Intramolecular iron(II)-catalyzed nitrogen transfer reactions of unsaturated alkoxycarbonyl azides: A facile and stereoselective route to 4,5-disubstituted oxazolidinones

Article abstract of DOI:10.1002/1521-3765(20010618)7:12<2581::AID-CHEM25810>3.0.CO;2-O

Intramolecular Fe¹¹-catalyzed reactions of various unsaturated alkoxycarbonyl azides are described. The reactions occur in the presence of stoichiometric amounts of trimethyl silyl chloride employing ethanol as the solvent. The corresponding 2-

Full text of DOI:10.1002/1521-3765(20010618)7:12<2581::AID-CHEM25810>3.0.CO;2-O

FULL PAPER
Intramolecular Iron(ii)-catalyzed Nitrogen Transfer Reactions
of Unsaturated Alkoxycarbonyl Azides: A Facile and Stereoselective Route
to 4,5-Disubstituted Oxazolidinones
Thorsten Bach,* Björn Schlummer, and Klaus Harms[a]=
Dedicated to Professor David A. Evans on the occasion of his 60th birthday
Abstract: Intramolecular FeII-catalyzed
reactions of various unsaturated alkoxy-
carbonyl azides are described. The re-
actions occur in the presence of stoi-
chiometric amounts of trimethyl silyl
chloride employing ethanol as the sol-
vent. The corresponding 2-alkenyloxy-
carbonyl azides 5, 9, 18, 20, 22, and 24
gave the products 7/8, 10/11, 19, 21, 23,
and 25 of an olefin chloroamination in
moderate to good yields (47 ± 72%). The
facial diastereoselectivity of the ring
closing C N-bond forming step is good
both in cyclic (20, 24) and in acyclic
substrates (5, 18, 22) (>90% ds). The
subsequent chlorine atom transfer oc-
curs selectively in cyclic systems (20, 24)
and in systems (9b, 18) which exhibit a
conformational bias in the postulated
radical intermediate 14. The lifetime t of
this elusive intermediate was estimated
from the loss of stereochemical infor-
mation in conformationally unrestricted
systems (9a, 22) and from the data
obtained with a radical clock (31 !
32). 2-Alkynyloxycarbonyl azides 34 and
36 also yield chloroamination products
which are obtained exclusively as the
(Z)-isomers 35 and 37 (81 ± 99% yield).
The products of the tert-butyl-substitut-
ed substrates 38 undergo an immediate
rearrangement/solvolysis reaction in the
reaction mixture and gave the 5-alkoxy-
oxazolidinones 39 (93 ± 99% yield).
Keywords: cyclization
neous catalysis iron
´
homoge-
´ nitrogen
´
heterocycles ´ radical reactions
occurs and the amide BocNH2 is obtained as the major
product after work-up. If sulfur nucleophiles are employed as
reaction partners, BocN3 allows for a smooth FeCl2-catalyzed
imidation (Scheme 1). Thus, sulfimides 3 and sulfoximides 4
are available from sulfides 1 and from sulfoxides 2. Subse-
quent 2,3-rearrangement reactions of allyl sulfimides yield
N,N-diprotected allyl amines in good yields.[7c]
Introduction
The reaction of alkoxycarbonyl azides and alkenes is known
to yield 1-alkoxycarbonyl-1,2,3-triazolines.[1] Strained alkenes
and alkenes activated by electron-releasing groups react
readily whereas the reaction of non-activated olefins is
slow.[2, 3] The corresponding triazolines can be converted into
aziridines through nitrogen extrusion.[3] Alternatively, azir-
idines are directly accessible by thermal or photochemical
decomposition of alkoxycarbonyl azides in the presence of
alkenes.[4, 5] Transition metal catalyzed processes of the latter
type have to the best of our knowledge not been studied.[6]
We have recently shown that tert-butyloxycarbonyl azide
(BocN3) is a suitable precursor for the generation of a N-Boc-
protected nitrogen fragment ªBocNº by transition metal
catalysis.[7] In the presence of FeCl2 a rapid nitrogen evolution
BocN3 [FeCl2]
(CH2Cl2)
X
S
X
NBoc
R1
S
R1
R
R
..
(44-92%)
(40-95%)
1
2
X =
3
4
X = O
Scheme 1. The FeII-catalyzed imidation of sulfides 1 and sulfoxides 2 with
BocN3.
The intermolecular FeII-catalyzed reaction of BocN3 with
alkenes proceeded sluggishly. Only electron rich alkenes gave
a notable conversion.[7a] With silyl enol ethers and ketene
acetals the 1,3-dipolar cycloaddition/dediazotation was a
significant background reaction[3c,e] which made it difficult to
distinguish between the catalyzed and the uncatalyzed path-
way.[8] In view of these problems we looked into the possibility
of an intramolecular nitrene transfer which was expected to
occur in unsaturated azidoformates. Recent studies by
[a] Prof. Dr. T. Bach,[‡] Dipl.-Chem. B. Schlummer, Dr. K. Harms=
Fachbereich Chemie der Philipps-Universität
Hans-Meerwein-Strasse, 35032 Marburg (Germany)
E-mail: thorsten.bach@ch.tum.de
‡
[ ] New address:
Lehrstuhl für Organische Chemie I, Technische Universität München
Lichtenbergstrasse 4, 85747 Garching (Germany)
Fax : (‡49)89-289-13315
[=] Crystal structure determination
Chem. Eur. J. 2001, 7, No. 12
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T. Bach et al.
FULL PAPER
Bergmeier et al. revealed that a thermal decomposition of
alkenyl azidoformates (alkenyloxycarbonyl azides) yields
bicyclic aziridines which in turn undergo a facile ring opening
to substituted oxazolidinones.[5] This intriguing reaction
sequence is exemplified by the reaction of azide 5a which
upon heating in 1,1,2,2-tetrachloroethane (TCE) yielded the
5-chloromethyl substituted oxazolidinone 7a via aziridine 6a
as intermediate (Scheme 2). The ring opening was caused by
hydrochloric acid which is likely to be formed from the
solvent at elevated temperature.
following account.[11] As it turned out the FeII-catalyzed
decomposition of unsaturated azido formates does not follow
an aziridination pathway. On the contrary, the reaction has to
be envisaged as an intramolecular chloroamination initiated
by an electron-deficient intermediate. This new intramolec-
ular reaction pathway accessible to azides and alkenes in the
presence of FeCl2 has been further investigated by structural
and spectroscopic studies. The unexpected mechanistic course
has an additional impact on the scope of the reaction. It is
applicable not only to alkenyl azidoformates but also to the
corresponding alkynyl derivatives.[11b]
O
O
O
N
O
∆T
O
HCl
O
N3
NH
R
R
Results and Discussion
R
Cl
Reaction of alkenyloxycarbonyl azides: In preliminary ex-
periments, we found that FeCl2 was suited to promote the
intramolecular reaction of 2-alkenyloxycarbonyl azides, such
as compound 5a. Not unexpectedly, the apparent ring opening
product 7a was formed in which a chlorine atom is incorpo-
rated. If FeCl2 was to deliver the chlorine atom it had to be
used stoichiometrically. The reaction of compound 5a with
FeCl2 (0.5 equiv) in acetonitrile as the solvent yielded 59% of
the desired product 7a. We quickly discovered that TMSCl
can be employed as a stoichiometric chlorine source. This
finding enabled us to use FeCl2 in catalytic quantities and
paved the way to the FeII-catalyzed aminochlorination
depicted in Scheme 3. Several substrates were employed in
the reaction to give acceptable yields (Scheme 3, Table 1). In
general, more complex, less volatile substrates gave better
yields than substrates with similar substitution pattern but
5a
R = Cyclohexyl
6a
7a
Scheme 2. Thermal intramolecular aziridination and ring opening of the
2-propenyloxycarbonyl azide 5a.
At room temperature there is no intramolecular reaction of
alkenyl azidoformates. It consequently appealed to us to study
possible FeII-catalyzed reactions of these substrates more
closely. We initially considered an aziridination via nitrene
transfer as the most likely reaction to occur.[8] The possibility
of an enantioselective aziridination,[9, 10] for example by ligand
tuning at the metal center, was a major benefit we associated
with a catalyzed versus a thermally induced pathway. In order
to investigate the general applicability of the planned reaction
we tested several substrates and looked more closely into the
mechanism. The results of this study are summarized in the
O
O
Abstract in German: Intramolekulare FeII-katalysierte Re-
aktionen verschiedener ungesättigter Alkoxycarbonylazide
werden beschrieben. Die Umsetzungen vollziehen sich in
Gegenwart stöchiometrischer Mengen von Trimethylsilylchlo-
rid in Ethanol als Lösungsmittel. Die entsprechenden 2-Al-
kenyloxycarbonylazide 5, 9, 18, 20, 22 und 24 ergaben die
Produkte 7/8, 10/11, 19, 21, 23 und 25 einer olefinischen
Chloraminierung in mittelmäûigen bis guten Ausbeuten (47 ±
72%). Die faciale Diastereoselektivität der ringschlieûenden
C N-Bindungsbildung ist sowohl in cyclischen (20, 24) als
auch in acyclischen (5, 18, 22) Substraten gut (>90% ds). Der
nachfolgende Chloratom-Transfer verläuft in cyclischen Sys-
temen (20, 24) und in Systemen, in denen die freie Rotation in
einem postulierten Radikalintermediat 14 eingeschränkt ist
(9b, 18), mit hoher Selektivität. Die Lebensdauer t dieses
Intermediats wurde aus dem Verlust der stereochemischen
Information in konformationell ungehinderten Systemen (9a,
22) und aus den Daten, die mit einer Radikaluhr (31 ! 32)
erhalten wurden, abgeschätzt. 2-Alkinyloxycarbonylazide 34
und 36 lieferten ebenfalls Chloraminierungsprodukte, die
ausschlieûlich als (Z)-Isomere 35 und 37 anfielen (81 ± 99%
Ausbeute). Die Produkte der tert-Butyl-substituierten Sub-
strate 38 unterzogen sich unter den Reaktionsbedingungen
einer Umlagerung/Solvolyse und ergaben die 5-Alkoxyoxazol-
idinone 39 (93 ± 99% Ausbeute).
O
O
O
NH
+
NH
O
N3
TMSCl [FeCl2]
R
R
0 °C → r.t.
R
Cl
Cl
(EtOH)
5
7
8
Scheme 3. FeII-catalyzed intramolecular chloroamination of the 2-prope-
nyloxycarbonyl azides 5.
Table 1. Preparation of the 4,5 disubstituted oxazolidinones 7 and 8
according to Scheme 3.
Azide
R
FeCl2
[mol%]
Products Yield[a] d.r.[b] [7/8]
[%]
1
2
3
5a
5b
5c
10
10
30
7a/8a
7b/8b
7c/8c[c]
72
64
60
91/9
88/12
94/6
Ph
4
5
6
5d
5e
5 f
10
30
10
7d/8d
7e/8e
7 f/8 f
60
33
68
88/12
92/8
90/10
[a] Yield of isolated product. [b] The diastereomeric ratio was determined
by integration of appropriate 1H NMR signals. [c] Mixture of two 4,5-trans-
isomers due to the additional stereogenic center at the cyclohexene ring.
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Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
lower molecular weight, for example entry 1 versus entry 5.
The facial diastereoselectivity, as expressed by the ratio of
trans- (7) and cis-diastereoisomer (8) was in direction and size
equal to the selectivity recorded for the thermal reaction.[5a]
The direction of the face discrimination can be interpreted by
conventional 1,3-allylic strain arguments which are valid for
an electrophilic attack at a double bond adjacent to a
stereogenic center.[12]
The starting materials 5 were conveniently prepared from
the corresponding allylic alcohols according to a known
procedure.[13] Successive treatment of the alcohols with 1,1'-
carbonyldiimidazole (CDI)/pyridine in benzene and subse-
quent reaction with NaN3 in DMF gave the desired azides in
good to excellent yields.
The results depicted in Scheme 3 and Table 1 were antici-
pated based on the expected analogy of thermal and metal-
catalyzed reactions. The azidoformates 9 derived from (E)-
configured allylic alcohols, however, showed significant
deviations in the stereochemical outcome of the chloroami-
nation (Scheme 4). The thermal reactions proceeded stereo-
Scheme 5. Proposed reaction course of the FeII-catalyzed intramolecular
chloroamination.
stereospecific nature of the chloroamination. Subsequent
chlorine atom transfer which is likely to occur in an intra-
molecular fashion yields the FeII-species 15. There is no hint as
to where the iron atom resides. Structure 16 is equal to 15 and
possibly an even more relevant structure. FeCl2 is liberated
either by reaction with TMSCl to intermediate 17 or by direct
HCl-mediated cleavage to the oxazolidinone diastereoisom-
ers 10 and 11.
O
O
O
O
O
NH
+
NH
O
N3
TMSCl [FeCl2]
(EtOH)
R1
Cl
R1
Cl
R1
9a
9b
R
R
1 = n Pr
1 = Ph
(84%)
(76%)
10a
10b
49/51
>99/1
11a
11b
According to this mechanistic picture the stereochemical
result recorded for the chloroamination of compound 9a is
rationalized by an unrestricted rotation in intermediate 14a.
The high threo-selectivity with which the phenyl-substituted
azide 9b reacts is due to the restricted rotation around the
C C-single bond. There should be a clear preference for
conformation 14b' from which the chlorine transfer can occur
Scheme 4. FeII-catalyzed chloroamination of the 2-alkenyloxycarbonyl
azides 9.
specifically through a syn-aziridination and a subsequent SN2-
type ring opening. The erythro-products 11 were the only
detectable oxazolidinones which could be obtained from
compounds 9 upon heating in TCE (11a: 62%, 11b: 42%).[11a]
Contrary, the FeII-catalyzed reactions yielded exclusively the
threo-product 10b if azide 9b was employed and a mixture of
threo- and erythro-products 10a and 11a if the n-propyl
substituted azide 9a was the substrate. The relative config-
uration of product 10b was proven by single crystal X-ray
analysis.[11a]
An (E)/(Z)-isomerization or a subsequent equilibration of
the products 11 under the reaction conditions of the FeII-
catalyzed process were ruled out by control experiments.
Clearly, the reaction of azide 9a is not stereospecific and an
intermediate must be formed which allows for free rotation
intramolecularly. A threo-preference was also found in the
reaction of the chiral azide 18 which yielded predominantly
the 4,5-trans-substituted oxazolidinone 19 with a threo-
relationship between the exocyclic stereogenic center and
the stereogenic center at C4. The crystal structure of this
compound is depicted in Figure 1.[15]
Further evidence for an intramolecular chlorine atom
transfer in intermediates related to 14 was collected from
the study of a cyclic alkenyloxycarbonyl azide. The 1-cyclo-2-
hexenol-derived azide 20 gave exclusively the bicyclic product
21 (Scheme 6) the relative configuration of which was proven
by single crystal X-ray analysis (Figure 2).[16] After formation
of the five-membered oxazolidinone ring the chlorine atom is
apparently delivered from the same face to which the FeCl2
fragment is coordinated via the nitrogen or the oxygen atom.
ˆ
around the former C C-bond. Bearing in mind that the
nitrogen evolution is induced by FeCl2 we suggest an electron
transfer from FeII to the carbonyl group as the initial step of
the reaction sequence[14] (Scheme 5); this in turn would lead
to an a-cleavage of the N N2-bond and to the evolution of N2.
The resulting species can be formulated as a radical-like FeIII-
compound 12 or as an FeIV-nitrene complex 13. While the
latter description would explain a direct aziridination via
nitrene transfer the former is apparently better suited to
account for the reactivity pattern of this iron complex. Indeed,
the intermediate 14 formed by radical addition to the olefinic
double bond is a reasonable intermediate to explain the non-
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T. Bach et al.
FULL PAPER
no bicyclic products (Scheme 7). The FeII-catalyzed decom-
position of azide 24 gave no hint on the formation of a
conceivable diquinane. The sole product isolated was the
oxazolidinone 25 which structure was elucidated by single
crystal X-ray analysis (Figure 3).[17]
O
O
O
O
N3
TMSCl [FeCl2]
(EtOH)
NH
Cl
22
(64%)
23
O
O
TMSCl
[FeCl2]
NH
5
1
O
Cl
6
O
(EtOH)
N3
(58%)
25
Figure 1. A molecule of compound 19 in the crystal.
O
O
150 °C
(TCE)
24
NH
5
O
O
1
Cl
O
O
N3
6
NH
Cl
TMSCl [FeCl2]
(EtOH)
(47%)
(16%)
26
Scheme 7. FeII-catalyzed chloroamination of 4-azidocarbonyloxy-1,5-hep-
tadiene (22) and 3-azidocarbonyloxy-1,5-cyclooctadiene (24).
20
21
Scheme 6. FeII-catalyzed chloroamination of 3-azidocarbonyloxy-1-cyclo-
hexene (20).
Figure 3. A molecule of compound 25 in the crystal.
The structure of product 25 deserves some comment. It is
apparent from the X-ray analysis that the trans-oxazolidinone
is fully planar and not significantly strained. Moreover, the
intermediate radical formed by nitrogen attack at the double
bond can abstract the chlorine atom intramolecularly only
such that an all-trans-arrangement at the eight-membered
ring arises. In this respect, the result is fully in line with the
mechanistic proposal detailed above although the trans-
configuration of C5 and C6 of cyclooctene 25 seems to
contradict an intramolecular chlorine atom transfer at first
sight. The thermal reaction of compound 24 delivered a single
product 26 in low yield (Scheme 7). Again, the proof of
relative configuration was carried out by single crystal X-ray
analysis (Figure 4).[18] The oxazolidinone is cis-configured
whereas the relative configuration of C5 and C6 is trans.
