Synthesis of an enantiopure fluorous 1,2-diphenyl-1,2-diaminoethane

Article abstract of DOI:10.1055/s-2004-834953

Enantiopure fluorous 1,2-diphenyl-1,2-ethanediamine bearing four fluorous ponytails and having 62.2% fluorine content has been prepared. Resolution of racemic 1,2-bis(3,5-dimethoxyphenyl)ethane-1,2-diamine with (-)-menthyl chloroformate followed by reduct

Full text of DOI:10.1055/s-2004-834953

PAPER
425
Synthesis of an Enantiopure Fluorous 1,2-Diphenyl-1,2-diaminoethane
E
nantiopu
e
re
F
luorous
r
1,2-Dip
o
henyl-1,2-di
m
a
minoethane e Bayardon, Denis Sinou*
Laboratoire de Synthèse Asymétrique, associé au CNRS, CPE Lyon, Université Claude Bernard Lyon 1, 43, boulevard du
11 novembre 1918, 69622 Villeurbanne cédex, France
Fax +33(4)72448183; E-mail: sinou@univ-lyon1.fr
Received 11 October 2004; revised 28 October 2004
NH4NO3 in refluxing aqueous acetic acid to afford benzil
2 in 33% yield. Refluxing benzil 2 in acetic acid with 1
equivalent of cyclohexanone and NH4OAc gave the cor-
responding 2,2-spirocyclohexane-4,5-diaryl-2H-imida-
Abstract: Enantiopure fluorous 1,2-diphenyl-1,2-ethanediamine
bearing four fluorous ponytails and having 62.2% fluorine content
has been prepared. Resolution of racemic 1,2-bis(3,5-dimethoxy-
phenyl)ethane-1,2-diamine with (–)-menthyl chloroformate fol-
lowed by reduction of the obtained carbamate afforded the zole (3) in 94% yield. Reduction of compound 3 with
corresponding enantiopure secondary diamines. Protection of the
lithium (4 equiv) in a mixture NH3/THF (5:4) at –78 °C,
amino function as an aminal, followed by the cleavage of the meth-
followed by acidic hydrolysis using aqueous HCl, afford-
oxy moiety and then the introduction of the four fluorous ponytails
ed stereoselectively the racemic d,l-primary diamine 4 in
gave after hydrolysis the enantiopure fluorous 1,2-diphenyl-1,2-
87% yield.
ethanediamine.
The resolution of this diamine 4 was performed using
Denmark’s procedure.11 Reaction of the racemic diamine
4 with (–)-menthyl chloroformate in the presence of pyri-
dine gave the corresponding bis(menthyl carbamate) dia-
Key words: enantiopure fluorous diamine, C2 axis, resolution
Enantiopure 1,2-diamines possessing C2 symmetry are
particularly attractive auxiliaries in asymmetric synthesis,
as chiral reagents or catalysts.1 Among the large variety of
1,2-diamine structures that have been designed and syn-
thesized, enantiopure 1,2-diaryl-1,2-ethanediamines and
their derivatives seem to be one of the most widely used
ligands, giving high ee in a large number of metal-cata-
lyzed enantioselective reactions. The functionalization of
these enantiopure diamines in order to facilitate their sep-
aration and the eventual recycling of the catalyst is an area
of intense research. Attachment of phenolic hydroxy
groups,2 polyethylene glycol chains,2,3 sulfonic acid4,5 or
phosphonic acid moieties,6 on the aromatic rings allowed
their hydrosolubilization. These chiral diamines have
been also immobilized by attachment to a chloromethylat-
ed polystyrene,7 or onto inorganic supports.8 Our group
has developed the synthesis of a series of enantiopure flu-
orous 1,2-diamines and diimines and described their use
mainly in asymmetric transfer hydrogenation using the
FBS (Fluorous Biphasic System) concept.9 In this paper
we report the first preparation of an enantiopure fluorous
1,2-phenyl-1,2-ethanediamine having 62.2% fluorine
content.
stereoisomers
(1R,2R)-
and
(1S,2S)-5.
