Metal and boron derivatives of fluorinated cyclic 1,3-dicarbonyl compounds

Article abstract of DOI:10.1515/znb-2009-0510

Starting from the corresponding cyclic 1,3-diketones or other precursors (cyclic ketones as well as lactones), several new salts and chelate complexes of fluorinated 1,3-dicarbonyls were obtained. Their preparative significance was demonstrated by straigh

Full text of DOI:10.1515/znb-2009-0510

Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl
Compounds
Dmitri V. Sevenarda, Oleg G. Khomutovb, Nadezhda S. Boltachovab, Vera I. Filyakovab,
Vera Vogelc, Enno Lorkc, Vyacheslav Ya. Sosnovskikhd, Viktor O. Iaroshenkoe,
and Gerd-Volker Ro¨schenthalerc
a Hansa Fine Chemicals GmbH, BITZ, Fahrenheit Straße 1, 28359 Bremen, Germany
b Institute of Organic Synthesis, Russian Academy of Sciences, Ural Branch,
S. Kovalevskoy Street 22, GSP-147, 620041 Ekaterinburg, Russian Federation
c Institute of Inorganic & Physical Chemistry, University of Bremen, Leobener Straße,
28334 Bremen, Germany
d Department of Chemistry, Ural State University, Lenina 51, 620083 Ekaterinburg,
Russian Federation
e National Taras Shevchenko University, 62 Volodymyrska Street, Kyiv-33, 01033, Ukraine
Reprint requests to Dr. Dmitri V. Sevenard. Fax: +49-421-2208409.
E-mail: sevenard@hfc-chemicals.com
Z. Naturforsch. 2009, 64b, 541 – 550; received January 30, 2009
Starting from the corresponding cyclic 1,3-diketones or other precursors (cyclic ketones as well
as lactones), several new salts and chelate complexes of fluorinated 1,3-dicarbonyls were obtained.
Their preparative significance was demonstrated by straightforward syntheses of fluorinated pyr-
azoles, benzimidazoles and 1,7-ketoesters. The structure of a boron chelate of 2-(trifluoroacetyl)-
cyclohexanone was investigated by X-ray diffraction.
Key words: Organofluorine Compounds, 1,3-Dicarbonyl Compounds, Salts, Chelates,
Synthetic Application
Introduction
seodymium tris(3-fluoroacyl-(+)-camphorates), which
are used in NMR spectroscopy as shift reagents
[15, 16]. These chelates as well as derivatives of
numerous d group metals could be synthesized
from the corresponding chiral 1,3-diketone and metal
salt [16, 17]. Synthesis of other related camphorates
was achieved using barium bis(3-trifluoroacetyl-(+)-
camphorate) as the starting compound [18]. As for
practical applications, cyclic fluorinated 1,3-diketon-
ates were used as catalysts in stereoselective reac-
tions [17], as components of the bonded phase for the
chromatographical separation of enantiomers [19], and
as starting compounds in the synthesis of quinoline and
phenanthridine derivatives [20].
We have synthesized the copper(II) and nickel(II)
complexes of 2-(polyfluoroacyl)cycloalkanones 2a – d
via treatment of the 1,3-diketones 1 with the cor-
responding metal acetates (Scheme 1). Acetate salts
were chosen because of their better solubility in
organic solvents as compared to chlorides; besides
that, the acidities of the starting 1,3-diketones and
Fluorinated compounds are the subject of growing
interest due to their interdisciplinary significance and
diverse practical uses [1]. Despite of great advances
in organofluorine chemistry, the straightforward syn-
thesis of target compounds remains a challenge for
chemists [2]. Fluorinated 1,3-dicarbonyls are of spe-
cial importance in this context: their versatility, high
reactivity and preparative availability make them of-
ten the starting compounds of choice [3 – 5]. At the
same time, fluorinated 1,3-dicarbonyl enolates (salts or
complexes) [4 – 7] give frequently better results, when
compared to the related 1,3-dicarbonyl compounds,
and are as a rule more convenient in handling [5, 6, 8].
In this paper we report the synthesis and several strik-
ing synthetic applications of metal derivatives of cyclic
fluorinated 1,3-dicarbonylcompounds which were col-
lected in our groups during studies in this field [9 – 14].
Results and Discussion
The most famous members of the family of com- acetic acid are comparable [21] which facilitates the
pounds under discussion are europium and pra- reaction.
c
0932–0776 / 09 / 0500–0541 $ 06.00 ꢀ 2009 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
Unauthenticated
Download Date | 6/15/17 1:20 PM

542
D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
2
k
l
m
n
O
1
o
O
1
p
O
2
q
O
–
r
S
–
Y
n
CH2 CH2 CH2
2
2
2
RF CF2H C3F7 CF(OMe)CF3 CF2H CF3 CF3 CF3 C2F5
M
Li
Li
Na
Na
Na Na Li
Li
Scheme 2.
this approach to produce salts 2 is superior to that de-
picted in Scheme 1.
2
a
b
c
d
e
f
g
h
i
All the substances 2 are crystalline powders; as ex-
pected, the copper and nickel complexes are colored
(see Experimental Section), but the residual salts are
colorless. They are stable and can be stored in a sealed
flask for months without any change. As reported [6b],
isolation of compounds 2 in analytically pure form
with satisfactory elemental analyses is quite difficult,
therefore, some of them could be characterized only
spectroscopically. The structure of the compounds 2 in
[D6]DMSO, [D6]acetone, and [D4]methanol solutions
n
1
2
2
2
2
2
2
2
2
RF CF3 CF3 CF3 CF2CF2H CF3 CF2CF2H C6F13 CF3 CF3
M
Cu Cu Ni Cu
Li Li
Li
Na Ba
Scheme 1.
Li, Na and Ba 2-(polyfluoroacyl)cyclohexanonates
2e – i were obtained reacting the 1,3-diketone with a
suitable base (Scheme 1). Additionally, the morpholin-
ium salt of 2-(trifluoroacetyl)cyclopentanone 2j was
formed in 60 % yield in a similar reaction.
Alkali enolates of 1,3-dicarbonyl compounds are
formed as intermediates in the course of Claisen-type
condensations [6]. Indeed, salts 2h, k – t could be syn-
thesized directly from the corresponding cyclic ketone
or lactone and fluorinated carboxylic acid esters in the
presence of LiH and NaOMe, respectively (Scheme 2).
1
was studied by H and 19F NMR spectroscopy. Only
one set of signals was always evident in the spectra of
the 1,3-diketonates, verifying the presence of only one
of two possible geometrical isomers at ambient tem-
perature. An especially valuable information is pro-
5
vided by the JF,H splittings observed. This coupling
Taking into account that the 1,3-dicarbonyls are results probably from the through-space interaction of
formed via acidic work-up of the crude reaction mix- the nuclei, and allows us to assign the U-structure to
tures after Claisen-condensation [6], it is obvious that the enolone backbones [23].
