Palladium(0)-catalyzed reaction of acidic anilines with (Z)-2-butene- 1,4-diyl dicarbonate - Preparation of N-aryl-4-vinyloxazolidin-2-ones

Article abstract of DOI:10.1002/(SICI)1099-0690(199901)1999:1<181::AID-EJOC181>3.0.CO;2-E

Palladium-catalyzed reaction of acidic anilines with (Z)-2-butene-1,4- diyl dicarbonate affords N-aryl-4-vinyloxazolidin-2-ones. The success of the reaction depends on the acidity of the aniline and requires in situ conversion of the dicarbonate into carb

Full text of DOI:10.1002/(SICI)1099-0690(199901)1999:1<181::AID-EJOC181>3.0.CO;2-E

FULL PAPER
Palladium(0)-Catalyzed Reaction of Acidic Anilines with (Z)-2-Butene-1,4-diyl
Dicarbonate – Preparation of N-Aryl-4-vinyloxazolidin-2-ones
[a]
[a]
[a]
[a]
˜
Marcial Moreno-Manas,* Lurdes Morral, Roser Pleixats, and Silvia Villarroya
Keywords: Palladium catalysis / Homogeneous catalysis / Anilines / Alkylation / Oxazolidinones
Palladium-catalyzed reaction of acidic anilines with (Z)-2-
butene-1,4-diyl dicarbonate affords N-aryl-4-vinyloxa-
zolidin-2-ones. The success of the reaction depends on the
acidity of the aniline and requires in situ conversion of the
dicarbonate into carbamate carbonate by nucleophilic attack
of the aniline conjugate base followed by palladium-
catalyzed intramolecular cyclization.
Pd0-catalyzed allylation of nucleophiles with butene-1,4-
diol derivatives produces cyclic products. Thus, dinucleo-
philes of type 1,1 (doubly nucleophilic reagents with a nu-
cleophilic atom which may react twice, such as RϪNH2,
RCOϪCH2ϪCOR, etc.) produce three- or five-membered
rings. In a mechanistically related work Ibuka and co-work-
ers have reported the Pd0-catalyzed isomerization of
cis- and trans-2-alkyl-N-alkyl(or -aryl)sulfonyl-3-vinylaziri-
dines[11] without formation of five-membered rings. In con-
trast, Oshima described the isomerization of 2-(1,3-butadi-
enyl)-N-tosylaziridines into 2,5-dihydro-N-tosyl-2-vinylpyr-
roles.[12] Strong electron-attracting N-sulfonyl groups are re-
quired in both cases for isomerization to occur through
aziridine opening. In contrast, five-membered pyrroles and
derivatives are directly formed from 1,4-difunctionalized
butenes under Pd catalysis.[13] Dinucleophiles of type 1,4
(YϪCϪCϪX) produce upon reaction with 2-butene-1,4-
diol derivatives, vinyl-substituted 6-membered rings where
Introduction
Oxazolidin-2-ones are masked amino alcohols which
have attracted a great deal of interest.[1] Oxazolidin-2-ones
can be prepared by thermal or catalytic reaction of oxiranes
with isocyanates (Scheme 1). For monosubstituted oxiranes
this method produces in general 5-substituted oxazolidin-
2-ones,[2] although certain catalysts favor the 4-substituted
isomers.[3] Trost[4a,4b] and Alper[4c] have reported the forma-
tion of N-aryl-4-vinyloxazolidin-2-ones by palladium-cata-
lyzed reaction of vinyloxiranes with isocyanates[4] but the
method failed in the case of 4-nitrophenyl isocyanate.[4c]
Related work by Hayashi[5a] and by Trost[5bϪf] consists of
the palladium(0)-catalyzed cyclization of 2-alkene-1,4-diyl
dicarbamates to 4-vinyloxazolidinones. Other recent prep-
arations of oxazolidin-2-ones under palladium catalysis are
the cyclization of propargyl tosylcarbamates[6] and of al-
lenyl tosylcarbamates.[7]
X
ϭ Y ϭ X ϭ NHR and Y ϭ
NHR,[14,15,16a]
OH,[14,15,16b,16c] and X ϭ Y ϭ OH.[17] This includes highly
acidic arenesulfonamide nucleophiles.[14,15,16c] However, the
reactions of dinucleophiles of types 1,5 and 1,6
[TsNH(CH2)nNHTs (n ϭ 3,4)] with butene-1,4-diyl dicar-
bonate afford 8- and 9-membered rings instead of vinyl sub-
Scheme 1. Oxazolidin-2-ones by reaction of oxiranes with isocyana-
tes
Palladium-catalyzed allylation of nucleophiles (the TsujiϪ stituted 6- and 7-membered rings.[14]
Trost reaction) is a synthetic method highly accepted due
The 4-membered ring N-(trifluoromethanesulfonyl)-2-vi-
to its broad applicability and facile experimental pro- nylazetidine opens under Pd0 catalysis and dimerizes to the
cedure.[8] Moreover, for most usual nucleophiles the TsujiϪ corresponding twelve-membered ring instead to recyclize to
Trost reaction takes place with overall retention of configu- the 6-membered ring.[18]
ration at the electrophilic center thus offering a stereochem-
ical complement to the noncatalyzed substitutions. We have
reported the palladium-catalyzed allylation of acidic ani-
lines[9] and of other acidic nitrogen nucleophiles,[10] which
Results and Discussion
occurs with overall stereochemical retention of configura-
tion.
However, unexpected results were obtained when acidic
anilines 1 reacted with (Z)-2-butene-1,4-diyl dicarbonate (2)
in the presence of Pd0 species and these results will be pres-
ented here.
With the above precedents in mind we were surprised to
find the results of Scheme 2 and Table 1. The reactions of
anilines 1 with dicarbonate 2 produce N-aryl-4-vinyloxazo-
lidin-2-ones 3 in excellent yields. The precatalytic system
[bis(dibenzylidene)acetone]palladium/1,1Ј-bis(diphenyl-
phosphanyl)ferrocene was used. The bidentate phosphane
1,1Ј-bis(diphenylphosphanyl)ethane gave also good results,
[a]
`
Department of Chemistry, Universitat Autonoma de Barcelona,
but with Pd(PPh3)4 the reaction failed and the anilines were
Cerdanyola, E-08193-Barcelona, Spain
E-mail: iqorb@cc.uab.es
not consumed. The IR (ν˜ in the range 1749Ϫ1758 cmϪ1
)
Eur. J. Org. Chem. 1999, 181Ϫ186
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ193X/99/0101Ϫ0181 $ 17.50ϩ.50/0
181

M. Moreno-Man˜as, L. Morral, R. Pleixats, S. Villarroya
FULL PAPER
and NMR spectra as well as analytical data are in agree-
An examination of Table 1 reveals that at least moderate
ment with the proposed structures (see Experimental Sec- electron-withdrawing groups are required for the success of
tion). NOE experiments were performed in order to ascer- the reaction. The experiments of Table 1 are ordered by
tain the position of the vinyl chain. In some cases minor decreasing σϪ values and it is evident that results syntheti-
isomers very similar to 3 in their general structure could be cally useful are not achieved for substituents H and 4-OMe.