These
diastereoisomers were separated by column chromatogra-
phy; the (1R,2R)-5 and (1S,2S)-5 diastereoisomers were
obtained in 40 and 34% yields, respectively. The absolute
configuration of the diamine moiety of these two diaste-
reoisomers was deduced by comparison of their 1H NMR
spectra with those of other bis(carbamates) described in
the literature, as well as their relative polarity on TLC.11
The less polar diastereoisomer showed a doublet of trip-
lets at d = 4.52, corresponding to the proton adjacent to the
oxygen of the menthyl moiety, and characteristic of the
R,R-configuration of the nitrogen-bearing stereocenters.
On the other hand, the more polar stereoisomer exhibited
a broad signal at d = 4.53 for the same protons, character-
istic of the S,S-configuration. Reduction of the diastereo-
isomer (1R,2R)-5 with LiAlH4 in anhydrous DME
afforded the corresponding (1R,2R)-1,2-diaryl-N,N¢-di-
methylethane-1,2-diamine that was immediately trans-
formed to the protected diamine 6 by reaction with
acetaldehyde in the presence of molecular sieve in 50%
yield. Slow addition of BBr3 to a dichloromethane solu-
tion of this protected diamine 6 gave the corresponding
tetrahydroxyamine 7 in 79% yield. Reaction of the pro-
tected diamine 7 with 1H,1H-perfluorooctan-1-yl nona-
fluorobutanesulfonate in the presence of CsCO3 in DMF
according to our methodology12 allowed the introduction
of four fluorous ponytails in the molecule. Further acidic
deprotection gave the fluorous (1R,2R)-1,2-diaryl-N,N¢-
dimethylethanediamine 8 in an overall 15% yield.
The preparation of the enantiopure fluorous 1,2-diphe-
nylethane-1,2-diamine 8 is described in Scheme 1. The re-
ductive coupling of 3,5-dimethoxybenzoic acid methyl
ester (1) with lithium naphthalenide (3 equiv) in THF at
–78 °C for 1 hour followed by quenching with TMSCl at
this temperature according to Corey’s procedure10 gave,
after hydrolysis, a mixture of benzil 2 and benzoin. This
mixture was directly oxidized with Cu(OAc)2 and
We measured the solubility of this fluorous diamine 8 in
different biphasic solvent combinations. The liquid-liquid
partition coefficients P (P = cfluorous phase/corganic solvent) of
this diamine using FC-72 as the fluorous solvent were
2.23, 5.25, and 10.35 when ethanol, toluene, and acetoni-
trile were used as the organic solvent, respectively.
SYNTHESIS 2005, No. 3, pp 0425–0428
x
x
.
x
x
.2
0
0
5
Advanced online publication: 08.12.2004
DOI: 10.1055/s-2004-834953; Art ID: Z19104SS
© Georg Thieme Verlag Stuttgart · New York

426
J. Bayardon, D. Sinou
PAPER
MeO
MeO OMe
MeO OMe
MeO OMe
a, b, c
d
e
CO2Me
MeO
OMe
MeO
OMe
MeO
OMe
MeO
H2N
NH2
( )-4
O
O
N
N
1
2
3
MeO OMe
MeO
MeO
OMe
MeO OMe
f
g, h, i
+
OMe
MeO
OMe
MeO
OMe
MenO2CNH
NHCO2Men
MenO2CNH
NHCO2Men
Me
N
N Me
Me
(S,S)-5
(R,R)-5
6
C7F15CH2O OCH2C7F15
C7F15CH2O OCH2C7F15
HOHO
j
k, l
HO
OH
Me NH HN Me
Me
N
N Me
Me
8
7
Scheme 1 Reagents and conditions: a) naphthalene, Li, THF, –78 °C; b) TMSCl, –78 °C, then H2O; c) Cu(OAc)2, NH4NO3, aq AcOH, reflux;
d) cyclohexanone, NH4OAc, AcOH; e) Li, THF/NH3, –78 °C, then H3O+; f) (–)-MenthOCOCl, pyr, CH2Cl2; g) separation by column chroma-
tography; h) LiAlH4 for (1R,2R)-5, DME; i) MeCHO, molecular sieves; j) BBr3, CH2Cl2, 0 °C; k) C7F15CH2OSO2C4F9, CsCO3, DMF, 80 °C;
l) H3O+.
idue that was purified by column chromatography using petroleum
ether–EtOAc (3:2) as the eluent to afford a mixture of the corre-
sponding benzil and benzoin. This mixture was treated by
Cu(OAc)2·H2O (16 mg, 80.1 mmol) and NH4NO3 (0.96 g, 12.01
mmol) in refluxing 80% aq AcOH (6 mL). The mixture was cooled
to r.t., the solid was filtered, and washed several times with H2O to
afford benzil 2; yield: 2.8 g (33%); yellow solid; mp 156–158 °C;
Rf 0.68 (petroleum ether–EtOAc, 3:2).