Unauthenticated
Download Date | 6/15/17 1:20 PM

D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
543
be paid to the essential equalization of C(1)–O(1)
and C(7)–O(2) [129.0(4) vs. 130.3(4) pm], and of
C(1)–C(2) and C(2)–C(7) [141.3(4) vs. 136.2(5) pm]
in 3, compared to the “ideal” values for C=O, C–O,
C=C, and C–C bonds [28]. This equalization is typical
for highly delocalized keto-enol systems [28, 29]. The
degree of electron density delocalization in the enolone
backbone can be estimated by the degree of equaliza-
tion of bond lengths, and the Q value (the sum of the
differences of C=O, C–O and C=C, C–C bond lengths)
of −6.4 in the case of 3 represents considerable de-
localization (Q = 0 corresponds to complete delocal-
ization, whereas Q = 32 corresponds to a completely
localized enolone system [28]).
Fig. 1. Molecular structure of compound 3, with displace-
ment ellipsoids at the 50 % probability level. The alternative
sites of the disordered tetramethylene moiety [atoms C(40)
and C(50)] are not depicted for clarity reasons. Selected
bond lengths of 3 (pm): C(1)–O(1) 129.0(4), C(1)–C(2)
141.3(4), C(1)–C(6) 147.0(5), C(2)–C(7) 136.2(5), C(2)–
C(3) 152.0(4), C(7)–O(2) 130.3(4), B(1)–F(4) 134.6(5),
B(1)–O(1) 148.2(5), B(1)–O(2) 149.8(4). Selected bond
angles (deg): O(1)–C(1)–C(2) 121.4(3), O(1)–C(1)–C(6)
115.0(3), C(7)–C(2)–C(1) 115.8(3), C(7)–C(2)–C(3)
124.2(3), O(2)–C(7)–C(2) 125.4(3), O(2)–C(7)–C(8)
111.2(3), F(4)–B(1)–O(1) 109.4(3), F(4)–B(1)–O(2)
108.4(3), O(1)–B(1)–O(2) 109.0(3), C(1)–O(1)–B(1)
122.5(3), C(7)–O(2)–B(1) 118.9(3).
The 19F NMR spectrum of 3 features two sig-
nals of fluorinated moieties in a 3 : 2 intensity ra-
tio. In addition to the signal of the CF3 group (δF =
−70.82 ppm) two singlets of intensity 1 : 4 were found
at −137.17 and −137.18 ppm, like for other 1,3,2-di-
oxaborines [25]. This pattern reflects the natural abun-
dance of the two boron isotopes, the signal of the 10BF2
moiety appearing at lower field.
Their availability and preparative handling conve-
nience (when compared to the frequently liquid cor-
responding 1,3-dicarbonyls) are not the only advanta-
geous features of compounds 2. We have found that
sometimes they are more synthetically preferable to
the conjugated 1,3-dicarbonyls 1. From the chemical
point of view, the results of the reactions are mostly
the same. As a rule, the reactions are carried out in
acids as solvents, i. e., the 1,3-dicarbonyl compounds
are generated in situ. Nevertheless, the higher yields of
products as well as the preparative facility prompt one
to use compounds 2.
The boron chelate 3 was synthesized in 77 % yield
via reaction of 2-(trifluoroacetyl)cyclohexanone (1b)
with boron trifluoride ethyl etherate (Scheme 1).
An X-ray single crystal investigation of com-
pound 3 revealed a bicyclic structure with a tetrahe-
drally four-coordinated boron atom (Fig. 1), in accor-
dance with earlier findings for related compounds [24 –
27]. The boron atom is centrally located between
both oxygen atoms [B(1)–O(1) 148.2(5) and B(1)–
Indeed, 2-hydroxy-2-(trifluoromethyl)pyrane is
O(2) 149.8(4) pm]. The atoms C(3), C(6), C(1), C(2), formed in a better yield starting from the sodium salt
C(7), O(1) and O(2) are almost co-planar (mean devia- of α-(trifluoroacetyl)-δ-valerolactone than from the
tion from the plane 5.8 pm). The atoms C(4) and C(5) corresponding β-ketoester [13]. Cyclocondensation
occupy positions on opposite sides of this plane (with of 1,3-diketones with hydrazines is a conventional
45.7 and 13.2 pm displacement, respectively) caus- synthetic route to pyrazoles, e. g., in the case 1b the
ing a twisted conformation of the carbocycle. There pyrazole 4h is formed in less than 50 % overall yield
is a disorder at the carbocycle with two different con- (referring to the starting cyclohexanone [11, 22]).
formations at both middle carbon atoms of the tetra- Use of sodium salt 2h allowed us to obtain com-
methylene moiety. Similar to BF2 derivatives of re- pound 4h in 70 % overall yield in a very simple
lated cyclic 1,3-dicarbonyl compounds [26], the six- two-step reaction sequence (Scheme 3). In the case
membered heterocycle of 3 adopts an envelope con- of sodium salt 2t such direct comparison with the
formation with the boron atom 38.0 pm out of the conjugated 1,3-diketone was not possible: its synthesis
mean plane. Interestingly, for the BF2 chelates of ben- via acidification of 2t failed, probably due to the
zoylacetones, the 1,3,2-dioxaborine ring was found presence of a basic center in the cyclic part of the
to be nearly planar [27]. A special attention should molecule in addition to the acidic 1,3-dicarbonyl
Unauthenticated
Download Date | 6/15/17 1:20 PM

544
D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
Scheme 4.
dene derivative 7 in 61 % yield [12], a mixture was ob-
tained in the case of 3, where both starting compounds
(even after the reaction being maintained for 78 h),
1b and 1,3,2-dioxaborine 8 (an insignificant amount)
could be identified by 1H and 19F NMR spectroscopy.
This fact indicates clearly that the Lewis acid activates
the aldehyde toward nucleophilic attack of 1, and that
the formation of a boron chelate of type 3 is not a cru-
cial step of the reaction.
Scheme 3.
moiety. Treatment of an acetic acid solution of 2t with
hydrazine hydrate provided the bicyclic compound 4t
in 71% yield (Scheme 3). In the framework of this
synthetic methodology, the salt 2t is indispensable for
the preparation of 4t.
Conclusion
In summary, a wide range of salts and chelate com-
plexes of fluorinated cyclic 1,3-diketones and 1,3-
Another advantageous example for the preparative ketoesters was prepared starting both from the corre-
application of enolates 2 is the ring opening of the sponding 1,3-dicarbonyl compounds or from their pre-
2-(trifluoroacetyl)cyclohexanone backbone upon treat- cursors – cyclic ketones or lactones. The compounds
ment of the corresponding salt with o-phenylenedi- obtained were shown to be promising reaction partners
amine (o-PDA) or methanol under acidic conditions in organofluorineand heterocyclic chemistry. From the
(Scheme 3). This procedure gives access to the highly synthetic point of view, the alkali enolates are precur-
promising [30] trifluoromethylated 1,7-ketoester 6 in sors of the corresponding 1,3-dicarbonyls, hence, their
a simple and convenient two-step procedure starting application instead of 1,3-dicarbonyls is methodologi-
from cyclohexanone. In addition to the preparative ad- cally reasonable and gives comparable results.
vantages, in the case of the reaction with o-PDA the
yield of the imidazole 5 was somewhat higher starting
from salt 2e rather than from 2-(trifluoroacetyl)cyclo-
hexanone [10]: 43 vs. 34 %.