Figure 2. A molecule of compound 21 in the crystal.
Radical clocks: The loss of stereochemical information in the
reaction of the (E)-configured azide 9a allows to calculate an
upper value for the rate of chlorine transfer in the postulated
intermediate 14. It is estimated at kmax ꢀ5.7 Â 1011
s
1 assum-
1
ing a rotational barrier of ꢁ15 kJmol at 300 K. Radical
clocks were considered as suitable tools to obtain further
kinetic data on intermediate radicals such as 14. Initial studies
were driven by our synthetic interests and by the relevant
comparison of the FeII-catalyzed reaction and the thermal
reaction. Substrate 5 f was in principle already suited for a
second 5-exo-trig ring closure which was not observed.
Similarly, substrate 22 yielded only the oxazolidinone 23 and
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Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
(Scheme 8).[21] The monoalkylation of (Z)-1,4-butenediol (29)
with either bromide 30 yielded the corresponding allylic
alcohols which were directly converted into the alkenyloxy-
carbonyl azides 31a and 31b.
KOH
1. CDI, py (PhH)
2. NaN3 (DMF)
OH
Br
(DMSO)
OH
+
(Z):
30a
30b
29
(E):
O
O
O
NH
O
TMSCl [FeCl2]
(EtOH)
Figure 4. A molecule of compound 26 in the crystal.
N3
O
O
Cl
As it was alluded to above, the substrates 5 f, 22, and 24
were more or less used accidentally as radical clocks and were
actually prepared in another context. The fact that the radical
center and the olefinic double bond, which is targeted for a
second ring closure, are connected via an oxazolidinone puts
steric constraints on the 1-hexenyl radical[19] which may slow
down the expected cyclization. Control experiments revealed
that the cyclization is slow even on the time scale of the
Bu3SnH reduction. Upon treatment of compounds 7 f and 25
with Bu3SnH and AIBN as the initatior in benzene as the
solvent the hydro-de-chlorinated products 27 and 28 were
obtained (72% yield).
(Z):
(40%)
(67%)
(79%)
(82%)
31a
31b
32a
32b
(E):
Scheme 8. Preparation and FeII-catalyzed chloroamination of the 2-alke-
nyloxycarbonyl azides 31.
The FeII-catalyzed chloroamination was conducted under
standard conditions (10 mol% FeCl2, 1.5 equiv TMSCl,
EtOH, 08C ! RT, 21 h) without any tetrahydrofuran ring
closure. The relative configuration of the double bonds was
fully retained in the products. (Z)-Alkene 31a was converted
to the (Z)-product 32a and (E)-alkene 31b gave the (E)-
diastereoisomer 32b. Not unexpectedly, no significant prefer-
ence for neither the erythro- nor the threo-diastereoisomer
was observed in either reaction. A ratio of 5:95 was estimated
as the limit (NMR spectroscopy) for the detection of the (E)-
alkene 32b in the presence of the (Z)-alkene 32a. Assuming a
O
NH
O
O
O
NH
rate constant of 8.5 Â 106 s for the ring closure a competing
1
27
28
process which does not produce any ring-closed product
within the detection limit must occur with a rate constant of k
1
ꢁ1.6 Â 108 s . The ring closure occurred readily when com-
For the construction of conformationally unrestricted
radical clocks we decided to place a suitable substituent at
the position R1 in substrate 9 (Scheme 5). Subsequent ring
opening or ring closure can occur independently and should
not be influenced by the oxazolidinone. Unfortunately, all
attempts to construct cyclopropyl-substituted alkenyloxycar-
bonyl azides of this type were unsuccessful. The cyclopropane
ring was not stable to the conditions employed for the
conversion of the allylic alcohol to the azide. The cyclization
of the 3-oxa-5-hexenyl radical to the (3-tetrahydrofuryl)meth-
yl radical was subsequently considered as an alternative
pounds 32a and 32b were subjected to the radical-based
Bu3SnH-reduction as depicted in Scheme 9. A mixture of four
O
O
Bu3SnH
NH
[AIBN] (PhH)
32a or 32b
33 (85%)
O
mixture of 4 diastereoisomers
Scheme 9. Radical-induced cyclization of the oxazolidinones 32.
1
radical clock. It is remarkably fast (k ˆ 8.5  106 s )[14]
compared with the 5-hexenyl ! cyclopentylmethyl radical
1
ring closure (k ˆ 2.5  105 s ) and only slightly slower than
diastereoisomers was obtained without a significant prefer-
ence for either diastereoisomer. One diastereoisomer was
crystalline and its structure could be determined by X-ray
analysis (Figure 5).[22]
Although the mechanism depicted in Scheme 5 is in accord
with all experimental facts there are certainly alternative
reaction pathways. We were not able to undoubtedly prove
the presence of the postulated radical intermediate 14. The
radical clock employed allowed an estimation of its lifetime
but we could not devise a radical clock fast enough to compete
the cyclopropylmethyl ! 3-butenyl radical ring opening (k ˆ
1
108 s ).[20] In order to detect a ring closure we planned to
subject both the (E)- and (Z)-isomer of the target compound
to the chloroamination. Even if the ring opening after
cyclization was fast and the chlorine transfer occurred exclu-
sively in the open-chain radical, the double bond geometry
would still indicate an intermediate cyclization. The synthesis
of the substrates commenced with the two allyl bromides 30a
and 30b which can be obtained in diastereomerically pure form
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T. Bach et al.
FULL PAPER
Table 2. Preparation of the (4-chloromethylidenyl)oxazolidinones (35)
according to Scheme 10.
Azide
R
FeCl2 [mol%] product yield[a] [%] (Z):(E)[b]
1
2
34a
5
35a
35a
99
98
> 99/1
> 99/1
34a
10
3
4
34b
34b
5
35b
35b
73
81
> 99/1
> 99/1
Ph
Ph
10
Figure 5. One diastereoisomer of compound 33 in the crystal.
5
6
34c
34c
5
35c[c]
35c[c]
79
90
> 99/1
> 99/1
with the postulated chlorine atom transfer. An important
implication of the postulated mechanism was the fact that a
chloroamination should also be possible for propargylic
substrates. This extension is certainly not expected for an
aziridination reaction nor for another reaction which pro-
ceeds via small ring intermediates.
10
7
8
34d
34e
10
10
35d
35e
99
99
> 99/1
> 99/1
H
[a] Yield of isolated product. [b] (Z) and (E) refer to the double bond
configuration. [c] Mixture of diastereoisomers due to the additional
stereogenic center at the cyclohexene ring.
Reaction of 2-alkynyloxycarbonyl azides: The formation of
C N-bonds by intra-[23] or intermolecular[24] attack of a
nitrogen electrophile at a triple bond has been used less
extensively than the corresponding reaction with alkenes.
There are scattered reports on the activation of triple bonds
by transition metals and subsequent nucleophilic nitrogen
attack.[25] We initially studied the reaction of the phenyl-
substituted 2-alkynyloxycarbonyl azides 34. The substrates
were readily available by alkynylation of aldehydes (RCHO)
with litihium phenylacetylide and subsequent transformation
of the propargylic alcohol to the azide via azidocarbonylation
(CDI/py in benzene; NaN3 in DMF).[13] A smooth reaction
occurred upon treatment of the azides 34 with TMSCl and
catalytic amounts of FeCl2 in ethanol as the solvent
(Scheme 10). The chloromethylidene-substituted oxazolidi-
nones 35 were isolated in almost quantitative yields as
crystalline, analytically pure solids (Table 2). In general, the
use of 5 mol% of the catalyst was sufficient to guarantee high
yields. A slight improvement was observed in some instances
by raising the catalyst amount to 10 mol%(entries 3/4 and
5/6).
Figure 6. A molecule of compound 35d in the crystal.
Although the oxazolidinones 35 proved to be stable in the
solid state at room temperature they decomposed notably in
solution. Distinct decomposition products could not be
isolated. The tendency to decompose is even more pro-
nounced in alkyl-substituted (4-chloromethylidene)oxazolidi-
nones which were obtained as oils. As an example the
synthesis of the n-butyl substituted product 37 from azide 36 is
depicted in Scheme 11. Its constitution was proven by NMR
spectroscopy whereas the relative configuration had to be
O
O
O
NH
Cl
O
N3
TMSCl [FeCl2]
(EtOH)
R
R
Ph
Ph
34
35
Scheme 10. FeII-catalyzed intramolecular chloroamination of the 2-prop-
argyloxycarbonyl azides 34.
O
O
O
The double bond in the products 35 is (Z)-configured as
proven by NOE experiments and single crystal X-ray analysis.
The crystal structure of compound 35d is depicted in Fig-
ure 6.[26] It nicely illustrates the formal cis-chloroamination
which according to our mechanistic picture occurs through
nitrogen radical attack and subsequent chlorine transfer to the
intermediate vinylic radical.
O
N3
TMSCl [FeCl2]
(EtOH)
NH
Ph
Ph
Cl
37 (95%)
36
Scheme 11. FeII-catalyzed intramolecular chloroamination of the 2-prop-
argyloxycarbonyl azide 36.
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Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
assigned based on analogy. The low stability of oxazolidinone
37 in CDCl3 solutions precluded us from conducting more
extensive NOE studies.
The structure of the products isolated from the chloroami-
nation of tert-butyl substituted 2-alkynyloxycarbonyl azides
38 was suprising at first sight (Scheme 12). Instead of the tert-
H/D-exchange experiments revealed the basic nature of the
enamine structure in the products 39.[11b] Given the steric bias
of the large tert-butyl group and the basicity at the exocyclic
methylidene carbon atom a tautomerization of the primary
chloroamination product 40 appears feasible (Scheme 13).
O
O
O
O
R1OH
O
O
NH
NH
39
O
R
R
O
N3
TMSCl [FeCl2]
(R1OH)
R
R1O
NH
t Bu
Cl
t Bu
Cl
R
t Bu
t Bu
40
41
38
39
Scheme 13. Mechanistic proposal on the formation of oxazolidinones 39.
Scheme 12. FeII-catalyzed cyclization of the 2-propargyloxycarbonyl
azides 38.
The resulting allylic chloride 41 can undergo solvolysis in a
SN'-fashion to yield the product 39. Proof for the intermediacy
of chloride 41 was obtained from the reaction of azide 38a in
acetonitrile. The less nucleophilic solvent facilitated the
isolation of compound 41a (R ˆ cyclohexyl) as the product
(16% yield). The reaction remained incomplete and 76% of
the starting material was recovered.
Based on this result the formation of compounds 39 can be
readily explained by consecutive reactions of the chloroami-
nation product.
butylchloromethylidene fragment to be expected the oxazo-
lidinones 39 carried a tert-butylmethylidene moiety at 4-posi-
tion. There was no chlorine incorporation. The 5-position was,
however, substituted by an additional alkoxy group which
apparently stemmed from the solvent. The products were
obtained in good yields. Some results are summarized in
Table 3. As an additional solvent the chiral cyclopropyl
methyl carbinol was used which yielded diastereomeric
products due to an additional stereogenic center.[11b]
Table 3. Preparation of the (4-tert-butylmethylidenyl)oxazolidinones 39
according to Scheme 12.
Conclusion
Azide
R
R1
Et
Product
Yield[a] [%]
93
(Z):(E)[b]
> 99/1
In summary, the FeII-catalyzed intramolecular chloroamina-
tion of azidoformates is a new and widely applicable reaction
for the synthesis of substituted oxazolidinones. At present, it
appears as if the reaction is limited to the construction of five-
membered ring compounds. Neither 3-alkenyloxycarbonyl
azides nor 3-alkynyloxycarbonyl azides underwent a cycliza-
tion under the commonly used reaction conditions. The
attempted reactions yielded only small amounts of the amides
and recovered starting material. If 30 mol% of the catalyst
were employed roughly 15% of the corresponding amide was
detected.[8] As mentioned in a previous paper[7c] we rationalize
the amide formation by an intermolecular attack of FeCl2 at a
complex 42 related to 12/13 (Scheme 5). The resulting m-imido
complex 43 (see Scheme 14) represents a thermodynamic
valley which yields the corresponding amide upon hydrolysis.
As a direct conclusion from this hypothesis any intermedi-
ate 42 which allows only for a slow intra- or intermolecular
reaction will end up as the inactive complex 43 (Scheme 14).
A catalytic cycle is impossible and the nitrogen evolution
slows down rather quickly.
1
38a
39a
2
3
38b
38b
Et
39b
39c
95
99
> 99/1
> 99/1
Ph
Ph
iPr
[a] The reaction was conducted with 10 mol% FeCl2. Yield of isolated
product. [b] (Z) and (E) refer to the double bond configuration.
The cis-arrangement of the tert-butyl group and the NH
group of the oxazolidinone was deduced from NOE studies. In
addition, we obtained crystals of compound 39a suitable for
X-ray analysis (Figure 7).[27] An additional crystal structure
corroborating this assignment has been published in a
preliminary publication.[11b]
Further studies have been initiated which aim at an
improvement of the catalytic cycle based on the presented
Scheme 14. Suggested deactivation pathway of the reactive Fe-complex
Figure 7. A molecule of compound 39a in the crystal.
42.
Chem. Eur. J. 2001, 7, No. 12
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2587

T. Bach et al.
FULL PAPER
(1H NMR)] and the (1'SR,4RS,5SR)/(1'SR,4RS,5SR)-isomer [d.r. ˆ 94:6
(1H NMR)]. The ratio of the pairs was determined as 44:56 (1H NMR). The
analytical data are provided for the major trans-isomers, that is, for
compounds 7c. Rf ˆ 0.20 (P/TBME 20:80).
results. The search for alternative metal catalysts is driven by
the goal to similarly slow down the reaction to the proposed m-
imido complex and to increase the rate of the nitro-
gen carbon bond formation. Other substrates are currently
being tested and a chiral modification of the catalyst is being
pursued. Results of this endeavour will be reported in due
course.
(1'RS,4RS,5SR)-Isomer: 1H NMR (200 MHz): d ˆ 7.11 (s, 1H, NH), 5.65
(brs, 2H, cyc-CH cyc-CH), 4.25 (dd, 3J ˆ 4.0, 3J ˆ 5.6 Hz, 1H,
ˆ
OCHCHCH2Cl), 3.88 (dt, 3J  3J ˆ 5.6 Hz, 1H, OCHCHCH2Cl), 3.54 (d,
3J ˆ 5.6 Hz, 2H, CH2Cl), 2.40 ± 1.70 (m, 6H, cyc-H), 1.60 ± 1.30 (m, 1H, cyc-
13
ˆ
ˆ
H); C NMR (50 MHz): d ˆ 159.6 (s, C O), 127.8 (d, cyc-CH CH), 125.5
ˆ
(d, cyc-CH CH), 83.9 (d, OCHCHCH2Cl), 56.6 (d, OCHCHCH2Cl), 46.6
(t, CH2Cl), 38.2 (d, cyc-CH), 26.8 (t, cyc-CH2), 24.9 (t, cyc-CH2), 24.1 (t, cyc-
CH2).
Experimental Section
(1'SR,4RS,5SR)-Isomer: 1H NMR (200 MHz): d ˆ 7.11 (s, 1H, NH), 5.65
(brs, 2H, cyc-CH cyc-CH), 4.25 (dd, 3J ˆ 4.0, 3J ˆ 5.6 Hz, 1H,
ˆ
General: For general remarks, see refs. [7b, 28] Abbreviations: Pˆ
n-pentane, TBME ˆ tert-butyl methyl ether. The azidoformates were
prepared from the corresponding alcohols by a known procedure.[5b, 13]
Caution: Azidoformates are potential explosives. Appropriate safety
protection and utmost care are required while preparing and handling
these compounds! The alcohols were prepared by carbonyl addition of the
corresponding alkenyl and alkynyl lithium or magnesium reagents to
aldehydes.[5b, 29]
General procedure for the FeII-catalyzed dediazotation: The azide
(1 mmol) was dissolved in a dry solvent (5 mL) and the solution was
degassed with a stream of argon for 15 min at 08C. Trimethyl silyl chloride
(1.5 mmol) was added to the stirred solution via syringe. Solid anhydrous
iron(ii) chloride (0.1 mmol) was subsequently added in one portion. The
solution was allowed to warm to room temperature during 21 h. Ethyl
acetate (10 mL) was added and the resulting solution was washed with
water (10 mL) and brine (2 Â 10 mL). The organic layer was dried over
magnesium sulfate and the solvent was removed in vacuo. The residue was
purified by flash chromatography.
OCHCHCH2Cl), 3.88 (t, 3J ˆ 5.6 Hz, 1H, OCHCHCH2Cl), 3.56 (d, 3J ˆ
5.6 Hz, 2H, CH2Cl), 2.40 ± 1.70 (m, 6H, cyc-H), 1.60 ± 1.30 (m, 1H, cyc-H);
13
ˆ
ˆ
C NMR (50 MHz): d ˆ 159.6 (s, C O), 127.3 (d, cyc-CH CH), 125.0 (d,
ˆ
cyc-CH CH), 83.4 (d, OCHCHCH2Cl), 56.5 (d, OCHCHCH2Cl), 46.5 (t,
CH2Cl), 38.2 (d, cyc-CH), 26.5 (t, cyc-CH2), 24.7 (t, cyc-CH2), 23.5 (t, cyc-
CH2); IR (film): nÄ ˆ3300 ± 3250 (br, NH), 2930 (m, CalH), 2840 (m, CalH),
1
ˆ
1745 (vs, C O), 1400 (m), 1240 (m, C-O-C), 1015 (m), 740 (w), 650 cm
‡
‡
(m); MS (EI, 70eV): m/z (%): 215 (17) [M] , 93 (50) [C7H9] , 91 (41), 81
‡
‡
‡
‡
(39) [C6H9] , 80 (56) [C6H8] , 79 (85) [C6H7] , 78 (100) [C6H6] ; elemental
analysis calcd (%) for C10H14NO2Cl (215.68): C 55.69, H 6.54, N 6.49;
found: C 55.48, H 6.70, N 6.37.
