M]ϩ, 429 (13.7) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ (CH3)3CCH2OP Ϫ
Eur. J. Org. Chem. 2000, 2219Ϫ2225
2223

S. G. Ruf, U. Bergsträßer, M. Regitz
FULL PAPER
2
1
H Ϫ CH3]ϩ, 337 (22.5) [M Ϫ (CH3)3CCH2OPH Ϫ 2CH3]ϩ, 298 [d, JC-P ϭ 18.1 Hz, C(CH3)3], 70.2 (d, JC-P ϭ 35.8 Hz, C-9), 74.7
2
2
(63.1) [C21H14O2]ϩ, 270 (4.5) [C21H14O2 Ϫ CO]ϩ, 221 (3.1)
[C21H14O2 Ϫ Ph]ϩ, 193 (1.2) [C21H14O2 Ϫ PhCO]ϩ, 165 (0.7)
(d, JC-P ϭ 12.4 Hz, C-a), 90.9 (d, JC-P ϭ 2.8 Hz, C-3), 92.9 (d,
1JC-P ϭ 27.3 Hz, C-1), 125.6 (d, JC-P ϭ 6.6 Hz), 127.4 (s), 127.5 (s),
[C21H14O2 Ϫ PhCO Ϫ CO]ϩ, 105 (7.7) [Ph Ϫ CO]ϩ, 77 (1.2) [Ph]ϩ, 127.8 (s), 127.9 (s), 128.0 (d, JC-P ϭ 2.8 Hz), 128.3 (d, JC-P
ϭ
ϭ
ϭ
57 (0.9) [C4H9]ϩ. Ϫ C31H35O3P (486.58): calcd. C 76.54, H 7.20; 2.4 Hz), 128.4 (s), 128.5 (s), 133.7 (s) aryl-C, 130.9 (d, JC-P
2
found C 76.16, H 7.28.
3.2 Hz), 139.1 (s), 140.5 (s), C-4a, C-8a, C-1Ј, 142.4 (d, JC-P
22.9 Hz, C-1ЈЈ), 193.2 (s, C-5), 205.9 (s, CH3CO). Ϫ 31P NMR
(CDCl3): δ ϭ 154.5 (s). Ϫ IR (CCl4): ν˜ ϭ 2960 (m, CH), 1709 and
1693 (vs, CϭO), 1596 (m), 1494 (w), 1474 (w), 1446 (m), 1357 (m),
1208 (m), 1060 (s), 850 (w), 790 (w) cmϪ1. Ϫ MS (70 eV, EI): m/z
(%) ϭ 472 (4.3) [M]ϩ, 415 (18.9) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ
CH3COCH2OP Ϫ H Ϫ CH3]ϩ, 337 (28.6) [M Ϫ CH3COCH2OPH
Ϫ 2CH3]ϩ, 298 (49.8) [C21H14O2]ϩ, 270 (2.9) [C21H14O2 Ϫ CO]ϩ,
221 (2.0) [C21H14O2 Ϫ Ph]ϩ, 105 (6.0) [Ph Ϫ CO]ϩ, 57 (6.9)
[C4H9]ϩ.
