On the redox reaction of 1,2-bis(diphenylphosphino) alkanes toward o -, and p-quinones

Article abstract of DOI:10.1080/10426507.2012.702822

The reaction of 1,2-bis(diphenylphosphino)ethane with substituted o-benzo-quinones afforded new bis(6-hydroxycyclohexa-2,4-dienone) derivatives. Treatment of the same reagent with o-naphthoquinone, phenanthrenequinone, and acenaphthenequinone gave the res

Full text of DOI:10.1080/10426507.2012.702822

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Phosphorus, Sulfur, and Silicon and the
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On the Redox Reaction of 1,2-
Bis(diphenylphosphino) Alkanes Toward
o-, and p-Quinones
Leila S. Boulos a , Ewies F. Ewies a & Amin F. M. Fahmy b
a Department of Organometallic and Organometalloid Chemistry ,
National Research Centre , Dokki , Cairo , Egypt
b Department of Organic Chemistry, Faculty of Science , Ain-Shams
University , Abassia , Cairo , Egypt
Accepted author version posted online: 22 Jun 2012.Published
online: 31 May 2013.
To cite this article: Leila S. Boulos , Ewies F. Ewies & Amin F. M. Fahmy (2013) On the Redox Reaction
of 1,2-Bis(diphenylphosphino) Alkanes Toward o-, and p-Quinones, Phosphorus, Sulfur, and Silicon and
the Related Elements, 188:6, 726-738, DOI: 10.1080/10426507.2012.702822
To link to this article: http://dx.doi.org/10.1080/10426507.2012.702822
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Phosphorus, Sulfur, and Silicon, 188:726–738, 2013
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2012.702822
ON THE REDOX REACTION OF
1,2-BIS(DIPHENYLPHOSPHINO)
ALKANES TOWARD O-, AND P-QUINONES
Leila S. Boulos,1 Ewies F. Ewies,1 and Amin F. M. Fahmy2
1Department of Organometallic and Organometalloid Chemistry, National
Research Centre, Dokki, Cairo, Egypt
2Department of Organic Chemistry, Faculty of Science, Ain-Shams University,
Abassia, Cairo, Egypt
GRAPHICAL ABSTRACT
O
Ph2P
O
PPh2
OH O
O HO
Ph2P
PPh2
(CH2)n
H
H
tBu
tBu
1
n = 2 (a), 1 (b)
tBu tBu
O
Ph2P
HO
O
O
PPh2
PPh2
O
PPh2
R
R
R'
O
R'
O
Abstract The reaction of 1,2-bis(diphenylphosphino)ethane with substituted o-benzo-
quinones afforded new bis(6-hydroxycyclohexa-2,4-dienone) derivatives. Treatment of the
same reagent with o-naphthoquinone, phenanthrenequinone, and acenaphthenequinone gave
the respective bis(diphenylphosphoryl)ethylidenes or diacenaphthylenone derivatives. On
the other hand, p-quinones react with 1,2-bis(diphenylphosphino)methane to yield the corre-
sponding 4-hydroxycyclohexa-2,5-dien-1-ones. Possible reaction mechanisms are considered
and the structural assignments are based on compatible analytical and spectroscopic data.
Keywords 1,2-Bis(diphenylphosphino)alkanes; o-quinones; p-quinones; bis(6-hydroxycyclo-
hexa-2,4-dienone); hydroquinones
Received 1 March 2012; accepted 6 June 2012.
Address correspondence to Leila S. Boulos, Department of Organometallic and Organometalloid Chemistry,
National Research Centre, El-Behoos St., Dokki, Cairo 12622, Egypt. E-mail: leilagoubran@yahoo.com
726

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
727
Figure 1 Reactants used in the present study.
INTRODUCTION
The intense development of the chemistry of quinones and related compounds is
due to the wide occurrence of these compounds in nature and their versatile biological
activity; they play the key part in many biological processes, such as respiration and
photosynthesis.1,2 Meanwhile, considerable interest has also been focused on the reaction
of trivalent phosphorus compounds with mono- and polycyclic-quinones.1,2
The presence of a reactive system of multiple bonds (C C and C O) in quinones
leads to an extensive employment of these compounds in organic synthesis as precur-
sors of various heterocyclic and spirocyclic compounds.3–9 Coordination complexes of
1,2-bis(diphenyl-phosphino)ethane (dppe) and bisphosphine ligands in general are almost
entirely used as homogenous catalysts in a wide range of reactions. The reactions of trivalent
phosphorus compounds with ortho- and para-quinones have been studied in considerable
detail by Ramirez and his coworkers.10 In view of this and in continuation of our work in
organophosphorus chemistry11–17, it was of considerable interest to study the reactivity of
bis(diphenylphosphino)alkanes 1a,b toward quinones (2–7) (Figure 1).
RESULTS AND DISCUSSION
Chemistry
1,2-Bis(diphenylphosphino)ethane 1a was treated with two molar equivalents
of 3,5-di-tert-butyl-o-benzoquinone (2) and the mixture was kept under stirring in
tetrahydrofuran at room temperature (r.t.) for 5 h. Column chromatography of the