4-(1-Chloromethyl)-5-heptyl-1,3-oxazolidin-2-one (7d/8d): According to
the general procedure 3-azidocarbonyloxy-1-decene (5d) (225 mg,
1.00 mmol) was treated with iron(ii) chloride (13 mg, 0.10 mmol) and
trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol (5 mL). After
chromatographic purification (P/TBME 20:80) 7d/8d (138 mg, 60%) was
obtained as a colorless oil. The product was a mixture of the (4RS,5SR)-
(7d) and (4RS,5RS)-isomer (8d) [d.r. ˆ 88:12 (1H NMR)]. The analytical
data are provided for the major isomer 7d. Rf ˆ 0.32 (P/TBME 20:80);
1H NMR (300 MHz): d ˆ 6.82 (s, 1H, NH), 4.36 (dt, 3J ˆ 5.3, 3J ˆ 7.2 Hz,
1H, OCHCHCH2Cl), 3.74 (ddd, 3J  3J  3J ˆ 5.3 Hz, 1H, OCHCHCH2Cl),
3.54 (d, 3J ˆ 5.3 Hz, 1H, CHHCl), 3.52 (d, 3J ˆ 5.3 Hz, 1H, CHHCl), 1.90 ±
4-(1-Chloromethyl)-5-cyclohexyl-1,3-oxazolidin-2-one (7a/8a):[5a] Accord-
ing to the the general procedure 1-azidocarbonyloxy-1-cyclohexyl-2-
propene (5a) (209 mg, 1.00 mmol) was treated with iron(ii) chloride
(13 mg, 0.10 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in
ethanol (5 mL). After chromatographic purification (P/TBME 20:80) 7a/
8a (156 mg, 72%) was obtained as a colorless solid. The product was a
mixture of the (4RS,5SR)- (7a) and (4RS,5RS)-isomer (8a) [d.r. ˆ 91:9
(1H NMR)]. The analytical data are provided for the major isomer 7a. Rf ˆ
1.00 (m, 12H, CH3CH2CH2CH2CH2CH2CH2), 0.78 (t, 3J ˆ 6.5 Hz, 3H,
13
ˆ
CH3); C NMR (75 MHz): d ˆ 159.0 (s, C O), 80.3 (d, OCHCHCH2Cl),
58.4 (t, OCHCHCH2Cl), 45.6 (d, OCHCHCH2Cl), 35.0 (t, CH2), 31.6 (t,
CH2), 29.1 (t, CH2), 29.0 (t, CH2), 24.4 (t, CH2), 22.5 (t, CH3CH2), 14.0 (q,
CH3); IR (film): nÄ ˆ3300 ± 3250 (br, NH), 2930 (vs, CalH), 2855 (s, CalH),
1
0.32 (P/TBME 20:80); m.p. 115 ± 1168C; H NMR (500 MHz): d ˆ 6.80 (s,
1H, NH), 4.07 (dd, 3J ˆ 4.3, 3J ˆ 6.0 Hz, 1H, OCHCHCH2Cl), 3.77 (ddd,
3J  3J  3J ˆ 6.0 Hz, 1H, OCHCHCH2Cl), 3.51 (dd, 2J ˆ 11.2, 3J ˆ 6.0 Hz,
1
ˆ
1750 (vs, C O), 1235 (m, C-O-C), 985 (w), 730 cm (w); MS (EI, 70eV):
‡
‡
m/z (%): 184 (100) [M CH2Cl] , 168 (6), 140 (11), 81 (20) [C6H9] , 67 (23)
2
3
1H, CHHCl), 3.50 (dd, J ˆ 11.2, J ˆ 6.0 Hz, 1H, CHHCl), 1.90 ± 1.45 (m,
6H, cyc-H), 1.40 ± 0.90 (m, 5H, cyc-H); 13C NMR (50 MHz): d ˆ 158.9 (s,
‡
‡
‡
‡
[C5H7] , 56 (42) [C4H8] , 55 (89) [C4H7] , 43 (49), 41 (57) [C3H5] ;
elemental analysis calcd (%) for C11H20NO2Cl (233.74): C 56.52, H 8.62, N
5.99; found: C 56.55, H 8.62, N 5.97.
ˆ
C O), 83.9 (d, OCHCHCH2Cl), 55.9 (d, OCHCHCH2Cl), 46.3 (t, CH2Cl),
41.8 (d, cyc-CH), 27.1 (t, cyc-CH2), 26.1 (t, cyc-CH2), 25.7 (t, cyc-CH2), 25.6
(t, cyc-CH2), 25.4 (t, cyc-CH2).
4-(1-Chloromethyl)-5-(1-methylethyl)-1,3-oxazolidin-2-one (7e/8e): Ac-
cording to the general procedure 3-azidocarbonyloxy-4-methyl-1-pentene
(5e) (170 mg, 1.00 mmol) was treated with iron(ii) chloride (38 mg,
0.30 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). After chromatographic purification (P/TBME 20:80) 7e/8e
(58 mg, 33%) was obtained as a colorless solid. The product was a mixture
of the (4RS,5SR)- (7e) and (4RS,5RS)-isomer (8e) [d.r. ˆ 92:8 (1H NMR)].
The analytical data are provided for the major isomer 7e. M.p. 65 ± 678C;
1H NMR (200 MHz): d ˆ 6.80 (s, 1H, NH), 4.07 (dd, 3J ˆ 6.4, 3J ˆ 5.5 Hz,
1H, OCHCHCH2Cl), 3.74 (ddd, 3J  3J  3J ˆ 5.5 Hz, 1H, OCHCHCH2Cl),
3.47 (d, 3J ˆ 5.5 Hz, 2H, CH2Cl), 1.88 (dqq, 3J  3J  3J ˆ 6.4 Hz, 1H,
4-(1-Chloromethyl)-5-(2-phenylethyl)-1,3-oxazolidin-2-one (7b/8b):[5a] Ac-
cording to the general procedure 3-azidocarbonyloxy-5-phenyl-1-pentene
(5b) (231 mg, 1.00 mmol) was treated with iron(ii) chloride (13 mg,
0.10 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). After chromatographic purification (P/TBME 20:80) 7b/8b
(153 mg, 64%) was obtained as a colorless oil. The product was a mixture
of the (4RS,5SR)- (7b) and (4RS,5RS)-isomer (8b) [d.r. ˆ 88:12
(1H NMR)]. The analytical data are provided for the major isomer 7b.
Rf ˆ 0.15 (P/TBME 20:80); 1H NMR (300 MHz): d ˆ 7.36 ± 7.16 (m, 5H,
3
3
Har), 7.04 (s, 1H, NH), 4.36 (dt, J ˆ 5.0, J ˆ 8.5 Hz, 1H, OCHCHCH2Cl),
3.74 (ddd, 3J  3J  3J ˆ 5.0 Hz, 1H, OCHCHCH2Cl), 3.48 (d, 3J ˆ 5.0 Hz,
1H, CHHCl), 3.46 (d, 3J ˆ 5.0 Hz, 1H, CHHCl), 2.98 ± 2.64 (m, 2H,
PhCH2CH2), 2.18 ± 1.86 (m, 2H, PhCH2CH2); 13C NMR (75 MHz): d ˆ
CH3CHCH3), 0.92 (d, 3J ˆ 6.4 Hz, 3H, CH3CHCH3), 0.90 (d, 3J ˆ 6.4 Hz,
13
ˆ
3H, CH3CHCH3); C NMR (75 MHz): d ˆ 159.1 (s, C O), 84.5 (d,
OCHCHCH2Cl), 55.9 (d, CHCH2Cl), 46.3 (t, CH2Cl), 32.2 (d,
CH3CHCH3), 17.2 (q, CH3), 16.6 (q, CH3); IR (KBr): nÄ ˆ 3300 ± 3250 (br,
ˆ
159.1 (s, C O), 140.2 (s, Car), 128.6 (d, CarH), 128.4 (d, CarH), 126.3 (d,
ˆ
NH), 2970 (m, CalH), 2930 (m, CalH), 2880 (m, CalH), 1750 (vs, C O), 1240
CarH), 79.5 (d, OCHCHCH2Cl), 58.5 (t, OCHCHCH2Cl), 45.6 (d,
OCHCHCH2Cl), 36.8 (t, PhCH2CH2), 30.8 (t, PhCH2CH2).
1
(m, C-O-C), 960 (m), 655 cm (m); MS (EI, 70eV): m/z (%): 128 (100)
[M CH2Cl] , 90 (20), 86 (26) [C3H3NO2] , 84 (31), 57 (50) [C4H9] , 55
(23) [C4H7] , 43 (46) [C3H7] , 42 (46) [C3H6] , 41 (75) [C3H5] , 29 (36)
[C2H5] , 27 (53) [C2H3] ; elemental analysis calcd (%) for C7H12NO2Cl
(177.63): C 47.33, H 6.81, N 7.88; found: C 47.78, H 6.87, N 7.63.
‡
‡
‡
4-(1-Chloromethyl)-5-(3-cyclohexenyl)-1,3-oxazolidin-2-one (7c/8c): Ac-
cording to the general procedure 1-azidocarbonyloxy-1-(3-cyclohexenyl)-
2-propene (5c) (207 mg, 1.00 mmol) was treated with iron(ii) chloride
(38 mg, 0.30 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in
ethanol (5 mL). After chromatographic purification (P/TBME 20:80)
7c/8c (130 mg, 60%) was obtained as a colorless oil. The product was a
mixture of the (1'RS,4RS,5SR)/(1'RS,4RS,5RS)-isomer [d.r. ˆ 94:6
‡
‡
‡
‡
‡
‡
4-(1-Chloromethyl)-5-(prop-2-enyl)-1,3-oxazolidin-2-one (7 f/8 f): Accord-
ing to the general procedure 3-azidocarbonyloxy-1,5-hexadiene (5 f)
(334 mg, 2.00 mmol) was treated with iron(ii) chloride (26 mg, 0.20 mmol)
2588
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Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
and trimethyl silyl chloride (0.38 mL, 3.00 mmol) in ethanol (5 mL). After
chromatographic purification (P/TBME 20:80) 7 f/8 f (239 mg, 68%) was
obtained as a yellow oil. The product was a mixture of the (4RS,5SR)- (7 f)
and (4RS,5RS)-isomer (8 f) [d.r. ˆ 90:10 (1H NMR)]. The analytical data
are provided for the major isomer 7 f. Rf ˆ 0.20 (P/TBME 20:80); 1H NMR
was dissolved in 1,1,2,2-tetrachloroethane (30 mL) and heated to 1508C for
3 h. After cooling the solvent was removed in vacuo and the residue was
purified by chromatography (P/TBME 20:80). 11b (265 mg, 42%) was
obtained as a colorless solid. Rf ˆ 0.14 (P/TBME 20:80); m.p. 135 ± 1458C;
1H NMR (200 MHz): d ˆ 7.70 ± 7.40 (m, 5H, Har), 5.90 (s, 1H, NH), 4.89 (d,
3J ˆ 8.5 Hz, 1H, CHCl), 4.66 (dd, 2J  3J ˆ 8.5 Hz, 1H, CHHO), 4.58 (dd,
3
3
(300 MHz): d ˆ 7.25 (brs, 1H, NH), 5.83 (ddt, 3J ˆ 6.0, Jcis ˆ 10.1, Jtrans
ˆ
17.1 Hz, 1H, OCHCH2CHCH2), 5.28 (d, 3Jtrans ˆ 17.1 Hz, 1H, CHCHHtrans),
2J ˆ 8.5, J ˆ 5.0 Hz, 1H, CHHO), 4.40 (ddd, J ˆ 5.0, J  3J ˆ 8.5 Hz, 1H,
3
3
3
3
13
5.26 (d, Jcis ˆ 10.1 Hz, 1H, CHCHcisH), 4.58 (dt, 3J  3J ˆ 6.0 Hz, 1H,
CHN); C NMR (50 MHz): d ˆ 158.7 (s, C O), 136.4 (s, Car), 129.4 (d,
ˆ
OCH), 3.92 (dt, 3J  3J ˆ 6.0 Hz, 1H, HNCH), 3.68 (d, 3J ˆ 6.0 Hz, 2H,
CH2Cl), 2.60 (dd, 3J  3J ˆ 6.0 Hz, 2H, OCHCH2CH); 13C NMR (75 MHz):
CarH), 129.1 (d, CarH), 127.6 (d, CarH), 68.1 (t, CH2O), 63.5 (d, CHCl), 58.2
(d, CHN); IR (KBr): nÄ ˆ 3300 ± 3250 (br, NH), 3140 (w, CarH), 1735 (vs,
1
ˆ
ˆ
d ˆ 158.9 (s, C O), 130.7 (d, CH2CHCH2), 119.8 (t, CH2CHCH2), 78.8 (d,
C O), 1450 (w), 1410 (w), 1250 (m, C-O-C), 1030 (m), 705 cm (m); MS
‡
‡
OCH), 57.1 (d, HNCH), 45.5 (t, CH2Cl), 38.7 (t, OCHCH2CH); IR (film):
(EI, 70eV): m/z (%): 125 (7) [C7H6Cl] , 91 (7) [C7H7] , 86 (100)
‡
‡
‡
ˆ
nÄ ˆ3300 ± 3250 (br, NH), 2980 (m, CalH), 2940 (m, CalH), 1755 (vs, C O),
[C3H3NO2] , 77 (2) [C6H5] , 42 (19) [HNCO] ; elemental analysis calcd
(%) for C10H10NO2Cl (211.65): C 56.75, H 4.76, N 6.62; found: C 56.48, H
4.93, N 6.57.
1400 (m), 1240 (m, C-O-C), 1060 (m), 990 (m), 950 (m), 730 cm 1 (w); MS
‡
‡
(EI, 70eV): m/z (%): 134 (100) [M C3H5] , 126 (48) [M CH2Cl] , 90
‡
‡
‡
(35), 86 (30) [C3H3NO2] , 84 (49) [C3H2NO2] , 63 (37), 49 (15) [CH2Cl] ,
41 (31) [C3H5] , 28 (95) [CO] ; elemental analysis calcd (%) for
C7H10NO2Cl (175.61): C 47.88, H 5.74, N 7.98; found: C 47.65, H 5.59, N 7.94.
(4RS,5SR,1'RS)-4-(1-Chloro-1-phenylmethyl)-5-methyl-1,3-oxazolidin-2-
one (19): According to the general procedure (1E)-3-azidocarbonyloxy-1-
butene (18) (217 mg, 1.00 mmol) was treated with iron(ii) chloride (38 mg,
0.30 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). After chromatographic purification (P/TBME 20:80) the product
(36 mg, 16%) was obtained as a yellow solid. The product was a mixture of
the (4RS,5SR,1'RS) (19) and the (4RS,5SR,1'SR) isomer [d.r. ˆ 75:25
(1H NMR)]. Analytical data are provided for the major isomer. Rf ˆ
0.25; m.p. 113 ± 1178C; 1H NMR (300 MHz): d ˆ 7.42 ± 7.34 (m, 5H, Har),
6.09 (brs, 1H, NH), 4.75 (d, 3J ˆ 8.9 Hz, 1H, CHCl), 4.25 (dq, 3J ˆ 6.1, 3J ˆ
5.2 Hz, 1H, CH3CH), 3.86 (brdd, 3J ˆ 5.2, 3J ˆ 8.9 Hz, 1H,
CH3CHCHCHCl), 1.05 (d, 3J ˆ 6.1 Hz, 3H, CH3); 13C NMR (75 MHz):
‡
‡
4-(1-Chlorobutyl)-1,3-oxazolidin-2-one (10a/11a): According to the gen-
eral procedure trans-1-azidocarbonyloxy-2-hexene (9a) (169 mg,
1.00 mmol) was treated with iron(ii) chloride (13 mg, 0.10 mmol) and
trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol (5 mL). After
work-up 10a/11a (150 mg, 84%) was obtained as a colorless oil. The
product was a mixture of the (4RS,1'SR)- (10a) and (4RS,1'RS)-isomer
(11a) [d.r. ˆ 49:51 (1H NMR)].
Thermal decomposition: trans-1-Azidocarbonyloxy-2-hexene (9a)
(500 mg, 2.96 mmol) was dissolved in 1,1,2,2-tetrachloroethane (50 mL)
and heated to 1508C for 4 h. After the reaction mixture was cooled most of
the solvent was removed in vacuo. A brown oil (800 mg) was obtained. By
integration of the 1H NMR signals the approximate yield could be
estimated (62%). 11a was obtained in diastereomerically pure form [d.r. >
95:5 (1H NMR)].
