Preparation of ruthenium azirinyl complexes and reversed regiospecificity of the carbonyl insertion reaction

Article abstract of DOI:10.1021/om049528t

Electrophilic addition of organic halides to [Ru]CN (1; [Ru] = Cp(PPh _]3)₂Ru) gave the cationic isocyanide complexes {[Ru]CNCH₂R}X (R = CN, 2a; R = CH=CH₂, 2b; R = Ph, 2c), which reacted with base (n-Bu₄NOH or n-Bu₄NF) to give the three-membered-ring azirinyl complexes. For the azirinyl complex with a phenyl group 3c, three isomers, assigned as ruthenium 2H- and 1H-azirinyl complexes, are observed at -20°C. Reaction of the methyl isocyanoacetate complex {[Ru]C≡NCH₂COOMe}X (2d) with n-Bu₄NOH causes hydrolysis of the ester group to give the ruthenium oxazolone complex 4d. The insertion of the C=O group of acetone, aldehyde, ester, and amide into the C-C bond of the three-membered azirinyl ring of 3a-c yields a variety of five-membered oxazolinyl complexes 5-7. The regiospecificity of the insertion differs from that observed in the photochemically induced carbonyl insertion in the organic azirine system. The diastereoselectivity in the formation of 5-7 is controlled by steric effects. In the formation of the pentamethylcyclopentadienyl oxazolinyl ruthenium complex 7a*, the intermediate 8a* is isolated before cyclization. Molecular structures of 7a* and 8a* have been determined by single-crystal X-ray diffraction analysis. Treatment of 7 with hydride gave [Ru]CN and alcohol.

Full text of DOI:10.1021/om049528t

5924
Organometallics 2004, 23, 5924-5933
Preparation of Ruthenium Azirinyl Complexes and
Reversed Regiospecificity of the Carbonyl Insertion
Reaction
Yih-Hsing Lo, Sheng-Cheng Hsu, Shou-Ling Huang, Ying-Chih Lin,*
Yi-Hong Liu, and Yu Wang
Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China
Received June 29, 2004
Electrophilic addition of organic halides to [Ru]CN (1; [Ru] ) Cp(PPh3)2Ru) gave the
cationic isocyanide complexes {[Ru]CNCH2R}X (R ) CN, 2a; R ) CHdCH2, 2b; R ) Ph,
2c), which reacted with base (n-Bu4NOH or n-Bu4NF) to give the three-membered-ring
azirinyl complexes. For the azirinyl complex with a phenyl group 3c, three isomers, assigned
as ruthenium 2H- and 1H-azirinyl complexes, are observed at -20 °C. Reaction of the methyl
isocyanoacetate complex {[Ru]CtNCH2COOMe}X (2d) with n-Bu4NOH causes hydrolysis
of the ester group to give the ruthenium oxazolone complex 4d. The insertion of the CdO
group of acetone, aldehyde, ester, and amide into the C-C bond of the three-membered
azirinyl ring of 3a-c yields a variety of five-membered oxazolinyl complexes 5-7. The
regiospecificity of the insertion differs from that observed in the photochemically induced
carbonyl insertion in the organic azirine system. The diastereoselectivity in the formation
of 5-7 is controlled by steric effects. In the formation of the pentamethylcyclopentadienyl
oxazolinyl ruthenium complex 7a*, the intermediate 8a* is isolated before cyclization.
Molecular structures of 7a* and 8a* have been determined by single-crystal X-ray diffraction
analysis. Treatment of 7 with hydride gave [Ru]CN and alcohol.
Introduction
shows interesting chemical behavior, and many reac-
tions of the compound can be used in the synthesis of
heterocyclic compounds. The effect of ring strain upon
chemical reactivity and the potential for their deriva-
tives to act as precursors to more sophisticated hetero-
cyclic molecules have stimulated interest in these
nitrogen-containing heterocycles. The total ring-strain
energy of 2H-azirine has been estimated at about 48
kcal/mol, mostly owing to deformation of normal bond
angles between the atoms of the ring,4 although lower
values of 44.6 and 46.7 kcal/mol have recently been
reported.5 The stabilities of these heterocycles are
attributable to the collective results of bond shortening
and angle compression as well as the presence of the
electron-rich nitrogen atom. A shorter C-N bond and
a longer C-C bond revealed by single-crystal X-ray data
of 2H-azirines may be a sign of polarization toward the
more electronegative nitrogen atom.6 The corresponding
values for the isoelectric cyclopropene ring are about 10
kcal/mol higher than for 2H-azirine at the same levels
of theory. Calculations showed that the azirinyl cation
exhibited aromatic properties.7
Azirine (azacyclopropene) has attracted much atten-
tion from the perspective of its strained molecular
structure and unique reactivity. The synthetic and
theoretical chemistry of azirine have been extensively
investigated, and a number of general reviews on
azirines have appeared.1 The ring system occurs natu-
rally with dysidazirine,2 found as a constituent of
marine sponges, and azirinomycin, an antibiotic isolated
from streptomyces aureus cultures.3 Due to the asym-
metry of the azirine there are two isomers, referred to
as 1H- and 2H-azirine. The former, known only as a
transient intermediate, represents a cyclic conjugated
system with four π-electrons. The 2H-azirine, however,
(1) (a) Palacios, F.; Ochoa de Retana, A. M.; de Marigorta, E. M.; de
los Santos, J. M. Eur. J. Org. Chem. 2001, 2401-2414. (b) Gilchrist,
T. L. Aldrichim. Acta 2001, 34, 51. (c) Ewing, D. F. In Rodd’s Chemistry
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M., Ed.; Elsevier Science: Amsterdam, 1997; Vol. IVA, pp 59-90. (d)
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Hassner, A., Ed.; Wiley: New York, 1983; Vol. 42, Part 1, Chapter 2,
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264.
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Chem. A 1999, 103, 3330-3335. (c) Mayer, P. M.; Taylor, M. S.; Wong,
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10.1021/om049528t CCC: $27.50 © 2004 American Chemical Society
Publication on Web 11/04/2004

Ruthenium Azirinyl Complexes
Organometallics, Vol. 23, No. 25, 2004 5925
A number of general methods8 are available for the
synthesis of organic 2H-azirines. These include the
modified Neber reaction, thermolysis and photolysis of
vinyl azide and isoxazoles, and thermolysis of oxaza-
phospholines. Strained azirine ring compounds show a
considerable variety of photochemical behavior, and
many of the reactions can be put to good use in the
synthesis of heterocyclic compounds.9 It is known that
photochemically induced reaction10 of azirines with
ketone or aldehyde leads to isolation of oxazolines,
whose metal complexes have been extensively used in
metal-catalyzed enantioselective synthesis.11 However,
metal complexes containing azirinyl ligands are rare,
possibly due to the lack of suitable synthetic methods.
We previously described a cyclization reaction by depro-
tonation of a cationic ruthenium vinylidene complex
containing a -CH2R group at Câ of the vinylidene ligand
to give a metal complex containing a strained cyclopro-
penyl ligand.12 Using this strategy, we reported the
preparation of several ruthenium cyclopropenyl com-
plexes containing various substituents. This reaction
also results in formation of a stereogenic carbon center
in the three-membered ring. These features render this
cyclization process potentially useful for organic syn-
thesis.13 Therefore, we set out to explore deprotonation
reactions of the cationic ruthenium isocyanide [Ru]Ct
NCH2R+ system. The expected three-membered azirinyl
complex is obtained and has been identified by spectro-
scopic methods. In the presence of ketone, aldehyde, or
ester, an unprecedented facile insertion reaction of a
carbonyl group of ketone, aldehyde, or ester into the
C-C bond of the azirinyl ring obtained from ruthenium
isocyanides is observed. Herein we report the prepara-
tion of the cationic ruthenium isocyanide complexes
[Cp(LL′)RuCNCH2R]X and subsequent deprotonation
reaction and insertion of a carbonyl group into the
azirinyl ligand.14
pared by direct ligand exchange.15 However, many free
isocyanides of the type CNCH2R are not commercially
available. Therefore, other methods for the synthesis of
isocyanide complexes are desirable. The chemistry of the
coordinated cyano ligand has been extensively investi-
gated in the past,16 and it is known that the nitrogen
atom of the cyano ligand is a good nucleophile. Thus, it
is reasonable to propose the preparation of isocyanide
complexes by alkylation reactions of transition-metal
cyanide complexes with carbon electrophiles.17 We found
that this preparative method is convenient to introduce
alkyl or aryl groups to the ruthenium-coordinated
cyanide ligand using various organic halides.
Treatment of 1 with excess bromoacetonitrile in
CHCl3 at reflux temperature afforded a green solution.
Evaporation of the solvent under reduced pressure gave
a green oil, which was then dissolved in a minimum
amount of CH2Cl2. Addition of this solution dropwise
into vigorously stirred Et2O caused the pale green solids
to precipitate out. The solid was collected by filtration
and washed with Et2O to afford {[Ru]CtNCH2CN}Br
(2a; [Ru] ) Cp(PPh3)2Ru) with 75% yield. Similarly,
preparations of complexes [Ru]CNCH2R+ (R ) CHdCH2,
2b; R ) C6H5, 2c; R ) COOCH3, 2d) have all been
achieved with good yields. Previously more than 40
equiv of allyl bromide and long reaction times were
employed for preparing 2b and the isolated yield was
45%. We use 5 equiv of allyl iodide, instead of allyl
bromide, for the preparation of 2b at room temperature,
and in 3 h the product is isolated with 92% yield. Use
of CHCl3 as a solvent usually achieved high yield for
the synthesis of these ruthenium isocyanide complexes.
Use of iodide reagents effectively increases the reaction
rate and the yield is also improved, except for the
preparation of 2a.