isolated (see experiments 1, 4, and 5 of Table 1). They were Nevertheless, experiments with ortho-substituted anilines
characterized as N-aryl-5-vinyl-1,3-oxazolidin-2-ones 14 by bearing electron-withdrawing groups (i.e. 2-nitroaniline,
NOE experiments and X-ray diffraction (for 14a, full de- 2,4-dinitroaniline, 2,6-dichloro-4-nitroaniline, 2,3,4,5,6-
tails on X-ray diffraction will be published elsewhere in due pentafluoroaniline) failed to give oxazolidinones, thus
time). Thus, for 4-vinyloxazolidinone 3a irradiation at δ ϭ pointing out that ortho positions must be free. In no case
8.76 (aromatic H ortho to the oxazolidinone ring) produces vinylaziridines 6 or dihydropyrroles 7 were isolated. The
NOE enhancements at the 4-H signal at δ ϭ 5.06 (2.9%) formation of these compounds was a priori possible as de-
and also at the terminal vinylic protons signals (0.8%); for picted in Scheme 3.
the regioisomeric compound 14a, by irradiation at δ ϭ 8.77
(aromatic H ortho to the oxazolidinone ring) NOE enhance-
ments were observed for 4-H and 4Ј-H at δ ϭ 3.95 (0.9%)
and 4.37 (1.9%). Similar results were also obtained for 3b.
Also, DEPT experiments performed on 3a, 14a and 3b con-
firmed the position of the vinyl group in the oxazolidi-
none ring.
Scheme 3. Alternative pathway leading to vinylaziridines 6 and di-
hydropyrroles 7
All experimental facts can be explained by the sequence
of events of Scheme 4.
Step 0 is the initiation step according to the well-known
reaction of Pd0 species with allylic carbonates.[19] The
ethoxide anion thus formed triggers the cycle of reactions
1Ϫ5, the net result of which is shown in Scheme 2.
Step 1 is quantitatively shifted to the right in all experi-
ments except for 12 and 13 (R ϭ H and 4-OMe). The order
of acidities in THF is assumed to be the same as in DMSO,
but different from the order in water.[20] Bordwell has pub-
Scheme 2. Pd0-catalyzed formation of N-aryl-4-vinyloxazolidin-2-
ones
Table 1. Palladium-catalyzed reactions of anilines 1 with dicarbo- lished lists of acidities of proton-active compounds in
nate 2[a]
DMSO and the following values are relevant:[20] pKa
(DMSO): 4-nitroaniline (1b): 20.9; methanol: 29.0; aniline
entry 1, R
[1]
2:1[b]
time [h] 3 (%)[c]
(1l): 30.6. Therefore, according to σϪ values all or nearly
all anilines of Table 1 should be more acidic than ethanol
(about the same pKa value than methanol) with the only
exceptions of 1l and 1m (experiments 12 and 13).
1
1a, 3,5-(NO2)2
0.2 
0.3 
0.6 
0.2 
0.2 
0.5 
0.5 
0.5 
0.4 
0.3 
0.6 
0.5 
0.3 
2:1
7
3a (52)[d,e]
2
1b, 4-(NO2)
1c, 4-NC
2:1
48
24
48
36
7
3b (81)
3c (80)
3d (93)[d]
3e (80)[d]
3f (74)
3g (83)
3h (47)
3i (73)
3
2:1
4
1d, 3,5-(CF3)2
1e, 3,5-(Cl)2
1f, 3-NO2
1g, 4-MeOCO
1h, 3-Cl, 4-F
1i, 4-CF3
2:1
Step 2 is a transamidation which probably does not re-
quire palladium in a specific form, but only the base (anion
ethoxide) generated in situ from allylic dicarbonate 2 and
5
2:1
6
2:1
7
1.5:1
2:1
24
24
6
24
24
48
48
8
the Pd0 species. Bäckvall has reported a close precedent[21]
,
9
2:1
10
11
12
13
1j, 4-I
1.5:1
1.5:1
2:1
3j (60)
the formation of the N-benzylcarbamate of cis-4-acetoxy-
2-cyclohexen-1-ol by reaction of its methylcarbonate with
benzylamine in the presence of Pd0,[21] although oxazolidi-
none formation was not observed.
Step 3 is again a straightforward reaction of an allylic
carbonate with the Pd0 species to afford intermediate 10;
anti-syn isomerization might occur at this level as it is usual
for cationic (η3-allyl)palladium complexes.
1k, 4-Cl
3k (50)
3l (22)
1l, H
1m, 4-MeO
1.5:1
3m (15)
[a]
All reactions were carried out in THF at room temp. for the
indicated non-optimized time in the presence of 5% Pd(dba)2 and
15% dppf unless otherwise stated. Ϫ [b] Yields of 3 were somehow
[c]
[d]
dependent on this molar excess of 2. Ϫ Isolated yields. Ϫ
3-
Aryl-5-vinyloxazolidin-2-one 14 were also isolated: 14a (15%), 14d
(4%), and 14e (5%). Ϫ [e] When bis(1,2-diphenylphosphanyl)ethane
(dppe) was used in the place of dppf, 3a (27%) and 14a (35%) were
isolated after 24 h.
Step 4 is the straightforward formation of the required
zwitterionic intermediate 11.
182
Eur. J. Org. Chem. 1999, 181Ϫ186

Palladium(0)-Catalyzed Reaction of Acidic Anilines with (Z)-2-Butene-1,4-diyl Dicarbonate
FULL PAPER
Scheme 5. Complementary experiments
OC6H4ϪNHϪCH2CHϭCHϪCH2ϪOEt [m/z (%): 221 (49)
[Mϩ], 122 (100)]; 4-MeOC6H4ϪNHCO2ϪCH2CHϭCHϪ
CH2ϪOCO2Et {m/z (%): 309 (6) [Mϩ], 135 (100)}; oxazoli-
dinone 3m {m/z (%): 219 (100) [Mϩ], see Scheme 2}; mixed
carbonate 4m {m/z (%): 265 (9) [Mϩ], 162 (100), see Scheme
3}; vinylaziridine 6m or dihydropyrrole 7m {m/z (%): 175
(100) [Mϩ], see Scheme 3}.
In summary, an efficient method to prepare N-aryl-4-vi-
nyloxazolidin-2-ones is reported as a consequence of an un-
precedented reactivity of 2-butene-1,4-diyl dicarbonate. In-
deed, the experimental results require that the conjugate
base of the arylamine reacts faster with dicarbonate 2 (un-
catalyzed reaction 2 of Scheme 4) than with the cationic
(η3-allyl)palladium complex 8 to afford products 4 of
Scheme 3.