ˆ
d ˆ signal for C O not observed, 135.9 (s, Car), 129.6 (d, CarH), 129.2 (d,
CarH), 127.7 (d, CarH), 75.6 (d, CHO), 65.6 (d, CHNH), 65.2 (d, CHCl), 15.1
(q, CH3); IR (KBr): nÄ ˆ 3300 ± 3200 (br, NH), 3140 (w, CarH), 2980 (w,
ˆ
CalH), 2930 (w, CalH), 1785 (vs, C O), 1730 (vs), 1380 (m), 1240 (s, C-O-C),
1
1075 (m), 1045 (m), 980 (m), 720 cm (s); MS (EI, 70eV): m/z (%): 167
‡
‡
(<1) [M CH3 Cl] , 149 (1), 125 (27) [C7H6Cl] , 100 (100) [M
1
(4RS,1'SR)-Isomer (10a): H NMR (200 MHz): d ˆ 7.40 (s, 1H, NH), 4.42
‡
‡
‡
‡
C7H6Cl] , 91 (22) [C7H7] , 77 (6) [C6H5] , 56 (78), 28 (35) [CO] ;
elemental analysis calcd (%) for C11H12NO2Cl (225.67): C 58.55, H 5.36, N
6.21; found: C 58.53, H 5.38, N 5.99.
(dd, 2J  3J ˆ 9.0 Hz, 1H, OCHHCH), 4.23 (dd, 2J ˆ 9.0, 3J ˆ 5.0 Hz, 1H,
OCHHCH), 4.04 (brddd, 3J  3J ˆ 5.0, 3J ˆ 9.0 Hz, 1H, OCH2CH), 3.87 ±
3
3.75 (m, 1H, CHCl), 1.80 ± 1.30 (m, 4H, CH2CH2CH3), 0.95 (t, J ˆ 7.1 Hz,
(1RS,2SR,6RS)-9-Aza-2-chloro-7-oxabicyclo[4.3.0]nonan-8-one (21): Ac-
cording to the general procedure 3-azidocarbonyloxycyclohex-1-ene (20)
(254 mg, 1.52 mmol) was treated with iron(ii) chloride (58 mg, 0.30 mmol)
and trimethyl silyl chloride (0.30 mL, 2.25 mmol) in ethanol (5 mL). After
chromatographic purification (P/TBME 20:80) 21 (125 mg, 47%) was
obtained as a colorless solid. Rf ˆ 0.13 (P/TBME 30:70); m.p. 120 ± 1268C;
1H NMR (200 MHz): d ˆ 5.90 (s, 1H, NH), 4.73 (td, 3J ˆ 5.0, 3J ˆ 7.2 Hz,
1H, CHO), 4.22 (dd, 3J ˆ 4.0, 3J ˆ 7.2 Hz, 1H, CHN), 4.07 (ddd, 3J ˆ 4.0,
3H, CH3); 13C NMR (50 MHz): d ˆ 160.4 (s, C O), 67.7 (t, OCH2CH), 64.2
ˆ
(d, OCH2CH), 57.5 (d, CHCl), 35.5 (t, CH2CH2CH3), 19.9 (t, CH2CH3), 13.7
(q, CH3).
1
(4RS,1'RS)-Isomer (11a): H NMR (200 MHz): d ˆ 7.05 (s, 1H, NH), 4.46
(dd, 2J  3J ˆ 9.0 Hz, 1H, OCHHCH), 4.28 (dd, 2J ˆ 9.0, 3J ˆ 5.0 Hz, 1H,
OCHHCH), 3.93 (brddd, 3J  3J ˆ 5.0, 3J ˆ 9.0 Hz, 1H, OCH2CH), 3.87 ±
3
3.75 (m, 1H, CHCl), 1.80 ± 1.30 (m, 4H, CH2CH2CH3), 0.95 (t, J ˆ 7.1 Hz,
3H, CH3); 13C NMR (50 MHz): d ˆ 160.7 (s, C O), 68.5 (t, OCH2CH), 64.3
ˆ
3J ˆ 5.6, 3J ˆ 10.3 Hz, 1H, CHCl), 2.10 ± 1.60 (m, 6H, CH2CH2CH2);
(d, OCH2CH), 57.6 (d, CHCl), 36.1 (t, CH2CH2CH3), 19.5 (t, CH2CH3), 13.7
(q, CH3); IR (film): nÄ ˆ3300 ± 3250 (br, NH), 2960 (m, CalH), 2930 (w,
13
ˆ
C NMR (50 MHz): d ˆ 159.0 (s, C O), 75.5 (d, CHO), 57.1 (d, CHCl),
56.1 (d, CHN), 27.8 (t, CH2CHO), 25.2 (t, CHClCH2CH2), 18.1 (t,
CH2CH2CH2); IR (KBr): nÄ ˆ 3250 ± 3200 (br, NH), 2950 (w, CalH), 1765
ˆ
CalH), 2875 (w, CalH), 1750 (vs, C O), 1230 (m, C-O-C), 1030 (m), 940 (w),
1
‡
765 cm (w); MS (EI, 70eV): m/z (%): 86 (100) [C3H3NO2] , 55 (28)
ˆ
(vs, C O), 1400 (s), 1310 (s), 1295 (s, C-O-C), 1240 (s), 1050 (s), 1010 (s),
‡
[C4H7] , 49 (37), 47 (41), 41 (23), 35 (29); elemental analysis calcd (%) for
940 (s), 785 (m), 750 (m), 720 cm 1 (m); MS (EI, 70eV): m/z (%): 177 (10)
C7H12NO2Cl (177.63): C 47.33, H 6.81, N 7.88; found: C 47.40, H 6.57, N 7.72.
[M(37Cl)] , 175 (30) [M(35Cl)] , 140 (<1) [M Cl] , 98 (98) [C6H10O] , 85
‡
‡
‡
‡
‡
‡
(4RS,1'RS)4-(1-Chloro-1-phenylmethyl)-1,3-oxazolidin-2-one (10b): Ac-
cording to the general procedure trans-1-azidocarbonyloxy-3-phenyl-2-
propene (9b) (203 mg, 1.00 mmol) was treated with iron(ii) chloride (38 mg,
0.30 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). After chromatographic purification (P/TBME 20:80) 10b (161 mg,
76%) was obtained as a colorless solid. Rf ˆ 0.26 (P/TBME 20:80); m.p.
85 ± 908C; 1H NMR (200 MHz): d ˆ 7.50 ± 7.25 (m, 5H, Har), 5.95 (s, 1H,
NH), 4.82 (d, 3J ˆ 8.5 Hz, 1H, CHCl), 4.34 (ddd, 3J ˆ 4.7, 3J ˆ 8.5, 3J ˆ
8.5 Hz, 1H, CHN), 4.24 (dd, 2J ˆ 8.5, 3J ˆ 8.5 Hz, 1H, CHHO), 4.03 (dd,
2J ˆ 8.5 Hz, 3J ˆ 4.7 Hz, 1H, CHHO); 13C NMR (50 MHz): d ˆ 158.9 (s,
(12) [C3H2NO2] , 68 (24), 54 (27), 41 (60) [C3H5] , 39 (30); elemental
analysis calcd (%) for C7H10NO2Cl (175.61): C 47.88, H 5.74, N 7.98; found:
C 47.49, H 5.75, N 7.67.
4-(1-Chloroethyl)-5-(prop-2-enyl)-1,3-oxazolidin-2-one (23): According to
the general procedure (5E)-4-azidocarbonyloxy-1,5-heptadiene (22)
(362 mg, 2.00 mmol) was treated with iron(ii) chloride (26 mg, 0.20 mmol)
and trimethyl silyl chloride (0.38 mL, 3.00 mmol) in ethanol (5 mL). After
chromatographic purification (P/TBME 20:80) the product (243 mg, 64%)
was obtained as a yellow oil in a mixture of the 4,5-trans-isomers (23) and
4,5-cis-isomers [d.r. ˆ 92:8, epimeric ratio: 65:35 (1H NMR)]. The analyt-
ical data are provided for the (4RS,5SR,1'SR) isomer. Rf ˆ 0.21 (P/TBME
20:80); 1H NMR (300 MHz): d ˆ 7.71 (s, 1H, NH), 5.97 ± 5.81 (m, 1H,
ˆ
C O), 135.9 (s, Car), 129.4 (d, CarH), 129.0 (d, CarH), 127.5 (d, CarH), 66.9 (t,
CH2O), 64.8 (d, CHCl), 58.6 (d, CHN); IR (KBr): nÄ ˆ 3300 ± 3250 (br, NH),
ˆ
3035 (w, CarH), 2960 (w, CalH), 2930 (w, CalH), 1775 (vs, C O), 1450 (w),
3
CH2CHCH2CHO), 5.34 (brd, Jtrans ˆ 17.1 Hz, CHCHHtrans), 5.32 (brd,
1
1400 (w), 1245 (m, C-O-C), 1230 (m), 1045 (m), 1025 (m), 765 (w), 690 cm
3Jcis ˆ 10.2 Hz, 1H, CHCHcisH), 4.70 ± 4.58 (m, 1H, OCH), 4.05 (dq, 3J 
3J ˆ 6.3 Hz, 1H, CHCl), 3.66 (dd, 3J ˆ 4.0 Hz, 3J ˆ 6.3 Hz, 1H, NHCH), 2.61
‡
‡
(m); MS (EI, 70eV): m/z (%): 125 (14) [C7H6Cl] , 91 (11) [C7H7] , 86 (100)
‡
‡
‡
[C3H3NO2] , 77 (4) [C6H5] , 42 (32) [HNCO] ; elemental analysis calcd
(%) for C10H10NO2Cl (211.65): C 56.75, H 4.76, N 6.62; found: C 56.48, H
4.93, N 6.57.
(dd, 3J  3J ˆ 6.0 Hz, 2H, OCHCH2CH), 1.61 (d, 3J ˆ 6.3 Hz, 3H, CH3);
13
ˆ
C NMR (75 MHz): d ˆ 159.4 (s, C O), 130.9 (d, CH2CHCH2CHO), 119.7
(t, CH2CHCH2CHO), 79.0 (d, OCH), 62.1 (d, CHCl), 58.3 (d, HNCH), 39.2
(t, OCHCH2), 20.6 (q, CH3); IR (film): nÄ ˆ 3300 ± 3250 (br, NH), 2980 (m,
(4RS,1'SR)-4-(1-Chloro-1-phenylmethyl)-1,3-oxazolidin-2-one
(11b):
ˆ
trans-1-Azidocarbonyloxy-3-phenyl-2-propene (9b) (610 mg, 3.00 mmol)
CalH), 2935 (m, CalH), 1755 (vs, C O), 1400 (m), 1240 (m, C-O-C), 1060
Chem. Eur. J. 2001, 7, No. 12
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
0947-6539/01/0712-2589 $ 17.50+.50/0
2589

T. Bach et al.
FULL PAPER
(m), 995 (m), 925 (m), 735 (w), 685 cm 1 (w); MS (EI, 70eV): m/z (%): 148
1H, NH), 5.05 (ddd, 3J ˆ 5.0, 7.0, 12.1 Hz, 1H, CHO), 4.28 (dt, 3J ˆ 4.1,
‡
‡
‡
3
(30) [M C3H5] , 126 (100) [M C2H4Cl] , 84 (11) [C3H2NO2] , 55 (30),
10.7 Hz, 1H, CHCl), 4.04 (dd, J ˆ 7.0, 10.7 Hz, 1H, CHClCHCHO), 2.66
‡
‡
41 (45) [C3H5] , 28 (72) [CO] ; elemental analysis calcd (%) for
C8H12NO2Cl (189.64): C 50.63, H 6.38, N 7.39; found: C 50.59, H 6.16, N
7.01.
(brddd, 2J ˆ 17.3, 3J ˆ 5.0, 12.1 Hz, 1H, CHCHHCHO), 2.57 (brddd, 2J ˆ
17.3, 3J  3J ˆ 5.0 Hz, 1H, CHCHHCHO), 2.31 (ddt, 2J ˆ 11.5, 3J ˆ 4.1,
13.9 Hz, 1H, CHHCHCl), 2.24 ± 2.12 (m, 2H, CH2CH2CHCl), 1.91 (ddt,
2J ˆ 11.5, 3J ˆ 4.1, 5.8 Hz, 1H, CHHCHCl); 13C NMR (125 MHz): d ˆ 157.3
3-Azidocarbonyloxy-cycloocta-1,5-diene (24): 1,5-Cyclooctadien-3-ol[30]
(3.65 g, 29.4 mmol) was dissolved in benzene (100 mL). Pyridine (8.37 g,
8.55 mL, 105.0 mmol) and 1,1'-carbonyldiimidazole (10.8 g, 66.0 mmol)
were added. The mixture was stirred at room temperature for 4 h. Ethyl
acetate (150 mL) was added and the slurry was washed with brine (2 Â
50 mL). The organic layer was dried over magnesium sulfate. The solvent
was removed in vacuo and the resulting residue was dissolved in N,N'-
dimethylformamide (100 mL). Sodium azide (10.71 g, 105.0 mmol) was
ˆ
(s, C O), 127.9 (d, CHCHCH2CHO), 126.2 (d, CHCHCH2CHO), 77.2 (d,
CHO), 61.6 (d, CHNH), 60.4 (d, CHCl), 37.3 (t, CH2CHCl), 31.0 (t,
CH2CHO), 23.7 (t, CH2CH2CHCl); IR (KBr): nÄ ˆ 3300 ± 3250 (br, NH),
ˆ
2940 (m, CalH), 1770 (vs, C O), 1470 (m), 1365 (m), 1220 (s), 1030 (m), 980
1
‡
(m), 730 cm (m); MS (EI, 70eV): m/z (%): 201 (14) [M] , 166 (8) [M
‡
‡
‡
Cl] , 124 (77) [C8H12O] , 94 (21), 86 (47) [C3H4NO2] , 85 (100)
‡
‡
[C3H3NO2] , 68 (35), 67 (25), 54 (52), 41 (21) [C3H5] , 39 (18); elemental
analysis calcd (%) for C9H12NO2Cl (201.65): C 53.61, H 6.00, N 6.95; found:
C 53.39, H 5.84, N 6.92.
added and the pH was adjusted to
4 by addition of concentrated
hydrochloric acid (ca. 15 mL). The slurry was stirred at room temperature
for 18 h. Ethyl acetate (100 mL) was added and the mixture was washed
with brine (3 Â 150 mL). The aqueous layer was extracted with ethyl
acetate (2 Â 150 mL) and the combined organic layers were dried over
magnesium sulfate. The solvent was removed in vacuo and the residue was
purified by flash chromatography (P/TBME 20:80). Compound 24 (4.84 g,
85%) was isolated as a yellow liquid. Rf ˆ 0.67 (P/TBME 20:80); 1H NMR
(500 MHz): d ˆ 5.91 (dddd, 3J ˆ 9.8, 3J ˆ 5.0, 3J ˆ 7.0, 5J ˆ 1.0 Hz, 1H,
OCH), 5.67 (dddd, 3J ˆ 12.4, 3J ˆ 5.4, 3J ˆ 7.0, 5J ˆ 1.8 Hz, 1H,
OCHCHCH), 5.59 (ddddd, 3J ˆ 11.8, 3J  3J ˆ 6.4, 4J ˆ 0.9, 5J ˆ 1.8 Hz,
(4RS,5SR)-4-Methyl-5-(prop-2-enyl)-1,3-oxazolidin-2-one
(27):[31]
(4RS,5SR)-4-(1-Chloromethyl)-5-(prop-2-enyl)-1,3-oxazolidin-2-one (7 f)
(649 mg, 3.70 mmol) was dissolved in benzene (50 mL). The solution was
degassed with a stream of argon for 15 min and subsequently heated to
reflux. A solution of tri-n-butyl tinhydride (1.40 g, 4.80 mmol) and N,N'-bis-
azoisobutyronitrile (50 mg) in dry benzene (20 mL) was added during a
period of 30 min. The solution was heated under reflux for 3 h. After
cooling the solvent was removed in vacuo and the residue was purified by
flash chromatography (P/TBME 10:90). Compound 27 (415 mg, 72%) was
3
3
5
1H, OCHCH2CHCH), 5.51 (dddd, J ˆ 12.4, J  3J ˆ 5.0, J ˆ 1.9 Hz, 1H,
OCHCH), 5.48 (dddd, 3J ˆ 11.8, 3J ˆ 5.3, 4J ˆ 0.9, 5J ˆ 1.9 Hz, 1H,
OCHCH2CH), 2.73 (dddd, 2J ˆ 16.0, 3J  3J ˆ 5.0, 5J ˆ 0.8 Hz, 1H,
OCHCHH), 2.48 (ddd, 2J ˆ 16.0, 3J ˆ 7.0, 3J ˆ 9.8 Hz, 1H, OCHCHH),
2.44 (ddd, 2J ˆ 8.0, 3J ˆ 5.3, 5J ˆ 0.8 Hz, 1H, OCHCHCHCH2CHH), 2.39
obtained as a colorless oil. Rf ˆ 0.23 (P/TBME 10:90); 1H NMR (200 MHz):
3
d ˆ 6.80 (s, 1H, NH), 5.78 ± 5.65 (m, 1H, CH2CHCH2), 5.12 (d, Jtrans
ˆ
17.1 Hz, 1H, CHCHHtrans), 5.10 (d, 3Jcis ˆ 10.0 Hz, 1H, CHCHcisH), 4.08 (dt,
3J  3J ˆ 6.0 Hz, 1H, CH3CHCH), 3.57 (dq, J  3J ˆ 6.0 Hz, 1H, CH3CH),
3
2.48 ± 2.30 (m, 2H, CHCH2CHO), 1.19 (d, 3J ˆ 6.0 Hz, 3H, CH3); 13C NMR
5
(ddd, 2J ˆ 10.9, 3J ˆ 5.1, J ˆ 0.8 Hz, 1H, OCHCHCHCHH), 2.29 (m, 1H,
ˆ
(75 MHz): d ˆ 159.4 (s, C O), 131.4 (d, CH2CHCH2CHO), 119.0 (t,
OCHCHCHCHH), 2.18 (m, 1H, OCHCHCHCH2CHH); 13C NMR
CH2CHCH2CHO), 82.8 (d, CHO), 52.6 (d, CHNH), 38.8 (t, CH2CHO),
ˆ
(125 MHz): d ˆ 156.9 (s, C O), 130.1 (d, OCHCHCH), 130.0 (d,
20.5 (q, CH3).
