Double phosphinylation of propargylic alcohols: A novel synthetic route to 1,2-bis(diphenylphosphino)ethane derivatives

Article abstract of DOI:10.1021/ol048347k

(Chemical Equation Presented) Double phosphinylation of propargylic alcohols with diphenylphosphine oxide in the presence of a thiolate-bridged diruthenium complex as catalyst gives the corresponding 2,3- bis(diphenylphosphinyl)-1-propenes in high yields

Full text of DOI:10.1021/ol048347k

ORGANIC
LETTERS
2004
Vol. 6, No. 22
3993-3995
Double Phosphinylation of Propargylic
Alcohols: A Novel Synthetic Route to
1,2-Bis(diphenylphosphino)ethane
Derivatives†
Marilyn Daisy Milton, Gen Onodera, Yoshiaki Nishibayashi,* and Sakae Uemura*
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering,
Kyoto UniVersity, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
ynishiba@scl.kyoto-u.ac.jp; uemura@scl.kyoto-u.ac.jp
Received August 19, 2004
ABSTRACT
Double phosphinylation of propargylic alcohols with diphenylphosphine oxide in the presence of a thiolate-bridged diruthenium complex as
catalyst gives the corresponding 2,3-bis(diphenylphosphinyl)-1-propenes in high yields with a complete selectivity.
Recently, we have disclosed the ruthenium-catalyzed efficient
propargylic substitution reactions of propargylic alcohols with
a variety of heteroatom- and carbon-centered nucleophiles
to give the corresponding functionalized propargylic products
in high yields with a complete regioselectivity.1 It is
noteworthy that the reactions are catalyzed only by thiolate-
bridged diruthenium complexes such as [Cp*RuCl(µ2-SR)2-
in the presence of 5 mol % of 1a at higher temperature
afforded the corresponding 2,3-bis(diphenylphosphinyl)-3-
phenyl-1-propene (3a) as a major product together with a
small amount of 3-diphenylphosphinyl-3-phenyl-1-propyne
(4a). This finding prompted us to investigate the double
phosphinylation of propargylic alcohols in detail because this
double phosphinylation provides a novel synthetic route to
1,2-bis(diphenylphosphino)ethane4 derivatives, which work
as suitable ligands for various transition metals. Preliminary
results are described here.
n
i
RuCp*Cl] (Cp* ) η5-C5Me5; R ) Me (1a), Pr (1b), Pr
(1c)), and [Cp*RuCl(µ2-SiPr)2RuCp*(OH2)]OTf (OTf )
OSO2CF3) (1d) (Scheme 1).2 During our continuous study
Scheme 2
Scheme 1
Treatment of 2a with diphenylphosphine oxide in the
presence of methanethiolate-bridged diruthenium complex
(1a) (5 mol %) and NH4BF4 (10 mol %) in 1,2-dichloro-
ethane (ClCH2CH2Cl) at 60 °C for 18 h afforded 3a in 90%
isolated yield (Scheme 3). Neither other products nor
regioisomers of 3a were detected by 1H NMR. The molecular
on the propargylic substitution reactions of propargylic
alcohols with diphenylphosphine oxide (Scheme 2),3 we
came across the phenomenon that a prolonged reaction of
1-phenyl-2-propyn-1-ol (2a) with diphenylphosphine oxide
† Dedicated to Professor Iwao Ojima on the occasion of his 60th birthday.