The 1H NMR spectrum of 2a shows the expected
methylene peak at δ 5.51. In the 31P{1H} NMR spec-
trum, the singlet resonance at δ 45.4 is assigned to the
1
PPh3 ligand. In the H NMR spectrum of 2d in CDCl3,
Results and Discussion
the singlet resonance at δ 4.92 is assigned to the
methylene group of the isocyanide ligand, slightly
shifted from that of 2a. Two singlet resonances at δ 4.76
and 3.60 are assigned to the Cp and methyl groups,
respectively. In the 13C NMR spectrum of 2d in CDCl3,
the most characteristic spectroscopic data consist of a
singlet resonance at δ 165.4 assigned to the carbonyl
carbon, and the triplet resonance at δ 158.6 with 2JC-P
) 20.2 Hz is assigned to the ruthenium-bonded iso-
cyanide carbon, symbolized here as CR. The methyl and
methylene resonances of the isocyanide ligand appear
Synthesis of Isocyanide Complexes by Alkyl-
ation. Cationic isocyanide complexes are usually pre-
(8) (a) Padwa, A.; Carlsen, P. H. J. J. Org. Chem. 1978, 43, 2029-
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metallics 1994, 13, 2150-2152. (b) Ting, P. C.; Lin, Y. C.; Lee, G. H.;
Cheng, M. C.; Wang, Y. J. Am. Chem. Soc. 1996, 118, 6433-6444. (c)
Chang, C. W.; Ting, P. C.; Lin, Y. C.; Lee, G. H.; Wang, Y. J.
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G. H.; Wang, Y. Organometallics 1999, 18, 982-988. (e) Lin, Y. C. J.
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3159.
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2001, 20, 3621-3623.
as two singlets at δ 52.5 and 47.8, respectively. The 31
P
(15) (a) Malatesta, L.; Bonati, F. Isocyanide Complexes of Metals;
Wiley: London, 1969. (b) Schaal, M.; Beck, W. Angew. Chem., Int. Ed.
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1991, 10, 3287-3291.
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A.; Skorsepa, J.; Feher, A. Coord. Chem. Rev. 2002, 224, 51-66.
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C. Coord. Chem. Rev. 2001, 218, 75-112. (b) Lentz, D.; Ro¨ttger, M. J.
Organomet. Chem. 1999, 592, 41-45. (c) Kunz, R.; Fehlhammer, W.
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1986, 863-868.

5926 Organometallics, Vol. 23, No. 25, 2004
Lo et al.
Scheme 1
Scheme 2
spectrum of 3a, the triplet resonance at δ 184.3 with
JC-P ) 19.9 Hz is assigned to CR. The 1H NMR
resonance of the azirinyl ring proton appears at δ 2.98,
similar to that of other organic azirine systems.19 In the
2D HMQC NMR spectrum of 3a, this resonance cor-
relates to the 13C resonance at δ 11.3 assignable to the
sp3 carbon atom of the azirinyl ligand. These data
establish the structure of 3a. Addition of protic acid to
3a opens the three-membered ring, generating 2a.
Similarly, deprotonation of {[Ru]CNCH2CHdCH2}I
(2b) by n-Bu4NF at 0 °C in CH2Cl2 affords the azirinyl
complex 3b in 88% yield. Use of DBU or n-Bu4NOH/
MeOH, instead of n-Bu4NF, gives several unidentifiable
NMR spectrum of 2d displays a singlet resonance at δ
46.0 in CDCl3. The FAB mass spectrum shows the
parent peak at m/z 790 as well as peaks at m/z 528 and
429 due to loss of a PPh3 and both PPh3 and isocyanide
ligand, respectively. Mass spectra of other ruthenium
isocyanide complexes display the same fragmentation
pattern.
Ruthenium isocyanide complexes with pentamethyl-
cyclopentadienyl and dppp ((diphenylphosphino)pro-
pane) ligands were also prepared. Treatment of [Ru*]CN
([Ru*] ) (η5-C5Me5)(dppp)Ru, 1*) with PhCH2Br affords
the cationic isocyanide complex {[Ru*]CNCH2Ph}Br
(2c*) in high yield. In the 13C NMR spectrum of 2c*,
the triplet resonance at δ 160.65 with JP-C ) 19.4 Hz
is assigned to CR. The CR resonance of the previously
reported ruthenium isocyanide compound Cp*Ru(CN)-
(CNtBu)(Ppyl3), (Ppyl3 ) tripyrrolylphosphine) was
found at δ 155.6 as a doublet with JP-C ) 25.8 Hz in
the 13C NMR spectrum.18
Reaction of Isocyanide Complexes 2a,b with
Base. The cationic character of complexes 2 is expected
to enhance the acidity of the methylene proton of the
isocyanide ligand. An additional terminal electron-
withdrawing CN group in 2a should cause deprotona-
tion to occur readily. It is therefore not surprising to
observe high-yield formation of the thermally unstable
three-membered-ring azirinyl complex 3a (see Scheme
1) when 2a in CH2Cl2 is treated with a solution of
n-Bu4NOH in methanol at 0 °C. MeONa in MeOH could
also be used as a base for this reaction, but the reaction
gives a lower yield of 3a. Complex 3a decomposes to 1
and some unidentifiable products at room temperature
and is characterized spectroscopically. The singlet 31P
NMR resonance at δ 45.4 for 2a is converted to two
doublet resonances at δ 49.1 and 48.7 with JP-P ) 34.8
Hz, clearly indicating the formation of an azirinyl ring
containing a stereogenic carbon center. In the 13C NMR
complexes along with 3b as a minor product. In the 31
P
NMR spectrum of 3b the two-doublet pattern, i.e.,
resonances at δ 52.0 and 48.8 with JP-P ) 34.8 Hz, is
consistent with the presence of a stereogenic center. In
the 1H NMR spectrum of 3b three multiplet resonances
at δ 5.73, 5.26, and 5.21 are assigned to three protons
of the vinyl group in the three-membered ring. The ddd
coupling pattern of the resonance at δ 5.73 assignable
to the internal dCH, as compared to the ddt coupling
pattern of the resonance at δ 5.59 in 2b, clearly discloses
the presence of a neighboring CH group of the ring
resulting from the deprotonation reaction. The doublet
resonance with relative integration of one proton at δ
2.76 is assigned to the proton on the azirinyl ring. Again
addition of protic acid to 3b yields 2b.
In contrast to the metal vinylidene system with a bent
structure at Câ, the isocyanide ligand is linear. There-
fore, the deprotonation step should yield a bent tran-
sient zwitterionic nitrile ylide (see Scheme 2) with an
anionic charge most likely located at the methyne
carbon atom of the isocyanide ligand, thus facilitating
formation of the three-membered azirinyl ring.20 This
reaction is analogous to the facile deprotonation-induced
cyclopropenation of the cationic ruthenium vinylidene
system. In the vinylidene complex, the bent structure
at Câ could assist formation of the cyclopropenyl ligand.21
It has been stressed that nitrile ylides, generated from
the photolysis of 2H-azirines, may be classified as
nitrilium betaines, a class of 1,3-dipoles containing a
(19) Banert, K.; Hagedorn, M. Angew. Chem., Int. Ed. Engl. 1990,
29, 103-105.
(20) (a) Yamamoto, Y. Coord. Chem. Rev. 1980, 32, 193-233. (b)
Singleton, E.; Oosthuizen, H. E. Adv. Organomet. Chem. 1983, 22,
209-310. (c) Carnahan, E.; Lippard, S. J. J. Am. Chem. Soc. 1990,
112, 3230-3231. (d) Aharonian, G.; Hubert-Pfalzgraf, L. G.; Zaki. A.;
Le Borgne, G. Inorg. Chem. 1991, 30, 3105-3107.
(21) (a) Beckhaus, R. J. Chem. Soc., Dalton Trans. 1997, 1991-2002.
(b) Bruneau, C.; Dixneuf, P. H. Acc. Chem. Res. 1999, 32, 311-323.
(c) Bustelo, E.; Carbo, J. J.; Lledos, A.; Mereiter, K.; Puerta, M. C.;
Valerga, P. J. Am. Chem. Soc. 2003, 125, 3311-3321. (d) Adams, C.
J.; Pope, S. J. A. Inorg. Chem. 2004, 43, 3492-3499.
(18) Rodrigurz, V.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.
Organometallics 1998, 17, 3809-3814.

Ruthenium Azirinyl Complexes
Organometallics, Vol. 23, No. 25, 2004 5927
13C NMR data caused extensive decomposition of the
product. On the basis of these NMR data and spectro-
scopic data of 3a,b we believe that 3c-I (Scheme 1) is
probably the most stable isomer among the three.
Reaction of {[Ru]CNCH2C6H4CN}Br (2c′) with base
yielded the corresponding azirinyl complex 3c′, which
also shows three isomeric forms in a similar ratio by
NMR. It seems that the presence of an aromatic group
at Cγ (the methylene group) of the isocyanide ligand is
required in order to see three azirinyl isomers. Even
though free 1H-azirine is considered as the least stable
isomer in a pure organic system, the three-membered
ring of the metalated 1H-azirine at one of the sp2
carbons (3c-II) could significantly be stabilized by
participation of metal d orbirals, thus making 3c-III the
least stable among the three.23
Hydrolysis of the Isocyanide Complex with an
Ester Group. Treatment of {[Ru]CtNCH2CO2CH3}I,
(2d) in acetone with n-Bu4NOH affords the orange
oxazolone complex 4d in 72% yield (Scheme 1). Hy-
drolysis of the ester group accounts for the formation
of 4d. Lacking a stereogenic carbon atom, complex 4d
displays a singlet resonance at δ 50.5 in the 31P NMR
Figure 1. 2D 31P NMR spectrum of complex 3c, revealing
the presence of three isomers.
central nitrogen and a π bond orthogonal to the 4π allyl
system. While metal to carbon back-bonding is substan-
tial, the bonding situation of the metal-isocyanide
linkage is probably more adequately represented by
bending of the coordinated CNR unit.22
1
spectrum, and in the H NMR spectrum the 5:2 ratio
for the two singlet resonances at δ 4.69 and 4.13,
assignable to the Cp and CH2 groups, is consistent with
the formula. In the FAB mass spectrum, a parent peak
at m/z 776.2 attributed to (M + 1)+ is observed.24 We
previously reported the deprotonation reaction of a
cationic vinylidene complex containing a methyl ester
group at Cγ, i.e. [Ru]dCdC(Ph)CH2CO2R+, leading to
a thermodynamically stable neutral five-membered
methoxyfuryl complex with no hydrolysis of the ester
group. The three-membered-ring cyclopropenyl complex
was observed as an intermediate at the initial stage of
the deprotonation reaction of the vinylidene complex.