OCHCH2CHCH), 127.5 (d, OCHCH2CH), 124.4 (d, OCHCH), 77.2 (d,
OCH), 33.5 (t, OCHCH2), 27.8 (t, OCHCHCHCH2), 27.7 (t,
OCHCH2CHCHCH2); IR (film): nÄ ˆ 2950 (w, CalH), 2895 (w, CalH), 2190
(1RS,2SR)-9-Oxa-11-azabicyclo[6.3.0]undec-5-en-10-one (28): As de-
scribed for the conversion 7 f ! 27 (1RS,2RS,8SR)-2-chloro-9-oxa-11-
azabicyclo[6.3.0]undec-5-en-10-one (25) (202 mg, 1.00 mmol) and tri-n-
butyltinhydride (392 mg, 1.35 mmol) were allowed to react for 4 h. After
chromatographic purification (P/TBME 20:80) 28 (120 mg, 72%) was
obtained as a colorless oil. Rf ˆ 0.17 (P/TBME 20:80); 1H NMR (200 MHz):
d ˆ 5.85 (s, 1H, NH), 5.67 (ddd, 3J  3J ˆ 6.8, 3J ˆ 11.0 Hz, 1H,
(s, N3), 2135 (s, N3), 1725 (vs, C O), 1240 cm 1 (vs, C-O-C); MS (EI, 70eV):
ˆ
‡
‡
m/z (%): 165 (14) [M N2] , 107 (31) [M OCON3] , 106 (38) [M
‡
‡
HOCON3] , 80 (43), 79 (74), 70 (47), 67 (60), 54 (100) [C4H6] , 53 (30),
41 (58), 39 (54), 28 (85) [N2, CO] ; elemental analysis calcd (%) for
C9H11N3O2 (193.20): C 55.95, H 5.74, N 21.75; found: C 56.48, H 5.80, N
21.24.
‡
CHCHCH2CHO),
5.58
(ddd,
3J  3J ˆ 6.0,
3J ˆ 11.0 Hz,
1H,
CHCHCH2CHO), 4.27 (ddd, 3J ˆ 3.8, 8.8, 11.4 Hz, 1H, CHO), 3.74 (brdd,
3J  3J ˆ 8.8 Hz, 1H, CH2CHCHO), 2.71 (ddd, 2J ˆ 15.0 Hz, 3J ˆ 3.8, 6.0 Hz,
1H, CHHCHO), 2.49 (ddd, 2J ˆ 15.0, 3J ˆ 6.0, 11.4 Hz, 1H, CHHCHO),
2.30 ± 1.50 (m, 6H, CH2CH2CH2CHNH); 13C NMR (50 MHz): d ˆ 159.0 (s,
(1RS,2RS,8SR)-2-Chloro-9-oxa-11-azabicyclo[6.3.0]undec-5-en-10-one
(25): According to the general procedure 3-azidocarbonyloxycycloocta-1,5-
diene (24) (193 mg, 1.00 mmol, purity: 88%) was treated with iron(ii)
chloride (13 mg, 0.10 mmol) and trimethyl silyl chloride (0.19 mL,
1.50 mmol) in ethanol (5 mL). After chromatographic purification
(P/TBME 30:70) 25 (100 mg, 58%) was obtained as a colorless solid. Rf ˆ
0.25 (P/TBME 30:70), m.p. 98 ± 1058C; 1H NMR (500 MHz): d ˆ 6.20 (s,
1H, NH), 5.66 (dddd, 3J  3J  3J ˆ 9.1, 4J ˆ 1.3 Hz, 1H, CHCHCH2CHO),
5.45 (m, 1H, CHCHCH2CHO), 4.88 (ddd, 3J ˆ 5.0, 3J ˆ 7.1, 3J ˆ 11.9 Hz,
1H, CHO), 3.98 (dt, 3J ˆ 6.5, 3J ˆ 10.3 Hz, 1H, CHCl), 3.87 (dd, 3J ˆ 7.1,
3J ˆ 10.3 Hz, 1H, CHClCHCHO), 2.86 (d, 3J ˆ 6.5 Hz, 1H, CHHCHCl),
2.48 ± 2.32 (m, 2H, CH2CHO), 2.24 ± 2.12 (m, 1H, CHHCH2CHCl), 2.04 ±
1.93 (m, 1H, CHHCH2CHCl), 1.84 ± 1.75 (m, 1H, CHHCHCl); 13C NMR
ˆ
C O), 131.6 (d, CHCHCH2CHO), 124.2 (d, CHCHCH2CHO), 84.0 (d,
CHO), 59.3 (d, CHNH), 30.6 (t, CH2CHO), 30.5 (t, CH2CHNH), 25.0 (t,
CH2CH2CH2CHNH), 24.2 (t, CH2CH2CH2CHNH); IR (film): nÄ ˆ 3300 ±
ˆ
3250 (br, NH), 2930 (m, CalH), 2865 (m, CalH), 1750 (vs, C O), 1450 (w),
1
1400 (w), 1360 (w), 1240 (w, C-O-C), 1020 (m), 1000 (m), 955 (m), 745 cm
‡
‡
(m); MS (EI, 70eV): m/z (%): 86 (77) [C8H10] , 84 (C3H2NO2] , 49 (39), 47
(32); elemental analysis calcd (%) for C9H13NO2 (167.21): C 64.65, H 7.84, N
8.38; found: C 64.48, H 7.83, N 8.03.
4-{1-Chloro-2-[(Z)-hex-2-enyloxy]ethyl}-1,3-oxazolidin-2-one (32a): Ac-
cording to the general procedure (Z)-1-(azidocarbonyloxy)-4-[(Z)-hex-2-
enyloxy]-but-2-ene (31a) (479 mg, 2.00 mmol) was treated with iron(ii)
chloride (25 mg, 0.20 mmol) and trimethyl silyl chloride (0.38 mL,
3.00 mmol) in ethanol (5 mL). After chromatographic purification
(P/TBME 20:80) 32a (393 mg, 79%) was obtained as a colorless oil. The
product was a mixture of the (4RS,1'RS)- and the (4RS,1'SR)-isomer [d.r. ˆ
53:47 (1H NMR)]. Rf ˆ 0.19 (P/TBME 20:80).
ˆ
(125 MHz): d ˆ 157.2 (s, C O), 129.7 (d, CHCHCH2CHO), 124.2 (d,
CHCHCH2CHO), 78.2 (d, CHO), 63.9 (d, CHCl), 63.0 (d, CHNH), 36.4 (t,
CH2CHO), 35.0 (t, CH2CHCl), 23.9 (t, CH2CH2CHCl); IR (KBr): nÄ ˆ
ˆ
3300 ± 3250 (br, NH), 2940 (m, CalH), 1745 (vs, C O), 1400 (m), 1295 (m,
1
C-O-C), 1250 (m), 1030 (m), 900 (m), 700 cm (m); MS (EI, 70eV): m/z
(%): 203 (16) [M(37Cl)] , 201 (43) [M(35Cl)] , 166 (50) [M Cl] , 124 (41)
[C8H12O] , 95 (30), 94 (31), 85 (74) [C3H3NO2] , 68 (40), 67 (43), 54 (89), 53
(47), 41 (59) [C3H5] , 39 (53); elemental analysis calcd (%) for C9H12NO2Cl
‡
‡
‡
‡
‡
1
‡
(4RS,1'RS)-Isomer: H NMR (300 MHz): d ˆ 6.57 (s, 1H, NH), 5.66 ± 5.40
(m, 2H, CHCHCH2CH2), 4.50 ± 4.16 (m, 3H, OCH2CHNH), 4.15 ± 3.90 (m,
(201.65): C 53.61, H 6.00, N 6.95; found: C 53.46, H 5.87, N 6.69.
3
3H, ClCHCH2O, CHCl), 3.76 ± 3.52 (m, 2H, OCH2CHCH), 2.00 (dt, J 
(1RS,2RS,3RS)-2-Chloro-9-oxa-11-azabicyclo[6.3.0]undec-5-en-10-one
(26): 3-Azidocarbonyloxycycloocta-1,5-diene (483 mg, 2.50 mmol, purity:
88%) (24) was dissolved in 1,1,2,2-tetrachloroethane (50 mL) and heated to
1508C for 2 h. After cooling the solvent was removed in vacuo and the
residue was purified by chromatography (P/TBME 20:80). 26 (65 mg, 16%)
was obtained as a colorless solid. Rf ˆ 0.21 (P/TBME 20:80); m.p. 108 ±
1158C; 1H NMR (500 MHz): d ˆ 5.69 (dtt, 3J ˆ 7.7, 11.3, 4J ˆ 1.7 Hz, 1H,
CHCHCH2CHO), 5.59 (dt, 3J ˆ 5.0, 11.3 Hz, 1H, CHCHCH2CHO), 5.52 (s,
3J ˆ 7.3 Hz, 2H, CH2CH2CH3), 1.36 (tq, 3J  3J ˆ 7.3Hz, 2H, CH2CH3), 0.87
(t, 3J ˆ 7.3 Hz, 3H, CH3); 13C NMR (75 MHz): d ˆ 159.3 (s, C O), 134.7 (d,
ˆ
OCH2CHCH), 124.9 (d, OCH2CH), 71.4 (t, CHClCH2O), 67.9 (t,
OCH2CHCH), 66.9 (t, OCH2CHNH), 59.6 (d, CHNH), 55.5 (d, CHCl),
29.5 (t, CH2CH2CH3), 22.5 (t, CH2CH3), 13.6 (q, CH3).
1
(4RS,1'SR)-Isomer: H NMR (300 MHz): d ˆ 6.50 (s, 1H, NH), 5.66 ± 5.40
(m, 2H, CHCHCH2CH2), 4.50 ± 4.16 (m, 3H, OCH2CHNH), 4.15 ± 3.90 (m,
2590
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
0947-6539/01/0712-2590 $ 17.50+.50/0
Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
3
3H, ClCHCH2O, CHCl), 3.76 ± 3.52 (m, 2H, OCH2CHCH), 2.00 (dt, J 
3J ˆ 7.3 Hz, 2H, CH2CH2CH3), 1.36 (tq, 3J  3J ˆ 7.3Hz, 2H, CH2CH3), 0.87
51.6 (d, NHCH), 47.1 (t, NHCHCHCH), 40.9 (t, NHCHCHCH), 33.6 (t,
CH3CH2CH2CH2), 30.6 (t, CH3CH2CH2), 22.8 (t, CH3CH2), 13.9 (q, CH3).
(t, 3J ˆ 7.3 Hz, 3H, CH3); 13C NMR (75 MHz): d ˆ 159.4 (s, C O), 134.7 (d,
ˆ
Isomer 2: 1H NMR (300 MHz): d ˆ 6.68 (s, 1H, NH), 4.43 (ddd, 3J ˆ 6.6,
3J  3J ˆ 8.0 Hz, 1H, CHNH), 4.10 ± 4.00 (m, 2H, OCH2CHNH), 3.98 (dd,
2J ˆ 9.0, 3J ˆ 6.5Hz, 1H, NHCHCHCHCHHO), 3.95 (dd, 2J ˆ 8.6,
3J ˆ 6.6 Hz, 1H, NHCHCHCHHO), 3.58 (dd, 2J ˆ 9.0, 3J ˆ 4.0 Hz,
1H, NHCHCHCHHO), 3.32 (dd, 2J ˆ 8.6, 3J ˆ 6.4 Hz, 1H,
NHCHCHCHCHHO), 2.35 ± 2.20 (m, 1H, NHCHCHCH), 1.95 ± 1.80 (m,
OCH2CHCH), 124.9 (d, OCH2CH), 71.0 (t, CHClCH2O), 67.5 (t,
OCH2CHCH), 66.9 (t, OCH2CHNH), 60.4 (d, CHNH), 55.1 (d, CHCl),
29.5 (t, CH2CH2CH3), 22.5 (t, CH2CH3), 13.6 (q, CH3).
IR (film): nÄ ˆ 3400 ± 3200 (br, NH), 2960 (m, CalH), 2930 (m, CalH), 2870
ˆ
(m, CalH), 1755 (vs, C O), 1410 (m), 1240 (m, C-O-C), 1115 (m), 1040 (m),
‡
935 cm 1 (w); MS (EI, 70eV): m/z (%): 178 (5) [M C5H9] , 166 (28) [M
3
1H, NHCHCHCH2O), 1.45 ± 1.15 (m, 6H, CH3CH2CH2CH2), 0.88 (t, J ˆ
‡
‡
‡
‡
13
ˆ
C6H9] , 114 (90) [C7H12O] , 86 (85) [C3H4NO2] , 84 (40) [C3H2NO2] , 82
7.0 Hz, 3H, CH3); C NMR (75 MHz): d ˆ 160.1 (s, C O), 73.9 (t,
‡
‡
(100), 55 (40) [C4H9] , 42 (24), 28 (25) [CO] ; elemental analysis calcd (%)
for C11H18NO3Cl (247.72): C 53.33, H 7.32, N 5.65; found: C 53.43, H 7.16, N
5.93.
NHCHCHCH2OCH2), 69.2 (t, NHCHCHCH2O), 68.5 (OCH2CHNH),
51.6 (d, NHCH), 49.5 (t, NHCHCHCH), 41.7 (t, NHCHCHCH), 33.8 (t,
CH3CH2CH2CH2), 30.3 (t, CH3CH2CH2), 22.7 (t, CH3CH2), 13.9 (q, CH3).
Isomer 3: 1H NMR (300 MHz): d ˆ 7.08 (s, 1H, NH), 4.04 (ddd, 3J ˆ 4.2,
3J  3J ˆ 6.8 Hz, 1H, CHNH), 4.00 ± 3.91 (m, 2H, OCH2CHNH), 3.90 ± 3.86
(m, 2H, NHCHCHCHCH2O), 3.85 (dd, 2J ˆ 8.9, 3J ˆ 6.8 Hz, 1H,
NHCHCHCHHO), 3.66 (dd, 2J ˆ 8.9, 3J ˆ 6.4 Hz, 1H, NHCHCHCHHO),
3.52 (dd, 2J ˆ 8.5, 3J ˆ 7.0 Hz, 1H, NHCHCHCHCHHO), 2.32 (dtt, 3J ˆ
7.0 Hz, 1H, NHCHCHCH), 2.02 ± 1.98 (m, 1H, NHCHCHCH2O), 1.35 ±
1.10 (m, 6H, CH3CH2CH2CH2), 0.86 (t, 3J ˆ 7.1 Hz, 3H, CH3); 13C NMR
4-{1-Chloro-2-[(E)-hex-2-enyloxy]ethyl}-1,3-oxazolidin-2-one (32b): Ac-
cording to the general procedure (Z)-1-(azidocarbonyloxy)-4-[(E)-hex-2-
enyloxy]-but-2-ene (31b) (447 mg, 1.87 mmol) was treated with iron(ii)
chloride (25 mg, 0.20 mmol) and trimethyl silyl chloride (0.38 mL,
3.00 mmol) in ethanol (5 mL). After chromatographic purification
(P/TBME 20:80) 32b (369 mg, 80%) was obtained as a colorless oil. The
product was a mixture of the (4RS,1'RS)- and (4RS,1'SR)-isomer [d.r. ˆ
53:47 (1H NMR)]. Rf ˆ 0.19 (P/TBME 20:80).
ˆ
(75 MHz): d ˆ 160.3 (s, C O), 73.8 (t, NHCHCHCH2OCH2), 69.3 (t,
(4RS,1'RS)-Isomer: 1H NMR (300 MHz): d ˆ 6.98 (s, 1H, NH), 5.64 (dt,
NHCHCHCH2O), 68.7 (OCH2CHNH), 54.8 (d, NHCH), 49.6 (t,
NHCHCHCH), 41.4 (t, NHCHCHCH), 33.6 (t, CH3CH2CH2CH2), 30.6
(t, CH3CH2CH2), 22.7 (t, CH3CH2), 13.8 (q, CH3).