In order to elucidate the role of BF3· Et2O in the
course of the condensation of 1,3-diketones 1 with
(het)aromatic aldehydes [12], we have studied the reac-
tion of boron chelate 3 with anisaldehyde (Scheme 4).
While the reaction of 1,3-diketone 1b in the presence
Experimental Section
General information: Melting and boiling points (m. p.,
b. p.) are uncorrected. NMR spectra, measured at 22 – 23 ◦C:
Tesla BS-567A spectrometer [100.0 MHz (1H)], Tesla BS-
587A spectrometer [80.0 MHz (1H)], Bruker DPX-200 spec-
trometer [200.1 (1H), 188.3 MHz (19F)]; chemical shifts (δ)
in parts per million (ppm), coupling constants (J) in Hz,
Me4Si (1H) and CCl3F (19F) as references. 1H NMR chem-
of catalytic amounts of BF3· Et2O delivered the aryli- ical shifts in CDCl3 solutions are referenced to the signal
Unauthenticated
Download Date | 6/15/17 1:20 PM

D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
545
at 7.25 ppm (residual CHCl3), in [D6]DMSO, [D6]acetone, tated with water from the methanol solution twice and dried
and CD3OD to the central line of the solvent signal at δ = in vacuo to afford 2b as a grayish-green powder, yield 1.7 g
2.50, 2.05 and 3.31 ppm, respectively. Mass spectra (FAB, (ca. 100 %), m. p. 180 – 182 ◦C (lit.: 182 – 182.5 ◦C [22]). An
Xe, 8 keV) were recorded on a Finnigan MAT-8200 spec- analytical sample was recrystallized from methanol / water
trometer. Elemental analyses: Institute of Organic Synthe- (1 : 1 by volume). – IR: ν = 1575 (conjugated C=O) cm−1. –
sis, Ural Branch, Russian Academy of Sciences, Ekater- C16H16CuF6O4 (449.8): calcd. C 42.72, H 3.59, F 25.34;
inburg, Russian Federation, and Mikroanalytisches Labor found C 42.88, H 3.58, F 25.78.
Beller, Go¨ttingen, Germany. The IR spectra were recorded
on a Specord-75 IR instrument on suspensions in Nu-
jol (film). 2-(Trifluoroacetyl)cyclopentanone, 2-(trifluoro-
acetyl)cyclohexanone [21, 22], 2-(2,2,3,3-tetrafluoroprop-
anoyl)cyclohexanone [9] and 2-(2,2,3,3,4,4,5,5,6,6,7,7,7-tri-
decafluoroheptanoyl)cyclohexanone [30] were prepared by a
Claisen-type condensation of a cycloalkanone and a suitable
fluorinated ester in the presence of NaOMe or LiH [6]. All
other chemicals are commercially available and were used
as purchased unless otherwise specified. Reactions in dried
solvents (hexane distilled from phosphorus pentoxide, di-
ethyl ether and benzene distilled from sodium/benzophenone
ketyl) were performed in oven-dried glassware under a static
nitrogen atmosphere.
Nickel(II) bis-[2-(trifluoroacetyl)cyclohexanonate]
trihydrate (2c)
A solution of 1b (1.50 g, 7.7 mmol) in diethyl ether
(10 mL) was added to a stirred solution of Ni(OAc)2 · 4H2O
(0.94 g, 3.8 mmol) in water (10 mL). The mixture was stirred
for 4 h at r. t., and the organic layer was separated. After
extraction with diethyl ether (3 × 5 mL) the combined or-
ganic layers were washed with water (5 mL) and evaporated.
The solid residue was precipitated with water from acetone
solution and dried in vacuo to afford 2b◦as a green pow-
der, yield 0.70 g (42 %), m. p. 165 – 168 C. An analytical
sample was recrystallized from methanol / water (1 : 1 by
volume). – IR: ν = 1590 (conjugated C=O), 3050 – 3650
(H2O) cm−1. – 1H NMR (80.0 MHz, [D6]DMSO): δ =
−11.6, 0.4, 1.1, 11.3 (4 br.s, 4 ×2 H, 4CH2), 3.3 (br.s, 6 H,
3H2O). – C16H16F6NiO4 · 3H2O (499.0): calcd. C 38.51,
H 4.44, F 22.84; found C 38.85, H 4.19, F 22.49.
Copper(II) bis-[2-(trifluoroacetyl)cyclopentanonate] (2a)
A mixture of cyclopentanone (15.0 g, 179 mmol) and tri-
fluoroacetic acid ethyl ester (28.0 g, 200 mmol) was added
dropwise to a well stirred suspension of potassium tert-
butoxide (20.0 g, 179 mmol) in diethyl ether (250 mL). Af-
ter the exothermic reaction, the brown hom◦ogeneous mix-
ture was stirred at r. t. for 16 h, cooled to 0 C, and treated
with 10 % sulfuric acid (175 mL). The mixture was stirred
for 10 min, and the organic layer was separated. After extrac-
tion with diethyl ether (3×15 mL) the combined organic lay-
ers were dried over MgSO4 and concentrated to 80 mL. The
solution of crude 2-(trifluoroacetyl)cyclopentanone 1a was
treated with a solution of Cu(OAc)2· H2O (20.0 g, 100 mmol)
in a mixture of acetic acid (50 mL) and water (250 mL). The
mixture was stirred for 1 h and the organic layer was sep-
arated. After extraction with diethyl ether (4 × 30 mL) the
combined organic layers were washed with water (20 mL)
and evaporated. The solid residue was dissolved in ethanol,
precipitated by addition of water at 0 ◦C and dried in vacuo
to afford 2a as a green powder, yield 16.5 g (44 %), m. p.
170 – 174 ◦C (lit.: 175 – 176 ◦C [22]).
Copper(II) bis-[2-(2,2,3,3-tetrafluoropropanoyl)cyclo-
hexanonate] (2d)
A solution of 2-(2,2,3,3-tetrafluoropropanoyl)cyclohex-
anone (1.0 g, 4.4 mmol) in diethyl ether (20 mL) was added
to a stirred solution of Cu(OAc)2· H2O (0.44 g, 2.2 mmol)
in water (20 mL). The mixture was stirred for 30 min at r. t.,
and the organic layer was separated. After extraction with
diethyl ether (3 × 5 mL) the combined organic layers were
washed with water (5 mL) and evaporated. The solid residue
was recrystallized from toluene to afford 2d as a grayish-
green powder, yield 0.80 g (71 %), m. p. 166.5 – 167.5 ◦C. –
IR: ν = 1570 (conjugated C=O) cm−1. – C18H18CuF8O4
(513.9): calcd. C 42.07, H 3.53, F 29.58; found C 42.51,
H 3.39, F 29.97.