However, in the reaction of 2d with base leading to 4d,
no azirinyl complex with an ester substituent was
observed during the reaction.
Transition-metal-induced reactions of azirine have
been reported in a few cases. Initial 1,3-bond cleavage
and generation of a nitrene-iron carbonyl complex as
an intermediate was proposed in the reaction of azirine
with diiron nonacarbonyls to give diimine complexes
and urea diiron complexes.25 Cycloaddition of alkynes
Three Isomers of the Phenylazirinyl Complex.
Deprotonation of {[Ru]CNCH2Ph}Br (2c) in CH2Cl2 by
n-Bu4NOH at 0 °C also affords, in high yield, the
thermally unstable azirinyl complex 3c along with
[Ru]CN (1) as a minor product (ca. 5%). Use of other
bases such as DBU and n-Bu4NF in THF also gave
similar products, but with lower yield. The 31P NMR
spectrum of 3c at -20 °C displays three sets of doublet
of doublets patterns at δ 51.98, 48.82, δ 51.89, 49.72,
and δ 51.17, 50.15 in a ratio of approximately 2:2:3. The
2D 31P NMR COSY spectrum (Figure 1) reveals coupling
pairs corroborating the presence of stereogenic centers
of all three isomers. At -40 °C only one isomer is
detected. These could possibly be due to the fluxional
behavior of the three isomers 3c-I, 3c-II, and 3c-III of
the azirinyl complex, i.e., 1H-azirinyl and two 2H-
azirinyl complexes (Scheme 1), with one of them being
thermodynamically more stable. The 1H NMR spectrum
at -20 °C displaying three Cp singlet resonances at δ
4.59, 4.58, and 4.57 also in a ratio of 3:2:2, respectively,
is consistent with the 31P NMR data. Two 1H NMR
resonances at δ 4.89 and 4.71 are assigned to the CH
groups, and the broad resonance at δ 3.23 is assigned
to the NH group. Addition of D2O to the solution of 3c
at -20 °C causes immediate disappearance of the
resonance at δ 3.23, confirming this assignment. This
is followed by slow vanishing of the resonances at δ 4.89
and 4.71, indicating the presence of exchange processes
between these three isomers. At -29 °C the species with
(23) MO calculations show 1H-azirine to be approximately 30 kcal
less stable than 2H-azirine: Hopkinson, A. C.; Lien, M. A.; Yates, K.;
Csizmadia, J. G. Intern. J. Quantum Chem. 1977, 12, 355. (Phthal-
imidonitrene, generated by lead tetraacetate oxidation of N-amino-
phthalimide, reacts with acetylenes to give the 1-azirines. This work
provides good evidence of the probable intermediate for the formation
of a 2-azirine system: Gilchrist, T. L.; Gymer, G. E.; Rees, C. W. J.
Chem. Soc., Chem. Commun. 1971, 1519-1520. Gilchrist, T. L.; Gymer,
G. E.; Rees, C. W. J. Chem. Soc., Perkin Trans. 1 1973, 555-561.) We
have used the Spartan semiempirical method to calculate the relative
energies of three simplified isomers Cp(PH3)2Ru(CNCHPh) (3c′-I, 3c′-
II, 3c′-III) and found that 3c-I is the most stable one among the
possible isomers.
(24) (a) Hoshimoto, S.; Matsunaga, H.; Wada, M.; Kunieda, T. Chem.
Pharm. Bull. 2002, 50, 435-438. (b) Sebahar, H. L.; Yoshida, K.;
Hegedus, L. S. J. Org. Chem. 2002, 67, 3788-3795. (c) Dialer, H.;
Schumann, S.; Polborn, K.; Steglich, W.; Beck, W. Eur. J. Inorg. Chem.
2001, 1675-1679. (d) Umetani, S.; Kawase, Y.; Le, Q. T. H.; Matsui,
M. Dalton 2000, 2787-2791. (e) Prem, M.; Bauer, W.; Polborn, K.;
Beck, W. Z. Naturforsch., B 1998, 53, 965-970.
1
31P resonances at δ 51.17 and 50.15 and H resonance
at δ 3.23 disappears first. Then at -40 °C only one
isomer with 31P resonances at δ 51.89 and 49.72 and
1H resonance at δ 4.71 was observed. Attempts to obtain
(25) (a) Alper, H.; Prickett, J. E. J. Chem. Soc., Chem. Commum.
1976, 191-192. (b) Inada, A.; Heimgartner, H.; Schmid, H. Tetrahedron
Lett. 1979, 2983-2986. (c) Alper, H.; Prickett, J. E. Tetrahedron Lett.
1976, 2589-2590. (d) Isomura, K.; Uto, K.; Taniguchi, H. J. Chem.
Soc., Chem. Commun. 1977, 664-665.
(22) (a) Strauch, H. C.; Wibbeling, B.; Fro¨hlich, R.; Erker, G.;
Jacobsen, H.; Berke, H. Organometallics 1999, 18, 3802-3812. (b)
Go´mex, M.; Martinezde Ilarduya, J. M.; Royo, P. J. J. Organomet.
Chem. 1989, 369, 197-204.

5928 Organometallics, Vol. 23, No. 25, 2004
Lo et al.
Scheme 3
ratio. In 3 days at room temperature, the minor isomer
in solution turned into the major one. This transforma-
tion may indicate the presence of a dynamic equilibrium
between the azirinyl and the oxazolinyl rings. In the
1H NMR spectrum of the crude product, two pairs of
two-doublet resonances at δ 4.53, 4.15 and δ 4.57, 4.01
are assigned to the ring protons of the major and minor
isomers, respectively. Coupling constants of these pro-
tons for both diastereomers are in the range of 11 Hz,
3
indicating JH-H coupling. The C-C bond formation is
thus believed to take place at the sp3 carbon of the
azirinyl ring. This regiochemistry is different from that
in the photolytically induced insertion reaction of ketone
with organic azirine. The photoinduced addition of
carbonyl groups of aldehydes, ketones, and esters to
organic 2H-azirines is also completely regiospecific.27 In
the photoinduced addition reaction, the C-C bond
formation takes place at the sp2 carbon of the azirine
ring. In our case the C-C bond formation at the sp3
carbon is confirmed by the single-crystal X-ray diffrac-
tion study described below. Usually, organic oxazolines
are synthesized from nitrile or carboxylic acid derivates
or amino alcohols, which could be easily prepared by
the reduction of R-amino acids, although other proce-
dures are also used because of some particularly sensi-
tive functionalities present on the precursors.28
The stereoselectivity of the insertion reaction is
determined by the steric effect of substituents neighbor-
ing the carbonyl functionality. We carried out reactions
of 3a with a number of ketones and aldehydes. In the
reaction of 3a with Me3CCHO only one diastereoisomer
of 5d was isolated. The carbonyl group on the coordi-
nated Cp ligand of CpFe(C5H4CHO) also inserts into the
three-membered ring to give the single diastereoisomer
5e. Coupling constants between ring protons in the
oxazolinyl groups in 5d,e are 9.3 and 9.4 Hz, respec-
tively, indicating that the C-C bond formation takes
place at the same carbon atom as that in 5c. Interest-
ingly, the acetone moiety in the oxazolinyl ring of 5a is
irreversibly replaced by organic aldehyde. Namely, the
reaction of 5a with PhCHO yielded 5c. Insertion of CO2
into the azirinyl ring has been reported, and CO2 can
also be replaced by ketone, aldehyde, or other carbonyl-
containing compounds.29
with 2-phenylazirines in the presence of Mo(CO)6 ap-
pears to proceed by an initial [2 + 2] cycloaddition
followed by a ring-opening reaction to give pyrrole
derivatives.26
Insertion of a Carbonyl Group into the Azirinyl
Ring. The reaction of 2a with n-Bu4NOH/MeOH in
acetone, instead of CH2Cl2, yields a different product,
identified as the oxazolinyl complex 5a (Scheme 3). The
reaction of 3a with acetone also gave 5a. For the latter
species, insertion of the carbonyl group of acetone into
the C-C bond of the azirinyl ring with C-C bond
formation occurring at the sp3 carbon of the azirinyl ring
satisfactorily accounts for the formation of 5a. Complex
5a with a five-membered-ring ligand is more stable than
that of 3a. The 31P NMR spectrum of 5a displays two
doublet resonances at δ 50.0 and 51.0 with JP-P ) 34.5
Hz, consistent with the presence of a stereogenic carbon
center in the oxazolinyl ring. In the 13C NMR spectrum
of 5a, the triplet resonance of CR at δ 197.6 with JC-P
) 18.8 Hz is in the vicinity of the corresponding
resonance in 3a. The reaction of methyl ethyl ketone
with 3a gave 5b in 79% yield. Two diastereoisomers in
a ratio of 5:4 are observed in the 31P NMR data, and
after 30 days at room temperature the minor species
decreases to give a ratio of 2:1. It is clear that the steric
bulk controls the stereoselectivity. The regiochemistry
of ketone insertion, however, is not directly revealed by
the spectroscopic data mentioned above. Fortunately,
the same insertion also takes place for organic aldehyde.
We carried out the reaction of 3a with PhCHO in
chloroform. This reaction requires mild heating and
results in a mixture of diastereoisomers of 5c in a 5:1
Treatment of 2b with MeONa in acetone also affords
the oxazolinyl complex 6a in high yield. The coupling
constant of 7.1 Hz between the internal vinyl proton and
the ring proton is consistent with the formulation. For
oxazolinyl complexes derived from 2c, even though three
(27) (a) Clause, P.; Gilgen, P.; Hansen, H. J.; Heimgartner, H.;
Jackson, B.; Schmid. H. Helv. Chim. Acta 1974, 57, 2173-2193. (b)
Orahovats, A.; Jackson. B.; Heimgartner, H.; Schmid, H. Helv. Chim.
Acta 1973, 56, 2007-2011.