3
3
3J ˆ 6.5, Jcis ˆ 15.2 Hz, 1H, OCH2CHCH), 5.42 (brdt, 3J ˆ 6.3, Jcis
ˆ
15.2 Hz, 1H, CHCHCH2CH2), 4.45 ± 4.03 (m, 3H, OCH2CHNH), 4.00 ±
3.92 (m, 1H, CHCl), 3.87 (d, 3J ˆ 6.8 Hz, 2H, ClCHCH2O), 3.70 ± 3.45 (m,
2H, OCH2CHCH), 1.94 (dt, 3J  3J ˆ 7.2 Hz, 2H, CH2CH2CH3), 1.30 (tq,
3J  3J ˆ 7.2 Hz, 2H, CH2CH3), 0.80 (t, 3J ˆ 7.2 Hz, 3H, CH3); 13C NMR
Isomer 4: 1H NMR (300 MHz): d ˆ 6.92 (s, 1H, NH), 4.04 (ddd, 3J ˆ 6.1,
3J  3J ˆ 3.2 Hz, 1H, CHNH), 4.00 ± 3.91 (m, 2H, OCH2CHNH), 3.90 (m,
2H, NHCHCHCHCH2O), 3.78 (dd, 2J ˆ 9.4, 3J ˆ 6.8 Hz, 1H,
NHCHCHCHHO), 3.62 (dd, 2J ˆ 9.4, 3J ˆ 4.5 Hz, 1H, NHCHCHCHHO),
3.30 (dd, 2J ˆ 8.8, 3J ˆ 6.6 Hz, 1H, NHCHCHCHCHHO), 2.24 ± 2.14 (m,
1H, NHCHCHCH), 1.89 ± 1.75 (m, 1H, NHCHCHCH2O), 1.35 ± 1.10 (m,
6H, CH3CH2CH2CH2), 0.86 (t, 3J ˆ 7.1 Hz, 3H, CH3); 13C NMR
ˆ
(75 MHz): d ˆ 159.7 (s, C O), 135.5 (d, OCH2CHCH), 125.2 (d, OCH2CH),
72.0 (t, CHClCH2O), 70.6 (t, OCH2CHCH), 67.5 (t, OCH2CHNH), 60.1 (d,
CHNH), 54.9 (d, CHCl), 34.0 (t, CH2CH2CH3), 21.9 (t, CH2CH3), 13.4 (q,
CH3).
(4RS,1'SR)-Isomer: 1H NMR (300 MHz): d ˆ 6.95 (s, 1H, NH), 5.64 (dt,
ˆ
(75 MHz): d ˆ 160.1 (s, C O), 72.5 (t, NHCHCHCH2OCH2), 69.3 (t,
3
3
3J ˆ 6.5, Jcis ˆ 15.2 Hz, 1H, OCH2CHCH), 5.42 (brdt, 3J ˆ 6.3, Jcis
ˆ
NHCHCHCH2O), 68.4 (OCH2CHNH), 51.7 (d, NHCH), 47.4 (t,
NHCHCHCH), 40.6 (t, NHCHCHCH), 33.7 (t, CH3CH2CH2CH2), 30.2
(t, CH3CH2CH2), 22.7 (t, CH3CH2), 13.8 (q, CH3).
15.2 Hz, 1H, CHCHCH2CH2), 4.45 ± 4.03 (m, 3H, OCH2CHNH), 4.00 ±
3.92 (m, 1H, CHCl), 3.87 (d, 3J ˆ 6.8 Hz, 2H, ClCHCH2O), 3.70 ± 3.45 (m,
2H, OCH2CHCH), 1.94 (dt, 3J  3J ˆ 7.2 Hz, 2H, CH2CH2CH3), 1.30 (tq,
3J  3J ˆ 7.2 Hz, 2H, CH2CH3), 0.80 (t, 3J ˆ 7.2 Hz, 3H, CH3); 13C NMR
IR (film): nÄ ˆ 3400 ± 3200 (br, NH), 2955 (s, CalH), 2930 (s, CalH), 2860 (s,
CalH), 1760 (vs, C O), 1415 (m), 1245 (m, C-O-C), 1025 (m), 730 cm 1 (m);
ˆ
ˆ
‡
(75 MHz): d ˆ 159.6 (s, C O), 135.5 (d, OCH2CHCH), 125.2 (d, OCH2CH),
MS (EI, 70eV): m/z (%): 116 (12), 86 (100) [C3H4NO2] , 84 (26)
‡
‡
72.0 (t, CHClCH2O), 70.4 (t, OCH2CHCH), 67.4 (t, OCH2CHNH), 60.4 (d,
CHNH), 54.7 (d, CHCl), 34.0 (t, CH2CH2CH3), 21.9 (t, CH2CH3), 13.4 (q,
CH3).
[C3H2NO2] , 68 (3) [C4H4O] ; elemental analysis calcd (%) for
C11H19NO3 (213.28): C 61.95, H 8.98, N 6.57; found: C 61.88, H 8.99, N 6.69.
(Z)-4-(1-Chloro-1-phenylmethylidene)-5-cyclohexyl-1,3-oxazolidin-2-one
(35a): According to the general procedure 1-azidocarbonyloxy-1-cyclo-
hexyl-3-phenyl-2-propyne (34a) (283 mg, 1.00 mmol) was treated with
iron(ii) chloride (6 mg, 0.05 mmol) and trimethyl silyl chloride (0.19 mL,
1.50 mmol) in ethanol (5 mL). Compound 35a (290 mg, 99%) was obtained
as a colorless solid after work-up. It gradually decomposed in CDCl3. M.p.
140 ± 1508C; 1H NMR (400 MHz): d ˆ 7.91 (s, 1H, NH), 7.39 ± 7.30 (m, 5H,
Har), 5.29 (brs, 1H, CHO), 1.90 ± 0.89 (m, 11H, cyc-H); 13C NMR
IR (film): nÄ ˆ 3400 ± 3200 (br, NH), 2960 (m, CalH), 2930 (m, CalH), 2870
ˆ
(m, CalH), 1755 (vs, C O), 1410 (w), 1245 (m, C-O-C), 1120 (m), 1040 (m),
‡
970 cm 1 (w); MS (EI, 70eV): m/z (%): 178 (2) [M C5H9] , 166 (16) [M
‡
‡
‡
‡
C6H9] , 114 (100) [C7H12O] , 86 (85) [C3H4NO2] , 84 (30) [C3H2NO2] , 55
‡
‡
‡
(44) [C4H9] , 41 (18) [C3H5] , 28 (27) [CO] ; elemental analysis calcd (%)
for C11H18NO3Cl (247.72): C 53.33, H 7.32, N 5.65; found: C 53.08, H 7.56, N
5.83.
ˆ
(50 MHz): d ˆ 156.2 (s, C O), 135.3 (s, Car), 133.1 (d, CarH), 128.9 (d,
4-(3-Butyltetrahydro-2-furyl)-1,3-oxazolidin-2-one (33): (4RS,1'RS)-4-(1-
Chloro-2-[(Z)-hex-2-enyloxy]ethyl-1,3-oxazolidin-2-one (32a) (325 mg,
1.31 mmol) was dissolved in benzene (50 mL). The solution was degassed
with a stream of argon for 15 min. After heating to reflux, a solution of tri-
n-butyltinhydride (497 mg, 1.70 mmol) and N,N'-bis-azoisobutyronitrile
(30 mg) in benzene (10 mL) was added via a syringe pump over a period of
3 h. The solution was refluxed for an additional hour. After cooling the
solvent was removed in vacuo and the residue was purified by chromatog-
raphy (P/TBME 20:80). 33 (257 mg, 92%) was obtained as a colorless oil.
In an analogous fashion compound 32b was converted to the bicyclic
product 33 (85%). The product was a mixture of four diastereoisomers
[d.r. ˆ 23:25:27:25 (13C NMR)]. Rf ˆ 0.08 (P/TBME 20:80).
CarH), 128.8 (s, CHCNH), 128.3 (d, CarH), 102.7 (s, CCCl), 83.8 (d, CHO),
34.9 (d, cyc-CH), 28.9 (t, cyc-CH2), 26.1 (t, cyc-CH2), 25.7 (t, cyc-CH2), 25.6
(t, cyc-CH2), 23.9 (t, cyc-CH2); IR (KBr): nÄ ˆ 3300 ± 3200 (br, NH), 3120 (w,
ˆ
CarH), 2930 (m, CalH), 2860 (m, CalH), 1765 (vs, C O), 1695 (m), 1445 (w),
1215 (m, C-O-C), 1075 (w), 1010 (w), 735 (w), 700 cm 1 (w); MS (EI, 70eV):
m/z (%): 293 (12) [M(37Cl)] , 291 (32) [M(35Cl)] , 211 (34) [M(37Cl)
‡
‡
C6H11] , 209 (100) [M(35Cl) C6H11] , 83 (38) [C6H11] , 77 (2) [C6H5] , 55
‡
‡
‡
‡
‡
‡
‡
(52) [C4H9] , 41 (34) [C3H5] , 28 (75) [CO] ; elemental analysis calcd (%)
for C16H18NO2Cl (291.78): C 65.86, H 6.22, N 4.80; found: C 65.88, H 6.43, N
4.84.
(Z)-4-(1-Chloro-1-phenylmethylidene)-5-(2-phenylethyl)-1,3-oxazolidin-2-
one (35b): According to the general procedure 3-azidocarbonyloxy-1,5-
diphenyl-1-pentyne (34b) (611 mg, 2.00 mmol) was treated with iron(ii)
chloride (26 mg, 0.20 mmol) and trimethyl silyl chloride (0.38 mL,
3.00 mmol) in ethanol (5 mL). Compound 35b (506 mg, 81%) was
obtained as a colorless solid after work-up. It gradually decomposed in
CDCl3. M.p. 110 ± 1128C; 1H NMR (400 MHz): d ˆ 7.85 (s, 1H, NH), 7.40 ±
6.60 (m, 10H, Har), 5.20 (t, 3J ˆ 6.3 Hz, 1H, CHO), 2.48 (ddd, 3J  3J ˆ 6.3,
Isomer 1: 1H NMR (300 MHz): d ˆ 6.60 (s, 1H, NH), 4.38 (ddd, 3J ˆ 6.1,
3J  3J ˆ 7.5 Hz, 1H CHNH), 4.05 (dd, 2J ˆ 7.6, 3J ˆ 7.5 Hz, 1H,
OCHHCHNH), 4.00 (dd, 2J ˆ 7.5, 3J ˆ 7.6 Hz, 1H, OCHHCHNH), 3.82
(dd, 2J ˆ 8.6, 3J ˆ 6.8Hz, 1H, NHCHCHCHCHHO), 3.80 (dd, 2J ˆ 8.5,
3J ˆ 6.2 Hz, 1H, NHCHCHCHHO), 3.55 (dd, 2J ˆ 8.5, 3J ˆ 6.2 Hz,
1H, NHCHCHCHHO), 3.50 (dd, 2J ˆ 8.6, 3J ˆ 6.4 Hz, 1H,
NHCHCHCHCHHO), 2.43 (dtt, 3J ˆ 6.8 Hz, 1H, NHCHCHCH), 2.04 ±
2.00 (m, 1H, NHCHCHCH2O), 1.45 ± 1.15 (m, 6H, CH3CH2CH2CH2), 0.88
3J ˆ 13.1 Hz, 2H, CH2CH2CHO), 1.52 (dd, 3J ˆ 6.3, 3J ˆ 13.1 Hz, 2H,
3
13
13
ˆ
ˆ
(t, J ˆ 7.0 Hz, 3H, CH3); C NMR (75 MHz): d ˆ 159.9 (s, C O), 72.5 (t,
NHCHCHCH2OCH2), 68.8 (t, NHCHCHCH2O), 68.1 (OCH2CHNH),
CH2CH2CHO); C NMR (50 MHz): d ˆ 156.2 (s, C O), 139.5 (s, Car),
134.9 (s, Car), 133.9 (d, CarH), 128.9 (d, CarH), 128.6 (s, HNCCCl), 128.5 (d,
Chem. Eur. J. 2001, 7, No. 12
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
0947-6539/01/0712-2591 $ 17.50+.50/0
2591

T. Bach et al.
FULL PAPER
‡
CarH), 128.4 (d, CarH), 128.1 (d, CarH), 126.2 (d, CarH), 102.9 (s, CCl), 78.7
(d, CHCHO), 33.5 (t, CH2CH2CHO), 29.9 (t, CH2CH2CHO); IR (KBr):
nÄ ˆ 3200 ± 3100 (br, NH), 3125 (w, CarH), 3065 (w, CarH), 3025 (w, CarH),
[C6H5] ; elemental analysis calcd (%) for C10H8NO2Cl (209.63): C 57.30, H
3.85, N 6.68; found: C 57.30, H 4.05, N 6.46.
3-Azidocarbonyloxy-1-phenyl-non-4-yne (36): As described for the prep-
aration of azide 24 1-phenyl-non-4-yn-3-ol (2.16 g, 10.0 mmol) was
subjected to azidocarbonylation. After chromatographic purification
(P/TBME 60:40) compound 36 (2.59 g, 91%) was obtained as a yellow
ˆ
2965 (w, CalH), 2930 (w, CalH), 2870 (w, CalH), 1770 (vs, C O), 1670 (m),
1
1445 (m), 1375 (m), 1230 (m, C-O-C), 1030 (m), 1010 (w), 745 (m), 695 cm
(m); MS (EI, 70eV): m/z (%): 315 (11) [M(37Cl)] , 313 (42) [M(35Cl)] , 277
(11) [M Cl H] , 209 (23) [M C8H8] , 174 (34), 115 (19), 105 (27)
[C8H9] , 104 (63) [C8H8] , 91 (100) [C7H7] , 77 (11) [C6H5] ; elemental
analysis calcd (%) for C18H16NO2Cl (313.78): C 68.90, H 5.14, N 4.46;
found: C 69.24, H 5.20, N 4.84.
‡
‡
‡
‡
1
liquid. Rf ˆ 0.64 (P/TBME 60:40); H NMR (200 MHz): d ˆ 7.25 ± 7.00 (m,
‡
‡
‡
‡
5H, Har), 5.18 (tt, 3J ˆ 6.5, J ˆ 2.0 Hz, 1H, OCH), 2.68 (t, J ˆ 7.8 Hz, 2H,
PhCH2CH2), 2.11 (dt, 3J ˆ 6.9, 5J ˆ 2.0 Hz, 2H, OCHCCCH2), 2.06 ± 1.92
(m, 2H, PhCH2CH2), 1.48 ± 1.20 (m, 4H, CH2CH2CH3), 0.80 (t, 3J ˆ 7.9 Hz,
5
3
3H, CH3); 13C NMR (50 MHz): d ˆ 156.7 (s, C O), 140.4 (s, Car), 128.5 (d,
ˆ
(Z)-4-(1-Chloro-1-phenylmethylidene)-5-(cyclohex-3-enyl)-1,3-oxazolidin-
2-one (35c): According to the general procedure 1-azidocarbonyloxy-1-
(cyclohex-3-enyl)-3-phenyl-2-propyne (34c) (563 mg, 2.00 mmol) was
treated with iron(ii) chloride (26 mg, 0.20 mmol) and trimethyl silyl
chloride (0.38 mL, 3.00 mmol) in ethanol (5 mL). 35c (520 mg, 90%) was
obtained as a colorless solid after work up. The product was a mixture of
the (1'RS,5RS)- and the (1'RS,5SR)-isomer [d.r. ˆ 57:43 (1H NMR)]. It
gradually decomposed in CDCl3. M.p. 140 ± 1448C.
CarH), 128.3 (d, CarH), 126.2 (d, CarH), 88.5 (s, OCHCCCH2), 75.6 (s,
OCHCCCH2), 68.8 (d, OCH), 36.5 (t, PhCH2CH2), 31.1 (t, PhCH2), 30.4 (t,
CH2CH2CH2CH3), 21.9 (t, CH2CH2CH3), 18.3 (t, CH2CH3), 13.5 (q, CH3);
IR (film): nÄ ˆ 3030 (w, CarH), 2960 (m, CalH), 2930 (m, CalH), 2190 (s, N3),
1
ˆ
2135 (s, N3), 1735 (vs, C O), 1235 (vs, C-O-C), 1010 (w), 750 (w), 700 cm
‡
‡
(w); MS (EI, 70eV): m/z (%): 198 (6) [M HOCN3] , 104 (14) [C8H8] , 91
‡
‡
(51) [C7H7] , 28 (100) [N2, CO] ; elemental analysis calcd (%) for
C16H19N3O2 (285.34): C 67.35, H 6.71, N 14.73; found: C 67.16, H 6.85, N
14.35.
(1'RS,5RS)-Isomer: 1H NMR (200 MHz): d ˆ 7.90 (brs, 1H, NH), 7.30 ± 7.10
3
ˆ
(m, 5H, Har), 5.50 ± 5.44 (m, 2H, HC CH), 5.38 (d, J ˆ 4.0 Hz, 1H, CHO),
13
(Z)-4-(1-Chloro-1-pentylidene)-5-(2-phenylethyl)-1,3-oxazolidin-2-one
(37): According to the general procedure 3-azidocarbonyloxy-1-phenyl-4-
nonyne (36) (285 mg, 1.00 mmol) was treated with iron(ii) chloride (13 mg,
0.10 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). Compound 37 (265 mg, 95%) was obtained as a yellow oil. It
considerably decomposed in CDCl3. 1H NMR (200 MHz): d ˆ 8.60 (s, 1H,
NH), 7.20 ± 6.90 (m, 5H, Har), 4.92 (t, 3J ˆ 5.7 Hz, 1H, CHO), 2.85 ± 2.50 (m,
2H, CH2CH2CHO), 1.92 (t, 3J ˆ 7.2 Hz, 4H, CH2CH2CHO, ClCCH2),
1.55 ± 1.00 (m, 4H, CH3CH2CH2), 0.75 (t, 3J ˆ 7.1 Hz, 3H, CH3); 13C NMR
ˆ
2.30 ± 1.20 (m, 7H, cyc-H); C NMR (50 MHz): d ˆ signal for C O not
observed, 135.1 (s, Car), 132.8 (d, CarH), 129.0 (d, CarH), 128.9 (s, HNCCCl),
ˆ
ˆ
128.2 (d, CarH), 126.6 (d, CH CHCH2CH), 124.9 (d, CH CHCH2CH),
102.8 (s, CCl), 83.3 (d, CHO), 35.9 (d, CHCHO), 27.5 (t, CH2), 25.1 (t, CH2),
23.0 (t, CH2).