Lithium 1,3-diketonates 2k, l, q – s. General Procedure A
To a mechanically stirred suspension of lithium hydride
(1.44 g, 0.18 mol) in hexane (for 2k, 170 mL) or benzene
Copper(II) bis-[2-(trifluoroacetyl)cyclohexanonate] (2b)
A solution of 2-(trifluoroacetyl)cyclohexanone 1b (1.5 g, (for 2l, q – s, 300 – 500 mL) a mixture of ketone (0.16 mol)
7.7 mmol) in diethyl ether (20 mL) was added to a stirred so- and fluorinated carboxylic acid ester (2k: HCF2COOMe, 2l:
lution of Cu(OAc)2· H2O (0.8 g, 3.8 mmol) in water (25 mL). C3F7COOMe, 0.18 mol) or a solution of ketone (0.16 mol)
The mixture was stirred for 30 min at r. t., and the or- and fluorinated carboxylic acid ester (2q, s: CF3COOEt, 2r:
ganic layer was separated. After extraction with diethyl ether C2F5COOMe, 0.18 mmol) in benzene (50 – 300 mL) was
(3 × 5 mL) the combined organic layers were washed with added dropwise within 1 h. Several drops of dried methanol
water (5 mL) and evaporated. The solid product was precipi- or ethanol, respectively, were added to start an exothermic
Unauthenticated
Download Date | 6/15/17 1:20 PM

546
D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
reaction (reflux condenser). The mixture was stirred either at stirred suspension of finely powdered LiH (0.25 g, 30 mmol)
ambient temperature (2k: for 48 h), or heated to reflux (2l: in benzene (15 mL). The mixture was stirred for 1 h at r. t.,
for 3 h, 2q: 20 h, 2r: 16 h, 2s: 2 h) followed by stirring for the precipitate was filtered off, washed with hexane (10 mL)
further several hours (2l: for 16 h, 2q: 1 h, 2r: 1 h, 2s: 12 h) at and dried in vacuo to afford salts 2e – g as white powders.
ambient temperature. The precipitate was filtered off, washed
with pentane (2×70 mL) and dried in vacuo to afford salts 2
Lithium 2-(trifluoroacetyl)cyclohexanonate (2e)
(2k,l,s: white powders, 2q,r: yellow powders).
Yield 83 % [after recrystallization from toluene / ace-
tone (3 : 1 by volume)], m. p. > 250 ◦C (dec.) – IR: ν =
Lithium 2-(difluoroacetyl)cyclohexanonate (2k)
1610 (conjugated C=O) cm−1. – 1H NMR (200.1 MHz,
◦
[D6]DMSO): δ = 1.40 – 1.80 (m, 4 H, 2CH2), 2.12 (t, 3JH,H
=
Yield: 75 %, m. p. > 230 C (dec.) – IR: ν = 1610 (con-
jugated C=O) cm−1. – 1H NMR (100.0 MHz, CD3OD): δ =
5.9 Hz, 2 H, CH2), 2.35 – 2.45 (m, 2 H, CH2). – 19F NMR
(188.3 MHz, [D6]DMSO): δ = −69.68 (s, 5JF,H = 1.6 Hz). –
C8H8F3LiO2 · 1/3 H2O (206.1): calcd. C 46.62, H 4.24;
found C 46.72, H 4.05.
2
1.41 – 2.82 (m, 8 H, 4CH2), 5.70 (t, JH,F = 55.6 Hz, 1 H,
CF2H).
Lithium 2-(perfluorobutanoyl)cyclohexanonate (2l)
Lithium 2-(2,2,3,3-tetrafluoropropanoyl)cyclohexanonate
(2f)
Yield: 75 % [after recrystallization from toluene / THF
(3 : 1 by volume)], m. p. > 280 ◦C (dec.) – IR: ν = 1605 (con-
jugated C=O) cm−1. – 1H NMR (80.0 MHz, [D6]DMSO):
δ = 1.45 – 1.81 (m, 4 H, 2CH2), 1.99 – 2.48 (m, 4 H, 2CH2). –
C10H8F7LiO2 (300.1): calcd. C 40.02, H 2.69, F 44.31;
found C 40.43, H 2.43, F, 44.03.
Yield: ca. 100 %, m. p. 240 – 242 ◦C (dec.) – IR: ν =
1610 (conjugated C=O) cm−1. – 1H NMR (100.0 MHz,
[D6]acetone): δ = 1.49 – 1.73 (m, 4 H, 2CH2), 2.18 – 2.34,
2
2.45 – 2.68 (both m, 2 × 2 H, 2CH2), 6.44 (tt, JH,F = 53.1,
3JH,F = 5.9 Hz, 1 H, CF2H).
Lithium 3-(trifluoroacetyl)chromanonate (2q)
◦
Yield: 83 %, m. p. > 230 C. – 1H NMR (200.1 MHz,
Lithium 2-(perfluoroheptanoyl)cyclohexanonate (2g)
[D6]acetone): δ = 4.98 (s, 2 H, CH2), 6.88 (d, 3JH,H = 8.3 Hz,
1 H, 8-H), 6.99 (dd, 3JH,H ≈ 7.3, 3JH,H ≈ 7.3 Hz, 1 H, 6-H),
Yield: ca. 100 %, m. p. > 220 ◦C (dec.) – IR: ν =
1610 (conjugated C=O) cm−1. – 1H NMR (100.0 MHz,
[D6]acetone): δ = 1.49 – 1.72 (m, 4 H, 2CH2), 2.16 – 2.36,
2.42 – 2.63 (both m, 2×2 H, 2CH2).
3
3
4
7.39 (ddd, JH,H = 8.3, JH,H = 7.1, JH,H = 1.0 Hz, 1 H,
3
4
7-H), 7.89 (dd, JH,H = 7.8, JH,H = 2.0 Hz, 1 H, 5-H). –
19F NMR (188.3 MHz, [D6]acetone): δ = −71.0 (t, 5JF,H
=
1.4 Hz).
Barium bis-[2-(trifluoroacetyl)cyclohexanonate] (2i)
Lithium 3-(pentafluoropropanoyl)thiochromanonate (2r)
To a solution of 1b (1.5 g, 7.7 mmol) in diethyl ether
(20 mL) barium oxide (0.6 g, 3.8 mmol) was added. The
mixture was stirred for 30 min at r. t., and the solvent was
removed in vacuo to leave 2i as a white solid, yield 2.0 g
Yield: ca. 100 %, m. p. > 230 ◦C. – 1H NMR (200.1 MHz,
5
[D6]acetone): δ = 3.85 (t, JH,F = 1.4 Hz, 2 H, CH2), 7.19
3
3
4
(ddd, JH,H = 7.7, JH,H = 5.7, JH,H = 2.8 Hz, 1 H, 6(7)-
3
◦
H), 7.24 – 7.35 (m, 2 H, 7(6), 8-H), 8.03 (ddd, JH,H
=
(ca. 100 %), m. p. > 250 C. – IR: ν = 1610 (conjugated
7.6, JH,H = 1.4, JH,H = 0.8 Hz, 1 H, 5-H). – 19F NMR
4
5
1
C=O) cm−1. – H NMR (100.0 MHz, CD3OD): δ = 1.61 –
5
(188.3 MHz, [D6]acetone): δ = −114.5 (t, JF,H = 1.3 Hz,
1.72, 2.16 – 2.46 (both m, 2×4 H, 4CH2). – C16H16BaF6O4
(523.6): calcd. C 36.70, H 3.08, F 21.77; found C 36.72,
H 3.30, F 21.86.