1H NMR (CDCl3): d = 3.82 (s, 12 H, OCH3), 6.73 (t, 2 Harom, J = 2.3
Hz), 7.06 (d, 4 Harom, J = 2.3 Hz).
13C NMR (CDCl3): d = 56.1 (CH3), 107.8 (Carom), 107.9 (Carom),
135.0 (Carom), 161.5 (Carom), 194.6 (C=O).
The use of this enantiopure fluorous C2 diamine as chiral
inductor in organic synthesis as well as in asymmetric ca-
talysis is now under investigation in our group.
THF and DME were distilled in the presence of sodium/benzophe-
none, DMF over NaH, and CH2Cl2 over CaH2, and were stored un-
der argon. All commercially available reagents were used as
received. All reactions were monitored by TLC analysis (TLC
plates GF254 Merck). Air- and moisture-sensitive reactions were
performed under inert atmosphere techniques. Melting points were
determined on a Büchi apparatus and are uncorrected. Column
chromatography was performed on silica gel 60 (230–240 mesh,
Merck). Optical rotations were recorded using a Perkin-Elmer 241
polarimeter. NMR spectra were recorded with Bruker AMX 300
spectrometer and referenced as following: 1H (300 MHz), internal
HRMS: m/z calcd for C18H19O6 [MH+]: 331.1181; found: 331.1178.
2,3-Bis(3,5-dimethoxyphenyl)-1,4-diazaspiro[4.5]deca-1,3-di-
ene (3)
SiMe4 at d = 0.00, 13C (75 MHz), internal CDCl3 at d = 77.23, 19
F
(282 MHz), external CFCl3 at d = 0.00. The partition coefficients
were determined by gravimetry. 1H,1H-Perfluorooctan-1-yl nona-
fluorobutanesulfonate was prepared according to the literature.12
Petroleum ether used had bp 40–65 °C.
A mixture of benzil 2 (2.17 g, 6.54 mmol), cyclohexanone (0.67 g,
6.74 mmol), and NH4OAc (3.5 g, 45.1 mmol) in AcOH (13 mL) was
refluxed for 1.5 h. H2O (20 mL) was added, and the mixture was ex-
tracted with CH2Cl2 (3 × 20 mL). The combined organic phases
were washed with a sat. aq solution of NaHCO3 (2 × 20 mL), and
dried (Na2SO4). Evaporation of the solvent under reduced pressure
gave a residue that was purified by column chromatography using
petroleum ether–EtOAc (3:2) as the eluent to give the diimine 3;
yield: 2.5 g (94%); yellow solid; mp 58–60 °C; Rf 0.66 (petroleum
ether–EtOAc, 3:2).
1,2-Bis(3,5-dimethoxyphenyl)ethane-1,2-dione (2)
To a solution of naphthalene (10.58 g, 82.6 mmol) in THF (100 mL)
was added Li (0.53 g, 76.5 mmol) under argon at –10 °C. The mix-
ture was stirred at r.t. for 12 h, then cooled down to –78 °C, and a
solution of methyl 3,5-dimethoxybenzoate (1; 5 g, 25.5 mmol) in
THF (15 mL) was added. After stirring for 1 h at r.t., the solution
was quenched with trimethylsilyl chloride (6 mL, 47.3 mmol), and
the mixture was stirred for 30 min. The mixture was hydrolyzed at
0 °C by addition of H2O (30 mL), and extracted with Et2O (4 × 30
mL). Evaporation of the solvent under reduced pressure gave a res-
1H NMR (CDCl3): d = 1.73–1.80 (m, 6 H, CH2), 1.96 (m, 4 H, CH2),
3.71 (s, 12 H, CH3), 6.52 (t, 2 Harom, J = 2.3 Hz), 6.66 (d, 4 Harom
,
J = 2.3 Hz).