9-tert-Butyl-10-isopropoxy-1,3-diphenyl-10-phospha-1,3-ethano-1H-
benzopyran-4(3H)-one (13e): Yield: 110 mg (36%); m.p. 109 °C. Ϫ
3
1H NMR (CDCl3): δ ϭ 0.59 [d, JH-H ϭ 6.2 Hz, 3 H, CH(CH3)2],
4
3
0.88 [d, JH-P ϭ 1.2 Hz, 9 H, C(CH3)3], 1.17 [d, JH-H ϭ 6.2 Hz, 3
2
H, CH(CH3)2], 2.47 (d, JH-P ϭ 12.1 Hz, 1 H, H at C-9), 3.79 [ds,
3JH-H ϭ 6.2 Hz, 3JH-P ϭ 3.3 Hz, 1 H, CH(CH3)2], 7.34Ϫ7.49 (m, 9
H), 7.87Ϫ7.89 (m, 2 H), 8.18Ϫ8.20 (m, 1 H), 8.55 (bd, 2 H) aryl-
H. Ϫ 13C NMR (CDCl3): δ ϭ 23.3 (d, JC-P ϭ 4.6 Hz), 24.1 (d,
3
3JC-P ϭ 3.0 Hz), C-b, C-c, 31.5 [d, JC-P ϭ 7.7 Hz, C(CH3)3], 34.7
3
1
2
[s, C(CH3)3], 64.0 (d, JC-P ϭ 29.7 Hz, C-9), 74.0 (d, JC-P
ϭ
9-tert-Butyl-10-(2-oxobutoxy)-1,3-diphenyl-10-phospha-
1,3-ethano-1H-benzo-pyran-4(3H)-one (14h): Yield: 155 mg (52%);
1
16.7 Hz, C-a), 86.7 (s, C-3), 93.5 (d, JC-P ϭ 27.6 Hz, C-1), 125.3
(d, JC-P ϭ 2.5 Hz), 126.9 (s), 127.3 (s), 127.6 (s), 127.7 (s), 128.2
(s), 128.3 (s), 128.7, 130.5 (s), 132.5 (s) arylϪC, 129.5 (s), 137.4 (s),
3
m.p. 132 °C. Ϫ 1H NMR (CDCl3): δ ϭ 1.43 (dd, JH-H ϭ 7.1,
7.3 Hz, 3 H, OCH2COCH2CH3), 1.0 [s, 9 H, C(CH3)3], 2.02 (dq,
3
C-4a, C-8a, 139.8 (d, JC - P ϭ 6.9 Hz, C-1Ј), 143.6 (d,
3
1
2JH-H ϭ 18.4 Hz, JH-H ϭ 7.3 Hz, 1 H) and 2.18 (dq, JH-H
ϭ
2JC-P ϭ 16.0 Hz, C-1ЈЈ), 192.8 (s, C-4). Ϫ 31P NMR (CDCl3): δ ϭ
133.0 (s). Ϫ IR (CCl4): ν˜ ϭ 1958 (s, CH), 1706 (vs, CϭO), 1595
(m), 1493 (w), 1447 (s), 1369 (m), 1283 (w), 1223 (m), 1206 (m),
1187 (w), 1106 (w), 1035 (s), 964 (s), 864 (w), 837 (m) cmϪ1. Ϫ MS
(70 eV, EI): m/z (%) 458 (1.4) [M]ϩ, 401 (32.1) [M Ϫ tBu]ϩ, 398
(26.3) [M Ϫ iC3H8OH]ϩ, 352 (94.3) [M Ϫ iC3H8OPH Ϫ CH3]ϩ,
337 (29.4) [M Ϫ iC3H8OP Ϫ H Ϫ 2CH3]ϩ, 298 (100) [C21H14O2]ϩ,
270 (43.6) [C21H14O2 Ϫ CO]ϩ, 221 (10.6) [C21H14O2 Ϫ Ph]ϩ, 193
(8.9) [C21H14O2 Ϫ PhCO]ϩ, 165 (11.2) [C21H14O2 Ϫ PhCO Ϫ
CO]ϩ, 105 (28.9) [Ph Ϫ CO]ϩ, 77 (33.4) [Ph]ϩ, 57 (8.9) [C4H9]ϩ.