2 F, CF2), −82.6 (s, 3 F, CF3).
Lithium 3-(trifluoroacetyl)indanonate (2s)
Yield: ca. 100 %, m. p. > 220 ◦C. – 1H NMR (200.1 MHz,
[D6]acetone + [D6]DMSO, 4 + 1 by volume): δ = 3.73 (q,
5JH,F = 1.5 Hz, 2 H, CH2), 7.32 – 7.41 (m, 1 H, Ar-H), 7.45 –
7.51 (m, 2 H, Ar-H), 7.69 (unresolv. ddd, 3JH,H = 7.4 Hz, 1 H,
7-H). – 19F NMR (188.3 MHz, [D6]acetone + [D6]DMSO, 4
+ 1 by volume): δ = −73.5 (t, 5JF,H = 1.2 Hz).
Sodium salts 2h, m – p, t. General Procedure A
To a well stirred suspension of sodium methoxide (5.4 g,
0.1 mol) in diethyl ether (250 mL) a mixture of cyclic ke-
tone or lactone (0.1 mol) and fluorinated ester (2h, o, p, t:
CF3COOEt, 2m: CF3CF(OMe)COOMe, 2n: HCF2COOMe,
0.1 mmol) was added dropwise within 30 min. The mix-
ture was either stirred at ambient temperature for 20 h and
then heated to reflux for 16 h (2m), or heated to reflux (2n:
Lithium 1,3-diketonates 2e – g. General Procedure B
A solution of the 2-(polyfluoroacyl)cyclohexanone 1 for 12 h, 2o: for 7 h) followed by stirring for further sev-
(30 mmol) in benzene (5 mL) was added carefully to a well eral h (2n: 1 h, 2o: 16 h), or stirred at r. t. for 20 h (2h, p, t).
Unauthenticated
Download Date | 6/15/17 1:20 PM

D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
547
◦
3
The reaction mixture was cooled to −30 C. The solid was (t, JH,H = 6.1 Hz, 2 H, CH2), 3.35, 3.57 (both s, 2 × 2 H,
separated [by filtration (2h, m, o, p, t) or decantation (2n)], 2CH2), 7.17 – 7.39 (m, 5 H, Ph). – 19F NMR (188.3 MHz,
washed with pentane (2 × 70 mL) and dried in vacuo to af- [D6]acetone): δ = −71.8 (t, JF,H = 1.4 Hz). – 19F NMR
5
ford salts 2h, m – p, t as white powders.
(188.3 MHz, CDCl3): δ = −72.3 br.s.
Sodium salt 2h. Procedure B
Sodium 2-(trifluoroacetyl)cyclohexanonate (2h)
Yield: 70 %, m. p. 294 – 296 ◦C (dec.) – IR: ν = 1615 (con-
jugated C=O) cm−1. – 1H NMR (200.1 MHz, [D6]acetone):
δ = 1.47 – 1.71 (m, 4 H, 2CH2), 2.14 (t, 3JH,H = 6.1 Hz, 2 H,
CH2), 2.36 – 2.51 (m, 2 H, CH2). – 19F NMR (188.3 MHz,
[D6]acetone): δ = −71.2 s. – C8H8F3NaO2 · 1/3 H2O
(222.1): calcd. C 43.26, H 3.93; found C 43.25, H 4.10.
To a solution of 1b (1.0 g, 5.2 mmol) in diethyl
ether (10 mL) finely powdered sodium hydroxide (0.2 g,
5.2 mmol) was added. The mixture was stirred for 30 min at
r. t., and the solvent was removed in vacuo. The white solid
left was recrystallized from hexane / acetone (1 : 1 by vol-
ume) to afford 2h, yield 0.9 g (80 %).
Sodium 2-(2,3,3,3-tetrafluoro-2-methoxypropanoyl)cyclo-
hexanonate (2m)
Morpholinium 2-(trifluoroacetyl)cyclopentanonate (2j)
To a well stirred solution of 1a (1.0 g, 5.6 mmol) in hex-
Yield: 22 %, m. p. 228 – 230 ◦C (dec.) – 1H NMR
(200.1 MHz, [D6]DMSO): δ = 1.39 – 1.65 (m, 4 H, 2CH2),
2.04 (t, 3JH,H = 6.8 Hz, 2 H, CH2), 2.36 – 2.48 (m, 2 H, CH2),
3.44 (s, 3 H, Me). – 19F NMR (188.3 MHz, [D6]DMSO):
δ = −126.8 (s, 1 F, ∗CF), −80.0 (s, 3 F, CF3). – MS (FAB,
4-NO2-C6H4-CH2OH (NBA), negative): m/z ( %) = 255 (20)
[A]−, 153 (100) [NBA]−. – C10H11F4NaO3 (278.2): calcd.
C 43.18, H 3.99, F 27.32; found C 43.05, H 3.89, F 27.20.
ane (10 mL) a solution of morpholine (0.49 g, 5.6 mmol) in
◦
hexane (5 mL) was added carefully at 0 C. After stirring
for 30 min at this temperature the precipitate was filtered off,
washed with cold hexane (2 × 5 mL) and dried in vacuo to
afford 2j as colorless crystals (yield 0.90 g, 60 %), m. p. 66 –
67 ◦C. – 1H NMR (200.1 MHz, CDCl3): δ = 1.76 – 1.96 (m,
2 H, CH2), 2.24 (t, 3JH,H = 8.0 Hz, 2 H, CH2), 2.68 – 2.80 (m,
2 H, CH2), 3.07, 3.71 (both t, 3JH,H = 4.4 Hz, 2×4 H, 4CH2),
9.5 (br.s, 2 H, NH2). – 19F NMR (188.3 MHz, CDCl3): δ =
−74.01 s.
Sodium α-(difluoroacetyl)-γ-butyrolactonate (2n)
◦
Yield: 78 %, m. p. > 240 C. – 1H NMR (200.1 MHz,
[D6]DMSO): δ = 2.57 – 2.65 (m, 2 H, CH2), 3.98 (t, 3JH,H
=
5,6,7,8-Tetrahydro-4-(trifluoromethyl)benzo-[d]-1,3,2-
dioxaborine (3)
8.1 Hz, 2 H, OCH2), 7.07 (t, 2JH,F = 56.7 Hz, 1 H, CF2H). –
19F NMR (188.3 MHz, [D6]DMSO): δ = −126.8 (d, 2JF,H
=
To a well stirred solution of 1b (1.94 g, 10 mmol) in
CH2Cl2 (40 mL) BF3· Et2O (1.41 g, 10 mmol) as added
carefully at r. t. After stirring for 10 min the solvent was re-
moved in vacuo. The residue (a brown oil which solidified
over night) was purified by recrystallization from heptane to
afford 3 as colorless crystals, yield 1.85 g (77 %), m. p. 94 –
56.9 Hz). – MS (FAB, glycerine, negative): m/z ( %) = 163
(58) [A]−, 135 (100) [A–CO]−.