Synthesis 2005, No. 3, 425–428 © Thieme Stuttgart · New York

PAPER
Enantiopure Fluorous 1,2-Diphenyl-1,2-diaminoethane
427
13C NMR (CDCl3): d = 24.5 (CH2), 26.0 (CH2), 35.0 (CH2), 55.8
(CH3), 103.2 (Carom), 104.3 (C–N), 107.1 (Carom), 135.1 (Carom),
160.9 (Carom), 164.1 (C=N).
1H NMR (CDCl3): d = 0.80–1.94 (m, 36 H, menthyl), 3.67 (s, 12 H,
OCH3), 4.53 (m, 2 H, CHO), 4.82 (m, 2 H, CHN), 5.62 (br, 2 H,
NH), 6.19 (m, 4 Harom), 6.29 (m, 2 Harom).
Anal. Calcd for C24H28N2O4: C, 70.59; H, 6.86. Found: C, 70.27; H,
7.03.
13C NMR (CDCl3): d = 16.7 (CH), 21.2 (CH3), 22.6 (CH), 23;5
(CH2), 26.4 (CH), 31.8 (CH3), 34.6 (CH2), 41.8 (CH2), 47.6 (CH),
55.6 (OCH3), 75.5 (CHN), 100.3 (Carom), 105.6 (Carom), 141.7
(Carom), 156.9 (Carom), 161.0 (C=O).
( )-1,2-Bis(3,5-dimethoxyphenyl)ethane-1,2-diamine (4)
To a solution of 3 (4.35 g, 10.67 mmol) in a NH3/THF mixture (36
mL, 5:4) at –78 °C was added Li (0.33 g, 46.95 mmol). The solution
was stirred at –78 °C for 2 h, during which time additional amounts
of EtOH were added (4 × 0.31 mL). The mixture was then treated
with NH4Cl (2.98 g), hydrolyzed with H2O (15 mL) at 0 °C, and
then extracted with Et2O (3 × 15 mL). The organic phase was
washed with brine (20 mL), and dried (Na2SO4). Evaporation of the
solvent under reduced pressure gave a residue that was diluted with
Et2O (20 mL). An aq 2 M solution of HCl (13 mL) was added at
0 °C, and the mixture was stirred at r.t. for 1 h. The precipitate was
filtered, the solid was washed with Et2O (3 × 20 mL), and then
poured into H2O (20 mL). A solution of aq 2 N NaOH (15 mL) was
added, the mixture was extracted with CH2Cl2 (3 × 30 mL), and the
combined organic phases were dried (Na2SO4). Evaporation of the
solvent under reduced pressure gave the racemic diamine 4; yield:
3.1 g (87%); yellow oil.
1H NMR (CDCl3): d = 1.55 (br, 4 H, NH2), 3.77 (s, 12 H, CH3), 4.05
(s, 2 H, CHN), 6.34 (t, 2 Harom, J = 2.3 Hz), 6.49 (d, 4 Harom, J = 2.3
Hz).
13C NMR (CDCl3): d = 55.7 (CH3), 62.1 (CHN), 99.4 (Carom), 105.3
(Carom), 146.4 (Carom), 161.0 (Carom).
HRMS: m/z calcd for C18H25N2O4 [MH+]: 333.1815; found:
333.1814.