(28) (a) Minakata, S.; Nishimura, M.; Takahashi, T.; Oderaotoshi,
Y.; Komatsu, M. Tetrahedron Lett. 2001, 42, 9019-9022. (b) Kamata,
K.; Agata, I.; Meyers, A. I. J. Org. Chem. 1998, 63, 3113-3116. (c)
Ager, D. J.; Prakash, I.; Schaad, D. R. Chem. Rev. 1996, 96, 835-876.
(d) Lafarge, P.; Guenot, P.; Lellouche, J.-P. Heterocycles 1995, 41, 947-
958. (e) Rieger, D.; Lotz, S. D.; Kernbach, U.; Andre, C.; Bertran-Nadal,
J.; Fehlhammer, W. P. J. Organomet. Chem. 1995, 491, 135-152. (f)
Gant, T. G.; Meyers, A. I. Tetrahedron 1994, 50, 2297-2360. (g)
Leonard, W. R.; Romine, J. L.; Meyers, A. I. J. Org. Chem. 1991, 56,
1961-1963. (h) Reuman, M.; Meyers, A. I. Tetrahedron 1985, 41, 837-
860. (i) Meyers, A. I.; Mihelich, E. D. Angew. Chem., Int. Ed. Engl.
1976, 15, 270-281. (j) Frump, J. A. Chem. Rev. 1971, 71, 483-505.
(29) (a) Orahovovats, A.; Heimgartner, H.; Schmid, H.; Heinzel-
mann, W. Helv. Chim. Acta 1974, 54, 2626-2633. (b) Padwa, A.;
Wetmore, S. I., Jr. J. Am. Chem. Soc. 1974, 96, 2414-2421. (c) Padwa,
A.; Wetmore, S. I., Jr. Org. Photochem. Synth. 1976, 2, 87-95.
(26) Alper, H.; Wollowitz, S. J. Am. Chem. Soc. 1975, 97, 3541-
3543.

Ruthenium Azirinyl Complexes
Organometallics, Vol. 23, No. 25, 2004 5929
Table 1. Crystal and Intensity Collection Data for
Cp*(dppp)Ru[CNCHPhC(Me)2O] (7a*) and
Cp*(dppp)Ru[CNCHPhC(Me)2OH][PF6] (8a*)
7a*
8a*
mol formula
mol wt
space group
a, Å
C
54H67NOP2Ru
C49H54NO2P3F6Ru
996.91
909.10
Pbca
P1h
15.8700(3)
18.9940(3)
32.5140(8)
90.00
90.00
90.00
11.2850(2)
13.8970(2)
16.0390(3)
78.8460(10)
83.4930(10)
75.9960(10)
2388.65(7)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
9800.9(3)
8
Z
cryst dimens, mm3
Mo KR radiation, Å
θ range, deg
no. of rflns collected
no. of indep rflns
max, min transmissn
0.25 × 0.20 × 0.20 0.30 × 0.25 × 0.20
0.710 73
1.79-25.00
38 008
8083
0.954, 0.795
2.13-25.00
37 778
8418
0.959, 0.864
8401/2/558
no. of data/restraints/ 8022/0/485
params
GOF
Figure 2. ORTEP drawing of 7a*.
2.130
1.332
final R indices
(I > 2σ(I))
R indices
(all data)
R1 ) 0.0711,
wR2 ) 0.1785
R1 ) 0.1095,
wR2 ) 0.2140
R1 ) 0.0521,
wR2 ) 0.1529
R1 ) 0.0631,
wR2 ) 0.1674
-0.63, +1.23
∆δ (in final map), e/Å3 -1.27, +0.83
azirinyl intermediates are observed at the initial stage
of the reaction of 2c with base in the absence of acetone,
interestingly, the reaction of 2c with MeONa in acetone
yields only the oxazolinyl complex 7a. We also prepared
complexes 7b-e using similar procedures. For ketones
and aldehydes, comparable stereoselectivity was ob-
served for the formation of 7.
Insertion of a carbonyl group of an ester or an amide
can also take place for 3c. Thus, reactions of 3c with
methyl benzoate and with dimethylacetamide give 7f
in 77% yield and 7g in 54% yield, respectively. The
single Cp resonance in the NMR spectra of both 7f and
7g indicates high regio- and stereoselectivity in these
reactions. In organic systems, no photoreaction has been
reported between azirine and amide.
Treatment of complex 2c* with n-Bu4NOH in acetone
affords 7a*, a product resulting from addition of acetone
after deprotonation of 2c*, in 60% yield. In the 1H NMR
spectrum of 7a*, the 1H singlet peak at δ 4.94 is
assigned to CHPh of the oxazolinyl ring. Two inequiva-
lent methyl groups of 7a* appear as two singlet reso-
nances at δ 1.53 and 0.82. The characteristic CR
resonance in the 13C NMR spectrum of 7a* appears as
a doublet of doublets at δ 193.7 with coupling constants
of JP-C ) 18.8 and 17.7 Hz. The 31P NMR spectrum of
7a* displays two well-separated doublet resonances at
δ 52.94 and 45.35 with JP-P ) 51.1 Hz.
Figure 3. ORTEP drawing of 8a*.
Recrystallization of 7a* from n-hexane gives yellow
crystals, and recrystallization of 8a* from acetone/
diethyl ether (1:2) affords colorless crystals. The molec-
ular structures of 7a* and 8a* have been confirmed by
single-crystal X-ray diffraction studies (Table 1). ORTEP
diagrams of 7a* and 8a* are shown in Figures 2 and 3,
respectively, with selected bond distances and angles
of 7a* and 8a* being listed in Tables 2 and 3, respec-
tively. For 7a*, the C(1)-N(1) distance of 1.300(7) Å
indicates a CN double bond.30 The Ru(1)-C(1) distance
of 7a* (2.054(5) Å) is slightly longer than the corre-
sponding Ru(1)-C(1) distance of 8a* (1.939(4) Å). In
8a*, the Ru(1)-C(1) distance of 1.939(4) Å is typical of
a Ru-C single bond. The C(1)-N(1) distance of 1.145(5)
Å indicates a typical CN triple bond. The Ru(1)-C(1)-
N(1) and C(1)-N(1)-C(2) angles are 172.2(3) and
173.0(4)°, respectively, indicating a linear isocyanide
structure. The structure of the five-membered oxazolinyl
ring confirms the regiospecific C-C bond formation.
Previously, a bis(oxazoline) ligand was introduced as a
chiral ligand for the preparation of asymmetric cata-
lysts. These ligands use the nitrogen atom of the
bis(oxazoline) to coordinate to the metal center rather
However, treatment of 2c* with NaOMe in the
presence of KPF6 in acetone solution affords
[Ru*]CNCHPhC(Me)2OH+ (8a*) in 38% yield. In the IR
spectrum of 8a*, the absorption peak at 2118 cm-1 is
assigned to νCtN stretching and the broad peak at 3576
1
cm-1 is assigned to νOH. In the H NMR spectrum of
8a*, two 1H singlet peaks at δ 5.46 and 2.53 are
assigned to the CHPh and the OH absorptions, respec-
tively, with the latter readily vanishing in the presence
of D2O. The 31P NMR spectrum of 8a* displaying AB
type resonances at δ 38.44 and 38.06 with JP-P ) 46.5
Hz differs significantly from that of 7a*.
(30) (a) Nishiyama, H.; Niwa, E.; Inoue, T.; Ishima, Y.; Aoki, K.
Organometallics 2002, 21, 2572-2574. (b) Braunstein, P.; Naud, F.;
Dedieu, A.; Rohmer, M. M.; DeCian, A.; Rettig, S. J. Organometallics
2001, 20, 2966-2981.

5930 Organometallics, Vol. 23, No. 25, 2004
Lo et al.
Table 2. Selected Bond Lengths (Å) and Bond
Angles (deg) for Complex 7a*
Experimental Section
General Procedures. All manipulations were performed
under nitrogen using vacuum-line, drybox, and standard
Schlenk techniques. CH2Cl2 was distilled from CaH2, and
diethyl ether and THF were distilled from Na/diphenylketyl.
All other solvents and reagents were of reagent grade and were
used as received. NMR spectra were recorded on Bruker AC-
300 and DMX-500 FT-NMR spectrometers at room tempera-
ture (unless stated otherwise) and are reported in units of δ
with residual protons in the solvents as a reference (CDCl3, δ
7.24: C2D6O, δ 2.04). FAB mass spectra were recorded on a
JEOL SX-102A spectrometer. Complexes [Ru]CtN (1; [Ru] )
(η5-C5H5)(PPh3)2Ru) and [Ru*]CtN (1*; [Ru*] ) (η5-C5Me5)-
(dppp)Ru)33 were prepared according to the methods reported
in the literature. Elemental analyses and X-ray diffraction
studies were carried out at the Regional Center of Analytical
Instrument located at the National Taiwan University.
Preparation of {[Ru]CNCH2CN}Br (2a). To a sample of
1 (3.00 g, 4.18 mmol) dissolved in 70 mL of CHCl3 at room
temperature was added BrCH2CN (1.0 mL, 14.4 mmol) via a
syringe. The resulting mixture was heated to reflux for 2 days.
After removal of all volatile substances in vacuo, 10 mL of
CH2Cl2 was added to the residue under nitrogen, and the
mixture was added to a vigorously stirred ether solution (100
mL) to cause green solid to precipitate out. The solid product
was collected by filtration followed by washing with ether and
was identified as 2a (2.63 g, 75% yield). Spectroscopic data
for 2a: 1H NMR (CDCl3) δ 7.32-7.05 (m, 30H, Ph), 5.51 (s,
2H, CH2), 4.86 (s, 5H, Cp); 13C NMR (CDCl3) δ 165.1 (t, JC-P
) 19.9 Hz, CR), 135.3-127.5 (Ph), 111.8 (CN), 88.4 (Cp), 35.4
(CH2); 31P NMR (CDCl3) δ 45.4; MS (FAB, m/z, Ru102) 757 (M+),
495 (M+ - PPh3). Anal. Calcd for C44H37N2P2BrRu: C, 63.16;
H, 4.46; N, 3.35. Found: C, 63.31; H, 4.59; N, 3.40.