Sodium α-(trifluoroacetyl)-γ-butyrolactonate (2o)
Yield: 51 % [after recrystallization from hexane-ethanol
(4 + 1 by volume)], m. p. > 220 ◦C (subl.) – 1H NMR
(200.1 MHz, [D6]acetone): δ = 2.86 – 2.94 (m, 2 H, CH2),
◦
95 C. – IR: ν = 1595 (conjugated C=O) cm−1. – 1H NMR
(200.1 MHz, CDCl3): δ = 1.74 – 1.95 (m, 4 H, 2CH2), 2.62
3
4.10 (t, JH,H = 7.8 Hz, 2 H, OCH2). – 19F NMR
3
3
(t, JH,H = 5.6 Hz, 2 H, CH2), 2.79 (t, JH,H = 6.4 Hz,
2 H, CH2). – 19F NMR (188.3 MHz, CDCl3): δ = −137.18,
−137.17 (both s, 4 : 1 integral ratio, 2 F, BF2), −70.82 (t,
5JF,H = 1.5 Hz, 3 F, CF3). – C8H8BF5O2 (242.0): calcd.
C 39.71, H 3.33, F 39.26; found C 39.87, H 3.11, F 39.60.
(188.3 MHz, [D6]acetone): δ = −73.0 (t, 5JF,H = 2.2 Hz). –
C6H4F3O3Na ·1/3 H2O (210.1): calcd. C 34.30, H 2.23,
F 27.13; found C 34.46, H 2.68, F 27.00.
Sodium α-(trifluoroacetyl)-δ-valerolactonate (2p)
4,5,6,7-Tetrahydro-3-trifluoromethyl-1H-indazole (4h)
Yield: 78 % [after recrystallization from ethanol-acetone
(4 + 1 by volume)], m. p. > 240 ◦C. – 1H NMR (200.1 MHz,
[D6]acetone): δ = 1.58 – 1.84, 2.32 – 2.57 (both m, 2 × 2 H,
2CH2), 3.90 – 4.12 (m, 2 H, OCH2). – 19F NMR (188.3 MHz,
[D6]acetone): δ = −69.6 s.
To a stirred solution of 2h (3.2 g, 15 mmol) in glacial
acetic acid (20 mL) 98 % hydrazine hydrate (1.2 g, 24 mmol)
◦
was added carefully. The mixture was stirred at 65 C (bath
temperature) for 16 h. The reaction mixture (a colorless solu-
tion) was concentrated in vacuo to 3/4 of its volume, and the
residue was mixed with water (50 mL). The white precipitate
Sodium 1-benzyl-3-(trifluoroacetyl)piperidin-4-onate (2t)
Yield: 41 %, m. p. > 230 C. – 1H NMR (200.1 MHz, was filtered off, washed with water (15 mL) and air-dried to
◦
3
[D6]acetone): δ = 2.24 (t, JH,H = 6.4 Hz, 2 H, CH2), 2.55 afford 3.0 g (ca. 100 %) of analytically pure pyrazole 4h [11].
Unauthenticated
Download Date | 6/15/17 1:20 PM

548
D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
5-Benzyl-4,5,6,7-tetrahydro-3-(trifluoromethyl)pyrazolo-
[4,3-c]-pyridine (4t)
was investigated by 1H and 19F NMR to reveal a mixture
(in 48 : 19 : 19 : 14 molar ratio, respectively) of anisalde-
hyde, 3, 2-(trifluoroacetyl)cyclohexanone (1b) [21, 22],
To a stirred solution of 2t (10.0 g, 33 mmol) in glacial
acetic acid (200 mL) 98 % hydrazine hydrate (3.7 g,
74 mmol) was added carefully. The mixture was stirred
at 55 ◦C (bath temperature) for 20 h to give a colorless solu-
tion which was concentrated in vacuo. The oily residue was
dissolved in water (300 mL) and treated with 10 % NaOH
solution to pH = 12. After extraction with CH2Cl2 (5 ×
30 mL) the combined organic layers were washed with brine
(20 mL), dried over MgSO4 and the solvents evaporated. The
oily residue solidified to give a practically pure pyrazole 4t
and
5,6,7,8-tetrahydro-2,2-difluoro-4-trifluoromethyl-8-
(E)-(p-methoxybenzylidene)benzo[d]-1,3,2-dioxaborine 8:
1H NMR (200.1 MHz, CDCl3): δ = 1.7 – 1.8, 2.5 – 2.7 (both
3
m, 2 × 2 H, 2CH2), 2.85 (t, JH,H = 6.0 Hz, 2 H, CH2),
3.88 (s, 3 H, OMe), 6.99, 7.60 (dd, AAꢀBBꢀ system, JA,B
=
ꢀ
ꢀ
JA ,B = 8.8 Hz, 4 H, Ar), 8.3 (unresolv. t, 1 H, =CH). –
19F NMR (188.3 MHz, CDCl3): δ = −140.46, −140.45
(both s, 4 : 1 integral ratio, 2 F, BF2), −69.73 (s, 3 F, CF3).
X-Ray structure determination of 3
1
as yellowish waxy crystals, yield 6.5 g, (71 %). – H NMR
(200.1 MHz, CDCl3): δ = 2.76 (s, 4 H, 2CH2), 3.61, 3.73
(both s, 2 ×2 H, 2CH2), 7.27 – 7.38 (m, 5 H, Ph), 12.3 (br.s,
1 H, NH). – 19F NMR (188.3 MHz, CDCl3): δ = −61.71 s. –
C14H14F3N3 (281.3): calcd. C 59.78, H 5.02; found C 59.89,
H 5.17.
Siemens-P4 diffractometer with graphite-monochrom-
atized MoKα radiation (λ = 71.073 pm) and the low-
temperature device LT2. Diffraction-quality single crystals
of 3 (colorless scales, 0.80×0.50×0.15 mm3) were selected
from an analytic sample; data collection at −100(2) ◦C. The
structure was solved by Direct Methods and refined by full-
matrix least-squares on F2 with the SHELXL-97 program
package [31]. All non-H atoms were refined anisotropically.
The positions of the hydrogen atoms were calculated as a
riding model.
Crystal and structure determination data: C8H8BF3O2
(241.95); monoclinic space group P21/c with a = 1294.3(8),
b = 765.3(7), c = 962.5(16) pm, β = 94.83(8)◦, V =
0.9500(19) nm3, D = 1.692 g cm−3, Z = 4. Index ranges
−15 ≤ h ≤ 15, −9 ≤ k ≤ 1, −11 ≤ l ≤ 11, 2θ range 3.10 –
24.99◦, 3943 collected reflections, 1667 independent reflec-
tions, Rint = 0.0626, completeness to θmax = 24.99◦: 99.9 %.
Data/restraints/parameters 1667/0/165, goodness-of-fit (F2)
2-(7,7,7-Trifluoro-6-oxoheptyl)benzimidazole hydrate (5)
To a stirred mixture of 2e (2.6 g, 13 mmol) and ortho-
phenylenediamine (1.5 g, 14 mmol) in methanol (20 mL)
acetic acid (2 mL) was added. After stirring for 5 min conc.
hydrochloric acid (10 mL) was added, and the mixture was
stirred for further 20 h. The resulting yellow solution with
a white precipitate was poured into water (150 mL) and
treated with 33 % NaOH solution carefully until pH = 10 was
reached. The precipitate was filtered off, washed with water
(20 mL) and dried. Recrystallization from toluene / ethyl ac-
etate (10 : 1 by volume) afforded 5, yield 1.7 g (43 %) as a
greyish powder [10].