Scheme 4. Sequence of events leading to N-aryloxazolidin-2-ones 3
and 14
Step 5 is the intramolecular cyclization of intermediate
11 to N-aryloxazolidin-2-ones 3 with recovery of the cata-
lytic species.
Long-lived zwitterions 11 are anticipated for strong elec-
tron-withdrawing substituents R. In such cases 11 can also
deliver aryl isocyanates 12 and vinyloxirane 13. We have no
direct evidence for the formation of 12 and/or 13, but their
noncatalyzed reaction explains the formation of minor
quantities of 5-vinyloxazolidinones 14 sometimes iso-
lated.[2]
Further experiments were performed to gain better mech-
anistic insight. Thus, N-(3,5-dinitrophenyl)-4-vinyloxazoli-
din-2-one (3a) was recovered after standard treatment with
the catalytic system for seven days, no isomerization to the
5-isomer being observed. Thus, cyclization of 11 into 3a is
not reversible under the reaction conditions (Scheme 4). 4-
Experimental Section
General: All reactions under Pd catalysis were performed under
Nitroaniline (1b) reacts with 2 in the presence of sodium inert atmosphere with anhydrous solvents using standard Schlenk
techniques. Syringes or cannulae were used for transfer of solu-
tions. Carbamates 15a,b were prepared by standard procedures by
reaction of corresponding anilines 1a,b with ethyl chloroformate or
diethyl carbonate and they have been reported in the literature.[22]
Oxazolidinones 3k[4c] and 3l[3] had been described in the literature.
THF was distilled from sodium benzophenone ketyl. All solutions
were concentrated under reduced pressure in a rotary evaporator.
Ϫ Melting points were determined with a Kofler apparatus and are
uncorrected. Ϫ IR spectra were recorded with a Nicolet FT-IR 510
ethoxide and a phase-transfer agent to afford carbamate 9b,
which cyclizes to 3b under Pd0 catalysis (Scheme 5). Reac-
tion of arylcarbamates 15a and 15b with 2 under palladium
catalysis affords only the disubstitution compounds 16 (un-
determined stereochemistry), thus ruling out the inter-
vention of 15 in the formation of oxazolidinones.
Finally, we examined by GLC-MS analysis the crude
product of the reaction of 4-methoxyaniline (1m) and dicar-
bonate 2 (experiment 13 in Table 1) and peaks were ob-
ZDX. Ϫ NMR spectra were recorded with a Bruker AC250 or a
1
served attributable to the following compounds: 4-Me- Bruker AM400. H-NMR (250 MHz) chemical shifts are reported
Eur. J. Org. Chem. 1999, 181Ϫ186
183

M. Moreno-Man˜as, L. Morral, R. Pleixats, S. Villarroya
FULL PAPER
relative to CHCl3 at δ ϭ 7.26 and tetramethylsilane at δ ϭ 0.00.
Coupling constants are reported in Hz. 13C-NMR (62.5 MHz)
chemical shifts are expressed relative to CDCl3 at δ ϭ 77.00 and
tetramethylsilane at δ ϭ 0.00. Ϫ Mass spectra (EIMS) were ob-
tained with a Hewlett-Packard 5989A spectrometer and deter-
mined at an ionizing voltage of 70 eV; relevant data are listed as
tane). Ϫ IR (KBr): ν˜ ϭ 2223 cmϪ1 (CN), 1749 (CϭO). Ϫ 1H NMR
(CDCl3): δ ϭ 4.16 (dd, J ϭ 8.7 and 5.1 Hz, 1 H, 5-H), 4.63
(apparent t, J ϭ 8.7 Hz, 1 H, 5-H), 4.93 (m, 1 H, 4-H), 5.41 (d,
J ϭ 10.2 Hz, 1 H, vinylic H), 5.43 (d, J ϭ 16.0 Hz, 1 H, vinylic
H), 5.83 (ddd, J ϭ 17.5, 10.2 and 7.3 Hz, 1 H, vinylic H), 7.63 (s,
4 H, aromatic H). Ϫ 13C NMR (CDCl3): δ ϭ 58.6 (C-4), 67.1 (C-
5), 117.8, 118.5, 120.0, 120.8, 132.8, 133.8, 141.1, 154.6 (CϭO). Ϫ
MS (70 eV, EI); m/z (%): 214 (47) [Mϩ], 169 (26), 155 (62), 143
(24), 129 (88) [Mϩ Ϫ C3H3NO2], 102 (100) [Mϩ Ϫ C5H6NO2], 75
(31), 51 (26). Ϫ C11H10N2O4 (214.2): calcd. C 67.28, H 4.70, N
13.08; found C 67.78, H 4.86, N 12.38.
`
m/z (%). Ϫ Elemental analyses were performed at Servei dЈAnalisi
´
`
Quımica de la Universitat Autonoma de Barcelona.
Reaction of 3,5-Dinitroaniline (1a) with Dicarbonate 2 under Pd0
Catalysis (Entry 1, Table 1). ؊ Formation of 3a and 14a. ؊ General
Procedure for the Formation of N-Aryl-4-vinyl-1,3-oxazolidin-2-ones
3: A degassed solution of 2 (1.267 g, 5.47 mmol) in anhydrous THF
(5 mL) was added to a stirred and degassed mixture of 1a (0.50 g,
2.73 mmol), Pd(dba)2 (0.070 g, 0.137 mmol), 1,1Ј-bis(diphenyl-
phosphanyl)ferrocene (0.227 g, 0.409 mmol), and anhydrous THF
(10 mL). The reaction mixture was stirred at room temp. under
argon for 7 h (GLC monitoring). The solvent was evaporated to
dryness and the residue was chromatographed on silica gel
(230Ϫ400 mesh), eluting with hexanes and hexanes/ethyl acetate
mixtures of increasing polarity. The following compounds were ob-
tained in the given order.
Reaction of 3,5-Bis(trifluoromethyl)aniline (1d) with Dicarbonate 2
(Entry 4, Table 1). ؊ Formation of 3d and 14d: The reaction was
carried out according to the general procedure (see above).
N-[3,5-Bis(trifluoromethyl)phenyl]-4-vinyl-1,3-oxazolidin-2-one (3d):
0.922 g, 93% yield, colorless oil. Ϫ IR (film): ν˜ ϭ 1764 cmϪ1 (Cϭ
1
O). Ϫ H NMR (CDCl3): δ ϭ 4.19 (dd, J ϭ 8.8 and 6.6 Hz, 1 H,
5-H), 4.67 (apparent t, J ϭ 8.8 Hz, 1 H, 5-H), 4.96 (m, 1 H, 4-H),
5.46 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.48 (d, J ϭ 18.3 Hz, 1 H,
vinylic H), 5.82 (ddd, J ϭ 16.8, 10.2 and 8.0 Hz, 1 H, vinylic H),
7.63 (s, 1 H, aromatic H), 7.99 (s, 2 H, aromatic H). Ϫ MS (70 eV,
EI); m/z (%): 325 (71) [Mϩ], 280 (28), 266 (77), 254 (23), 240 (100)
[Mϩ Ϫ C3H3NO2], 213 (86) [Mϩ Ϫ C5H6NO2], 163 (22). Ϫ
C13H9F6NO2 (324.6): calcd. C 47.99, H 2.79, N 4.31; found 48.40,
H 3.06, N 4.27.