Bond Lengths
Ru(1)-C(1)
C(1)-N(1)
N(1)-C(2)
C(3)-C(4)
C(2)-C(6)
Ru(1)-P(2)
2.054(5)
1.300(7)
1.464(7)
1.512(8)
1.512(8)
2.279(1)
C(1)-O(1)
O(1)-C(3)
C(2)-C(3)
C(3)-C(5)
Ru(1)-P(1)
1.389(6)
1.464(6)
1.541(8)
1.512(8)
2.274(1)
Bond Angles
Ru(1)-C(1)-O(1)
C(1)-O(1)-C(3)
O(1)-C(3)-C(2)
O(1)-C(1)-N(1)
O(1)-C(3)-C(5)
N(1)-C(2)-C(6)
115.0(3)
109.6(4)
100.5(4)
111.8(4)
107.7(5)
113.9(5)
Ru(1)-C(1)-N(1)
C(1)-N(1)-C(2)
N(1)-C(2)-C(3)
O(1)-C(3)-C(4)
C(3)-C(2)-C(6)
P(1)-Ru(1)-P(2)
133.2(4)
109.5(4)
104.5(4)
108.0(5)
115.9(4)
90.55(5)
Table 3. Selected Bond Lengths (Å) and Bond
Angles (deg) for Complex 8a*
Bond Lengths
Ru(1)-C(1)
N(1)-C(2)
C(3)-O(1)
C(3)-C(5)
Ru(1)-P(1)
1.939(4)
1.458(5)
1.434(6)
1.525(7)
2.305(1)
C(1)-N(1)
C(2)-C(3)
C(3)-C(4)
C(2)-C(6)
Ru(1)-P(2)
1.145(5)
1.542(6)
1.510(8)
1.523(6)
2.309(1)
Bond Angles
Ru(1)-C(1)-N(1)
N(1)-C(2)-C(3)
C(2)-C(3)-C(4)
N(1)-C(2)-C(6)
172.2(3)
107.9(3)
113.5(4)
110.5(3)
C(1)-N(1)-C(2)
C(2)-C(3)-O(1)
C(2)-C(3)-C(5)
P(1)-Ru(1)-P(2)
173.0(4)
102.6(4)
109.9(4)
90.91(3)
than CR of the oxazolinyl ring in 7a*.31 Treatment of
7a with NaBH3CN in MeOH afforded the organic
alcohol PhCH2CMe2OH and 1 in greater than 90% yield.
Two products were separated by column chromatogra-
phy. In the presence of D2O the reaction gave PhCH2-
CMe2OD. NCC6H4CH2CMe2OH and F3CC6H4PhCH2-
CMe2OH were also prepared from the corresponding
complexes. The reaction in 0.1 g scale also occurred in
hexane with slightly lower yield.32
Concluding Remarks. We prepared ruthenium
azirinyl complexes by deprotonation reactions of ruthe-
nium isocyanide complexes. In the ruthenium coordi-
nated azirinyl system with a phenyl substituent three
isomers, including a 1H-azirinyl complex, could be
observed by NMR spectroscopy. Facile insertion of a
carbonyl group of ketone, aldehyde, ester, and amide
into the ruthenium-bound azirinyl ring to give oxa-
zolinyl complexes followed a different regiospecificity
from that in photolytic organic azirine systems. Subse-
quent hydride reduction releases organic alcohol and the
ruthenium nitrile complex. Thus, C-C bond formation
between organic halide and a carbonyl group could be
catalyzed in a stepwise manner using the coordinated
nitrile ligand.
Other isocyanide complexes {[Ru]CNCH2R}X (R ) CHd
CH2, 2b, 90% yield; R ) C6H5, 2c, 92% yield; R ) COOCH3,
2d, 74% yield) were prepared similarly from the reactions of
1 with ICH2CHdCH2, BrCH2C6H5, and BrCH2COOCH3, re-
spectively. Spectroscopic data for 2b: 1H NMR (CDCl3) δ 7.36-
7.04 (m, 30H, Ph), 5.59 (ddt, JH-H ) 15.4, 10.0, 7.2 Hz, 1H,
dCH), 5.16 (d, JH-H ) 15.4 Hz, 1H, dCH), 5.09 (d, JH-H
)
10.0 Hz, 1H, dCH), 4.79 (s, 5H, Cp), 4.57 (d, JH-H ) 7.2 Hz,
CH2); 13C NMR (CDCl3) δ 153.0 (t, JC-P ) 21.0 Hz, CR), 135.8-
128.3 (Ph), 129.3 (CH), 118.9 (CH2), 87.6 (Cp), 49.2 (CH2); 31
P
NMR (CDCl3) δ 46.3; MS (FAB, m/z, Ru102) 758 (M+), 496 (M+
- PPh3), 429 (M+ - PPh3-CNC3H5). Anal. Calcd for C45H40-
NP2IRu: C, 61.09; H, 4.56; N, 1.58. Found: C, 61.15; H, 4.64;
N, 1.49. Spectroscopic data for 2c: 1H NMR (CDCl3) δ 7.34-
6.92 (m, 30H, Ph), 5.11 (s, 2H, CH2), 4.77 (s, 5H, Cp); 31P NMR
(CDCl3) δ 45.4; MS (FAB, m/z, Ru102) 808 (M+), 546 (M+
-
PPh3). Anal. Calcd for C49H42NP2BrRu: C, 66.29; H, 4.77; N,
1.58. Found: C, 66.25; H, 4.83; N, 1.62. Spectroscopic data for
2d: 1H NMR (CDCl3) δ 7.28-7.05 (m, 30H, Ph), 4.92 (s, 2H,
CH2), 4.76 (s, 5H, Cp), 3.60 (s, 3H, CH3); 13C NMR (CDCl3) δ
165.4 (CdO), 158.2 (t, JC-P ) 20.2 Hz, CR), 135.5-127.6 (Ph),
87.7 (Cp), 52.5 (CH2), 47.8 (CH3); 31P NMR (CDCl3) δ 46.0; MS
(FAB, m/z, Ru102) 790 (M+), 528 (M+ - PPh3). Anal. Calcd for
C45H40NO2P2BrRu: C, 62.14; H, 4.64; N, 1.61. Found: C, 62.39;
H, 4.89; N, 1.70.
Synthesis of {[Ru*]CNCH2Ph}Br (2c*). To a Schlenk
flask charged with [Ru*]CN (1*; 0.20 g, 0.30 mmol) and CHCl3
(40 mL) was added BrCH2Ph (0.20 mL, 1.16 mmol). The clear
solution was heated to reflux for 6 h. After the mixture was
cooled, the solvent was reduced to about 5 mL. The mixture
was slowly added to a diethyl ether solution (90 mL). The white
precipitate thus formed was filtered off and washed with
diethyl ether and n-hexane. The product was recrystallized
from CH2Cl2/n-hexane (1:10) and was identified as 2c* (0.14
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Capiello, J. Tetrahedron: Asymmetry 1998, 9, 1-45. (e) Jørgensen, K.
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(33) (a) Baird, G. J.; Davies, S. G.; Moon, S. D.; Simpson, S. J.; Jones,
R. H. J. Chem. Soc., Dalton Trans. 1985, 1479-1486. (b) Laidlaw, W.
M.; Denning, R. G. J. Organomet. Chem. 1993, 463, 199-204.

Ruthenium Azirinyl Complexes
Organometallics, Vol. 23, No. 25, 2004 5931
g, 57% yield). Spectroscopic data for 2c*: IR (KBr) 2115 cm-1
(s, νCN); H NMR (CDCl3) δ 7.42-7.08 (m, 30H, Ph), 5.18 (s,
Cp), 4.13 (s, 2H, CH2); 31P NMR (CD3COCD3) δ 50.5; MS (FAB,
m/z) 776.2 (M+ + 1), 514.0 (M+ + 1 - PPh3), 428.9 (M+ + 1 -
PPh3, CNCH2CO2).
1
2H, CH2), 2.59-1.52 (m, 6H, CH2), 1.34 (s, 15H, 5 CH3); 13C
NMR (CDCl3) δ 160.6 (t, JP-C ) 19.4 Hz, CN), 136.1-128.1
(Ph), 96.6 (s, Cp), 50.1 (s, CH2), 30.4 (t, JP-C ) 17.5 Hz, CH2),
20.9 (s, CH2), 9.7 (s, 5CH3)’ 31P NMR (CDCl3) δ 37.80; MS (FAB,
m/z, Ru102) 766.3 (M+), 649.3 (M+ - CNCH2Ph). Anal. Calcd
for C45H48NP2RuBr: C, 63.90; H, 5.68; N, 1.66. Found: C,
64.11; H, 5.99; N, 1.32.
Synthesis of 5a. To a solution of 2a (0.11 g, 0.13 mmol) in
10 mL of acetone was added a solution of n-Bu4NOH (0.20 mL).
The color of the solution changed from green to yellow
immediately. The solvent was removed under vacuum, the
residue was extracted with hexane, and then after filtration
the solution was dried under vacuum to afford the yellow
product 5a (0.080 g, 82% yield). Spectroscopic data of 5a: 1H
NMR (C6D6) δ 7.44-6.99 (m, 30 H, Ph), 4.48 (s, 5H, Cp), 4.03
(s, 1H, CH), 1.32 (s, 3H, Me), 0.82 (s, 3H, Me); 13C NMR (C6D6)
δ 197.6 (t, JP-C ) 18.8 Hz, CR), 140.4-127.4 (Ph), 119.2 (CN),
Synthesis of 3a. To a solution of 2a (0.12 g, 0.14 mmol) in
5 mL of CH2Cl2 at 0 °C was added a solution of n-Bu4NOH
(0.5 mL, 1 M in MeOH). The mixture was stirred for 10 min,
and the color changed from green to yellow. Then the solvent
was removed under vacuum at 0 °C and the solid residue was
extracted with cool ether. The extract was filtered through
Celite. Solvent of the filtrate was removed under vacuum to
give 3a (0.10 g, 94% yield). Complex 3a is thermally unstable
and decomposes to some unidentifiable products in solution
over 30 min. Spectroscopic data for 3a: 1H NMR (CD3CN, -20
°C) δ 7.63-7.18 (m, 30H, Ph), 4.26 (s, 5H, Cp), 2.98 (s, 1H,
CH); 13C NMR (CD3CN, -20 °C) δ 184.3 (t, JP-C ) 19.9 Hz,
CR), 138.1-127.3 (Ph), 119.3 (CN), 88.9 (Cp), 11.3 (CH); 31P
NMR (CD3CN, -20 °C) δ 49.1, 48.7 (2d, JP-P ) 34.8 Hz). MS
(FAB) m/z: 757.3 (M+ + 1), 495.0 (M+ + 1 - PPh3), 429.0 (M+
+ 1 - PPh3, CNCHCN). The elemental analysis is not
satisfactory, possibly due to the instability of 3a.