728
L. S. BOULOS ET AL.
tBu
OH
OH
O
[O]
Ph2P
2
1a
+
+
PPh2
O
redox reaction
tBu
8a
9
+ 2
THF, r.t.
O
O
O
PPh2
O
Ph2P
PPh2
OH O
PPh2
O HO
tBu
2
+
Hb Ha
OH
O
tBu
tBu
tBu
tBu tBu
A
10
Scheme 1
crude product yielded 2,2ꢁ-4,4ꢁ-di-tert-butyl-6,6ꢁ-[1,2-bis(diphenylphosphoryl)ethane-
1,2-diyl-]bis(6-hydroxycyclohexa-2,4-dien-1-one) (10, 65%) and ethane 1,2-
diylbis(diphenylphosphane)dioxide (8a, 15%) (Scheme 1). Moreover, 3,5-di-tert-
butyl-catechol (9, 10%) was also isolated and identified by comparing its melting point
(mp) and Infrared (IR) spectrum with those of an authentic sample.18
The most important feature of structure 10 is the presence of one signal at
1
δP = 36.1 ppm (s) in its 31P NMR spectrum. Moreover, the H NMR spectrum of com-
pound 10 (at 500 MHz) revealed signals at δH = 1.25 (s, 18H, tert-butyl), 1.27 ppm (s,
2
3
18H, tert-butyl), and 2.41 (ddd, JHH = 6.8 Hz, JPH = 25.3 Hz, JPH = 11.0 Hz, 2H,
Ph2P(O)CH-CH-P(O)Ph2), corresponding to the two methine protons attached to the two
phosphorus atoms. It is worth mentioning that only one isomer of compound 10, most
probably the (RRRR/SSSS) isomer, is formed. The assignment (RRRR/SSSS) for this prod-
uct, although not established with certainty, is supported by an inspection of the Newman
projections19 as well as by the 1H NMR chemical shifts and coupling constant of the two
ortho methine protons near the phosphorus atom. The observed 3JHH coupling constant of
6.8 Hz indicates a cis configuration, rather than a trans configuration, which would give rise
to larger coupling constants ranging from 9 to 15 Hz. Moreover, the presence of one singlet
in the 31P NMR spectrum indicates the presence of only one stereoisomer. The structure
of compound 10 has also been assigned on the basis of 13C NMR data, elemental analysis,
and mass spectral data (FAB+, cf. Experimental Section).
Compound 8a (minor product, 15% yield) was identified as ethane-1,2-diylbis-
(diphenylphosphane)dioxide on the basis of the IR, 1H, 13C, 31P NMR, and mass spectral
data (cf. Experimental Section).
A possible explanation of the course of the reaction of the bisphosphine 1a with
o-quinone 2 is depicted in Scheme 1. Apparently, this reaction is redox in nature leading to
oxidation of the tertiary phosphine 1a to the respective dioxide 8a, whereby the o-quinone 2

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
729
is partially reduced to the respective catechol derivative 9. It is worth mentioning that 1a was
recovered practically unchanged (according to mp and mixed mp) upon long boiling alone
in THF (or dry toluene) even for 10 h. Concurrent with the aforementioned transformations,
the methylene group in the resulting bisphosphoryl compound 8a can add to the carbonyl
function in 2 to give intermediate A. The same process can be repeated through the other
methylene function in 8a to yield 10 (Scheme 1).
The reaction of 1,2-bis(diphenylphosphino)ethane 1a with tetrabromo-o-
benzoquinone 3a was also investigated. The reaction of 1a with 3a in dry tetrahydrofuran
was almost completed at r.t.. The crude product was purified by column chromatography to
give 6,6ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diyl]bis(2,3,4,5-tetrabromo-6-hydroxy-
cyclohexa-2,4-dien-1-one) (12) as the major product (65% yield), and ethane-1,2-diylbis-
(diphenylphosphane)dioxide (8a, 15% yield). 3,4,5,6-Tetrabromobenzene-1,2-diol (11)
was also isolated from the reaction mixture and identified by comparing its mp and
IR spectrum with those of an authentic sample (Scheme 2). Elemental analysis and
molecular weight determination (MS) for compound 12 are related to C38H24Br8O6P2.
The IR spectrum of compound 12 (in KBr) shows absorption bands at υ = 1185 (P O),
3252(OH), and 1677 (C O) cm−1. The 1H NMR spectrum of compound 12 (at 500 MHz)
displays signals at δH = 2.35 ppm (ddd, JHH = 5.6 Hz, 2JPH = 30.0 Hz, 3JPH = 18.0 Hz,
2H, Ph2P(O)CH-CH-P(O)Ph2) corresponding to the two methine protons next to the two
phosphorus atoms. The D2O exchangeable protons (OH) appear as a broad singlet at
δ = 2.80 ppm. The aromatic protons fall in the region δ = 7.06–7.18 ppm as a multiplet.
The structure of compound 12 has also been confirmed by its 13C and 31P NMR as well as
mass spectral data (cf. Experimental Section).
Scheme 2
On the other hand, when two mole equivalents of tetrachloro-o-benzoquinone 3b
were treated with one mole of 1,2-bis(diphenylphosphino)ethane 1a in dry tetrahydrofuran