10.1021/ol048347k CCC: $27.50
© 2004 American Chemical Society
Published on Web 09/23/2004

Scheme 3
Table 1. Ru-Catalyzed Double Phosphinylation of Propargylic
Alcohols (2) with Diphenylphosphine Oxide Affording
Double-Phosphinylated Compounds (3)a
structure of 3a was unambiguously clarified by preliminary
X-ray analysis. An ORTEP drawing of 3a is shown in
Supporting Information as Figure S1. When 1b or 1c was
used as catalyst in place of 1a, 3a was obtained in only 49%
or 44% isolated yield, respectively, together with the
formation of 4a in 29 or 30% isolated yield. In the reaction
at room temperature for 18 h, 4a and 3a were obtained in
77% and 8% isolated yields. Separately, we confirmed that
no reaction occurred at all in the absence of 1a. We have
also investigated the reactions of 2a with diethyl phosphite
or diphenyl phosphite under the same reaction conditions,
but they resulted in a formation of only some unidentified
products unfortunately.
a All the reactions of propargylic alcohol 2 (0.60 mmol) with diphenyl-
phosphine oxide (3.00 mmol) were carried out in the presence of 1a (0.03
mmol) and NH4BF4 (0.06 mmol) in ClCH2CH2Cl at 60 °C for 18 h.
b Isolated yield. c The corresponding propargylic substituted product (4e)
was obtained in 72% isolated yield. d 4f in 28% isolated yield. e 4g in 31%
isolated yield. f 4h in 79% isolated yield.
Reactions of various 1-aryl-2-propyn-1-ols (2) with di-
phenylphosphine oxide were carried out in the presence of
1a (5 mol %) and NH4BF4 (10 mol %) at 60 °C for 18 h.
Typical results are shown in Table 1. A p-halogeno sub-
stituent such as fluoro, chloro, or bromo to the benzene ring
was tolerant of the catalytic reaction (Table 1, runs 2-4).
In sharp contrast, introduction of an electron-donating group
such as methyl or methoxy substituent to the benzene ring
decreased the yield of double-phosphinylated products (3)
(Table 1, runs 5-7). In particular, no double phosphinylation
occurred when 1-o-tolyl-2-propyn-1-ol was used as substrate
(Table 1, run 8). In these cases, the corresponding propargylic
diphenylphosphine oxides (4) were obtained in moderate to
good isolated yields. These results indicate that the kind of
substituent on the benzene ring has a dramatic influence on
the reactivity. Unfortunately, the reaction of 1-cyclohexyl-
2-propyn-1-ol did not proceed at all. When other terminal
alkynes such as 1-octyne, phenylacetylene, ethyl propiolate,
and 4-phenyl-5-hexyn-2-one were used in place of propar-
gylic alcohols, no reaction occurred at all in all cases.
oxide in the presence of 1a (5 mol %) in ClCD2CD2Cl at 60
°C for 50 h by H NMR. The conversion of 4a into an
1
intermediate was observed, and the intermediate was then
converted into the double phosphinylated product 3a. Inter-
estingly, the intermediate was actually isolated in 72% yield
in a separate experiment by heating 4a in the presence of
1a at 60 °C for 50 h (eq 1), which was characterized as an
allenyldiphenylphosphine oxide (5a).5 Separately, we con-
firmed the transformation of 4a into 3a in the presence of
1a (5 mol %) in ClCH2CH2Cl at 60 °C for 18 h, 3a being
obtained in 85% isolated yield (eq 2). The addition of
diphenylphosphine oxide to the isolated 5a was also con-
1
firmed by H NMR, 3a being formed in quantitative yield
(eq 3).6 These results clearly show that the double phosphi-
nylation of 2a proceeds via pathways shown in Scheme 4.
Scheme 4
To obtain some information of the reaction mechanism,
we monitored the reaction of 4a with diphenylphosphine
(1) (a) Nishibayashi, Y.; Wakiji, I.; Hidai, M. J. Am. Chem. Soc. 2000,
122, 11019. (b) Nishibayashi, Y.; Onodera, G.; Inada, Y.; Hidai, M.;
Uemura, S. Organometallics 2003, 22, 873. (c) Nishibayashi, Y.; Imajima,
H.; Onodera, G.; Hidai, M.; Uemura, S. Organometallics 2004, 23, 26. (d)
Nishibayashi, Y.; Yoshikawa, M.; Inada, Y.; Hidai, M.; Uemura, S. J. Org.
Chem. 2004, 69, 3408.