(1'RS,5SR)-Isomer: 1H NMR (200 MHz): d ˆ 7.90 (brs, 1H, NH), 7.30 ± 7.10
3
ˆ
(m, 5H, Har), 5.50 ± 5.44 (m, 2H, HC CH), 5.37 (d, J ˆ 5.3 Hz, 1H, CHO),
13
ˆ
2.30 ± 1.20 (m, 7H, cyc-H); C NMR (50 MHz): d ˆ signal for C O not
observed, 135.2 (s, Car), 133.0 (d, CarH), 129.0 (d, CarH), 128.9 (s, HNCCCl),
ˆ
(50 MHz): d ˆ 156.9 (s, C O), 139.9 (s, Car), 131.6 (s, HNCCCl), 128.4 (d,
ˆ
ˆ
128.2 (d, CarH), 126.6 (d, CH CHCH2CH), 125.5 (d, CH CHCH2CH),
102.8 (s, CCl), 82.8 (d, CHO), 36.3 (d, CHCHO), 27.5 (t, CH2), 24.9 (t, CH2),
20.5 (t, CH2).
CarH), 126.2 (d, CarH), 125.9 (d, CarH), 105.9 (s, CCl), 77.6 (d, CHO), 36.3 (t,
CH2), 32.4 (t, PhCH2CH2), 29.9 (t, PhCH2CH2), 29.4 (t, CH2), 21.7 (t, CH2),
13.6 (q, CH3); IR (film): nÄ ˆ 3200 ± 3100 (br, NH), 3060 (w, CarH), 3030 (w,
IR (KBr): nÄ ˆ 3300 ± 3200 (br, NH), 3125 (w, CarH), 2930 (m, CalH), 2840 (w
ˆ
CarH), 2960 (w, CalH), 2930 (w, CalH), 2870 (w, CalH), 1760 (vs, C O), 1600
(m), 1455 (m), 1400 (m), 1055 (m), 1010 (w), 700 cm 1 (m); MS (EI, 70eV):
ˆ
ˆ
CalH), 1770 (vs, C O), 1695 (m), 1680 (m, C C), 1445 (w), 1215 (m, C-O-
C), 1055 (w), 980 (w), 760 (m), 700 cm 1 (m); MS (EI, 70eV): m/z (%): 291
‡
‡
‡
m/z (%): 293 (<1) [M] , 258 (1) [M Cl] , 230 (9) [M Cl CHCH3] ,
(5) [M(37Cl)] , 289 (20) [M(35Cl)] , 210 (50) [M(37Cl) C6H7] , 164 (39)
[M C7H6Cl] , 81 (100) [C6H9] , 80 (83) [C6H8] , 79 (39) [C6H7] ;
elemental analysis calcd (%) for C16H16NO2Cl (289.76): C 66.32, H 5.57,
N 4.83; found: C 66.21, H 5.46, N 5.03.
‡
‡
‡
‡
‡
215 (10) [M Cl CH2CH2CH3] , 207 (96), 133 (87) [C9H9O] , 105 (87)
‡
‡
‡
‡
‡
‡
‡
‡
[C8H9] , 91 (100) [C7H7] , 55 (15) [C4H7] , 43 (40) [C3H7] ; HRMS calcd
for C16H20NO235Cl: 293.1183; found: 293.1187.
(Z)-5-Cyclohexyl-4-[1-(2,2-dimethylpropylidene)]-5-ethoxy-1,3-oxazoli-
din-2-one (39a): According to the general procedure 5-azidocarbonyloxy-
7-cyclohexyl-2,2-dimethyl-3-heptyne (38a) (263 mg, 1.00 mmol) was treat-
ed with iron(ii) chloride (13 mg, 0.10 mmol) and trimethyl silyl chloride
(0.19 mL, 1.50 mmol) in ethanol (5 mL). Compound 39a (261 mg, 93%)
was obtained as a colorless solid. It gradually decomposed in CDCl3. M.p.
180 ± 1858C; 1H NMR (300 MHz): d ˆ 7.85 (brs, 1H, NH), 4.48 [s, 1H,
(Z)-4-(1-Chloro-1-phenylmethylidene)-5-propyl-1,3-oxazolidin-2-one
(35d): According to the general procedure 3-azidocarbonyloxy-1-phenyl-1-
hexyne (34d) (243 mg, 1.00 mmol) was treated with iron(ii) chloride (13 mg,
0.10 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL).Compound 35d (249 mg, 99%) was obtained as a colorless solid
after work-up. It gradually decomposed in CDCl3. M.p. 124 ± 1258C;
1H NMR (300 MHz): d ˆ 7.40 (s, 1H, NH), 7.40 ± 7.25 (m, 5H, Har), 5.45 (dd,
HCC(CH3)3], 3.45 (dq, 3J ˆ 7.2, 6J ˆ 1.5 Hz, 2H, CH3CH2), 2.05 ± 1.00 [m,
3
3J ˆ 3.2, J ˆ 6.4 Hz, 1H, CHO), 1.44 ± 1.25 (m, 4H, CH3CH2CH2), 0.74 (t,
ˆ
13
23H, cyc-H, C(CH3)3, CH2CH3]; C NMR (75 MHz): d ˆ 156.0 (s, C O),
3J ˆ 7.0 Hz, 3H, CH3); 13C NMR (50 MHz): d ˆ signal for C O not
ˆ
130.1 (s, OOCCNH), 112.0 [d, HCC(CH3)3], 111.9 (s, OOCCNH), 58.5 (t,
CH3CH2), 47.0 (d, cyc-CH), 31.7 [s, C(CH3)3], 30.3 [q, C(CH3)3], 26.2 (t, cyc-
CH2), 26.0 (t, cyc-CH2), 25.9 (t, cyc-CH2), 25.2 (t, cyc-CH2), 14.9 (q,
CH3CH2); IR (KBr): nÄ ˆ 3200 ± 3100 (br, NH), 2975 (w, CalH), 2930 (m,
observed, 135.1 (s, Car), 134.1 (d, CarH), 129.0 (s, HNCCCl), 128.9 (d,
CarH), 128.3 (d, CarH), 102.7 (s, CCl), 79.7 (d, CHO), 34.2 (t, CH3CH2CH2),
17.0 (t, CH3CH2), 13.3 (q, CH3); IR (KBr): nÄ ˆ 3300 ± 3200 (br, NH), 3115
ˆ
(w, CarH), 2955 (w, CalH), 2930 (w, CalH), 2875 (w, CalH), 1760 (vs, C O),
ˆ
CalH), 2880 (w, CalH), 1755 (vs, C O), 1695 (m), 1370 (w), 1320 (w), 1230
(w, C-O-C), 1200 (w), 1165 (w), 905 (w), 690 cm 1 (w); MS (EI, 70eV): m/z
ˆ
1680 (m, C C), 1445 (m), 1375 (m), 1220 (m, C-O-C), 1065 (m), 1035 (m),
1
‡
765 (m), 695 cm (m); MS (EI, 70eV): m/z (%): 253 (27) [M(37Cl)] , 251
‡
‡
(%): 237 (4) [M C2H5OH] , 208 (66), 198 (43) [M C6H11] , 152 (47), 87
(100) [M(35Cl)] , 208 (32) [M(35Cl) C3H7] , 165 (50); elemental analysis
calcd (%) for C13H14NO2Cl (251.71): C 62.03, H 5.61, N 5.56; found: C
62.13, H 5.64, N 5.89.
‡
‡
‡
‡
‡
(36), 83 (57) [C6H11] , 82 (53) [C6H10] , 69 (47), 57 (46) [C4H9] , 55 (58)
‡
‡
[C4H7] , 41 (100) [C3H5] ; elemental analysis calcd (%) for C16H27NO3
(281.39): C 68.30, H 9.67, N 4.98; found: C 68.57, H 9.42, N 5.10.
(Z)-4-(1-Chloro-1-phenylmethylidene)-1,3-oxazolidin-2-one (35e): Ac-
cording to the general procedure 3-azidocarbonyloxy-1-phenyl-1-propyne
(34e) (201 mg, 1.00 mmol) was treated with iron(ii) chloride (13 mg,
0.10 mmol) and trimethyl silyl chloride (0.19 mL, 1.50 mmol) in ethanol
(5 mL). Compound 35e (211 mg, 99%) was obtained as a colorless solid
after work-up. It gradually decomposed in CDCl3. M.p. 110 ± 1158C;
1H NMR (300 MHz): d ˆ 8.35 (brs, 1H, NH), 7.75 ± 7.40 (m, 5H, Har), 5.35
(Z)-4-[1-(2,2-Dimethylpropylidene)]-5-ethoxy-5-(2-phenylethyl)-1,3-oxa-
zolidin-2-one (39b): According to the general procedure 5-azidocarbony-
loxy-7-phenyl-2,2-dimethyl-3-heptyne (38b) (285 mg, 1.00 mmol) was
treated with iron(ii) chloride (13 mg, 0.10 mmol) and trimethyl silyl
chloride (0.19 mL, 1.50 mmol) in ethanol (5 mL). Compound 39b
(285 mg, 95%) was obtained as a colorless solid. It gradually decomposed
in CDCl3. M.p. 153 ± 1588C; 1H NMR (200 MHz): d ˆ 8.25 (brs, 1H, NH),
7.30 ± 7.00 (m, 5H, Har), 4.51 [s, 1H, HCC(CH3)3], 3.46 (dq, 3J ˆ 7.0, 5J ˆ
1.2 Hz, 2H, CH3CH2), 2.70 (ddd, 2J ˆ 13.6, 3J ˆ 5.0, 3J ˆ 13.6 Hz, 1H,
CCHHCH2COO), 2.68 (ddd, 2J ˆ 13.6, 3J ˆ 5.0, 3J ˆ 13.6 Hz, 1H,
CHHCH2COO), 2.16 (ddd, 2J ˆ 11.8, 3J ˆ 5.0, 3J ˆ 13.6 Hz, 1H,
CH2CHHCOO), 1.97 (ddd, 2J ˆ 11.8, 3J ˆ 5.0, 3J ˆ 13.6 Hz, 1H,
CH2CHHCOO), 1.10 (t, 3J ˆ 7.0 Hz, 3H, CH3CH2), 1.08 [s, 9H, (CH3)3];
(s, OCH2); 13C NMR (75 MHz): d ˆ 156.4 (s, C O), 134.7 (s, Car), 130.4 (d,
ˆ
CarH), 128.8 (d, CarH), 128.4 (d, CarH), 127.0 (s, HNCCCl), 103.5 (s, CCl),
68.1 (t, OCH2); IR (KBr): n ˆ 3300 ± 3200 (br, NH), 3120 (w, CarH), 1755
ˆ
ˆ
ˆ
(vs, C O), 1680 (w, C C), 1660 (m, C C), 1385 (m), 1225 (m, C-O-C), 1040
1
(m), 1030 (m), 765 (m), 725 cm (m); MS (EI, 70eV): m/z (%): 209 (100)
‡
‡
‡
[M] , 138 (41), 130 (78) [M Cl CO2] , 103 (74), 89 (29) [C7H5] , 77 (26)
2592
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
0947-6539/01/0712-2592 $ 17.50+.50/0
Chem. Eur. J. 2001, 7, No. 12

Substituted Oxazolidinones
2581±2594
13
ˆ
C NMR (50 MHz): d ˆ 155.6 (s, C O), 141.0 (s, Car), 130.5 (s, OOCCNH),
128.4 (d, CarH), 128.3 (d, CarH), 125.9 (d, CarH), 112.5 [d, HCC(CH3)3],
109.8 (s, OOCCNH), 58.7 (t, CH3CH2O), 41.7 (t, CH2CH2COO), 31.8 [s,
C(CH3)3], 30.3 [q, C(CH3)3)], 29.0 (t, CH2CH2COO), 14.9 (q, CH3CH2); IR
(KBr): nÄ ˆ 3200 ± 3100 (br, NH), 3100 (w, CarH), 3025 (w, CarH), 2965 (w,
[2] a) R. Fusco, G. Biancchetti, D. Pocar, Gazz. Chim. Ital. 1961, 91, 933 ±
957; b) E. Kuehne, G. DiVincenzo, J. Org. Chem. 1972, 37, 1023 ± 1028;
c) T. Sasaki, K. Kanematsu, K. Hayakawa, M. Uchide, J. Chem. Soc.
Perkin Trans. 1 1972, 2750 ± 2755; d) J. S. Oakland, F. Scheinmann, J.
Chem. Soc. Perkin Trans. 1 1973, 800 ± 806; e) T. Sasaki, T. Manabe, S.
Nishida, J. Org. Chem. 1980, 45, 479 ± 482.
[3] a) H. Tanida, T. Tsuji, T. Irie, J. Org. Chem. 1966, 31, 3941 ± 3947; b) P.
Scheiner, J. Org. Chem. 1967, 32, 2022 ± 2023; c) M. L. Graziano, R.
Scarpati, J. Heterocycl. Chem. 1976, 13, 205 ± 210; d) M. Christl, H.
Leininger, Tetrahedron Lett. 1979, 1553 ± 1556; e) A. Cipollone, M. A.
Loreto, L. Pellacani, P. A. Tardella, J. Org. Chem. 1987, 52, 2584 ±
2586; f) Y. Auberson, P. Vogel, Tetrahedron 1990, 46, 7019 ± 7032; g) S.
Allemann, J.-L. Reymond, P. Vogel, Helv. Chim. Acta 1990, 73, 674 ±
689; h) S. Hünig, P. Kraft, J. Prakt. Chem. 1990, 332, 133 ± 142; i) G.
Maier, C. Schmidt, H. P. Reisenauer, E. Endlein, D. Becker, J.
Eckwert, B. A. Hess, L. J. Schaad, Chem. Ber. 1993, 126, 2337 ± 2352;
j) S. Hünig, M. Schmitt, Liebigs Ann. 1996, 559 ± 574.
[4] Intermolecular aziridination: a) W. Lwowski, T. W. Mattingly Jr., J.
Am. Chem. Soc. 1965, 87, 1947 ± 1958; b) O. E. Edwards, J. W. Elder,
M. Lesage, R. W. Retallack, Can. J. Chem. 1975, 53, 1019 ± 1029; c) S.
Lociuro, L. Pellacani, P. A. Tardella, Tetrahedron Lett. 1983, 24, 593 ±
596; d) W. Lwowski in Azides and Nitrenes (Ed.: E. Scriven),
Academic Press, Orlando, 1984, pp. 231 ± 235; e) S. Fioravanti, M. A.
Loreto, L. Pellacani, P. A. Tardella, Tetrahedron 1991, 47, 5877 ± 5882.
[5] Intramolecular aziridination: a) S. C. Bergmeier, D. M. Stanchina,
Tetrahedron Lett. 1995, 36, 4533 ± 4536; b) S. C. Bergmeier, D. M.
Stanchina, J. Org. Chem. 1997, 62, 4449 ± 4456; c) S. C. Bergmeier,
D. M. Stanchina, J. Org. Chem. 1999, 64, 2852 ± 2859; d) D. R.
Williams, C. M. Rojas, S. L. Bogen, J. Org. Chem. 1999, 64, 736 ± 746.
[6] The role of PdCl2 in the thermal reaction of azidoformates with allylic
ethers appears to be the isomerization of allylic to vinylic ethers: T.
Migita, K. Hongoh, H. Naka, S. Nakaido, M. Kosugi, Bull. Chem. Soc.
Jpn. 1988, 61, 931 ± 938.
ˆ
CalH), 2935 (w, CalH), 2870 (w, CalH), 1755 (vs, C O), 1695 (m), 1455 (w),
1330 (m), 1205 (w, C-O-C), 995 (m), 885 (m), 690 cm 1 (m); MS (EI, 70eV):
m/z (%): 303 (<1) [M] , 258 (2) [M OCH2CH3] , 199 (97) [M
OCH2CH3 HC(CH3)3] , 168 (79), 105 (26) [C8H9] , 91 (100) [C7H7] ,
57 (22) [C(CH3)3] ; elemental analysis calcd (%) for C18H25NO3 (303.40): C
71.26, H 8.31, N 4.83; found: C 71.29, H 8.11, N 4.83.
‡
‡
‡
‡
‡
‡
(Z)-4-[1-(2,2-Dimethylpropylidene)]-5-(1-methylethoxy)-5-(2-phenyleth-
yl)-1,3-oxazolidin-2-one (39c): According to the general procedure 5-azi-
docarbonyloxy-7-phenyl-2,2-dimethyl-3-heptyne
(38b)
(285 mg,
1.00 mmol) was treated with iron(ii) chloride (13 mg, 0.10 mmol) and
trimethyl silyl chloride (0.19 mL, 1.50 mmol) in isopropanol (5 mL).