730
L. S. BOULOS ET AL.
Scheme 3
at r.t. for 3 h, products 14 (70%) and 8a (15%) were isolated together with 3,4,5,6-
tetrachlorobenzene-1,2-diol (13, 5%) (Scheme 3).
Structural assignments for compound 14 are based upon elemental analysis and
spectroscopic (IR, 1H, 13C, 31P NMR, and MS) data (cf. Experimental Section).
We have found that one mole of 1,2-bis(diphenylphosphino)ethane 1a reacts with
two equivalents of o-naphthoquinone 4 in refluxing dry toluene to give a yellow crystalline
compound identified as 1-[1,2-bis(diphenylphosphoryl)ethylidene]naphthalene-2(1H)-one
(16) as the major product and compound 8a as a minor product (Scheme 4). Naphthalene-
1,2-diol (15) was also isolated from the reaction mixture and identified (mp and mixed mp).
Structural assignment for compound 16 is based upon elemental analysis and spectroscopic
(IR, 1H, 13C, 31P NMR, as well as MS) data (cf. Experimental Section).
Similarly, when one mole of phenanthrenequinone 5 is allowed to react with one
equivalent of 1,2-bis(diphenylphosphino)ethane (1a) in refluxing dry toluene for 8 h,
10-[1,2-bis(diphenylphosphoryl)ethylidene]phenantherene-9-(10H)-one 18, compound 8a,
and phenanthrene-9,10-diol (17) are obtained (Scheme 5). The structure of compound 18
results from its spectral data (cf. Experimental Section).
Performing the reaction of 1a with acenaphthenequinone 6 in refluxing dry toluene for
7 h leads to the formation of 2,2ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diylidene]diace-
naphthylenone 20 as the main product (65% yield), ethane-1,2-diylbis(diphenylphosphane)-
dioxide (8a, 15% yield), and acenaphthene-1,2-diol (19) (Scheme 6). The structural assign-
1
ment for compound 20 is based upon elemental analysis and spectroscopic (IR, H, 13C,
31P NMR) as well as MS data (cf. Experimental Section).
The study was extended to also include the behavior of p-quinones 7a,b toward 1,2-
bis(diphenylphosphino)methane (1b) in order to determine the preferential site of attack.
We have found that when 7a was allowed to react with 1,2-bis(diphenylphosphino)methane

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
731
Scheme 4
(1b) in refluxing dry THF for 20 h, the corresponding 4-[bis(diphenylphosphonyl)methyl]-
4-hydroxycyclohexa-2,5-dien-1-one (22a) was isolated as the major product (65% yield).
Methane-1,2-diylbis(diphenylphosphane)dioxide (8b) was also isolated as a minor product
(15%). Hydroquinone 21a,b was also isolated (5%) from the reaction mixture and identified
by comparing its mp and IR spectrum with those of an authentic sample (Scheme 7).
Scheme 5

732
L. S. BOULOS ET AL.
Scheme 6
OH
OH
O
O
R
R
R'
R'
[O]
7a,b
1b
+
Ph2P
PPh2
+
redox reaction
8b
21a, R = R' = H
b, R = CN, R' = Cl
THF
reflux
7a b
,
+
O
O
Ph2P
HO
PPh2
R
R
R'
R'
O
22a, R = R' = H
b, R = CN, R' = Cl
Scheme 7