(2) (a) The thiolate-bridged diruthenium complexes (1) were found to
provide an unique bimetallic reaction site for activation and transformation
of various terminal alkynes; see: Nishibayashi, Y.; Yamanashi, M.; Wakiji,
I.; Hidai, M. Angew. Chem., Int. Ed. 2000, 39, 2909 and references therein.
(b) The methanethiolate-bridged diruthenium complex [Cp*RuCl(µ2-SMe)2-
RuCp*Cl] (1a) is commercially available from Wako Pure Chemical
Industries (Japan) as met-DIRUX (methanethiolate-bridged diruthenium
complex) (130-14581).
At first, 2a is transformed rapidly into propargylic substituted
product 4a by the catalysis of 1a. Isomerization from 4a into
(3) Nishibayashi, Y.; Milton, M. D.; Inada, Y.; Yoshikawa, M.; Wakiji,
I.; Hidai, M.; Uemura, S. Chem. Eur. J., in press.
3994
Org. Lett., Vol. 6, No. 22, 2004

5a occurs, and then the addition of another diphenylphos-
phine oxide to 5a catalyzed by 1a gives 3a.
complete selectivity. Although transition metal-catalyzed
addition of phosphorus-centered nucleophiles to an alkyne
or alkene is known as a synthetic method for the preparation
of the compounds with carbon-phosphorus single bond,8
the double phosphorylation and phosphinylation of alkynes
are limited to only a few cases reported by Lin and
co-workers.9 The method reported here provides a more
convenient route to the double phosphinylated products from
propargylic alcohols and diphenylphosphine oxide.10 The
double phosphinylated products are considered to be precur-
sors of modified chiraphos11 (2,3-bis(diphenylphosphinyl)-
butane derivatives), which have a potential to work as new
types of chiral bidentate ligands for asymmetric synthesis.
Further studies on the reduction of optically active 3a into
the corresponding 1,2-bis(diphenylphosphino)propanes are
currently in progress and the detailed results will be reported
in due course.
The direct addition of diphenylphosphine oxide to 4a
catalyzed by 1a might also be considered as another pathway
for this catalytic reaction although we have already confirmed
that no catalytic reaction of other terminal alkynes such as
1-octyne and phenylacetylene with diphenylphosphine oxide
proceeded even in the presence of catalyst 1a.
Acknowledgment. This work was supported by a Grant-
in-Aid for Scientific Research for Young Scientists (A) (No.
15685006) from the Ministry of Education, Culture, Sports,
Science and Technology, Japan.
As a preliminary result, we have already found the optical
resolution of racemic 3a by using optically active (2S,3S)-
(+)-2,3-O-dibenzoyltartaric acid ((+)-DBTA) as a resolving
agent.7 The result of X-ray analysis of the complex with (+)-
DBTA indicates that the absolute configuration of optically
active 3a in the complex is S. An ORTEP drawing of (S)-
3a‚(+)-DBTA is shown in the Supporting Information as
Figure S2. Unfortunately, we have not yet succeeded in
practical preparation of the optically active (S)-3a by using
this method. Detailed experimental results will be reported
in due course.
Supporting Information Available: Experimental pro-
cedures and spectral data for all new compounds. Crystal-
lographic data (CIF). This material is available free of charge
via the Internet at http://pubs.acs.org.
OL048347K
(8) Some recent examples: (a) Han, L.-B.; Zhang, C.; Yazawa, H.;
Shimada, S. J. Am. Chem. Soc. 2004, 126, 5080. (b) Je´roˆme, F.; Monnier,
F.; Lawicka, H.; De´rien, S.; Dixneuf, P. H. Chem. Commun. 2003, 696. (c)
Depre´le, S.; Montchamp, J.-L. J. Am. Chem. Soc. 2002, 124, 9386. (d) Han,
L.-B.; Zhao, C.-Q.; Tanaka, M. J. Org. Chem. 2001, 66, 5929 (e) Han,
L.-B.; Mirzaei, F.; Zhao, C.-Q.; Tanaka, M. J. Am. Chem. Soc. 2000, 122,
5407. (f) Han, L.-B.; Choi, N.; Tanaka, M. Organometallics 1996, 15, 3259.