Dibenzylideneacetone: 0.077 g.
N-(3,5-Dinitrophenyl)-5-vinyl-1,3-oxazolidin-2-one (14a): 0.107 g,
15% yield, m.p. 121Ϫ123°C (dichloromethane/pentane). Ϫ IR
(KBr): ν˜ ϭ 1760 cmϪ1 (CϭO) . Ϫ 1H NMR (CDCl3): δ ϭ 3.95
(dd, J ϭ 8.8 and 7.3 Hz, 1 H, 4-H), 4.37 (apparent t, J ϭ 8.8 Hz,
1 H, 4-H), 5.24 (m, 1 H, 5-H), 5.50 (d, J ϭ 10.2 Hz, 1 H, vinylic
H), 5.60 (d, J ϭ 17.5 Hz, 1 H, vinylic H), 6.02 (ddd, J ϭ 16.8, 10.2
and 6.6 Hz, 1 H, vinylic H), 8.77 (s, 3 H, aromatic H). Ϫ 13C NMR
(CDCl3): δ ϭ 50.1 (C-4), 73.8 (C-5), 113.1, 117.2, 120.9, 132.8,
140.6, 148.9, 153.8 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 279 (17)
[Mϩ], 235 (60) [Mϩ Ϫ CO2], 234 (73), 194 (100) [Mϩ Ϫ C3H3NO2],
148 (61), 75 (64), 63 (39). Ϫ C11H9N3O6 (279.2): calcd. C 47.30, H
3.25, N 15.05; found C 47.62, H 3.49, N 15.09.
N-[3,5-Bis(trifluoromethyl)phenyl]-5-vinyl-1,3-oxazolidin-2-one
1
(14d): 0.039 g, 4% yield, oil. Ϫ H NMR (CDCl3): δ ϭ 3.84 (dd,
J ϭ 8.8 and 7.3 Hz, 1 H, 4-H), 4.25 (apparent t, J ϭ 8.8 Hz, 1 H,
4-H), 5.16 (m, 1 H, 5-H), 5.51 (d, J ϭ 10.2 Hz, 1 H, vinylic H),
5.57 (d, J ϭ 16.8 Hz, 1 H, vinylic H), 6.00 (ddd, J ϭ 16.8, 10.2
and 6.6 Hz, 1 H, vinylic H), 7.64 (s, 1 H, aromatic H), 8.03 (s, 2
H, aromatic H). Ϫ MS (70 eV, EI); m/z (%): 325 (65) [Mϩ], 280
(26), 266 (71), 240 (100) [Mϩ Ϫ C3H3NO2], 213 (86) [Mϩ
Ϫ
C5H6NO2], 163 (25).
N-(3,5-Dinitrophenyl)-4-vinyl-1,3-oxazolidin-2-one (3a): 0.393 g,
52%, m.p. 128Ϫ130°C (dichloromethane/pentane). Ϫ IR (KBr):
Reaction of 3,5-Dichloroaniline (1e) with Dicarbonate 2 (Entry 5,
Table 1). ؊ Formation of 3e and 14e: The reaction was carried out
according to the general procedure (see above).
1
ν˜ ϭ 1753 cmϪ1 (CϭO). Ϫ H NMR (CDCl3): δ ϭ 4.26 (dd, J ϭ
8.7 and 5.8 Hz, 1 H, 5-H), 4.74 (apparent t, J ϭ 8.7 Hz, 1 H, 5-
H), 5.06 (m, 1 H, 4-H), 5.54 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.60
(d, J ϭ 16.8 Hz, 1 H, vinylic H), 5.87 (ddd, J ϭ 17.5, 10.2 and 8.02
Hz, 1 H, vinylic H), 8.76 (s, 3 H, aromatic H). Ϫ 13C NMR
(CDCl3): δ ϭ 59.0 (C-4), 67.3 (C-5), 113.5, 119.3, 122.5, 132.8,
139.7, 148.7, 154.4 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 279 (58)
[Mϩ], 234 (52), 220 (51), 194 (100) [Mϩ Ϫ C3H3NO2], 148 (51), 75
(98), 63 (61). Ϫ C11H9N3O6 (279.2): calcd. C 47.30, H 3.25, N
15.05; found C 47.66, H 3.43, N 14.85.
N-(3,5-Dichlorophenyl)-4-vinyl-1,3-oxazolidin-2-one (3e): 0.640 g,
80% yield, colorless oil. Ϫ IR (film): ν˜ ϭ 1756 cmϪ1 (CϭO). Ϫ 1H
NMR (CDCl3): δ ϭ 4.13 (dd, J ϭ 8.8 and 5.1 Hz, 1 H, 5-H), 4.60
(apparent t, J ϭ 8.8 Hz, 1 H, 5-H), 4.82 (m, 1 H, 4-H), 5.41 (d,
J ϭ 10.2 Hz, 1 H, vinylic H), 5.42 (d, J ϭ 16.8 Hz, 1 H, vinylic
H), 5.80 (ddd, J ϭ 17.5, 10.2 and 8.0 Hz, 1 H, vinylic H), 7.12 (s,
1 H, aromatic H), 7.42 (s, 2 H, aromatic H). Ϫ 13C NMR (CDCl3):
δ ϭ 58.8 (C-4), 67.1 (C-5), 118.7, 120.9, 124.4, 133.8, 135.1, 138.9,
154.7 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 261/259/257 (6/57/87)
[Mϩ], 258 (13), 212 (27), 200 (37), 198 (57), 178 (39), 176/174/172
N-(4-Nitrophenyl)-4-vinyl-1,3-oxazolidin-2-one (3b; Entry 2, Table
1): 0.686 g, 81% yield, m.p. 78.5Ϫ80°C (dichloromethane/hexane).
Ϫ IR (KBr): ν˜ ϭ 1756 cmϪ1 (CϭO). Ϫ 1H NMR (CDCl3): δ ϭ
4.16 (dd, J ϭ 8.8 and 5.4 Hz, 1 H, 5-H), 4.63 (apparent t, J ϭ 8.8
Hz, 1 H, 5-H), 4.88Ϫ4.99 (m, 1 H, 4-H), 5.41 (d, J ϭ 9.9 Hz, 1 H,
vinylic H), 5.42 (d, J ϭ 17.2 Hz, 1 H, vinylic H), 5.82 (ddd, J ϭ
17.2, 9.9 and 7.5 Hz, 1 H, vinylic H), 7.66 (d, J ϭ 9.3 Hz, 2 H,
aromatic H), 8.19 (d, J ϭ 9.3 Hz, 2 H, aromatic H). Ϫ 13C NMR
(CDCl3): δ ϭ 58.8 (C-4), 67.2 (C-5), 119.5, 121.0, 124.6, 133.7,
142.9, 143.5, 154.6 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 234 (98)
[Mϩ], 189 (29), 175 (47), 149 (100) [Mϩ - C3H3NO2], 144 (20), 143
(26), 129 (54), 117 (45), 103 (58), 90 (24), 76 (59), 77 (23), 75 (21),
64 (29), 63 (28), 50 (29), 44 (30). Ϫ C11H10N2O4 (234.2): calcd. C
56.41, H 4.30, N 11.96; found C 56.41, H 4.27, N 11.78.