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
733
Similarly, 3,4-dichloro-6,7-dicyano-o-benzoquinone 7b reacts with 1b to give 22b
(major product), 8b (minor product), and 4,5-dichloro-3,6-dihydroxybenzene-1,2-dinitrile
(21, 3%). Structures of 22a,b and 8b have been confirmed on the basis of full sets of their
spectral data (cf. Experimental Section).
A possible explanation of the course of the reaction of the bisphosphine 1b with p-
quinones 7a,b is depicted in Scheme 7. Apparently, this reaction is redox in nature leading to
oxidation of the tertiary phosphine 1b to the respective dioxide 8b whereby, the p-quinones
7a,b are reduced to the respective hydroquinone derivatives 21a,b. The methylene group
in the resulting dioxide 8b can add to one of the carbonyl functions in 7a,b to yield 22a,b
(Scheme 7).
CONCLUSION
Results of the present investigation allow for certain interesting conclusions
to be drawn. Thus, 1,2-bis(diphenylphosphino)ethane (1a) and 1,2-bis(diphenylphos-
phino)methane (1b) showed marked stability toward auto-oxidation even upon prolonged
heating solely in the presence of a solvent. On the other hand, the same tertiary phosphines
(1a,b) undergo redox reaction with ortho-quinones (e.g. 3b, 4, 5, or 6) or para-quinones
(7a,b) leading to bisphosphine dioxides (10, 12, 14) together with the corresponding
hydroquinone (cf. 9, 11, 13, 15, 17, 19, 21a,b). This process is accompanied by addition or
condensation reaction of 8a or 8b with another molecule of the respective quinone. These
mechanisms represent a new approach for the synthesis of a variety of phosphorylated aryl
compounds. The fast oxidation of the tertiary phosphines 1a,b prevents the lone pair at
the phosphorus atom to attack the carbonyl carbon atom in quinones 2–7 according to the
conventional reactions.1,2,10
EXPERIMENTAL
Melting points were determined in open glass capillaries using Electrothermal IA
9000 series digital mp apparatus and are uncorrected. The IR spectra were measured in
KBr pellets with a Perkin-Elmer Infracord Spectrophotometer model 157(Grating). The 1H
and 13C NMR spectra were recorded in CDCl3 or DMSO as solvent with a JEOL-500 MHz
spectrometer and the chemical shifts are reported relative to TMS. The 31P NMR spectra
were obtained with a Varian CFT-20 spectrometer. 31P chemical shifts are refered to 85%
H3PO4 as external standard. The mass spectra were recorded at 70 eV with a Shimada
GCS-OP 1000 Ex Spectrometer equipped with a data system. Elemental analyses were
performed using Elmenter Varu EL Germany Instrument. The reported yields refer to pure
materials isolated by column chromatography. Solvents were dried/purified according to
conventional procedures.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) with
3,5-di-tert-butyl-o-benzo-quinone (2)
(0.44 g, 2 mmol) 3,5-di-tert-butyl-o-benzoquinone (2) and (0.39 g, 1 mmol)
1,2-bis(diphenyl-phosphino)ethane (1a) were stirred in 30 mL dry THF at r.t. for 5 h. The
course of the reaction was monitored by TLC. The volatile materials were evaporated under