86.3 (Cp), 79.5 (C(Me)2), 68.2 (CH), 27.8 (CH3), 25.3 (CH3); 31
P
NMR (CDCl3) δ 51.0, 50.0 (AB, JP-P ) 34.5 Hz); MS (FAB,
m/z) 815.3 (M+ + 1), 553.1 (M+ + 1 - PPh3), 429.0 (M+ + 1 -
PPh3 - CNCHCNC(CH3)2O). Anal. Calcd for C47H42N2OP2Ru:
C, 69.36; H, 5.20; N, 3.44. Found: C, 69.47; H, 5.44; N, 3.27.
Complex 5a can also be obtained from the reaction of 3a with
acetone.
Complex 5b (79% yield) was similarly prepared from 2a
(0.076 g) and 2-butanone (0.012 mL, 0.10 mmol) and n-Bu4NOH
(0.5 mL) in 20 mL of CH2Cl2 at room temperature. A mixture
containing two diastereomers (5:4) was isolated. Spectroscopic
data for 5b: 1H NMR (CDCl3, major product) δ 7.62-7.00 (m,
30 H, PPh3), 4.51 (s, 5H, Cp), 4.22 (s, 1H, CH), 1.78 (m, 1H,
CH2), 1.58 (m, 1H, CH2), 1.27 (s, 3H, Me), 0.88 (m, 3H,
CH2CH3); 1H NMR (CDCl3, minor product) δ 7.62-7.00 (m,
30 H, PPh3), 4.53 (s, 5H, Cp), 4.19 (s, 1H, CH), 1.78 (m, 1H,
one proton of CH2), 1.58 (m, 1H, one proton of CH2), 0.97 (t,
JH-H ) 7.1 Hz, 3H, CH2CH3), 0.79 (s, 3H, Me); 13C NMR (C6D6,
major product) δ 197.4 (t, JP-C ) 19.3 Hz, CR), 140.6-123.9
(Ph), 118.4 (CN), 82.8 (Cp), 75.5 (CMeEt), 69.1 (CH), 29.8
(CH2), 24.1 (CH3), 8.5 (CH3); 13C NMR (C6D6, minor product)
δ 197.9 (t, JP-C ) 19.6 Hz, CR), 140.6-123.9 (Ph), 117.9 (CN),
82.6 (Cp), 75.1 (CMeEt), 70.2 (CH), 26.8 (CH2), 23.8 (CH3), 9.1
(CH3); 31P NMR (C6D6) δ 52.6, 49.7 (AB, JP-P ) 34.1 Hz), 52.3,
Synthesis of 3b. To a solution of 2b (0.10 g, 0.13 mmol) in
20 mL of CH2Cl2 at 0 °C was added a THF solution of n-Bu4NF.
The mixture was stirred for 10 min, and the color changed to
bright yellow. Then the solvent was removed under vacuum
at 0 °C and the solid residue was extracted with cool hexane.
The extract was filtered through Celite. The solvent of the
filtrate was removed under vacuum to give 3b (0.087 g, 88%
yield). Complex 3b is soluble in THF, ether, and hexane and
is thermally unstable, decomposing to some unidentifiable
products. Spectroscopic data for 3b: 1H NMR (C6D6, 10 °C) δ
7.42-7.06 (m, 30H, PPh3), 5.73 (ddd, JH-H ) 18.2, 9.1, 7.2 Hz,
1H, dCH), 5.26 (d, JH-H ) 18.2 Hz, 1H, dCH), 5.21 (d, JH-H
) 9.1 Hz, 1H, dCH), 4.73 (s, 5H, Cp), 2.76 (d, JH-H ) 7.2 Hz,
49.7 (AB, JP-P ) 34.3 Hz) (5:4); MS (FAB, m/z) 829.2 (M+
+
1), 567.3 (M+ + 1 - PPh3), 429.0 (M+ - PPh3, CNCHCNC-
(CH3)(CH2CH3)O). Anal. Calcd for C48H44N2OP2Ru: C, 69.63;
H, 4.91; N, 3.25. Found: C, 69.38; H, 4.97; N, 3.09.
1H, CNCH); 31P NMR (C6D6, 10 °C) δ 52.0, 48.8 (AB, JP-P
)
34.8 Hz); MS (FAB, m/z) 758.2 (M+ + 1), 496.1, (M+ + 1 -
PPh3), 429,0 (M+ + 1 - PPh3, CNCHdCH2).
Complex 5c (87% yield) was similarly prepared from 2a
(0.051 g, 0.061 mmol), benzaldehyde (0.0062 mL, 0.061 mmol),
and n-Bu4NOH (0.5 mL) in 20 mL of CH2Cl2 at room temper-
ature. A mixture containing two diastereomers in a 5:1 ratio
was isolated. Spectroscopic data for 5c: 1H NMR (CDCl3, major
isomer) δ 7.62-6.80 (m, 35 H, Ph), 4.53 (d, 1H, JH-H ) 11.4
Hz, CH), 4.51 (s, 5H, Cp), 4.15 (d, 1H, JH-H ) 11.4 Hz, CH);
1H NMR (CDCl3, minor isomer) δ 7.62-6.80 (m, 35 H, Ph),
4.57 (d, 1H, JH-H ) 11.4 Hz, OCH), 4.41 (s, 5H, Cp), 4.01 (d,
1H, JH-H ) 11.4 Hz, CCH); 13C NMR (C6D6, major isomer) δ
197.5 (t, JP-C ) 19.7 Hz, CR), 139.1-121.6 (Ph), 119.5 (CN),
86.4 (CHPh), 85.6 (Cp), 80.1 (CH); 13C NMR (C6D6, minor
isomer) δ 196.4 (t, JP-C ) 19.6 Hz, CR), 119.1 (CN), 85.3
(CHPh), 85.1 (Cp), 78.3 (CH); 31P NMR (C6D6) δ 51.8, 49.4 (AB,
JP-P ) 34.5 Hz), 51.2, 49.7 (AB, JP-P ) 34.4 Hz) (5:1); MS
(FAB, m/z) 863.1 (M+ + 1), 602.3 (M+ + 1 - PPh3), 429.0 (M+
- PPh3, CNCHCNCPhHO). Anal. Calcd for C51H42N2OP2Ru:
C, 71.07; H, 4.91; N, 3.25. Found: C, 71.35; H, 4.69; N, 3.58.
Complex 5d was prepared using the following method. A
mixture of complex 3a (0.22 g, 0.30 mmol) and trimethyl-
acetaldehyde (0.03 mL, 0.3 mmol) in 10 mL of benzene was
heated to reflux for 1 h. The workup procedure was the same
as that for 5a. Only one isomer is observed. Purification by
recrystallization of the product from CH2Cl2/ether (1:3) gave
5d (0.19 g, 78% yield). Spectroscopic data for 5d: 1H NMR
(CDCl3) δ 7.62-6.94 (m, 30 H, PPh3), 4.48 (s, 5H, Cp), 4.05 (d,
1H, JH-H ) 9.3 Hz, CHCN), 3.80 (d, 1H, JH-H ) 9.3 Hz, OCH),
0.94 (s, 9H, C(CH3)3); 13C NMR (C6D6) δ 195.1 (t, JP-C ) 19.4
Hz, CR), 139.4-122.8 (Ph), 118.1 (CN), 81.7 (Cp), 76.4
(CC(CH3)3), 70.3 (CH), 57.1 (CMe3), 29.4 (CMe3); 31P NMR
Reaction of {[Ru]CNCH2C6H5}Br with n-Bu4NOH. To
a solution of 2c (0.14 g, 0.16 mmol) in 20 mL of acetone was
added a solution of n-Bu4NOH (0.5 mL) at 0 °C. The mixture
was stirred for 10 min, and the color changed to yellow-orange.
Then the solvent was removed under vacuum and the solid
residue was extracted with ether at 0 °C. The extract was
filtered through Celite. The solvent of the filtrate was removed
under vacuum at 0 °C to give the products 3c (0.12 g, 95%
yield). Three isomers are observed in the spectra of 3c at -20
°C. Spectroscopic data for 3c: 1H NMR (C6D5CD3 at -20 °C)
δ 7.55-6.94 (m, Ph), 4.89, 4.71 (2s, 1H, CH), 4.59, 4.58, 4.57
(3s, 5H, Cp), 3.23 (br, 1H, NH); 31P NMR (C6D5CD3 at -20
°C) δ 51.98, 48.82 (2d, JP-P ) 34.8 Hz), 51.89, 49.72 (2d, JP-P
) 34.8 Hz), 51.17, 50.15 (2d, JP-P ) 34.9 Hz); MS (FAB of the
mixture, m/z) 808.4 (M+ + 1), 546.2 (M+ + 1 - PPh3), 429.0
(M+ + 1 - PPh3, CNCH2Ph); high-resolution MS (FAB, m/z)
calcd for C49H42RuP2N (M + 1) 808.1850, found 808.1836.
Complex 3c in pure form was not obtained. Variable-temper-
ature NMR data were collected in C6D5CD3, and at -40 °C
only one isomer is observed.
Reaction of 2d with n-Bu4NOH. To a solution of 2d (0.14
g, 0.16 mmol) in 20 mL of acetone was added a solution of
n-Bu4NOH (0.5 mL). The mixture was stirred for 10 min, and
the color changed to orange. Then the solvent was removed
under vacuum and the solid residue was extracted with ether.
The extract was filtered through Celite. The solvent of the
filtrate was removed under vacuum to give 4d (0.090 g, 72%
yield) after recrystallization from ether. Spectroscopic data for
4d: 1H NMR (CDCl3) δ 7.65-7.00 (m, 30H, Ph), 4.69 (s, 5H,

5932 Organometallics, Vol. 23, No. 25, 2004
Lo et al.