(4R,5R)-4,5-Bis(3,5-dimethoxyphenyl)-1,2,3-trimethylimidazo-
lidine [(4R,5R)-6]
To a solution of the biscarbamate (1R,2R)-5 (1.07 g, 1.54 mmol) in
anhyd DME (60 mL) maintained at 0 °C was added LiAlH4 (0.58 g,
15.4 mmol) portionwise. The reaction mixture was heated at 85 °C
for 20 h. H2O (2 mL) was added slowly at 0 °C, and then the mixture
was heated back at 85 °C for 30 min. The mixture was cooled to r.t.,
and the white precipitate was filtered through a layer of Celite and
washed with THF (3 × 20 mL). Evaporation of the solvent under re-
duced pressure gave a residue that was diluted with Et2O (20 mL);
a solution of 1 M solution of gaseous HCl (3.7 mL) in Et2O was then
added. The mixture was stirred at r.t. for 30 min, and the solid ob-
tained was filtered and washed with Et2O. The solid was suspended
in Et2O and treated with a solution of aq 1% NaOH until dissolution
of the solid. The organic phase was separated, washed with H2O
(2 × 5 mL), and dried (Na2SO4). Evaporation of the solvent gave a
residue that was poured into Et2O (10 mL) containing 4 Å molecular
sieves (0.54 g) under magnetic stirring; acetaldehyde (0.16 mL,
2.85 mmol) was then added. The mixture was stirred at r.t. for 1 h,
and then diluted with CH2Cl2 (10 mL). The molecular sieves were
removed by filtration. Evaporation of the solvent and the excess ac-
etaldehyde under reduced pressure gave a residue that was purified
by column chromatography using CH2Cl2–MeOH (10:1) as the elu-
ent to give compound 6; yield: 300 mg (50%); brown oil; Rf 0.62
(CH2Cl2–MeOH, 10:1); [a]D25 +8.6 (c = 0.4, CHCl3).
Resolution of N,N¢-Bis[(–)-menthoxycarbonyl]-1,2-bis(3,5-di-
methoxyphenyl)ethane-1,2-diamine (5)
1H NMR (CDCl3): d = 1.29 (d, 3 H, J = 5.8 Hz, CH3), 2.24 (s, 3 H,
NCH3), 2.28 (s, 3 H, NCH3), 3.27 (d, 1 H, J = 8.3 Hz, CHN), 3.55
(d, 1 H, J = 8.3 Hz, CHN), 3.72 (s, 12 H, OCH3), 3.83 (q, 1 H,
J = 5.8 Hz, CH), 6.33 (m, 4 Harom), 6.38 (d, 2 Harom, J = 2.3 Hz).
13C NMR (CDCl3): d = 15.1 (CH3), 33.6 (NCH3), 36.5 NCH3), 53.4
(OCH3), 53.5 (OCH3), 74.7 (CHN), 76.4 (CHN), 79.0 (CH), 97.5–
97.6 (Carom), 104.0–104.1 (Carom), 141.2–141.5 (Carom), 158.7–158.8
(Carom).
To a solution of the racemic diamine 4 (0.6 g, 1.8 mmol) and pyri-
dine (0.51 mL, 6.25 mmol) in anhyd CH2Cl2 (10 mL) maintained at
0 °C was added (–)-menthyl chloroformate (1.0 mL, 4.67 mmol).
The solution was stirred at r.t. for 4 h, the solvent was co-evaporated
with toluene, and the residue was purified by column chromatogra-
phy using CH2Cl2–EtOAc (20:1) as the eluent to give 500 mg of the
less polar (1R,2R)-5 and 430 mg of the more polar (1S,2S)-5 com-
ponents as white solids (74% combined yield for the two diastereo-
isomers).
Anal. Calcd for C22H30N2O4: C, 68.39; H, 7.77. Found: C, 68.51; H,
7.64.
(1R,2R)-N,N¢-Bis[(–)-menthoxycarbonyl]-1,2-bis(3,5-dimeth-
oxyphenyl)ethane-1,2-diamine [(1R,2R)-5]
5,5¢-[(4R,5R)-1,2,3-Trimethylimidazolidine-4,5-diyl]dibenzene-
1,2-diol [(4R,5R)-7]
Yield: 500 mg (40%); white solid; mp 221–223 °C; Rf 0.52
(CH2Cl2–EtOAc, 20:1); [a]D25 –49.0 (c = 1, CHCl3).
A 1 M solution of BBr3 in CH2Cl2 (5.1 mL, 5.1 mmol) was added
slowly at 0 °C to a solution of the acetaminal (4R,5R)-6 (0.22 g,
0.58 mmol) in CH2Cl2 (5 mL). After stirring for 20 h at r.t., the mix-
ture was hydrolyzed by treatment with aq 1 M NaOH (10 mL). After
evaporation of CH2Cl2, the mixture was filtered through Celite, and
the pH was adjusted to 8.5 with aq 0.1 M HCl. EtOAc (10 mL) was
added, the organic layer was separated, and the aqueous layer was
extracted with EtOAc (5 × 10 mL). The combined organic phases
were washed with brine (2 × 10 mL), and dried (Na2SO4). Evapo-
ration of the solvent under reduced pressure gave acetaminal 7 that
was directly used for the next step without further purification;
yield: 151 mg (79%); brown solid (151 mg, 79%); Rf 0.28 (CH2Cl2–
MeOH, 5:1).