(11/63/100) [Mϩ Ϫ C3H3NO2], 149/147/145 (9/49/76) [Mϩ
Ϫ
C5H6NO2], 109 (37). Ϫ C11H9Cl2NO2 (257.9): calcd. C 51.36, H,
3.53, N 5.45; found C 51.23, H 3.79, N 5.14.
N-(3,5-Dichlorophenyl)-5-vinyl-1,3-oxazolidin-2-one (14e): 0.039 g,
1
5% yield, oil. Ϫ H NMR (CDCl3): δ ϭ 3.73 (dd, J ϭ 8.8 and 6.6
Hz, 1 H, 4-H), 4.13 (apparent t, J ϭ 8.8 Hz, 1 H, 4-H), 5.09 (m, 1
H, 5-H), 5.43 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.53 (d, J ϭ 16.8
Hz, 1 H, vinylic H), 5.97 (ddd, J ϭ 16.8, 10.2 and 6.6 Hz, 1 H,
vinylic H), 7.12 (s, 1 H, aromatic H), 7.49 (s, 2 H, aromatic H). Ϫ
MS (70 eV, EI); m/z (%): 261/259/257 (3/18/27) [Mϩ], 258 (4), 212
(41), 176/174/172 (11/65/100) [Mϩ Ϫ C3H3NO2], 149/147/145 (6/26/
41) [Mϩ Ϫ C5H6NO2].
N-(4-Cyanophenyl)-4-vinyl-1,3-oxazolidin-2-one (3c; Entry 3, Table
N-(3-Nitrophenyl)-4-vinyl-1,3-oxazolidin-2-one (3f; Entry 6, Table
1): 1.010 g, 80% yield, m.p. 104Ϫ106°C (dichloromethane/pen- 1): 0.873 g, 74% yield, m.p. 76Ϫ77°C (tert-butyl methyl ether/pen-
184 Eur. J. Org. Chem. 1999, 181Ϫ186

Palladium(0)-Catalyzed Reaction of Acidic Anilines with (Z)-2-Butene-1,4-diyl Dicarbonate
FULL PAPER
1
tane). Ϫ IR (KBr): ν˜ ϭ 1758 cmϪ1 (CϭO). Ϫ H NMR (CDCl3): 159.5 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 316 (14) [Mϩ1], 315
δ ϭ 4.19 (dd, J ϭ 8.8 and 5.8 Hz, 1 H, 5-H), 4.67 (apparent t, J ϭ (100) [Mϩ], 256 (16), 230 (37) [Mϩ Ϫ C3H3NO2], 203 (24) [Mϩ
8.8 Hz, 1 H, 5-H), 4.97 (m, 1 H, 4-H), 5.43 (d, J ϭ 10.2 Hz, 1 H, C5H6NO2], 76 (20). Ϫ C11H10INO2 (315.1): calcd. C 41.93, H 3.20,
Ϫ
vinylic H), 5.48 (d, J ϭ 16.8 Hz, 1 H, vinylic H), 5.83 (ddd, J ϭ N 4.44; found C 42.48, H 3.13, N 4.19.
17.5, 10.2 and 8.0 Hz, 1 H, vinylic H), 7.54 (apparent t, J ϭ 8.0
N-(4-Methoxyphenyl)-4-vinyl-1,3-oxazolidin-2-one (3m; Entry 13,
Table 1): 0.187 g, 15% yield; oil. Ϫ IR (film): ν˜ ϭ 1750 cmϪ1 (Cϭ
O). Ϫ H NMR (CDCl3): δ ϭ 3.80 (s, 3 H, CH3O), 4.09 (dd, J ϭ
Hz, 1 H, aromatic H), 7.97 (m, 2 H, aromatic H), 8.27 (apparent
t, J ϭ 2.2 Hz, 1 H, aromatic H). Ϫ 13C NMR (CDCl3): δ ϭ 59.0
(C-4), 67.1 (C-5), 115.0, 119.0, 121.3, 126.3, 129.7, 133.7, 138.3,
148.4, 155.0 (CϭO). Ϫ MS (70 eV, EI); m/z (%): 234 (80) [Mϩ],
190 (25) [Mϩ Ϫ CO2], 175 (49), 149 (100) [Mϩ Ϫ C3H3NO2], 143
(28), 129 (40), 117 (39), 103 (38), 76 (58), 63 (35). Ϫ C11H10N2O4
(234.2): calcd. C 56.41, H 4.30, N 11.96; found C 56.69, H 4.29,
N 11.64.
1
8.7 and 6.6 Hz, 1 H, 5-H), 4.57 (apparent t, J ϭ 8.7 Hz, 1 H, 5-
H), 4.75 (m, 1 H, 4-H), 5.28 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.31
(d, J ϭ 16.8 Hz, 1 H, vinylic H), 5.78 (ddd, J ϭ 16.8, 10.2 and 8.0
Hz, 1 H, vinylic H), 6.88 (d, J ϭ 8.7 Hz, 2 H, aromatic H), 7.29
(d, J ϭ 8.7 Hz, 2 H, aromatic H). Ϫ MS (70 eV, EI); m/z (%): 219
(100) [Mϩ], 160 (28), 134 (51) [Mϩ Ϫ C3H3NO2], 107 (14) [Mϩ
Ϫ
C5H6NO2], 77 (14).
N-(4-Methoxycarbonylphenyl)-4-vinyl-1,3-oxazolidin-2-one (3g; En-
try 7, Table 1): 1.145 g, 83% yield, m.p. 83Ϫ84°C (dichlorometh-
ane/pentane). Ϫ IR (KBr): ν˜ ϭ 1757 cmϪ1 (CϭO), 1707 (CϭO).
Reaction of 4-Nitroaniline (1b) with Dicarbonate 2 in the Presence
of Sodium Ethoxide and in the Absence of Pd0. ؊ Formation of
Carbamate 9b: A mixture of 1b (0.600 g, 4.344 mmol), sodium
ethoxide (0.295 g, 4.344 mmol), n-tetrabutylammonium chloride
(1.18 g, 4.344 mmol), and anhydrous THF (5 mL) was stirred at
room temp. for 20 min. Then, a solution of 2 (2.017 g, 8.688 mmol)
in anhydrous THF (5 mL) was added and the stirred mixture was
left at room temp. for 5 d. The solvent was evaporated to dryness
and the residue was chromatographed on silica gel (230Ϫ400
mesh), eluting with hexanes and mixtures of hexanes/ethyl acetate
of increasing polarity. The following compounds were obtained in
that order.