0.991, final R indices [I ≥ 2σ(I)]: R1 = 0.0573, wR2
=
Methyl 8,8,8-trifluoro-7-oxooctanonate (6)
0.1442; R indices (all data): R1 = 0.0957, wR2 = 0.16−463,
To a stirred suspension of 2h (6.6 g, 31 mmol) in dried
methanol (50 mL) 98 % formic acid (0.98 g, 21 mmol) was
added. The reaction mixture was stirred at r. t. for 24 h,
poured onto water (200 mL) and treated with 10 % H2SO4
to pH = 5. After extraction with CH2Cl2 (5 × 25 mL) the
combined organic layers were dried over MgSO4 and the
solvent evaporated. The residue was distilled to afford ke-
toester 6 as a pale yellow liquid, yield 4.35 g (62 %), b. p.
˚
residual difference electron density 0.261 and −0.275 e A
.
CCDC 718414 contains the supplementary crystallo-
graphic data for compound 3. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data request/cif.
Acknowledgements
◦
1
210 – 214 C (760 Torr). – H NMR (200.1 MHz, CDCl3):
δ = 1.28 – 1.41 (m, 2 H, CH2), 1.54 – 1.73 (m, 4 H, 2CH2),
2.28, 2.69 (both t, 3JH,H = 7.3 Hz, 2 × 2 H, 2CH2), 3.62 (3,
3 H, Me). – 19F NMR (188.3 MHz, CDCl3): δ = −79.83 s. –
C9H13F3O3 (226.2): calcd. C 47.79, H 5.79; found C 47.50,
H 5.55.
We are grateful to Dr. K.-H. Hellberg, Solvay Fluor und
Derivate GmbH, Hannover, Germany, and Dr. M. Braun,
Solvay Organics GmbH, Bensberg, Germany, for the gener-
ous gift of chemicals. Mrs. D. Kemken, Mrs. I. Erxleben,
Dr. P. Schulze, Dr. T. Du¨lcks, Institute of Organic Chemistry,
University of Bremen, Germany, are thanked for recording
mass spectra, and Mr. P. Brackmann, Institute of Inorganic &
Physical Chemistry, University of Bremen, Germany, for the
Reaction of 3 with anisaldehyde
To a stirred solution of 3 (0.80 g, 3.3 mmol) in diethyl X-ray diffraction measurements. We are indebted Dr. L. N.
ether anisaldehyde (0.45 g, 3.3 mmol) was added carefully. Bazhenova and coworkers, Institute of Organic Synthesis,
The mixture was stirred in a sealed flask at r. t. for 78 h. Ural Branch, Russian Academy of Sciences, Ekaterinburg,
After evaporation of the volatiles in vacuo the waxy residue Russian Federation, for carrying out elemental analyses.
Unauthenticated
Download Date | 6/15/17 1:20 PM

D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
549
[1] a) J. T. Welch, Tetrahedron 1987, 43, 3123 – 3197;
b) P. Lin, J. Jiang, Tetrahedron 2000, 56, 3635 – 3671;
c) J. T. Welch, S. Eswarakrishnan, Fluorine in Bioor-
ganic Chemistry, John Wiley & Sons, New York,
1991; d) R. E. Banks, B. E. Smart, J. C. Tatlow (Eds.),
Organofluorine Chemistry – Principles and Commer-
cial Applications, Plenum Press, New York, 1994; e) J.-
P. Be´ gue´, D. Bonnet-Delpon, Chimie bioorganique et
me´dicinale du fluor; CNRS Editions, Paris, 2005.
[2] a) T. Hiyama, Organofluorine Compounds. Chem-
istry and Application, Springer-Verlag, Berlin, 2000;
b) P. Kirsch, Modern Fluoroorganic Chemistry, Syn-
thesis, Reactivity, Applications, Wiley-VCH, Wein-
heim, 2004; c) R. D. Chambers, Fluorine in Organic
Chemistry; Blackwell Publishing, Oxford, 2004.
[3] a) P. Mushak, M. T. Glenn, J. Savory, Fluorine Chem.
Rev. 1973, 6, 43 – 133; b) K. I. Pashkevich, V. I. Sa-
loutin, Russ. Chem. Rev. 1985, 54, 1185 – 1200; Usp.
Khim. 1985, 54, 1997 – 2026; c) V. P. Kuhar, Yu. L.
Yagupolskii, I. I. Gerus, M. T. Kolycheva, Usp. Khim.
1991, 60, 2047 – 2063; d) V. P. Kuhar, N. Yu. Svis-
tunova, V. A. Solodenko, V. A. Soloshonok, Usp. Khim.
1993, 62, 284 – 302; e) K. I. Pashkevich, V. I. Saloutin,
I. Ya. Postovskii, Russ. Chem. Rev. 1981, 50, 180 –
195; Usp. Khim. 1981, 50, 325 – 354; f) V. V. Takhistov,
A. A. Rodin, B. N. Maximova, Usp. Khim. 1991, 60,
2143 – 2166; g) E. I. Tsyganova, L. M. Dyagileva, Usp.
Khim. 1996, 65, 334 – 349; h) K. C. Joshi, R. Joshi, J.
Indian Chem. Soc. 2001, 78, 653 – 661.
P. J. Toscano, J. T. Welch, Inorg. Chim. Acta 2003, 351,
291 – 304; h) N. S. Karpenko, V. I. Filyakova, G. G.
Alexandrov, V. N. Charushin, Zh. Struct. Khim. 2005,
46, 987 – 991.
[8] N. S. Boltachova, O. V. Fedorova, I. G. Ovchinnikova,
O. N. Kazheva, A. N. Chekhlov, O. A. Dyachenko,
G. L. Rusinov, V. I. Filyakova, V. N. Charushin, J. Flu-
orine Chem. 2007, 128, 762 – 768, and refs. therein.
[9] K. I. Pashkevich, O. G. Khomutov, D. V. Sevenard,
Russ. J. Org. Chem. 1998, 34, 1727 – 1730, Zh. Org.
Khim. 1998, 34, 1798 – 1801.
[10] K. I. Pashkevich, D. V. Sevenard, O. G. Khomutov,
Russ. Chem. Bull., Eng. Transl. 1999, 48, 557 – 560;
Izv. Akad. Nauk, Ser. Khim. 1999, 562 – 565.
[11] D. V. Sevenard, O. G. Khomutov, M. I. Kodess, K. I.
Pashkevich, I. Loop, E. Lork, G.-V. Ro¨schenthaler,
Can. J. Chem. 2001, 79, 183 – 194.
[12] D. V. Sevenard, O. G. Khomutov, M. I. Kodess, K. I.
Pashkevich, I. Loop, E. Lork, G.-V. Ro¨schenthaler,
Aust. J. Chem. 2001, 54, 157 – 163.
[13] D. V. Sevenard, E. Lork, J. Fluorine Chem. 2004, 125,
125 – 128.
[14] a) D. V. Sevenard, O. Kazakova, D. L. Chizhov, D. S.
Yachevskii, E. Lork, J. Poveleit, V. N. Charushin, G.-
V. Ro¨ schenthaler, Helv. Chim. Acta 2007, 90, 369 –
384, and refs. therein; b) D. V. Sevenard, O. Kazakova,
E. Lork, T. Du¨lcks, D. L. Chizhov, G.-V. Ro¨schen-
thaler, J. Mol. Struct. 2007, 846, 87 – 96; c) D. V.