734
L. S. BOULOS ET AL.
reduced pressure. The residue was chromatographed on silica gel column to give two prod-
ucts: 2,2ꢁ-4,4ꢁ-di-tert-butyl-6,6ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diyl-]bis(6-hyd-
roxycyclohexa-2,4-dien-1-one) (10) and ethane 1,2-diylbis(diphenylphosphane)dioxide
(8a).
When 1,2-bis(diphenylphosphino)ethane (1a) was boiled in dry THF or dry toluene
for more than 10 h, the same reagent 1a was isolated unchanged (mp and mixed mp).
2,2ꢀ-4,4ꢀ-Di-tert-butyl-6,6ꢀ-[1,2-bis(diphenylphosphoryl)ethane-1,2-
diyl-]bis(6-hydroxy-cyclohexa-2,4-dien-1-one) (10)
Eluent: petroleum ether/acetone◦(90/10, v/v). Product 10 was separated as colorless
crystals, yield 0.53 g (65%), mp 192 C. IR (KBr): ν = 1182 (P O), 1435 (P-Ph), 1677
(C O), 3262 (OH) cm−1. 1H NMR (500 MHz, CDCl3): δ = 1.25 (s, 18H, tert-butyl), 1.27 (s,
18H, tert-butyl), 2.41 (ddd, JHH = 6.8 Hz, 2JPH = 25.3 Hz, 3JPH = 11.0 Hz, 2H, Ph2P(O)CH-
CH-P(O)Ph2), 2.80 (s, 2H, OH, exchangeable with D2O), 6.59 (s, 2H, cyclohexadienone),
6.64 (s, 2H, cyclohexadienone), 7.46-7.71 (m, 20H, arom-H). 13C NMR (125 MHz, CDCl3):
δ = 21.8 (d, JPC = 130.0 Hz, C-P O), 30.0 (s, tert-butyl), 32.0 (s, tert-butyl), 34.3 (s, tert-
butyl), 35.0 (s, tert-butyl), 82.6 (d, 2JPC = 40.1 Hz, cyclic C-OH), 113.6 (arom-CH), 129.3
(arom-C), 131.0 (arom-C), 132.4 (arom-C), 135.0 (arom-C), 140.4 (arom-C), 141.8 (arom-
C), 144.8 (arom-C), 189.5 (C O). 31P NMR (CDCl3): δ = 36.1. MS (FAB+): m/z (%) = 871
(M+, 10), 670 (M+-(O PPh2), 25), 428 (Ph2P(O)CH-CH-P(O)Ph2, 55). Anal. Calcd. for
C54H64O6P2 (871.03): C, 74.46; H, 7.41; P, 7.11. Found: C, 74.41; H, 7.42; P, 7.12%.
Ethane 1,2-Diylbis(diphenylphosphane)dioxide (8a)
Eluent: petroleum ether/acetone (50/50, v/v). Product 8a was separated as colorless
crystals, yield 0.09 g (15%), mp 276 ◦C. IR (KBr): ν = 1183 (P O), 1437 (P-Ph) cm−1
.
1H NMR (500 MHz, CDCl3): δ = 2.41 (s, JPH = 6.8 Hz, 4H, Ph2P(O)CH2-CH2-P(O)Ph2),
7.36-7.63 (m, 20H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 21.4 (C-P O), 128.7
(arom-C), 130.4 (arom-C), 131.8 (arom-C), 132.5 (arom-C). 31P NMR (CDCl3): δ = 33.2.
MS (EI): m/z (%) = 430 (M+, 60). Anal. Calcd. for C26H24O2P2 (430.42): C, 72.55; H,
5.62; P, 14.39. Found: C, 72.50; H, 5.63; P, 14.38.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) with
3,4,5,6-Tetrabromo-o-benzo-quinone (3a)
3,4,5,6-Tetrabromo-o-benzoquinone (3a, 0.84 g, 2 mmol) and 1,2-bis(diphenylphos-
phino)-ethane (1a, 0.39 g, 1 mmol) were stirred in 30 mL dry THF. The reaction was
almost completed at r.t.; the course of the reaction was monitored by TLC. The volatile
materials were evaporated under reduced pressure. The residue was chromatographed on
silica gel column to give the 6,6ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diyl]bis(2,3,4,5-
tetrabromo-6-hydroxycyclohexa-2,4-dien-1-one) (12) and compound 8a.
6,6ꢀ-[1,2-Bis(diphenylphosphoryl)ethane-1,2-diyl]bis(2,3,4,5-
tetrabromo-6-hydroxycyclo-hexa-2,4-dien-1-one) (12)
Eluent: petroleum ether/ethyl acetate (75/25, v/v). Product 12 was separated as col-
orless crystals, yield 0.79 g (65%), mp 130 ◦C. IR (KBr): ν = 1185 (P O), 1435 (P-Ph),
1677 (C O), 3252 (OH) cm−1. 1H NMR (500 MHz, CDCl3): δ = 2.35 (ddd, JHH = 5.6 Hz,