Ϫ
1H NMR (CDCl3): δ ϭ 3.89 (s, 3 H, CH3), 4.14 (dd, J ϭ 8.8
and 5.1 Hz, 1 H, 5-H), 4.60 (apparent t, J ϭ 8.8 Hz, 1 H, 5-H),
4.92 (m, 1 H, 4-H), 5.37 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.40 (d,
J ϭ 17.5 Hz, 1 H, vinylic H), 5.82 (ddd, J ϭ 17.5, 10.2 and 8.0 Hz,
1 H, vinylic H), 7.57 (dt, J ϭ 8.7 and 2.9 Hz, 2 H, aromatic H),
8.02 (dt, J ϭ 8.7 and 2.9 Hz, 2 H, aromatic H). Ϫ 13C NMR
(CDCl3): δ ϭ 51.8 (CH3), 58.8 (C-4), 67.1 (C-5), 119.5, 120.4,
125.8, 130.4, 134.2, 141.2, 154.9 (CϭO), 166.4 (CϭO ester). Ϫ MS
(70 eV, EI); m/z (%): 247 (100) [Mϩ], 216 (26) [Mϩ Ϫ OCH3), 188
(38) [Mϩ Ϫ COOCH3], 162 (43) [Mϩ Ϫ C3H3NO2], 135 (27) [Mϩ
Ϫ C5H6NO2]. Ϫ C13H13NO4 (247.2): calcd. C 63.15, H 5.30, N
5.66; found C 63.20, H 5.27, N 5.46.
Carbamate 9b: 0.703 g, 50%, m.p. 107Ϫ108°C (dichloromethane/
pentane). Ϫ IR (film): ν˜ ϭ 3260 cmϪ1 (NϪH), 1741 (br., CϭO).
1
N-(3-Chloro-4-fluorophenyl)-4-vinyl-1,3-oxazolidin-2-one (3h; Entry
8, Table 1): 0.485 g, 47% yield, b.p. 170°C (oven temp.)/0.08 Torr.
Ϫ IR (film): ν˜ ϭ 1755 cmϪ1 (CϭO). Ϫ 1H NMR (CDCl3): δ ϭ
4.11 (dd, J ϭ 8.7 and 6.6 Hz, 1 H, 5-H), 4.60 (apparent t, J ϭ 8.8
Hz, 1 H, 5-H), 4.81 (m, 1 H, 4-H), 5.37 (d, J ϭ 10.2 Hz, 1 H,
vinylic H), 5.38 (d, J ϭ 16.8 Hz, 1 H, vinylic H), 5.78 (ddd, J ϭ
17.5, 10.2 and 8.0 Hz, 1 H, vinylic H), 7.11 (apparent t, J ϭ 8.8
Hz, 1 H, aromatic H), 7.29 (m, 1 H, aromatic H), 7.55 (apparent
dd, J ϭ 6.6 and 2.9 Hz, 1 H, aromatic H). Ϫ 13C NMR (CDCl3):
δ ϭ 59.6 (C-4), 67.0 (C-5), 116.3, 116.7, 120.9, 121.1, 123.5, 134.0,
153.2, 155.3, 157.1. Ϫ MS (70 eV, EI); m/z (%): 241 (90) [Mϩ], 196
(22), 158 (31), 156 (100) [Mϩ Ϫ C3H3NO2], 135 (22), 131 (22), 129
(68) [Mϩ Ϫ C5H6NO2]. Ϫ C11H9ClFNO2 (241.6): calcd. C 54.67,
H 3.75, N 5.79; found C 54.42, H 3.69, N 5.63.
Ϫ H NMR (CDCl3): δ ϭ 1.33 (t, J ϭ 6.6 Hz, 3 H, CH3), 4.27 (q,
J ϭ 6.6 Hz, 2 H, CH2OCO), 4.75 (m, 4 H, 2 OCH2Cϭ), 5.80 (m,
2 H, CHϭCH), 7.02 (br. s, 1 H, NH), 7.56 (d, J ϭ 8.7 Hz, 2 H,
aromatic H), 8.21 (d, J ϭ 8.7 Hz, 2 H, aromatic H).
4-Nitroaniline (1b): 0.168 g, 28% recovery.
Formation of Oxazolidinone 3b from Carbamate 9b under Pd0 Ca-
talysis: A degassed and stirred solution of 9b (0.400 g, 1.234 mmol),
Pd(dba)2 (0.034 g, 0.062 mmol), and 1,1Ј-bis(diphenylphosphanyl)-
ferrocene (0.102 g, 0.185 mmol) in anhydrous THF (10 mL) was
left at room temp. under argon for 2 d. GLC, TLC and 1H-NMR
monitoring showed the disappearance of 9b and the formation of
3b.
Reaction of Carbamate 15a with Dicarbonate 2 under Pd0 Catalysis.
؊ Formation of 16a: A degassed solution of 2 (0.382 g, 1.646 mmol)
in anhydrous THF (5 mL) was added to a stirred and degassed
mixture of 15a (0.35 g, 1.372 mmol), Pd(dba)2 (0.036 g, 0.069
mmol), 1,1Ј-bis(diphenylphosphanyl)ferrocene (0.114 g, 0.206
mmol), and anhydrous THF (5 mL). The reaction mixture was
stirred at room temp. under argon for 24 h (GLC monitoring). The
solvent was evaporated to dryness and the residue was chromatog-
raphed on silica gel (230Ϫ400 mesh), eluting with hexanes and hex-
anes/ethyl acetate mixtures of increasing polarity. The following
compounds were obtained in that order.
N-(4-Trifluoromethylphenyl)-4-vinyl-1,3-oxazolidin-2-one (3i; Entry
9, Table 1): 0.815 g, 73% yield, oil. Ϫ IR (film): ν˜ ϭ 1758 cmϪ1
1
(CϭO). Ϫ H NMR (CDCl3): δ ϭ 4.14 (dd, J ϭ 8.8 and 5.8 Hz,
1 H, 5-H), 4.61 (apparent t, J ϭ 8.8 Hz, 1 H, 5-H), 4.91 (m, 1 H,
4-H), 5.38 (d, J ϭ 10.2 Hz, 1 H, vinylic H), 5.41 (d, J ϭ 16.8 Hz,
1 H, vinylic H), 5.80 (ddd, J ϭ 17.5, 10.2 and 8.0 Hz, 1 H, vinylic
H), 7.60 (s, 4 H, aromatic H). Ϫ MS (70 eV, EI); m/z (%): 258 (11)
[Mϩ1], 257 (69) [Mϩ], 238 (9) [Mϩ Ϫ F], 212 (25), 198 (59), 172
(68) [Mϩ
Ϫ Ϫ C5H6NO2]. Ϫ
C3H3NO2], 145 (100) [Mϩ
C12H10F3NO2 (257.2): calcd. C 56.04, H 3.92, N 5.44; found C
56.18, H 4.03, N 5.37.