3
18.4 Hz, JH-H ϭ 7.1 Hz, 1 H, OCH2COCH2CH3), 3.41 (d,
2JH-P ϭ 8.3 Hz, 1 H, H at C-9), 4.07 (dd, JH-H ϭ 17.1 Hz,
1
3JH-P ϭ 8.0 Hz, 1 H) and 4.13 (dd, JH-H ϭ 17.1 Hz, JH-P
ϭ
1
3
7.3 Hz, 1 H, OCH2COCH2CH3), 7.30Ϫ7.48 (m, 9 H), 7.68Ϫ7.70
(m, 2 H), 8.06Ϫ8.08 (m, 2 H), 8.18Ϫ8.20 (bd, 1 H) aryl-H. Ϫ 13C
NMR (CDCl3): δ ϭ 6.9 (s, C-d), 31.3 [d, 3JC-P ϭ 9.4 Hz, C(CH3)3],
2
1
31.7 (s, C-c), 32.5 [d, JC-P ϭ 18.4 Hz, C(CH3)3], 70.2 (d, JC-P
ϭ
ϭ
ϭ
2
2
35.7 Hz, C-9), 74.4 (d, JC-P ϭ 12.5 Hz, ϪC-a), 90.9 (d, JC-P
2.7 Hz, C-3), 92.8 (d, JC-P ϭ 27.0 Hz, C-1), 125.7 (d, JC-P
1
4.2 Hz), 127.4 (d, JC-P ϭ 1.1 Hz), 127.5 (d, JC-P ϭ 1.4 Hz), 127.8
(s), 127.9 (s), 128.0 (s), 128.1 (s), 128.4 (s), 128.5 (s), 133.8 (s) aryl-
C, 130.9 (d, JC-P ϭ 3.1 Hz), 139.1 (d, JC-P ϭ 3.8 Hz), 140.6 (s), C-
9-tert-Butyl-10-cyclohexoxy-1,3-diphenyl-10-phospha-1,3-ethano-
1H-benzopyran-4(3H)-one (13f): Yield: 85 mg (29%); m.p. 117 °C.
Ϫ 1H NMR (CDCl3): δ ϭ 0.88 [s, C(CH3)3], 0.90Ϫ1.68 (m, 10 H),
2.48 (d, 2JH-P ϭ 12.0 Hz, 1 H, H at C-9), 3.44 (m, 1 H), 7.34Ϫ7.49
(m, 9 H), 7.87Ϫ7.89 (m, 2 H), 8.18Ϫ8.20 (m, 1 H), 8.57 (bd, 2 H)
2
4a, C-8a, C-1Ј, 142.6 (d, JC-P ϭ 22.5 Hz, C-1ЈЈ), 194.0 (s, C-5),
206.6 (s, EtCO). Ϫ 31P NMR (CDCl3): δ ϭ 154.3 (s). Ϫ IR (CCl4):
ν˜ ϭ 2960 (m), 1711 and 1692 (vs, CϭO), 1595 (m), 1493 (w), 1446
(m), 1283 (m), 1208 (s), 1060 (s), 1020 (s), 792 (w) cmϪ1. Ϫ MS
(70 eV, EI): m/z (%) ϭ 486 (2.1) [M]ϩ, 429 (23.3) [M Ϫ tBu]ϩ,
352 (48.3) [M Ϫ EtCOCH2OP Ϫ H Ϫ CH3]ϩ, 337 (37.8) [M Ϫ
EtCOCH2OPH Ϫ 2CH3]ϩ, 298 (100) [C21H14O2]ϩ, 270 (5.5)
[C21H14O2 Ϫ CO]ϩ, 221 (6.2) [C21H14O2 Ϫ Ph]ϩ, 105 (66.0) [Ph Ϫ
CO]ϩ, 77 (23.2) [Ph]ϩ, 57 (15.4) [C4H9]ϩ.