Compound 39c (315 mg, 99%) was obtained as a colorless solid. It
gradually decomposed in CDCl3. M.p. 93 ± 958C; 1H NMR (200 MHz): d ˆ
7.98 (brs, 1H, NH), 7.50 ± 7.20 (m, 5H, Har), 4.70 [s, 1H, HCC(CH3)3], 3.98
(sept, 3J ˆ 6.1 Hz, 1H, CH(CH3)2), 2.85 (ddd, 2J ˆ 13.9, 3J ˆ 5.5, 3J ˆ
2
3
3
13.9 Hz, 1H, CCHHCH2COO), 2.78 (ddd, J ˆ 13.9, J ˆ 5.5, J ˆ 13.9 Hz,
1H, CHHCH2COO), 2.33 (ddd, 2J ˆ 11.5, 3J ˆ 5.5, 3J ˆ 13.9 Hz, 1H,
CH2CHHCOO), 2.10 (ddd, 2J ˆ 11.5, 3J ˆ 5.5, 3J ˆ 13.9 Hz, 1H,
CH2CHHCOO), 1.32 (d, 3J ˆ 6.1 Hz, 6H, CH(CH3)2), 1.25 [s, 9H,
13
ˆ
(CH3)3]; C NMR (50 MHz): d ˆ 155.5 (s, C O), 141.1 (s, Car), 131.4 (s,
OOCCNH), 128.4 (d, CarH), 128.3 (d, CarH), 125.9 (d, CarH), 112.5 [d,
HCC(CH3)3], 110.5 (s, OOCCNH), 68.2 (d, CH(CH3)2), 42.2 (t,
CH2CH2COO), 31.9 [s, C(CH3)3], 30.3 [q, C(CH3)3], 29.0 (t, CH2CH2COO),
24.1 [q, CH(CH3)2]; IR (KBr): nÄ ˆ 3200 ± 3100 (br, NH), 3095 (w, CarH),
ˆ
3060 (w, CarH), 2970 (m, CalH), 2870 (w, CalH), 1755 (vs, C O), 1695 (vs),
1600 (s), 1500 (w), 1455 (m), 1370 (m), 1310 (m), 1230 (m), 1210 (m), 1160
(m), 1000 (m), 960 (m), 895 (m), 750 (m), 700 cm 1 (m); MS (EI, 70eV): m/z
(%): 273 (1), 258 (6) [M OC3H7], 216 (48), 171 (31), 140 (42), 127 (36),
105 (28) [C8H9] , 91 (100) [C7H7] , 57 (30) [C4H9] , 43 (80) [C3H7] ;
elemental analysis calcd (%) for C19H27NO3 (317.43): C 71.89, H 8.57, N
4.41; found: C 72.28, H 8.35, N 4.63.
‡
‡
‡
‡
[7] a) T. Bach, C. Körber, Tetrahedron Lett. 1998, 39, 5015 ± 5016; b) T.
Bach, C. Körber, Eur. J. Org. Chem. 1999, 1033 ± 1039; c) T. Bach, C.
Körber, J. Org. Chem. 2000, 65, 2358 ± 2367.
[8] B. Schlummer, Ph.D. thesis, Philipps-University Marburg, Germany,
2000.
4-[1-Chloro-1-(2,2-dimethylpropyl)]-5-cyclohexyl-1,3-oxazolin-2-one
(41a): According to the general procedure 1-azidocarbonyloxy-1-cyclo-
hexyl-4,4-dimethyl-2-pentyne (38a) (270 mg, 1.02 mmol) was treated with
iron(ii) chloride (13 mg, 0.10 mmol) and trimethyl silyl chloride (0.19 mL,
1.50 mmol) in acetonitrile (5 mL). A yellow oil was obtained (246 mg). n-
Pentane (5 mL) was added and the supernatant solution was collected.
After removal of the solvent in vacuo 1-azidocarbonyloxy-1-cyclohexyl-
4,4-dimethyl-2-pentyne (38b) (200 mg, 74%) was isolated. The residue
which was not soluble in n-pentane was identified as 4-[1-chloro-1-(2,2,-
dimethylpropyl)]-5-cyclohexyl-1,3-oxazolin-2-one (41b) (44 mg, 16%).
The compound quickly decomposed in CDCl3. 1H NMR (300 MHz): d ˆ
[9] Selected references: a) D. A. Evans, M. M. Faul, M. T. Bilodeau, J.
Org. Chem. 1991, 56, 6744 ± 6746; b) K. J. OꢁConnor, S.-J. Wey, C. J.
Burrows, Tetrahedron Lett. 1992, 33, 1001 ± 1004; c) K. Noda, N.
Hosoya, R. Irie, Y. Ito, T. Katsuki, Synlett 1993, 469 ± 471; d) D. A.
Evans, M. M. Faul, M. T. Bilodeau, J. Am. Chem. Soc. 1994, 116,
2742 ± 2753; e) Z. Li, R. W. Quan, E. N. Jacobsen, J. Am. Chem. Soc.
1995, 117, 5889 ± 5890; f) P. Müller, C. Baud, Y. Jacquier, Tetrahedron
1996, 52, 1543 ± 1548; g) J. du Bois, C. S. Tomooka, J. Hong, E. M.
Carreira, Acc. Chem. Res. 1997, 30, 364 ± 372; h) J. U. Jeong, B. Tao, I.
Sagasser, H. Henniges, K. B. Sharpless, J. Am. Chem. Soc. 1998, 120,
6844 ± 6845; i) P. Brandt, M. J. Södergren, P. G. Andersson, P.-O.
Norrby, J. Am. Chem. Soc. 2000, 122, 8013 ± 8020.
[10] Reviews: a) P. Müller, Adv. Catal. Processes 1997, 2, 131 ± 151;
b) H. M. I. Osborn, J. Sweeney, Tetrahedron: Asymmetry 1997, 8,
1693 ± 1715.
[11] Preliminary publications: a) T. Bach, B. Schlummer, K. Harms, Chem.
Commun. 2000, 287 ± 288; b) T. Bach, B. Schlummer, K. Harms,
Synlett 2000, 1330 ± 1332.
9.30 (s, 1H, NH), 4.50 (brs, 1H, CHCl), 1.80 ± 0.80 [m, 20H, C(CH3)3, cyc-
13
ˆ
H]; C NMR (75 MHz): d ˆ 156.3 (s, C O), 142.4 (s, OCCCCHCl), 117.5
(s, HNCCHCl), 62.6 (d, CHCl), 41.9 (d, cyc-CH), 30.7 (t, cyc-CH2), 30.6 (t,
cyc-CH2), 30.4 [s, C(CH3)3], 26.9 [q, C(CH3)3], 26.0 (t, cyc-CH2), 25.9 (t, cyc-
CH2), 25.4 (t, cyc-CH2); IR (film): nÄ ˆ 3200 ± 3000 (br, NH), 2930 (m, CalH),
ˆ
ˆ
2860 (m, CalH), 1760 (vs, C O), 1680 (w, C C), 1450 (w), 1235 (m, C-O-C),
1
‡
970 (m), 760 cm (m); MS (EI, 70eV): m/z (%): 271 (7) [M] , 236 (13)
[M Cl] , 235 (20) [M Cl H] , 220 (18) [M Cl H-CH3] , 215 (38)
[M Cl
‡
‡
‡
‡
‡
H
2 Â CH3], 83 (74) [C6H11, C3HNO2] , 81 (11) [C6H9] , 57
(100) [C4H9] , 41 (44) [C3H5] ; HRMS calcd for C14H22NO235Cl: 271.1339;
found: 271.1334.
‡
‡
[12] a) F. Johnson, Chem. Rev. 1968, 68, 375 ± 413; b) R. W. Hoffmann,
Chem. Rev. 1989, 89, 1841 ± 1860.
[13] P. Yuan, P. Plourde, M. R. Shoemaker, C. L. Moore, D. E. Hansen, J.
Org. Chem. 1995, 60, 5360 ± 5364.
[14] a) N. G. Connelly, W. E. Geiger, Chem. Rev. 1996, 96, 877 ± 910; b) M.
Schmittel, T. Linker, Radikale und Radikalanionen in der Organischen
Synthese, Wiley-VCH, Weinheim, 1998.
Acknowledgements
[15] Crystal data of compound 19 (C11H12ClNO2, Mr ˆ 225.67): crystal size
0.75  0.17  0.17 mm3, orthorhombic, space group Iba2, a ˆ
1104.78(12), b ˆ 2802.4(3), c ˆ 726.93(7) pm, U ˆ 2250.6(4) Š3,
This project was supported by the Deutsche Forschungsgemeinschaft (SFB
Â
260) and by the Fonds der Chemischen Industrie (Kekule fellowship to
B.S.).
3
1
1calcd ˆ 1.332 gcm
for Z ˆ 8, F(000) ˆ 944, m ˆ 0.319mm
, Stoe
IPDS diffractometer, l ˆ 0.71073 Š, w scan, 6369 reflections ( h,
‡k, Æl), Vmax ˆ 26.18, 2182 independent and 1556 observed reflec-
tions [F ꢁ 4s(F)], 184 refined parameters, R ˆ 0.0322, wR2 ˆ 0.0785,
residual electron density 0.199 eŠ 3, direct methods, hydrogen atoms
calculated.[32]
[1] Reviews: a) P. K. Kadab, B. Stanovnik, M. Tisler, Adv. Heterocycl.
Chem. 1984, 37, 217 ± 361; b) R. Huisgen, Angew. Chem. 1963, 75,
604 ± 637.
Chem. Eur. J. 2001, 7, No. 12
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
0947-6539/01/0712-2593 $ 17.50+.50/0
2593

T. Bach et al.
FULL PAPER
[16] Crystal data of compound 21 (C7H10ClNO2, Mr ˆ 175.61): crystal size
0.30  0.18  0.03 mm3, monoclinic, space group P2(1)/c, a ˆ
533.39(8), b ˆ 1246.01(17), c ˆ 1182.03(17) pm, U ˆ 783.80(19) Š3,
1 1980, 2732 ± 2737; c) J. Barluenga, F. Aznar, R. Liz, C. Postigo, J.
Chem. Soc. Chem. Commun. 1986, 1465 ± 1467.
[25] a) Y. Tamaru, M. Kimura, S. Tanaka, S. Kure, Z.-i. Yoshida, Bull.
Chem. Soc. Jpn. 1994, 67, 10, 2838 ± 2849; b) A. Lei, X. Lu, Org. Lett.
2000, 2, 2699 ± 2702.
3
1
1calcd ˆ 1.488 gcm
for Z ˆ 4, F(000) ˆ 368, m ˆ 0.433mm
, Stoe
IPDS diffractometer, l ˆ 0.71073 Š, w scan, 4857 reflections ( h,
‡k, Æl), Vmax ˆ 25.98, 1500 independent and 990 observed reflections
[F ꢁ 4s(F)], 140 refined parameters, R ˆ 0.0345, wR2 ˆ 0.0719, resid-
ual electron density 0.225 eŠ 3, direct methods, hydrogen atoms
calculated.[32]
[26] Crystal data of compound 35d (C13H14ClNO2, Mr ˆ 251.70): crystal
size 1.20  0.60  0.24 mm3, monoclinic, space group P2(1)/n, a ˆ
691.44(6), b ˆ 935.2(3), c ˆ 1994.86(11) pm, U ˆ 1272.6(4) Š3, 1calcd
ˆ
3
1.314 gcm for Z ˆ 4, F(000) ˆ 528, m ˆ 2.577mm 1, Enraf Nonius
CAD4 diffractometer, l ˆ 1.54178 Š, w scan, 4955 reflections ( h,
‡k, Æl), Vmax ˆ 69.98, 2409 independent and 1464 observed reflections
[F ꢁ 4s(F)], 191 refined parameters, R ˆ 0.0593, wR2 ˆ 0.1735, resid-
ual electron density 0.339 eŠ 3, direct methods, hydrogen atoms
calculated.[32]
[17] Crystal data of compound 25 (C9H12ClNO2, Mr ˆ 201.65): crystal size
0.45  0.45  0.15 mm3, monoclinic, space group P2(1)/n, a ˆ
992.46(5), b ˆ 689.08(3), c ˆ 1419.18(10) pm, U ˆ 965.77(9) Š3,
3
1calcd ˆ 1.387 gcm for Z ˆ 4, F(000) ˆ 424, m ˆ 3.246mm 1, Enraf
Nonius CAD4 diffractometer, l ˆ 1.54178 Š, w scan, 1924 reflections
(
h, ‡k, Æl), Vmax ˆ 70.38, 1817 independent and 1650 observed
[27] Crystal data of compound 39a (C16H27NO3, Mr ˆ 281.39): crystal size
3
Å
reflections [F ꢁ 4s(F)], 166 refined parameters, R ˆ 0.0599, wR2 ˆ
0.1780, residual electron density 0.383 eŠ 3, direct methods, hydrogen
atoms calculated.[32]
0.52  0.24  0.12 mm , triclinic, space group P1, a ˆ 935.39(8), b ˆ
943.38(6), c ˆ 1024.06(5) pm, U ˆ 813.61(10) Š3, 1calcd ˆ 1.149 gcm
3
for Z ˆ 2, F(000) ˆ 308, m ˆ 0.625mm 1, Enraf Nonius CAD4 diffrac-
[18] Crystal data of compound 26 (C9H12ClNO2, Mr ˆ 201.65): crystal size
0.45  0.40  0.18 mm3, monoclinic, space group P2(1)/n, a ˆ
1196.78(13), b ˆ 629.49(3), c ˆ 1374.72(10) pm, U ˆ 950.75(16) Š3,
tometer, l ˆ 1.54178 Š, w scan, 3263 reflections ( h, ‡k, Æl), Vmax ˆ
69.98, 3076 independent and 2516 observed reflections [F ꢁ 4s(F)],
289 refined parameters, R ˆ 0.0571, wR2 ˆ 0.1613, residual electron
density 0.259 eŠ 3, direct methods, hydrogen atoms calculated.[32]
[28] T. Bach, J. Schröder, J. Org. Chem. 1999, 64, 1265 ± 1273.
[29] Alkenyl magnesium reagents: M. S. Kharash, O. Reinmuth, Grignard
Reactions of Nonmetallic Substances, Prentice Hall, New York 1954,
pp. 138 ± 453. Alkynyl lithium reagents: a) W. Ziegenbein in Chem-
istry of Acetylenes (Ed.: H. G. Viehe), Marcel Dekker, New York,
1969, pp. 169 ± 264; b) K. A. Parker, M. W. Ledeboer, J. Org. Chem.
1996, 61, 3214 ± 3217.
3
1calcd ˆ 1.409 gcm for Z ˆ 4, F(000) ˆ 424, m ˆ 3.298mm 1, Enraf
Nonius CAD4 diffractometer, l ˆ 1.54178 Š, w scan, 1255 reflections
(
h, ‡k, Æl), Vmax ˆ 55.08, 1197 independent and 1050 observed
reflections [F ꢁ 4s(F)], 122 refined parameters, R ˆ 0.0617, wR2 ˆ
0.1855, residual electron density 0.295 eŠ 3, direct methods, hydrogen
atoms calculated.[32]
[19] a) A. G. Fallis, I. M. Brinza, Tetrahedron 1997, 53, 17543 ± 17594;
b) J. L. Esker, M. Newcomb, Adv. Heterocycl. Chem. 1993, 58, 1 ± 45.
[20] M. Newcomb, A. G. Glenn, J. Am. Chem. Soc. 1989, 111, 275 ± 277.
[21] E. Truscheit, K. Eiter, Liebigs Ann. 1962, 658, 65 ± 90.
[22] Crystal data of compound 33 (C11H19NO3, Mr ˆ 213.27): crystal size
[30] H. Meier, T. Echter, H. Petersen, Angew. Chem. 1978, 90, 997 ± 998;
Angew. Chem. Int. Ed. Engl. 1978, 17, 942 ± 943.
[31] S. Knapp, J. J. Hale, M. Bastos, A. Molina, K. Y. Cheng, J. Org. Chem.
1992, 57, 6239 ± 6256.
[32] Crystallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no.
CCDC-153441 (19), -153442 (21), -153443 (25), -153444 (26),
-153445 (33), -153446 (35d), -153447 (39a). Copies of the data can
be obtained free of charge on application to CCDC, 12 Union Road,
Cambridge CB2 EZ1, UK (fax: (‡44) 1223-336033; e-mail: deposit@
ccdc.cam.ac.uk).
3
Å
0.40  0.30  0.20 mm , triclinic, space group P1, a ˆ 561.4(1), b ˆ
705.8(1), c ˆ 1590.2(1) pm, U ˆ 585.1(1) Š3, Dc ˆ 1.211 gcm
for
3
Z ˆ 2, F(000) ˆ 232, m ˆ 0.713mm 1, Enraf Nonius CAD4 diffracto-
meter, l ˆ 1.54184 Š, w scan, 1810 reflections ( h, ‡k, Æl), Vmax
ˆ
59.98, 1738 independent and 1078 observed reflections [F ꢁ 4s(F)],
176 refined parameters, R ˆ 0.0688, wR2 ˆ 0.1971, residual electron
density 0.252 eŠ 3, direct methods, hydrogen atoms calculated. In the
crystal a mixture of two diastereoisomers was present.[32]
[23] a) N. Shachat, J. J. Bagnell Jr., J. Org. Chem. 1963, 28, 991 ± 995; b) P.
Dimroth, H. Pasedach, E. Schefczik, Chem. Abstr. 1964, 60, 2934.
[24] a) P. F. Hudrlik, A. M. Hudrlik, J. Org. Chem. 1973, 38, 4254 ± 4258;
b) J. Barluenga, F. Aznar, R. Liz, R. Rodes, J. Chem. Soc. Perkin Trans.
Received: November 30, 2000 [F2906]
2594
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Chem. Eur. J. 2001, 7, No. 12