Dibenzylideneacetone: 0.037 g.
N-(4-Iodophenyl)-4-vinyl-1,3-oxazolidin-2-one (3j; Entry 10, Table
1): 0.570 g, 60% yield; m.p. 66Ϫ68°C (diethyl ether/pentane). Ϫ IR
(KBr): ν˜ ϭ 1753 cmϪ1 (CϭO). Ϫ 1H NMR (CDCl3): δ ϭ 4.10 (dd,
J ϭ 8.8 and 5.8 Hz, 1 H, 5-H), 4.58 (apparent t, J ϭ 8.8 Hz, 1 H,
5-H), 4.82 (m, 1 H, 4-H), 5.35 (d, J ϭ 10.2 Hz, 1 H, vinylic H),
5.37 (d, J ϭ 17.5 Hz, 1 H, vinylic H), 5.77 (ddd, J ϭ 17.5, 10.2
Dicarbamate 16a: 0.182 g, 47% with respect to 15a, m.p.
171Ϫ172°C (dichloromethane/pentane). Ϫ IR (KBr): ν˜ ϭ 1717
1
cmϪ1 (CϭO). Ϫ H NMR (CDCl3): δ ϭ 1.30 (t, J ϭ 7.3 Hz, 6 H,
2 CH3), 4.28 (q, J ϭ 7.3 Hz, 4 H, 2 CH2OCO), 4.48 (m, 4 H, 2
NCH2Cϭ), 5.86 (m, 2 H, CHϭCH), 8.50 (s, 4 H, aromatic H),
8.84 (s, 2 H, aromatic H). Ϫ 13C NMR (CDCl3): δ ϭ 14.1 (CH3),
and 8.0 Hz, 1 H, vinylic H), 7.22 (d, J ϭ 8.7 Hz, 2 H, aromatic 50.9, 63.2, 115.1, 124.8, 128.4, 144.2, 148.3, 154.0 (CϭO). Ϫ
H), 7.65 (d, J ϭ 8.7 Hz, 2 H, aromatic H). Ϫ 13C NMR (CDCl3): C22H22N6O12 (562.45): calcd. C 46.96, H 3.94, N 14.95; found C
δ ϭ 59.2 (C-4), 67.1 (C-5), 88.6, 120.7, 122.8, 134.3, 136.8, 137.8,
47.99, H 4.12, N 14.11.
Eur. J. Org. Chem. 1999, 181Ϫ186
185

M. Moreno-Man˜as, L. Morral, R. Pleixats, S. Villarroya
FULL PAPER
28, 1173Ϫ1192. Ϫ [8e] S. A. Godleski, “Nucleophiles with Allyl-
Metal Complexes” in Comprehensive Organic Synthesis (Eds.:
B. M. Trost, I. Fleming), Pergamon Press, New York, 1991, vol.
4, chapter 3.3. Ϫ [8f] J. Tsuji, I. Minami, Acc. Chem. Res. 1987,
20, 140Ϫ145. Ϫ [8g] J. Tsuji, Tetrahedron 1986, 42, 4361Ϫ4401.
Reaction of Carbamate 15b with Dicarbonate 2 under Pd0 Catalysis.
؊ Formation of 16b: Obtained in 85% yield (0.115 g) from 15b
according to an analogous procedure as described for 16a. M.p.
125Ϫ126°C (dichloromethane/pentane). Ϫ IR (KBr): ν˜ ϭ 1717
[8h] R. F. Heck, Palladium Reagents in Organic Synthesis, Aca-
[8i]
1
cmϪ1 (CϭO). Ϫ H NMR (CDCl3): δ ϭ 1.25 (t, J ϭ 7.3 Hz, 6 H,
Ϫ
demic Press, London, 1985. Ϫ
outh, Chem. Rev. 1989, 89, 257Ϫ276. Ϫ
Howarth, J. M. J. Williams, Tetrahedron: Asymmetry 1992, 3,
G. Consiglio, R. M. Waym-
2 CH3), 4.21 (q, J ϭ 7.3 Hz, 4 H, 2 CH2OCO), 4.35 (m, 4 H, 2
NCH2Cϭ), 5.70 (m, 2 H, CHϭCH), 7.35 (d, J ϭ 8.7 Hz, 4 H,
aromatic H), 8.17 (d, J ϭ 8.7 Hz, 4 H, aromatic H). Ϫ 13C NMR
(CDCl3): δ ϭ 14.4 (CH3), 51.2, 62.5, 124.2, 125.5, 128.3, 144.8,
147.8, 154.4 (CϭO). ؊ C22H24N4O8 (472.1): calcd. C 55.91, H 5.12,
N 11.86; found C 56.32, H 5.37, N 11.32.
[8j]
C. G. Frost, J.
[8k]
1089Ϫ1122. Ϫ
John Wiley and Sons, Chichester, 1995. Ϫ
J. Tsuji, Palladium Reagents and Catalysis,
[8l]
P. J. Harrington,
“Transition Metal Allyl Complexes: Pd, W, Mo-assisted Nucle-
ophilic Attack” in Comprehensive Organometallic Chemistry II
(Eds.: E. W. Abel, F. G. A. Stone, G. Wilkinson), Pergamon
Press, New York, 1995, vol. 12, chapter 8.2. Ϫ [8m] M. Moreno-
Man˜as, R. Pleixats, Adv. Heterocycl. Chem. 1996, 96, 73Ϫ129.
M. Moreno-Man˜as, L. Morral, R. Pleixats, J. Org. Chem. 1998,
63, 6160Ϫ6166.
[9]
[10] [10a]
Acknowledgments
´
S. Cerezo, J. Cortes, M. Moreno-Man˜as, R. Pleixats, A.
[10b]
´
S. Cerezo, J. Cortes, J.-
Roglans, Tetrahedron, in press. Ϫ
´
M. Lopez, M. Moreno-Man˜as, R. Pleixats, A. Roglans, Tetra-
Financial support from DGICYT (Ministry of Education and Sci-
ence of Spain; project PB93Ϫ0896 and a predoctoral scholarship
to L. M.) and from CIRIT (Generalitat de Catalunya, project
SGR96Ϫ0030) is gratefully acknowledged.
hedron, in press.
[11] [11a] T. Ibuka, N. Mimura, H. Aoyama, M. Akaji, H. Ohno, Y.
Miwa, T. Taga, K. Nakai, H. Tamamura, N. Fujii, J. Org.
[11b]
Chem. 1997, 62, 999Ϫ1015. Ϫ
T. Ibuka, N. Mimura, H.
Ohno, K. Nakai, M. Akaji, H. Habashita, H. Tamamura, Y.
Miwa, T. Taga, N. Fujii, Y. Yamamoto, J. Org. Chem. 1997,
62, 2982Ϫ2991.