5
aryl-H. Ϫ 13C NMR (CDCl3): δ ϭ 24.4 (d, JC-P ϭ 5.1 Hz, C-d),
3
25.5 (s, C-c, C-e), 31.9 [d, JC-P ϭ 8.0 Hz, C(CH3)3], 33.8 (d,
3JC-P ϭ 3.7 Hz), 34.5 (d, 3JC-P ϭ 2.9 Hz) C-b, C-f, 35.0 [s, C(CH3)3],
64.4 (d, 1JC-P ϭ 30.5 Hz, C-9), 80.1 (d, 2JC-P ϭ 15.3 Hz, C-a), 86.9
1
(s, C-3), 93.9 (d, JC-P ϭ 28.4 Hz, C-1), 125.6 (d, JC-P ϭ 2.9 Hz),
127.2 (s), 127.5 (s), 127.9 (s), 128.0(s), 128.5 (s), 129.0 (s), 128.7,
130.7 (s), 132.9 (s) aryl-C, 129.7 (s), 137.8 (s), C-4a, C-8a, 140.1 (d,
9-tert-Butyl-1,3-diphenyl-10-(2-phenyl-2-oxoethoxy)-10-phospha-
1,3-ethano-1H-benzopyran-4(3H)-one (14i): Yield: 155 mg (44%);
m.p. 138 °C. Ϫ 1H NMR (CDCl3): δ ϭ 0.96 [s, 9 H, C(CH3)3], 3.52
2
3JC-P ϭ 6.6 Hz, C-1Ј), 143.9 (d, JC-P ϭ 16.0 Hz, C-1ЈЈ), 193.2 (s,
C-4). Ϫ 31P NMR (CDCl3): δ ϭ 126.1 (s). Ϫ IR (CCl4): ν˜ ϭ 2934
(s, CH), 1706 (s, CϭO), 1595 (m), 1493 (w), 1446 (s), 1369 (w),
1282 (w), 1223 (m), 1206 (m), 1187 (w), 1039 (s), 1016 (m), 977
(m), 853 (w), 837 (w), 816 (w) cmϪ1. Ϫ MS (70 eV, EI): m/z (%) ϭ
498 (0.2) [M]ϩ, 441 (12.3) [M Ϫ tBu]ϩ, 352 (100) [M Ϫ C6H11OP
Ϫ H Ϫ CH3]ϩ, 337 (27.0) [M Ϫ C6H11OPH Ϫ 2CH3]ϩ, 298 (68.3)
[C21H14O2]ϩ, 270 (7.3) [C21H14O2 Ϫ CO]ϩ, 221 (7.2) [C21H14O2 Ϫ
2
2
(d, JH-P ϭ 8.3 Hz, 1 H, H at C-9), 4.65 (dd, JH-H ϭ 16.7 Hz,
3JH-P ϭ 8.3 Hz, 1 H) and 4.95 (dd, JH-H ϭ 16.7 Hz, JH-P
ϭ
1
3
8.3 Hz, 1 H, OCH2COPh), 7.30Ϫ7.55 (m, 12 H), 7.65Ϫ7.74 (m, 4
H), 7.98Ϫ8.00 (m, 2 H), 8.16Ϫ8.17 (bd, 1 H) aryl-H. Ϫ 13C NMR
3
2
(CDCl3): δ ϭ 31.3 [d, JC-P ϭ 9.2 Hz, C(CH3)3], 32.6 [d, JC-P
ϭ
ϭ
ϭ
ϭ
1
2
18.5 Hz, C(CH3)3], 69.4 (d, JC-P ϭ 36.6 Hz, C-9), 74.4 (d, JC-P
11.2 Hz, C-a), 91.3 (d, JC-P ϭ 2.3 Hz, C-3), 93.0 (d, JC-P
27.0 Hz, C-1), 125.7 (d, JC-P ϭ 4.5 Hz), 127.4 (s), 127.5 (d, JC-P
Ph]ϩ, 193 (7.5) [C21H14O2 Ϫ PhCO]ϩ, 165 (15.8) [C21H14O2
Ϫ
2
1
PhCO Ϫ CO]ϩ, 105 (36.0) [Ph Ϫ CO]ϩ, 77 (11.1) [Ph]ϩ, 57 (6.9)
[C4H9]ϩ. Ϫ C32H35O3P (498.60): calcd. C 77.11, H 7.03; found C
76.72, H 6.95.