1H NMR (CDCl3): d = 0.70 (d, 6 H, J = 6.8 Hz, CH3), 0.84–2.05 (m,
30 H, menthyl), 3.67 (s, 12 H, OCH3), 4.52 (dt, 2 H, J = 10.9, 4.3
Hz, CHO), 4.85 (m, 2 H, CHN), 5.56 (br, 2 H, NH), 6.22 (d, 4 Harom
,
J = 2.3 Hz), 6.29 (dd, 2 Harom, J = 2,3 Hz).
13C NMR (CDCl3): d = 16.5 (CH3), 21.2 (CH3), 22.6 (CH), 23.5
(CH2), 26.4 (CH), 31.8 (CH3), 34.6 (CH2), 41.8 (CH2), 47.6 (CH),
55.6 (OCH3), 75.5 (CHN), 100.4 (Carom), 105.7 (Carom), 141.7
(Carom), 157.2 (Carom), 161.1 (C=O).
Anal. Calcd for C40H60N2O8: C, 68.97; H, 8.62. Found: C, 69.18; H,
8.44.
1H NMR (CDCl3): d = 1.30 (d, 3 H, J = 5.8 Hz, CH3), 2.21 (s, 6 H,
NCH3), 2.23 (s, 6 H, NCH3), 3.27 (d, 1 H, J = 8.5 Hz, CHN), 3.55
(d, 1 H, J = 8.5 Hz, CHN), 3.63 (q, 1 H, J = 5.8 Hz, CH), 6.11–6.17
(m, 4 Harom), 6.22 (d, 2 Harom, J = 2.1 Hz).
(1S,2S)-N,N¢-Bis[(–)-menthoxycarbonyl]-1,2-bis(3,5-dimeth-
oxyphenyl)ethane-1,2-diamine [(1S,2S)-5]
Yield: 430 mg (34%); white solid; mp 174–176 °C; Rf 0.34
(CH2Cl2–EtOAc, 20:1); [a]D25 –61.0 (c = 1, CHCl3).
Synthesis 2005, No. 3, 425–428 © Thieme Stuttgart · New York

428
J. Bayardon, D. Sinou
PAPER
13C NMR (CDCl3): d = 17.5 (CH3), 36.9 (NCH3), 39.1 (NCH3), 77.7
(CHN), 79.6 (CHN), 83.0 (CH), 103.3 (Carom), 108.0–108.6 (Carom),
144.0–144.3 (Carom), 159.9–160.0 (Carom).
Acknowledgment
One of us (J. B.) thanks the French Ministry of Education for a fel-
lowship.
(1R,2R)-1,2-Bis{3,5-bis[(1H,1H-perfluorooctyl)oxy]phenyl)-
N,N¢-dimethylethane-1,2-diamine [(1R,2R)-8]
References
A mixture of compound (4R,5R)-7 (204 mg, 0.62 mmol), CsCO3
(1.37 g, 4.2 mmol), and C7F15CH2OSO2C4F9 (3.2 g, 7.2 mmol), in
anhyd DMF (6 mL) was stirred at 80 °C for 18 h. After cooling
down to r.t., H2O (10 mL) was added, and the mixture was extracted
with Et2O (3 × 10 mL). The combined organic phases were washed
with brine (10 mL), and dried (Na2SO4). Evaporation of the solvent
under reduced pressure gave a residue, that was purified by column
chromatography using petroleum ether–EtOAc (6:1) as the eluent to
give the corresponding fluorous compound. The product obtained
was diluted with Et2O (5 mL), and a 1 N solution of gaseous HCl in
Et2O (2.4 mL) was added at 0 °C. After stirring for 1 h at r.t., the
solvent was evaporated under reduced pressure, and the solid ob-
tained was filtered, and washed with Et2O (3 × 5 mL). To the solid
was added Et2O (5 mL), followed by aq 1% NaOH until all the solid
had dissolved. The organic phase was separated, washed with H2O
(3 × 5 mL), and dried (Na2SO4). Evaporation of the solvent under
reduced pressure afforded the fluorous diamine (1R,2R)-8; yield:
170 mg (15%); yellow oil; Rf 0.20 (EtOAc); [a]D25 +13.5 (c = 0.37,
CHCl3).