(C6D6) δ 51.6, 49.6 (AB, JP-P ) 34.2 Hz); MS (FAB, m/z) 843.3
(M+ + 1), 581.1 (M+ + 1 - PPh3), 429.0 (M+ - PPh3,
CNCHCNCHCMe3O). Anal. Calcd for C49H46N2OP2Ru: C,
69.90; H, 5.51; N, 3.33. Found: C, 70.00; H, 5.58; N, 3.39.
Synthesis of 5e. To 50 mL of a CH2Cl2 solution of 2a (0.07
g, 0.084 mmol) were added a slight excess of ferrocenecarbox-
aldehyde (0.02 g, 0.12 mmol) and n-Bu4NOH (0.5 mL), and
the solution was heated to reflux for 90 min. The color changed
from yellow to bright yellow, and then the solvent was removed
under vacuum. The residual solid was extracted with 2 × 20
mL of ether, and the solution was filtered through Celite. The
solvent of the filtrate was removed under vacuum to give 5e
(0.054 g, 67% yield). Spectroscopic data for 5e: 1H NMR (C6D6)
δ 7.56-7.01 (m, 30 H, Ph), 5.09 (d, 1H, JH-H ) 9.4 Hz, OCH),
4.47 (s, 5H, Cp), 4.21 (d, 1H, JH-H ) 9.4 Hz, NCH), 4.07 (br,
2H, Fe(C5H4)CO), 4.05 (br, 2H, Fe(C5H4)CO), 3.94 (s, 5H,
(C5H5)Fe); 13C NMR (C6D6) δ 197.5 (t, JP-C ) 19.7 Hz, CR),
139.1-121.6 (m, Ph), 119.5 (CN), 99.1 (CHFe(C5H5)2), 85.6
(Cp), 80.7 (CHCN), 71.4 (C5H5), 68.6 (C5H5), 64.6 (C5H5), 64.1
(C5H5); 31P NMR (CDCl3) δ 51.3, 50.8 (AB, JP-P ) 34.9 Hz);
MS (FAB, m/z) 971.3 (M+ + 1), 709.2 (M+ + 1 - PPh3), 429.0
(M+ - PPh3, CNCHCNCH Fe(C5H5)2O). Anal. Calcd for
C55H46N2OP2RuFe: C, 68.11; H, 4.78; N, 2.89. Found: C, 68.15;
H, 4.80; N, 3.01.
Synthesis of 6a. To a solution of 2b (0.11 g, 0.13 mmol) in
20 mL of acetone was added a solution of n-Bu4NOH (0.5 mL).
The color of the solution changed from yellow to bright yellow
immediately. The solvent was removed under vacuum, the
residue was extracted with hexane, and then the solution was
dried under vacuum to afford 6a (0.092 g, 91% yield). Spec-
troscopic data of 6a: 1H NMR (C6D6) δ 7.55-6.97 (m, 30 H,
PPh3), 5.69 (ddd, JH-H ) 16.9, 9.9, 7.1 Hz, 1H, HCd), 5.23 (dd,
JH-H ) 16.9, 2.4 Hz, 1H, dCHH), 5.01 (dd, JH-H ) 9.9, 2.4 Hz,
1H, dCHH), 4.57 (s, 5H, Cp), 4.01 (d, 1H, JH-H ) 7.1 Hz), 1.15
(s, 3H, Me), 1.05 (s, 3H, Me); 13C NMR (C6D6) δ 198.4 (t, JP-C
) 18.1 Hz, CR), 152.4 (CHdCH2), 142.3-123.6 (Ph), 110.4
(CHdCH2), 83.7 (Cp), 78.4. (CMe2), 64.1 (CH), 28.5 (CH3), 24.2
(CH3); 31P NMR (CDCl3) δ 51.2, 50.4 (AB, JP-P ) 34.7 Hz);
MS (FAB, m/z) 816.3 (M+ + 1), 554.1 (M+ + 1 - PPh3), 429.0
(M+ - PPh3, CNCH(HCdCH2)C(CH3)2O). Anal. Calcd for
C48H45NOP2Ru: C, 70.75; H, 5.57; N, 1.72. Found: C, 70.86;
H, 5.49; N, 1.99.
125.9, (Ph), 94.3 (s, Cp), 80.8 (s, CHPh), 29.3 (dppp), 29.2 (s,
CMe2), 25.2 (s, Me2), 24.8 (m, dppp), 10.5 (s, 5Me); 31P NMR
(C6D6) δ 52.94, 45.35 (2 d, JP-P ) 51.1 Hz); MS (FAB, m/z,
Ru102): 824.2 (M+), 766.2 (M+ - CO(CH3)2). Anal. Calcd for
C48H53NOP2Ru: C, 70.07; H, 6.45; N, 1.70. Found: C, 70.32;
H, 6.43; N, 1.69.
Synthesis of 7b. Complex 7b (87% yield) was similarly
prepared from 3c (0.051 g) and benzaldehyde in 20 mL of
CH2Cl2 at room temperature. Spectroscopic data for 7b: 1H
NMR (C6D6, major isomer) δ 7.58-6.94 (m, 40 H, Ph), 5.12 (d,
1H, JH-H ) 11.4 Hz, NCHPh), 4.64 (s, 5H, Cp), 4.49 (d, 1H,
JH-H ) 11.4 Hz, OCHPh); 1H NMR (C6D6, minor isomer) δ
7.58-6.94 (m, 40 H, Ph), 5.12 (d, 1H, JH-H ) 11.4 Hz, OCHPh),
4.73 (s, 5H, Cp), 4.49 (d, 1H, JH-H ) 11.4 Hz, NCHPh); 31P
NMR (C6D6) δ 51.8, 49.3 (AB, JP-P ) 34.7 Hz), 51.0, 49.7 (AB,
JP-P ) 34.6 Hz) (4:1); MS (FAB, m/z) 914.2 (M+ + 1), 651.2
(M+ + 1 - PPh3), 429.0 (M+ - PPh3, CNCHPhCPhHO). Anal.
Calcd for C56H47NOP2Ru: C, 73.67; H, 5.19; N, 1.53. Found:
C, 73.49; H, 5.33; N, 1.50.
Synthesis of 7c. Complex 7c (81% yield) was similarly
prepared from 3c (0.096 g) and 2-butanone (0.010 mL, 0.12
mmol) in 20 mL of CH2Cl2 at room temperature. Spectroscopic
data for 7c: 1H NMR (C6D6, major) δ 7.57-6.99 (m, 35H, Ph),
4.85 (s, 1H, CH), 4.63 (s, 5H, Cp), 1.78 (m, 1H, CH2), 1.58 (m,
1H, CH2), 1.24 (s, 3H, Me), 0.87 (m, 3H, CH3); 1H NMR (C6D6,
minor) δ 7.57-6.99 (m, 35 H, Ph), 4.76 (s, 1H, CH), 4.61 (s,
5H, Cp), 1.78 (m, 1H, CH2), 1.58 (m, 1H, CH2), 0.96 (t, JH-H
)
7.3 Hz, 3H, CH2CH3), 0.64 (s, 3H, Me); 31P NMR (C6D6) δ 52.1,
49.6 (AB, JP-P ) 34.7 Hz), 52.2, 49.6 (AB, JP-P ) 34.6 Hz) (5:
4); MS (FAB, m/z) 880.3 (M+ + 1), 618.2 (M+ + 1 - PPh3),
429.0 (M+ - PPh3, CNCHPhCMe(Et)O). Anal. Calcd for C53H49-
NOP2Ru: C, 72.42; H, 5.62; N, 1.59. Found: C, 72.49; H, 5.57;
N, 1.63.
Synthesis of 7d. Complex 7d was prepared using the
following method. A mixture of complex 3c (0.48 g) and
trimethylacetaldehyde (0.1 mL, 0.1 mmol) in 40 mL of benzene
was heated to reflux for 1 h. The workup procedure was the
same as that for 7d. Purification by recrystallization from
CH2Cl2/hexane (1:5) gave 7d (0.46 g, 87% yield). Spectroscopic
data for 7d: 1H NMR (C6D6) δ 7.64-6.97 (m, 35 H, Ph), 4.96
(d, 1H, JH-H ) 9.7 Hz, NCHPh), 4.67 (s, 5H, Cp), 3.82 (d, 1H,
JH-H ) 9.7 Hz, OCH); 31P NMR (C6D6) δ 52.0, 48.9 (AB, JP-P
) 34.7 Hz); MS (FAB, m/z) 894.3 (M+ + 1), 632.2 (M+ + 1 -
PPh3), 429.0 (M+ - PPh3, CNCHPhCHC(Me)3O). Anal. Calcd
for C54H51NOP2Ru: C, 72.63; H, 5.76; N, 1.57. Found: C, 72.90;
H, 5.51; N, 1.38.
Synthesis of 7e. To a 50 mL CH2Cl2 solution of 2c (0.47 g,
0.53 mmol) were added excess ferrocenecarboxaldehyde (0.14
g, 0.67 mmol) and n-Bu4NOH (0.7 mL), and the solution was
heated to reflux for 90 min. The color changed from yellow to
bright yellow, and then the solvent was removed under
vacuum. The residual solid was extracted with 2 × 20 mL of
hexane, and the solvent was filtered through Celite. The
solvent of the filtrate was removed under vacuum to give 7e
(0.45 g, 83% yield). Spectroscopic data for 7e: 1H NMR (C6D6)
δ 7.52-6.98 (m, 35 H, Ph), 5.06 (d, 1H, JH-H ) 9.5 Hz,
NCHPh), 4.64 (s, 5H, Cp), 4.53 (d, 1H, JH-H ) 9.5 Hz, OCH),
4.04 (br, 2H, Fe(C5H4)CO), 3.97 (br, 2H, Fe(C5H4)CO), 3.91 (s,
5H, (C5H5)Fe); 31P NMR (C6D6) δ 51.0, 50.7 (AB, JP-P ) 35.1
Hz); MS (FAB, m/z) 1021.1 (M+ + 1), 759.2 (M+ + 1 - PPh3),
429.0 (M+ - PPh3), CNCHPhCH,Fe(C5H5)2O). Anal. Calcd for
C60H51NOP2RuFe: C, 70.59; H, 5.04; N, 1.37. Found: C, 70.72;
H, 4.97; N, 1.54.