1.6 Hz), 127.7 (s), 127.8 (s), 127.9 (s), 128.0 (s), 128.1 (s), 128.2 (s),
128.4 (s), 128.5 (s), 128.6 (s), 133.6 (s), 134.4 (s), aryl-C, 131.0 (s),
133.6 (s), 139.3 (d, JC-P ϭ 4.1 Hz), 140.3 (s), C-4a, C-8a, C-1Ј,
9-tert-Butyl-10-(2-oxopropoxy)-1,3-diphenyl-10-phospha-
1,3-ethano-1H-benzopyran-4(3H)-one (14g): Yield: 160 mg (54%);
m.p. 131 °C. Ϫ 1H NMR (CDCl3): δ ϭ 1.0 [s, 9 H, C(CH3)3], 1.83
2
142.7 (d, JC-P ϭ 22.5 Hz, C-1ЈЈ), 194.0 (s, C-4), 195.1 (s, PhCO).
Ϫ
31P NMR (CDCl3): δ ϭ 154.0 (s). Ϫ IR (CCl4): ν˜ ϭ 2959 (m,
(s, 3 H, CH2COCH3), 3.43 (d, 2JH-P ϭ 8.4 Hz, 1 H, H at C-9), 4.05 CH), 1701 and 1693 (vs, CϭO), 1597 (m), 1446 (m), 1283 (m), 1225
1
3
2
(dd, JH-H ϭ 17.2 Hz, JH-P ϭ 8.0 Hz, 1 H) and 4.15 (dd, JH-H
ϭ
(m), 1209 (m), 1110 (w), 1071 (w), 850 (w) cmϪ1. Ϫ MS (70 eV,
17.2 Hz, JH-P ϭ 7.1 Hz, 1 H, CH2COCH3), 7.34Ϫ7.49 (m, 9 H), EI): m/z (%) ϭ 534 (2.2) [M]ϩ, 477 (17.2) [M Ϫ tBu]ϩ, 352 (46.2)
7.68Ϫ7.70 (m, 2 H), 8.06Ϫ8.08 (m, 2 H), 8.18Ϫ8.20 (bd, 1 H) aryl-
[M Ϫ PhCOCH2OP Ϫ H Ϫ CH3]ϩ, 337 (46.6) [M Ϫ PhCOCH2-
H. Ϫ 13C NMR (CDCl3): δ ϭ 25.5 (s, C-c), 31.3 [s, C(CH3)3], 32.5 OPH Ϫ 2CH3]ϩ, 298 (64.1) [C21H14O2]ϩ, 270 (8.8) [C21H14O2
3
Ϫ
2224
Eur. J. Org. Chem. 2000, 2219Ϫ2225

Organophosphorus Compounds, 145
FULL PAPER
[13]
[14]
CO]ϩ, 221 (8.8) [C21H14O2 Ϫ Ph]ϩ, 105 (100) [Ph Ϫ CO]ϩ, 77
R. Appel, in Multiple Bonds and Low Coordination in Phos-
phorus Chemistry (Eds.: M. Regitz, O. J. Scherer), Thieme,
Stuttgart, 1990, p. 157ff.
A more detailed discussion of the bonding parameters deter-
mined in this way is not given because of the poor quality of
the obtained data set.
(30.9) [Ph]ϩ, 57 (14.2) [C4H9]ϩ.
Acknowledgments
[15] [15a]
R. Appel, F. Knoll, I. Ruppert, Angew. Chem. 1981, 93,
We thank the Fonds der Chemischen Industrie for generous finan-
cial support (postgraduate grant for S. R.) and the Deutsche For-
schungsgemeinschaft (Graduate College Phosphorus as Con-
necting Link Between Various Chemical Disciplines).
771Ϫ784; Angew. Chem. Int. Ed. Engl. 1981, 20, 731Ϫ743. Ϫ
[15b] P. Binger, in Multiple Bonds and Low Coordination in Phos-
phorus Chemistry (Eds.: M. Regitz, O. J. Scherer), Thieme,
[15c]
Stuttgart, 1990, S. 90. Ϫ
M. Slany, Ph. D. Thesis, Univer-
sität Kaiserslautern, 1993.