[12]
[1] [1a]
M. E. Dyen, D. Swern, Chem. Rev. 1967, 67, 197Ϫ246.
[1b]
Ϫ
D. J. Ager, I. Prakash, D. R. Schaad, Chem. Rev. 1996,
K. Fugami, Y. Morizawa, K. Oshima, H. Nozaki, Tetrahedron
Lett. 1985, 26, 857Ϫ860.
96, 835Ϫ875.
[2] [2a]
J. E. Herweh, T. A. Foglia, D. Swern, J. Org. Chem. 1968,
[13] [13a] S.-I. Murahashi, T. Shimamura, I. Moritani, J. Chem. Soc.,
[13b]
33, 4029Ϫ4033. Ϫ [2b] D. Braun, J. Weinert, Liebigs Ann. Chem.
Chem. Commun. 1974, 931Ϫ932. Ϫ
J.-E. Bäckvall, J.E.
1976, 221Ϫ224. Ϫ [2c] D. Braun, J. Weinert, Liebigs Ann. Chem.
Nyström, J. Chem. Soc., Chem. Commun. 1981, 59Ϫ61.
T. Tsuda, T. Kiyoi, T. Saegusa, J. Org. Chem. 1990, 55,
3388Ϫ3390.
[2d]
[14]
[15]
1979, 200Ϫ209. Ϫ
W. A. Gregory, D. R. Brittelli, C.-L. J.
Wang, M. A. Wuonola, R. J. McRipley, D. C. Eustice, V. S.
Eberly, P. T. Bartholomew, A. M. Slee, M. Forbes, J. Med.
Chem. 1989, 32, 1673Ϫ1681.
Y. Uozumi, A. Tanahashi, T. Hayashi, J. Org. Chem. 1993, 58,
6826Ϫ6832.
[3]
[4]
M. Fujiwara, A. Baba, H. Matsuda, J. Heterocycl. Chem. 1988,
25, 1351Ϫ1357.
[16] [16a] A. Yamazaki, K. Achiwa, Tetrahedron: Asymmetry 1995, 6,
[16b]
´
C. Thorey, J. Wilken, F. Henin, J. Martens,
1021Ϫ1024. Ϫ
T. Mehler, J. Muzart, Tetrahedron Lett. 1995, 36, 5527Ϫ5530.
[16c] P. Lhoste, M. Massacret, D. Sinou, Bull. Soc. Chim. Fr.
1997, 134, 343Ϫ347.
[4a] B. M. Trost, A. R. Sudhakar, J. Am. Chem. Soc. 1988, 110,
7933Ϫ7935. Ϫ [4b] B. M. Trost, A. R. Sudhakar, J. Am. Chem.
Soc. 1987, 109, 3792Ϫ3794. Ϫ [4c] C. Larksarp, H. Alper, J. Am.
Chem. Soc. 1997, 119, 3709Ϫ3715.
Ϫ
[17] [17a]
M. Massacret, C. Goux, P. Lhoste, D. Sinou, Tetrahedron
[5] [5a]
[17b]
T. Hayashi, A. Yamamoto, Y. Ito, Tetrahedron Lett. 1988,
Lett. 1994, 35, 6093Ϫ6096. Ϫ
C. Goux, M. Massacret, P.
[5b]
29, 99Ϫ102. Ϫ
B. M. Trost, D. L. Van Vranken, J. Am.
Lhoste, D. Sinou, Organometallics 1995, 14, 4585Ϫ4593.
A. Satake, H. Ishii, I. Shimizu, Y. Inoue, H. Hasegawa, A. Ya-
mamoto, Tetrahedron 1995, 51, 5331Ϫ5340.
[18]
[19]
Chem. Soc. 1990, 112, 1261Ϫ1263. Ϫ [5c] B. M. Trost, D. L. Van
Vranken, Angew. Chem. Int. Ed. Engl. 1992, 31, 228Ϫ230. Ϫ [5d]
B. M. Trost, D.L. Van Vranken, C. Bingel, J. Am. Chem. Soc.
J. Tsuji, I. Shimizu, I. Minami, Y. Ohashi, T. Sugiura, K. Taka-
1992, 114, 9327Ϫ9343. Ϫ [5e] B. M. Trost, D. L. Van Vranken,
hashi, J. Org. Chem. 1985, 50, 1523.
[5f]
[20b]
J. Am. Chem. Soc. 1993, 115, 444Ϫ458. Ϫ
B. M. Trost, D.
[20] [20a] F. G. Bordwell, Acc. Chem. Res. 1988, 21, 456Ϫ463. Ϫ
F. G. Bordwell, D. J. Algrim, J. Am. Chem. Soc. 1988, 110,
2964Ϫ2968. Ϫ [20c] F. G. Bordwell, X.-M. Zhang, J.-P. Cheng J.
Org. Chem. 1993, 58, 6410Ϫ6416.
E. Patterson, J. Org. Chem. 1998, 63, 1339Ϫ1341.
[6] [6a]
[6b]
A. Arcadi, Synlett 1997, 941Ϫ943. Ϫ
D. Bouyssi, M.
Cavicchioli, G. Balme, Synlett 1997, 944Ϫ946.
[7] [7a]
[21]
M. Kimura, K. Fugami, S. Tanaka, Y. Tamaru, J. Org.
R. G. P. Gatti, A. L. E. Larsson, J.-E. Bäckvall, J. Chem. Soc.,
[7b]
Chem. 1992, 57, 6377Ϫ6379. Ϫ
M. Kimura, S. Tanaka, Y.
Perkin Trans. 1 1997, 577Ϫ584.
[22]
[22a]
Tamaru, J. Org. Chem. 1995, 60, 3764Ϫ3772.
For 15a see:
J. J. Blanksma, G. Verberg, Recl. Trav. Chim.
[8]
For reviews see: [8a] B. M. Trost, T. R. Verhoeven, “Organopal-
ladium Compounds in Organic Synthesis and in Catalysis” in
Comprehensive Organometallic Chemistry (Eds.: G. Wilkinson,
F. G. A. Stone, E. W. Abel), Pergamon Press, New York, 1982,
Pays-Bas 1934, 53, 1037Ϫ1046. Ϫ
For 15b see: [22b] E. Angeles, A. Santillan, I. Martınez, A. Ramı-
´
´
´
rez, E. Moreno, M. Salmon, R. Martınez, Synth. Commun.
1994, 24, 2441Ϫ2447. Ϫ [22c] R. Leardini, G. Zanardi, Synthesis
vol. 8, chapter 57. Ϫ [8b] B. M. Trost, Acc. Chem. Res. 1980, 13,
1982, 225Ϫ227.
Received July 31, 1998
[O98337]
[8c]
385Ϫ393. Ϫ
B. M. Trost, Chemtracts: Org. Chem. 1988, 1,
415Ϫ435. Ϫ [8d] B. M. Trost, Angew. Chem. Int. Ed. Engl. 1989,
186
Eur. J. Org. Chem. 1999, 181Ϫ186