Synthesis of 7a. To a solution of 2c (0.086 g, 0.10 mmol)
in 20 mL of acetone at room temperature was added a solution
of n-Bu4NOH (0.1 mL). The mixture was stirred for 5 min,
and the color changed from green to yellow. Then the solvent
was removed under vacuum and the solid residue was ex-
tracted with hexane. The extract was filtered through Celite.
The solvent of the filtrate was removed under vacuum to give
7a (0.08 g, 91% yield). Spectroscopic data for 7a: 1H NMR
(C6D6) δ 7.79-7.15 (m, 35 H, Ph), 4.93 (s, 1H, CH), 4.80 (s,
5H, Cp), 1.52 (s, 3H, Me), 0.98 (s, 3H, Me); 13C NMR (C6D6) δ
187.3 (t, JP-C ) 19.4 Hz, CR), 143.6-126.9 (Ph), 87.5 (Cp), 85.9
(CH), 79.8 (CMe2), 28.3 (CH3), 27.9 (CH3); 31P NMR (C6D6) δ
51.8, 50.1 (AB, JP-P ) 34.6 Hz); MS (FAB) m/z: 866.3 (M+
+
1), 604.1 (M+ + 1 - PPh3), 429.0 (M+ + 1 - PPh3, CNCHPhC-
Me2O). Anal. Calcd for C52H47NOP2Ru: C, 72.41; H, 5.38; N,
1.60. Found: C, 72.19; H, 5.53; N, 1.69.
Synthesis of 7a*. To a solution of 2c* (0.25 g, 0.30 mmol)
in 20 mL of acetone was added a solution of n-Bu4NOH (0.31
mL). The color of the solution changed to yellow immediately.
The mixture was stirred for 10 min. The solvent was removed
under vacuum, the residue was extracted with n-hexane, and
then the solution was dried under vacuum to afford 7a*.
Complex 7a* was recrystallized from n-hexane (0.15 g, 60%
yield). Spectroscopic data for 7a*: IR (KBr) 1633 cm-1 (m,
Synthesis of 7f. A mixture of complex 3c (0.27 g, 0.33
mmol) and methyl benzoate (0.062 mL, 0.5 mmol) in 40 mL of
benzene was heated to reflux for 3 h. The workup procedure
was the same as that for 7a. Purification by recrystallization
from CH2Cl2/hexane (1:5) gave 7f (0.23 g, 77% yield). Spec-
troscopic data for 7f: 1H NMR (C6D6) δ 7.33-6.08 (m, 40 H,
Ph), 5.02 (s, 1H, CH), 4.83 (s, 5H, Cp), 3.66 (s, 3H, Me); 31P
NMR (C6D6) δ 52.3, 48.9 (AB, JP-P ) 34.4 Hz); 13C NMR (C6D6)
1
νCdN); H NMR (C6D6) δ 7.78-6.72 (m, 25H, Ph), 4.94 (s, 1H,
CHPh), 4.12-4.05 (m, 1H, dppp), 3.55-3.46 (m, 1H, dppp),
2.34-2.27 (m, 1H, dppp), 1.92-1.66 (m, 3H, dppp), 1.53 (s,
3H, CH3), 1.50 (s, 15H, 5CH3), 0.82 (s, 3H, CH3); 13C NMR
(C6D6) δ 193.7 (dd, JP-C ) 18.8 Hz, JP-C ) 17.7 Hz), 145.8-

Ruthenium Azirinyl Complexes
Organometallics, Vol. 23, No. 25, 2004 5933
δ 191.3 (t, JP-C ) 19.1 Hz, CR), 141.2-127.3 (Ph), 88.7 (Cp),
84.7 (CHPh), 81.2 (CPh(OMe)), 56.9 (CH3); MS (FAB, m/z)
944.3 (M+ + 1), 682.1 (M+ + 1 - PPh3), 429.0 (M+ - PPh3,
CNCHPhCPhC(OMe)O).
130.8, 128.3, 126.5 (Ph), 70.3 (COH), 50.0 (CMe), 29.3 (CH3);
high-resolution MS (m/z) found 150.1041, calcd 150.2200. Anal.
Calcd for C10H14O: C, 79.96; H, 9.39. Found: C, 79.91; H, 9.44.
X-ray Diffraction Analysis of 8a* and 7a*. Single
crystals of 8a* suitable for X-ray diffraction study were grown
as mentioned above. A single crystal of dimensions 0.30 × 0.25
× 0.20 mm3 was glued to a glass fiber and mounted on a
SMART CCD diffractometer. The data were collected using
Mo KR radiation (T ) 295 K) from a sealed tube. Exposure
time was 5 s per frame. SADABS34 (Siemens area detector
absorption) correction was applied, and decay was negligible.
Data were processed, and the structures were solved and
refined by the SHELXTL35 program. The structure was solved
using direct methods and confirmed by Patterson methods
refining on F2 using all data.36 Hydrogen atoms were placed
geometrically using the riding model, with thermal parameters
set to 1.2 times that for the atoms to which the hydrogen is
attached and 1.5 times that for the methyl hydrogens. The
procedures for the structure determination of 7a* were similar
to those for 8a*. Crystal data of these complexes are listed in
Table 1.
Synthesis of 7g. A mixture of complex 3c (0.30 g, 0.37
mmol) and N,N-dimethylacetamide (0.05 mL, 0.5 mmol) in 40
mL of benzene was heated to reflux for 7 h. The workup
procedure was the same as that for 7a. Purification by
recrystallization from CH2Cl2/hexane (1:5) gave 7g (0.17 g, 54%
yield). Spectroscopic data for 7g: 1H NMR (C6D6) δ 7.49-7.31
(m, 35 H, Ph), 5.12 (s, 1H, CH), 4.77 (s, 5H, Cp), 2.46 (s, 6H,
NMe2), 1.13 (s, 3H, Me); 31P NMR (C6D6) δ 51.8.0, 49.8 (AB,
JP-P ) 34.6 Hz); 13C NMR (C6D6) δ 192.7 (t, JP-C ) 19.4 Hz,
CR), 137.9-126.5 (m, Ph), 89.1 (Cp), 86.9 (CHPh), 82.0 (CMe),
37.6 (N(CH3)2) 24.3 (CH3); MS (FAB, m/z) 894.2 (M+ + 1), 632.1
(M+ + 1 - PPh3), 429.0 (M+ - PPh3, CNCHPhCMe(NMe2)O).
Synthesis of {[Ru]CNCHPhC(CH3)2OH}[PF6] (8a*). A
solution of 2c* (0.22 g, 0.26 mmol), NaOMe (0.25 g, 4.5 mmol),
and KPF6 (0.15 g, 0.8 mmol) in acetone (20 mL) was stirred
at room temperature for 2 days. The solvent was then removed
under reduced pressure, the white residue was recrystallized
from CH2Cl2/diethyl ether (1:10) to give suitable single crystals
for diffraction analysis, and the product was identified as
complex 8a* (0.10 g, 38% yield). Spectroscopic data for 8a*:
IR (KBr) 2118 cm-1 (s, νCN), 3576 cm-1 (br, νOH); 1H NMR
(CDCl3) δ 7.53-7.12 (m, 30H, Ph), 5.46 (s, 1H, CH), 2.67-
2.27 (m, 6H, CH2CH2CH2), 2.53 (s, 1H, OH), 1.39 (s, 15H,
5CH3), 1.26 (s, 3H, CH3), 1.27 (s, 3H, CH3); 31P NMR (CDCl3)
δ 38.44, 38.06 (AB, JP-P ) 46.5 Hz); MS (FAB, m/z, Ru102) 824.3
(M+), 766.3 (M+ - CMe2OH). Anal. Calcd for C48H54F6-
NOP3Ru: C, 59.50; H, 5.58; N, 1.44. Found: C, 59.59; H, 5.44;
N, 1.51.
Reduction of 7a by NaBH3CN in MeOH. To a solution
of 7a (1.20 g, 1.38 mmol) in 30 mL of MeOH at room
temperature was added NaBH3CN (0.11 g, 1.6 mmol). The
mixture was stirred for 1 h, and the color changed from yellow
to bright yellow. The solvent was removed under vacuum, and
the solid residue was extracted with hexane. The extract was
filtered through silica gel and the residue passed through a
silica gel packed column to give 1 (0.88 g, 94%). The solvent
of the filtrate was removed under vacuum to give PhCH2-
CMe2OH (10a; 0.21 g, 96% yield). Spectroscopic data for 10a:
1H NMR (C6D6) δ 7.24-7.04 (m, 5 H, Ph), 2.56 (s, 2H, CH2),
1.24 (s, 1H, OH), 1.04 (s, 6H, 2Me); 13C NMR (C6D6) δ 138.5,
Acknowledgment. Financial support from the Na-
tional Science Council of Taiwan is gratefully acknowl-
edged.
Supporting Information Available: Details of the struc-
tural determination for complexes 7a* and 8a*, including
tables of crystal data and structure refinement, positional and
anisotropic thermal parameters, and listings of bond distances
and angles (CIF files). This material is available free of charge
via the Internet at http://pubs.acs.org.
OM049528T
(34) SAINT (Siemens Area Detector Integration) program; Siemens
Analytical X-ray, Madison, WI, 1995.
(35) (a) The SADABS program is based on the method of Blessing;
see: Blessing, R. H. Acta Crystallogr., Sect. A 1995, 51, 33-38. (b)
SHELXTL: Structure Analysis Program, version 5.04; Siemens In-
dustrial Automation Inc., Madison, WI, 1995.
(36) GOF ) [∑[w(Fo - Fc2)2]/(n - p)]1/2, where n and p denote the
2
number of data and parameters. R1 ) (∑||Fo| - |Fc||)/∑|Fo|; wR2 )
[∑[w(Fo2 - Fc2)2]/∑[w(Fo2)2]]1/2, where w ) 1/[σ2(Fo2) + (aP)2 + bP] and
P ) [(max; 0, Fo2) + 2Fc2]/3.