[16]
[17]
W. Nießen, Ph. D. Thesis, Universität Kaiserslautern, 1996.
K. Knoll, G. Huttner, M. Wasiucionek, L. Zsolnai, Angew.
Chem. 1984, 96, 708Ϫ709; Angew. Chem. Int. Ed. Engl. 1984,
23, 739Ϫ740.
W. Rösch, Ph. D. Thesis, Universität Kaiserslautern, 1986.
R. Appel, U. Kündgen, Angew. Chem. 1982, 94, 227; Angew.
Chem. Int. Ed. Engl. 1982, 21, 219Ϫ220.
M. Hafner, T. Wegemann, M. Regitz, Synthesis 1993,
1247Ϫ1252.
W. D. Herzog, M. Messerschmidt, NMR-Spektroskopie für
Anwender, VCH, Weinheim, 1995.
[1]
T. L. B. Boivin, Tetrahedron 1987, 43, 3309Ϫ3362.
[2]
Y. Kishi, G. Schmid, T. Fukuyama, K. Akasaka, J. Am. Chem.
Soc. 1979, 101, 259Ϫ260.
[3]
[18]
[19]
Y. Lin, M. Risk, S. Ray, D. Engen, J. Clardy, J. James, K. Nak-
anishi, J. Am. Chem. Soc. 1981, 103, 6773Ϫ6775.
[4]
Y. Shimizu, H. Chou, H. Bando, G. Duyne, J. Clardy, J. Am.
Chem. Soc. 1986, 108, 514Ϫ515.
[20]
[21]
[5]
M. H. Osterhout, W. R. Nadler, A. Padwa, Synthesis 1994,
123Ϫ141.
[6]
A. Padwa, D. J. Austin, Angew. Chem. 1994, 106, 1881Ϫ1889;
Angew. Chem. Int. Ed. Engl. 1994, 33, 1879Ϫ1886.
[22] [22a]
J. J. Breen, S. I. Featherman, L. D. Quin, R. C. Stocks,
[7]
[22b]
M. Hamaguchi, T. Ibata, Tetrahedron Lett. 1974, 4475Ϫ4476.
J. Chem. Soc., Chem. Commun. 1972, 657Ϫ658. Ϫ
A. P.
[8]
S. G. Ruf, Ph. D. Thesis, Universität Kaiserslautern, 1999.
Marchand, in Stereochemical Applications of NMR Studies in
Rigid Bicyclic Systems, Methods in Stereochemical Analysis
(Ed.: A. P. Marchand), VCH, Weinheim, 1982. Ϫ [22c] J. B. Sto-
thers, Carbon-13 NMR Spectroscopy, Academic Press, New
York, 1972.
[9]
[9a] K. H. Dötz, A. Tiriliomis, K. Harms, J. Chem. Soc., Chem.
[9b]
Commun. 1989, 788Ϫ790. Ϫ
K. H. Dötz, A. Tiriliomis, K.
Harms, Tetrahedron 1993, 49, 5577Ϫ5597.
R. Huisgen, Angew. Chem. 1977, 89, 589Ϫ602; Angew. Chem.
Int. Ed. Engl. 1977, 16, 572Ϫ585.
[10]
[23]
[24]
A. Weitz, E. Scheffer, Chem. Ber. 1921, 54, 2341Ϫ2344.
[11] [11a]
E. F. Ullmann, J. E. Milks, J. Am. Chem. Soc. 1962, 84,
W. Rösch, T. Allspach, U. Bergsträßer, M. Regitz, in Synthetic
Methods of Organometallic and Inorganic Chemistry, Vol. 3
(Ed.: H. H. Karsch), Thieme, Stuttgart, 1996.
Received September 7, 1999
[11b]
1315Ϫ1317. Ϫ
E. F. Ullmann, J. E. Milks, J. Am. Chem.
Soc. 1964, 86, 3814Ϫ3819.
[12]
J. Leonard, B. Lygo, G. Procter, Praxis der Organischen Chemie,
VCH, Weinheim, 1996.
[O99459]
Eur. J. Org. Chem. 2000, 2219Ϫ2225
2225