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
735
2JPH = 30.0 Hz, 3JPH = 18.0 Hz, 2H, Ph2P(O)CH-CH-P(O)Ph2), 2.80 (s, 2H, OH, exchange-
able with D2O), 7.06-7.18 (m, 20H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 21.8 (d,
JPC = 130.0 Hz, C-P O), 86.5 (d, 2JPC = 40.1 Hz, cyclic C-OH), 113.8 (arom-C), 118.1
(arom-C), 125.3 (arom-C), 128.3 (arom-C), 129.3 (arom-C), 129.6 (arom-C), 131.2 (arom-
C), 133.5 (arom-C), 142.9 (arom-C), 185.6 (C O). 31P NMR (CDCl3): δ = 33.3. MS
(FAB+): m/z (%) = 1278 (M+, 5), 1076 (M+-(O PPh2), 25), 852 (M+-(C6HBr4O2), 70),
428 (Ph2P(O)CH-CH-P(O)Ph2, 85). Anal. Calcd. for C38H24Br8O6P2 (1277.77): C, 35.72;
H, 1.89; Br, 50.03; P, 4.85. Found: C, 35.70; H, 1.86; Br, 50.04; P, 4.85%.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) With
3,4,5,6-Tetrachloro-o-benzo-quinone (3b)
3,4,5,6-Tetrachloro-o-benzoquinone (3b, 0.48 g, 2 mmol) and 1,2-bis(diphenylphos-
phino)-ethane (1a, 0.39 g, 1 mmol) were stirred in 30 mL dry THF at r.t. for 3 h.
The course of the reaction was monitored by TLC. The volatile materials were evap-
orated under reduced pressure. The residue was chromatographed on silica gel to give
three products: 6,6ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diyl]bis(2,3,4,5-tetrachloro-
6-hydroxycyclohexa-2,4-diene-1-one) (14), compound 8a, and 3,4,5,6-tetrachlorobenzene-
1,2-diol (13, 5%).
6,6ꢀ-[1,2-Bis(diphenylphosphoryl)ethane-1,2-diyl]bis(2,3,4,5-
tetrachloro-6-hydroxycyclo-hexa-2,4-diene-1-one) (14)
Eluent: petroleum ether/ethyl acetate (85/15, v/v). Compound 14 was separated as
◦
colorless crystals, yield 0.60 g (70%), mp 185 C. IR (KBr): ν = 1186 (P O), 1435
(P-Ph), 1677 (C O), 3252 (OH) cm−1. H NMR (500 MHz, CDCl3): δ = 2.31 (ddd,
1
2
3
JHH = 6.8 Hz, JPH = 25.3 Hz, JPH = 11.0 Hz, 2H, Ph2P(O)CH-CH-P(O)Ph2), 2.80 (s,
2H, OH, exchangeable with D2O), 7.42-7.68 (m, 20H, arom-H). 13C NMR (125 MHz,
2
CDCl3): δ = 21.8 (d, JPC = 130.0 Hz, C-P O), 86.5 (d, JPC = 40.1 Hz, cyclic C-OH),
119.3 (arom-C), 121.0 (arom-C), 125.2 (arom-C), 128.1 (arom-C), 130.4 (arom-C), 131.8
(arom-C), 137.3 (arom-C), 143.4 (arom-C), 195.6 (C O). 31P NMR (CDCl3): δ = 30.8.
MS (EI): m/z (%) = 922 (M+, 15). Anal. Calcd. for C38H24Cl8O6P2 (922.17): C, 49.49; H,
2.62; Cl, 30.76; P, 6.72. Found: C, 49.45; H, 2.64; Cl, 30.73; P, 6.75%.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) With
o-Naphthoquinone (4)
o-Naphthoquinone (4, 0.15 g, 1 mmol) and 1,2-bis(diphenylphosphino)ethane (1a,
0.39 g, 1 mmol) were refluxed in 30 mL dry toluene for 7 h. The course of the reaction was
monitored by TLC. The volatile materials were evaporated under reduced pressure. The
residue was chromatographed on silica gel column to give the products: naphthalene-1,2-
diol (15), 1-[bis(diphenylphosphoryl)methylidene]naphthalen-2(1H)-one (16), and com-
pound 8a.
1-[Bis(diphenylphosphoryl)methylidene]naphthalen-2(1H)-one (16)
Eluent: petroleum ether/ethyl acetate (80/20, v/v). Product 16 was separated as yel-
◦
low crystals, yield 0.27 g (50%), mp 150 C. IR (KBr): ν = 1187, 1190 (P O), 1698