Sevenard, O. Kazakova, R.-M. Schoth, E. Lork,
J. Poveleit, G.-V. Ro¨schenthaler, Synthesis 2008,
1867 – 1878.
[15] M. Hesse, H. Meier, B. Zeeh, Spektroskopische Meth-
oden in der organischen Chemie, Thieme, Stuttgart,
2005.
[16] H. L. Goering, J. N. Eikenberry, G. S. Koermer, C. J.
Lattimer, J. Am. Chem. Soc. 1974, 96, 1493 – 1501.
[17] a) C. Do¨bler, Z. Chem. 1978, 18, 218 – 219; b) S. A.
Matlin, W. J. Lough, L. Chan, D. M. H. Abram,
Z. Zhou, J. Chem. Soc., Chem. Commun. 1984, 1038 –
1040; c) F. Keller, H. Weinmann, V. Schurig, Chem.
Ber./Recueil 1997, 130, 879 – 885.
[18] a) V. Schurig, Inorg. Chem. 1972, 11, 736 – 738;
b) S. M. Kalashnikov, L. K. Tarasov, V. I. Spitsyn, Zh.
Neorg. Khim. 1975, 20, 3132 – 3134; c) L. K. Tarasov,
S. M. Kalashnikov, V. I. Spitsyn, Zh. Neorg. Khim.
1976, 21, 93 – 95; d) N. Kurskii, Yu. A. Pentin, L. K.
Tarasov, V. I. Spitsyn in β-Diketonaty Metallov (in
Russian), Moscow, 1978, pp. 28; e) L. K. Tarasov, L. I.
Martynenko, V. I. Spitsyn in β-Diketonaty Metallov (in
Russian), Moscow, 1978, pp. 53.
[19] B. T. Golding, P. J. Sellars, A. K. Wong, J. Chem. Soc.,
Chem. Commun. 1977, 570 – 571.
[20] N. S. Karpenko, V. I. Filyakova, E. G. Matochkina,
M. I. Kodess, K. I. Pashkevich, Russ. Chem. Bull., Int.
[4] V. I. Saloutin, Ya. V. Burgart, O. N. Chupakhin, Ftor-
soderzhashchie Trikarbonil’nye Soedineniya (in Rus-
sian), UrO RAN, Ekaterinburg, 2002.
[5] K. I. Pashkevich, V. I. Filyakova, V. G. Ratner, O. G.
Khomutov, Russ. Chem. Bull., Eng. Transl. 1998, 47,
1239 – 1247; Izv. Akad. Nauk, Ser. Khim. 1998, 1279 –
1286.
[6] a) K. I. Pashkevich, V. G. Ratner, O. G. Khomutov,
V. B. Korolev, V. I. Filyakova, Russ. Chem. Bull., Eng.
Transl. 1996, 45, 1423 – 1424; Izv. Akad Nauk, Ser.
Khim. 1996, 1493 – 1495; b) V. I. Filyakova, N. S.
Karpenko, O. A. Kuznetsova, K. I. Pashkevich, Zh.
Org. Khim. 1998, 34, 411 – 417.
[7] a) J. P. Fackler, Jr., Progr. Inorg. Chem. 1966, 7, 361 –
425; b) K. S. Joshi, V. N. Pathak, Coord. Chem. Rev.
1977, 22, 37; c) A. R. Siedle in Comprehensive Coordi-
nation Chemistry, Vol. 2 (Ed.: G. Wilkinson), Oxford,
1987, chapter 15.4, pp. 365; d) S. Aygen, Y. Kitamura,
K. Kuroda, R. Kume, H. Kelm, R. van Eldik, Inorg.
Chem. 1985, 24, 423 – 429; e) J. D. Croxtall, J. Fawcett,
E. G. Hope, A. M. Stuart, J. Fluorine Chem. 2003, 119,
65 – 73; f) M. J. DelaRosa, K. K. Banger, S. Higashiya,
S. C. Ngo, D. H. Hunt, K. S. Bousman, P. J. Toscano,
J. T. Welch, J. Fluorine Chem. 2003, 123, 109 – 117;
g) S. Higashiya, K. K. Banger, S. C. Ngo, P. N. Lim,
Unauthenticated
Download Date | 6/15/17 1:20 PM

550
D. V. Sevenard et al. · Metal and Boron Derivatives of Fluorinated Cyclic 1,3-Dicarbonyl Compounds
Ed. 2003, 52, 1215 – 1216; Izv. Akad. Nauk, Ser. Khim.
2003, 1149 – 1150.
[21] K. A. K. Ebraheem, Monatsh. Chem. 1991, 122, 157 –
163.
S. Sumaria, J. Chem. Soc., Perkin Trans. 1, 1990,
1959 – 1968; b) H. Quast, M. Witzel, E.-M. Peters,
K. Peters, H. G. von Schnering, Liebigs Ann. 1995,
725 – 738.
[22] J. D. Park, H. A. Brown, J. R. Lacher, J. Am. Chem. Soc.
1953, 75, 4753 – 4756.
[23] O. Y. Neyland, Y. P. Stradyn’, E. A. Silin’sh, D. R.
Balode, S. P. Valtere, V. P. Kadysh, S. V. Kalnin’, V. E.
Kampar, I. B. Mazheyka, L. F. Taure, Stroenie i Tau-
tomernye Prevrashcheniya β-Dikarbonil’nykh Soedi-
neniy (in Russian), Zinatne, Riga, 1977.
[24] a) L. H. Toporcer, R. E. Dessy, S. I. E. Green, In-
org. Chem. 1965, 4, 1649 – 1655; b) U. Bo¨hme,
H. Hartmann, G. Go¨rlitz, Z. Kristallogr. 1996, 211,
133 – 134.
[27] a) A. W. Hanson, E. W. Macaulay, Acta Cryst. Sect. B
1972, 28, 1961; b) Y. Dromze´e, J. Kossanyi, V. Wint-
gens, P. Valat, H. Hartmann, G. Go¨rlitz, Z. Kristallogr.
1997, 212, 372 – 375.
[28] a) G. Gilli, F. Bellocci, V. Ferretti, V. Bertolasi, J. Am.
Chem. Soc. 1989, 111, 1023 – 1028; b) V. Bertolasi,
P. Gilli, V. Ferretti, G. Gilli, Chem. Eur. J. 1996, 2,
925 – 934, and refs. therein.
[29] Z. Rappoport (Ed.), The Chemistry of Enols, John Wi-
ley & Sons, Chichester, 1990.
[30] H. Trabelsi, A. Cambon, Synthesis 1992, 315 – 319.
[31] G. M. Sheldrick, SHELXL-97, Program for the Refine-
ment of Crystal Structures, University of Go¨ttingen,
Go¨ttingen (Germany) 1997.
[25] N. M. D. Brown, P. Bladon, J. Chem. Soc. A 1969,
526 – 532.
[26] a) R. C. F. Jones, M. J. Begley, G. E. Peterson,
Unauthenticated
Download Date | 6/15/17 1:20 PM