(1) (a) Bennani, Y. L.; Hanessian, S. Chem. Rev. 1997, 97,
3161. (b) Lucet, D.; Le Gall, T.; Mioskowski, C. Angew.
Chem. Int. Ed. 1998, 37, 2580. (c) Fache, F.; Schulz, E.;
Tommasino, M.; Lemaire, M. Chem. Rev. 2000, 100, 2159.
(2) Ferrand, A.; Bruno, M.; Tommasino, M. L.; Lemaire, M.
Tetrahedron: Asymmetry 2002, 13, 1379.
(3) Li, X.; Chen, W.; Hems, W.; King, F. X. J. Tetrahedron Lett.
2004, 45, 951.
(4) Ma, Y.; Liu, H.; Chen, L.; Cui, X.; Zhu, J.; Deng, J. Org.
Lett. 2003, 5, 2103.
(5) Bubert, C.; Blacker, J.; Brown, S. M.; Crosby, J.; Fitzjohn,
S.; Muxworthy, J. P.; Thorpe, T.; Williams, J. M. J.
Tetrahedron Lett. 2001, 42, 4037.
(6) Maillet, C.; Praveen, T.; Janvier, P.; Minguet, S.; Evain, M.;
Saluzzo, C.; Tommasino, M. L.; Bujoli, B. J. Org. Chem.
2002, 67, 8191.
(7) Itsuno, S.; Tsuji, A.; Takahashi, M. Tetrahedron Lett. 2003,
44, 3825.
1H NMR (CDCl3): d = 1.97 (br, 2 H, NH), 2.29 (s, 6 H, NCH3), 3.35
(s, 2 H, CHN), 4.15–4.38 (m, 8 H, OCH2), 6.25 (d, 4 Harom, J = 2.2
Hz), 6.31 (dd, 2 Harom, J = 2.2 Hz).
13C NMR (CDCl3): d = 34.9 (NCH3), 65.6 (t, J = 26.0 Hz, OCH2),
72.0 (CHN), 101.7 (Carom), 108.4 (Carom), 145.1 (Carom), 158.8
(Carom).
19F NMR (CDCl3): d = –126.8 (m, 8 F, CF2), –123.8 (m, 8 F, CF2),
–123.4 (m, 8 F, CF2), –122.6 (16 F, CF2), –120.2 (m, 8 F, CF2),
–81.5 (t, J = 10.3 Hz, 12 F, CF3).
(8) Liu, P. N.; Gu, P. M.; Wang, F.; Tu, Y. Q. Org. Lett. 2004,
6, 169.
(9) (a) Maillard, D.; Nguefack, C.; Pozzi, G.; Quici, S.; Valadé,
B.; Sinou, D. Tetrahedron: Asymmetry 2000, 11, 2881.
(b) Maillard, D.; Pozzi, G.; Quici, S.; Sinou, D. Tetrahedron
2002, 58, 3971. (c) Bayardon, J.; Sinou, D. Tetrahedron
Lett. 2003, 44, 1449. (d) Bayardon, J.; Sinou, D. J. Org.
Chem. 2004, 69, 3121.
(10) Corey, E. J.; Lee, D.-H.; Sarshar, S. Tetrahedron:
Asymmetry 1995, 6, 3.
(11) Denmark, S. E.; Su, X.; Nishigaichi, Y.; Coe, D. M.; Wong,
K.-T.; Winter, S. B. D.; Choi, J. Y. J. Org. Chem. 1999, 64,
1958.
HRMS: m/z calcd for C48H25N2O4F60 [MH+]: 1833.0855; found:
1833.0851.
(12) Maillard, D.; Pozzi, G.; Sinou, D. Eur. J. Org. Chem. 2002,
269.
Synthesis 2005, No. 3, 425–428 © Thieme Stuttgart · New York