736
L. S. BOULOS ET AL.
(C O), 1644 (C C) cm−1. 1H NMR (500 MHz, CDCl3): δ = 2.46 (dd, 2JPH = 35.3 Hz,
3JPH = 10.5 Hz, 2H, CH2), 6.56-7.78 (m, 26H, arom-H). 13C NMR (125 MHz, CDCl3):
δ = 21.7 (dd, 1JPC = 135.6 Hz, 2JPC = 55.4 Hz, CH2-P), 128.8 (arom-C), 128.9 (arom-C),
130.8 (arom-C), 131.3 (arom-C), 131.4 (arom-C), 131.8 (arom-C), 132.1 (arom-C), 132.2
1
2
(arom-C), 132.4 (arom-C), 140.3 (dd, JPC = 135.6 Hz, JPC = 55.4 Hz, P-C C), 175.6
(C O). 31P NMR (CDCl3): δ = 33.2 (d), 33.3 (d), 3JPP = 50.8 Hz. MS (EI): m/z (%) = 570
(M+, 15), 369 (M+- (O PPh2), 25), 201 (O PPh2, 75). Anal. Calcd. for C36H28O3P2
(570.55): C, 75.78; H, 4.95; P, 10.86. Found: C, 75.74; H, 4.92; P, 10.84%.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) with
Phenanthrene-9,10-dione (5)
Phenanthrene-9,10-dione (5, 0.20 g, 1 mmol) and 1,2-bis(diphenylphosphino)ethane
(1a, 0.39 g, 1 mmol) were refluxed in 30 mL dry toluene for 8 h. The course of the reaction
was monitored by TLC. The volatile materials were evaporated under reduced pressure.
The residue was chromatographed on silica gel column to give the products: phenanthrene-
9,10-diol (17), 10-[1,2-bis(diphenylphosphoryl)ethylidene]phenanthren-9(10H)-one (18),
and compound 8a.
10-[1,2-Bis(diphenylphosphoryl)ethylidene]phenanthren-9(10H)-one
(18)
Eluent: petroleum ether/ethyl acetate (80/20, v/v). Compound 18 was separated as
◦
yellow crystals, yield 0.29 g (50%), mp 170 C. IR (KBr): ν = 1180, 1185 (P O),
1
1445 (P-Ph), 1697 (C O), 1623 (C C) cm−1. H NMR (500 MHz, CDCl3): δ = 2.35
(dd, 2JPH = 43.2 Hz, 3JPH = 11.5 Hz, 2H, CH2), 7.25-7.78 (m, 28H, arom-H). 13C NMR
(125 MHz, CDCl3): δ = 21.7(dd, 1JPC = 135.6Hz, 2JPC = 55.4 Hz, CH2-P), 128.8 (arom-C),
128.9 (arom-C), 130.8 (arom-C), 131.3 (arom-C), 131.4 (arom-C), 131.8 (arom-C), 132.1
(arom-C), 132.2 (arom-C), 132.7 (arom-C), 136.3 (dd, 1JPC = 135.6 Hz, 2JPC = 55.4 Hz,
P-C C), 175.8 (C O). 31P NMR (CDCl3): δ = 33.3(d), 33.4 (d), 3JPP = 50.8 Hz. MS (EI):
m/z (%) = 620 (M+, 15), 420 (M+-(O PPh2), 25), 201 (O PPh2, 50), 192 (phenantherene,
35). Anal. Calcd. for C40H30O3P2 (620.61): C, 77.41; H, 4.87; P, 9.98. Found: C, 77.44; H,
4.85; P, 9.95%.
Reaction of 1,2-Bis(diphenylphosphino)ethane (1a) with
Acenaphthenequinone (6)
Acenaphthenequinone (6, 0.40 g, 2 mmol) and 1,2-bis(diphenylphosphino)ethane
(1a, 0.39 g, 1 mmol) were refluxed in 30 mL dry toluene for 7 h. The course of the reaction
was monitored by TLC. The volatile materials were evaporated under reduced pressure.
The residue was chromatographed on silica gel column to give the products: acenaphthene-
1,2-diol (19), 2,2ꢁ-[1,2-bis(diphenylphosphoryl)ethane-1,2-diylidene]diacenaphthylenone
(20), and compound 8a.
2,2ꢀ-[1,2-Bis(diphenylphosphoryl)ethane-1,2-
diylidene]diacenaphthylenone (20)
Eluent: petroleum ether/ethyl acetate (85/15, v/v). Compound 20 was separated
◦
as brown crystals, yield 0.51 g (65%), mp 165 C. IR (KBr): ν = 1180 (P O), 1447