(g) Han, L.-B.; Tanaka, M. J. Am. Chem. Soc. 1996, 118, 1571.
(9) (a) Palladium-catalyzed bisphosphorylation of alkynes with dialkyl
phosphites to give the corresponding 1,2-bisphosphonates has been re-
ported: Allen, A., Jr.; Manke, D. R.; Lin, W. Tetrahedron Lett. 2000, 41,
151. (b) Palladium-catalyzed bisphosphinylation of alkynes with diphe-
nylphosphine oxide to give the corresponding 1,2-bisphosphine oxides has
been reported: Allen, A., Jr.; Ma, L.; Lin, W. Tetrahedron Lett. 2002, 43,
3707.
(10) A related Ni-catalyzed phosphinylation of propargylic alcohols with
diphenylphosphine oxide to give the corresponding phosphoroyl-substituted
1,3-butadienes has been reported; Han, L.-B.; Yazawa, H. The 84th Annual
Meeting of the Chemical Society of Japan, Kobe, March 2004, Abstract
3PC-193.
(11) Chiraphos (2,3-bis(diphenylphosphinyl)butane) has been widely used
as a chiral bidentate ligand for various transition metals. For some recent
examples, see: (a) Kimmich, B. F. M.; Somsook, E.; Landis, C. R. J. Am.
Chem. Soc. 1998, 120, 10115. (b) Wicht, D. K.; Zhuravel, M. A.; Gregush,
R. V.; Glueck, D. S.; Guzei, I. A.; Liable-Sands, L. M.; Rheingold, A. L.
Organometallics 1998, 17, 1412. (c) Casado, M. A.; Perez-Torrente, J. J.;
Ciriano, M. A.; Oro, L. A.; Orejon, A.; Claver, C. Organometallics 1999,
18, 3035. (d) Kuwano, R.; Sato, K.; Kurokawa, T.; Karube, D.; Ito, Y. J.
Am. Chem. Soc. 2000, 122, 7614.
In summary, we have found the ruthenium-catalyzed
double phosphinylation of propargylic alcohols with di-
phenylphosphine oxide to give the corresponding 2,3-bis-
(diphenylphosphinyl)-1-propenes in high yields with a
(4) ,2-Bis(diphenylphosphino)ethane (dppe) has been used as a typical
bidentate ligand for various transition metals, see some recent examples:
(a) Arisawa, M.; Yamaguchi, M J. Am. Chem. Soc. 2003, 125, 6624. (b)
Maleczka, R. E.; Shi, F.; Holmes, D.; Smith, M. R. J. Am. Chem. Soc.
2003, 125, 7792. (c) Kuwano, R.; Kondo, Y.; Matsuyama, Y. J. Am. Chem.
Soc. 2003, 125, 12104.
(5) Representative spectral data of 5a: IR (KBr, cm-1) 1929, 1953; 1H
NMR (CDCl3) δ 4.72 (d, 2H, 4JPH ) 10.9 Hz), 7.02-7.12 (m, 3H), 7.27-
7.33 (m, 6H), 7.51 (d, 2H, J ) 7.6 Hz), 7.60-7.68 (m, 4H); 31P NMR
(CDCl3) δ 26.4 (s); HRMS calcd for C21H17OP [M] 316.1017, found
316.1015.
(6) (a) Denmark, S. E.; Marlin, J. E. J. Org. Chem. 1991, 56, 1003. (b)
Pravia, K.; White, R.; Fodda, R.; Maynard, D. F. J. Org. Chem. 1996, 61,
6031.
(7) Takaya, H.; Mashima, K.; Koyano, K.; Yagi, M.; Kumobayashi, H.;
Taketomi, T.; Akutagawa, S.; Noyori, R. J. Org. Chem. 1986, 51, 629.
Org. Lett., Vol. 6, No. 22, 2004
3995