REACTION OF 1,2-BIS(DIPHENYLPHOSPHINO)ALKANES
737
1
(P-Ph), 1695 (C O), 1628 (C C) cm−1. H NMR (500 MHz, CDCl3): δ = 7.41–7.67
(m, 32H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 127.6 (arom-C), 128.5 (arom-C),
130.4 (arom-C), 131.8 (arom-C), 132.6 (arom-C), 134.6 (arom-C), 135.1 (arom-C), 150.3
(arom-C), 140.7 (d, JPC = 135.6 Hz, C-P), 189.8 (C O). 31P NMR (CDCl3): δ = 33.3. MS
(EI): m/z (%) = 758 (M+, 15), 557 (M+-(O PPh2), 25), 201 (O PPh2, 80). Anal. Calcd.
for C50H32O4P2 (758.73): C, 79.15; H, 4.25; P, 8.16. Found: C, 79.19; H, 4.21; P, 8.13%.
Reaction of 1,2-Bis(diphenylphosphino)methane (1b) with p-Quinones
(7a,b)
The respective p-quinone (7a or 7b, 1 mmol) and 1,2-bis(diphenylphosphino)methane
(1a) (0.38 g, 1 mmol) were refluxed in 30 mL dry THF for 20 h. The course of the reaction
was monitored by TLC. The volatile materials were evaporated under reduced pressure.
The residue was chromatographed on silica gel column to give the products: hydro-
quinones 21a,b, 4-[bis(diphenylphosphoryl)methyl]-4-hydroxycyclohexa-2,5-dien-1-one
(22a) or 3-[bis(di-phenylphosphoryl)methyl]-4,5-dichloro-3-hydroxy-6-oxocyclohexa-
1,4-diene-1,2-dicarbo-nitrile (22b), and methane-1,2-diylbis(diphenylphosphane)dioxide
(8b).
4-[Bis(diphenylphosphoryl)methyl]-4-hydroxycyclohexa-2,5-dien-1-one
(22a)
Eluent: petroleum ether/ethyl acetate (85/15, v/v). Product 22a was separated as
brown crystals, yield 0.31 g (65%), mp 200 ◦C. IR (KBr): ν = 1180 (P O), 1447 (P-Ph),
1
1665 (C = O), 1628 (C = C), 3245 (OH) cm−1. H NMR (500 MHz, CDCl3): δ = 1.98
2
(t, JPH = 43.2 Hz, 1H, CH), 2.86 (s, 1H, OH, exchangeable with D2O), 6.48-7.68 (m,
24H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 40.5 (t, 1JPC = 135.6 Hz, C-P), 54.2 (d,
2JPC = 55.4 Hz, cyclic C-OH), 116.1 (arom-C), 128.7 (arom-C), 129.7 (arom-C), 131.0
(arom-C), 131.1 (arom-C), 131.8 (arom-C), 150.3 (d, 2JPC = 33.4 Hz, cyclic C-OH), 185.8
(C = O). 31P NMR (CDCl3): δ = 24.2. MS (EI): m/z (%) = 524 (M+, 15), 323 (M+-
(O = PPh2), 25), 201 (O = PPh2, 80). Anal. Calcd. for C31H26O4P2 (524): C, 70.99; H,
5.00; P, 11.81. Found: C, 70.98; H, 5.01; P, 11.83%.
3-[Bis(diphenylphosphoryl)methyl]-4,5-dichloro-3-hydroxy-6-
oxocyclohexa-1,4-diene-1,2-dicarbonitrile (22b)
Eluent: petroleum ether/ethyl acetate (85/15, v/v). Product 22b was separated as
brown crystals, yield 0.39 g (65%), mp 211 ◦C. IR (KBr): ν = 1180 (P O), 1445 (P-Ph),
1665 (C = O), 1628 (C = C), 2225 (CN), 3245 (OH) cm−1. 1H NMR (500 MHz, CDCl3):
δ = 1.50 (t, 2JPH = 43.2 Hz, 1H, CH), 2.06 (s, 1H, OH, exchangeable with D2O), 7.37-7.75
(m, 20H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 40.5 (t, 1JPC = 135.6 Hz, C-P), 61.3
(t, 2JPC = 55.4 Hz, cyclic C-OH), 102.2 (CN), 114.3 (CN), 128.6 (arom-C), 129.7 (arom-
C), 131.0 (arom-C), 131.1 (arom-C), 131.8 (arom-C), 151.3 (arom-C), 170.2 (C = O). 31P
NMR (CDCl3): δ = 24.3. MS (EI): m/z (%) = 643 (M+, 15), 442 (M+-(O = PPh2), 25),
201 (O = PPh2, 80). Anal. Calcd. for C33H22Cl2N2O4P2 (643.39): C, 61.60; H, 3.45; Cl,
11.02; N, 4.35; P, 9.63. Found: C, 61.62; H, 3.45; Cl, 11.04; N, 4.32; P, 9.64%.

738
L. S. BOULOS ET AL.
Methane-1,2-diylbis(diphenylphosphane)dioxide (8b)
Eluent: petroleum ether/ethyl acetate (50/50, v/v). Product 8b was separated as color-
less crystals, yield 0.09 g (15%), mp 156 ◦C. IR (KBr): ν = 1183 (P O), 1435 (P-Ph) cm−1
.
1H NMR (500 MHz, CDCl3): δ = 2.41 (d, JHH = 6.8 Hz, 2H, Ph2P(O)-CH2-P(O)Ph2), 7.36-
7.63 (m, 20H, arom-H). 13C NMR (125 MHz, CDCl3): δ = 21.5 (t, 1JPC = 135.6 Hz, O P-
C-P O), 128.8 (arom-C), 131.3 (arom-C), 132.5 (arom-C). 31P NMR (CDCl3): δ = 25.5.
MS (EI): m/z (%) = 416 (M+, 60). Anal. Calcd. for C26H24O2P2 (416.38): C, 72.11; H,
5.33; P, 14.88. Found: C, 72.10; H, 5.33; P, 14.87%.
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