Total synthesis of amiclenomycin, an inhibitor of biotin biosynthesis.

Article abstract of DOI:10.1002/1521-3765(20020118)8:2<439::AID-CHEM439>3.0.CO;2-5

We describe the first synthesis of amiclenomycin, a natural product that has been found to inhibit biotin biosynthesis and, as a consequence, to exhibit antibiotic properties. Structure 1, with a trans relationship between the ring substituents. had previously been proposed for amiclenomycin on the basis of its 1H NMR spectrum. We have prepared the trans and cis isomers 1 and 2 by unequivocal routes and we conclude that the natural product is in fact the cis isomer 2. The properly substituted cyclohexadienyl rings were constructed first. A cycloaddition reaction between 1,2-di(phenylsulfonyl)ethylene and the N-allyloxycarbonyl diene 13, followed by reductive elimination of the phenylsulfinyl groups, gave the cis isomer 15. To obtain the trans isomer, the O-trimethylsilyl diene was used to give the cis hydroxylated Diels-Alder adduct 33, which was transformed into the corresponding trans amino derivative by means of a Mitsunobu reaction. The L-alpha-amino acid functionality was introduced by means of a Strecker reaction on the aldehydes 16 and 42, followed by enzymatic hydrolysis with immobilised pronase.

Full text of DOI:10.1002/1521-3765(20020118)8:2<439::AID-CHEM439>3.0.CO;2-5

FULL PAPER
Total Synthesis of Amiclenomycin, an Inhibitor of Biotin Biosynthesis
Ste¬phane Mann, Sophie Carillon≤, Olivier Breyne, and Andre¬e Marquet*[a]
We dedicate this paper to Sophie Carillon, who recently died in a car accident. She performed a great part of this work.
Abstract: We describe the first synthe-
sis of amiclenomycin, a natural product
that has been found to inhibit biotin
biosynthesis and, as a consequence, to
exhibit antibiotic properties. Structure 1,
with a trans relationship between the
ring substituents, had previously been
proposed for amiclenomycin on the
basis of its 1H NMR spectrum. We have
prepared the trans and cis isomers 1 and
2 by unequivocal routes and we con-
clude that the natural product is in fact
the cis isomer 2. The properly substitut-
ed cyclohexadienyl rings were construct-
ed first. A cycloaddition reaction be-
phenylsulfinyl groups, gave the cis iso-
mer 15. To obtain the trans isomer, the
O-trimethylsilyl diene was used to give
the cis hydroxylated Diels Alder ad-
duct 33, which was transformed into the
corresponding trans amino derivative by
means of a Mitsunobu reaction. The l-
a-amino acid functionality was intro-
duced by means of a Strecker reaction
on the aldehydes 16 and 42, followed by
enzymatic hydrolysis with immobilised
pronase.
tween
1,2-di(phenylsulfonyl)ethylene
and the N-allyloxycarbonyl diene 13,
followed by reductive elimination of the
Keywords:
amiclenomycin
¥
aminocyclohexadiene
¥
antibiotics
¥ enzymatic resolution ¥ Strecker
reaction
Introduction
H2N
O
H2N
NH2
Ado Met
COOH
COOH
DAPA amino
transferase
Amiclenomycin (2) has been isolated from cultures of differ-
ent Streptomyces strains either as the free amino acid[1] or as a
component of di- and tripeptides,[2] all of which show anti-
biotic properties, with a specificity against mycobacteria.[1, 2b,c]
Scheme 1. Action of DAPA aminotransferase, blocked by amiclenomycin.
recognised at the substrate binding site. Inactivation of the
enzyme was observed after preincubation, but this was found
to be reversible, the activity being recovered after dialysis.
This may correspond to tight binding or, more probably, to the
reversible formation of a covalent adduct. The analogy with
the inhibition of g-amino-butyric acid (GABA) aminotrans-
ferase by gabaculine (3)[6] should be explored.
H2N
COOH
H2N
COOH
COO-
+
NH2
NH2
NH3
1
2
3
In connection with our general interest in inhibitors of
biotin biosynthesis with potential herbicidal properties,[7] we
decided to revisit the mechanism of action of amiclenomycin.
Unfortunately, the natural product was no longer available,
and all our attempts to isolate it from cultures of S.
Lavandulae–with a strain kindly supplied by Dr. Okami–
failed, maybe because of mutations in the strain. Thus, we
decided to undertake the total synthesis of amiclenomycin.
A trans geometry between the two substituents on the
cyclohexadienyl ring in 1 had been tentatively proposed by
Okami et al,[1] on the basis of the 5J coupling constant (7.5 Hz)
between the two allylic hydrogens,[1] and this later became
accepted.[2b] The other isomer had, of course, not been
available, and in order to establish the stereochemistry of
the natural product with more certainty, we decided to
synthesise both isomers by unequivocal routes.
The antimutagenic effects of the dipeptide N-methylvalyl-
amiclenomycin have also been described.[3] These antibiotic
properties were reversed by biotin and some of its precursors,
and it has been established that the target of amiclenomycin is
7,8-diaminopelargonic acid (DAPA) aminotransferase[4]
(Scheme 1).
The mechanism of inhibition has been investigated,[5] and
kinetic studies showed that amiclenomycin was probably
[a] Prof. A. Marquet, S. Mann, Dr. S. Carillon≤, Dr. O. Breyne
Laboratoire de Chimie Organique Biologique
¬
Universite Paris VI, UMR CNRS 7613
4, place Jussieu, 75252 Paris Cedex 05 (France)
Fax : (‡33)1-44-27-71-50
E-mail: marquet@ccr.jussieu.fr
Chem. Eur. J. 2002, 8, No. 2
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439

A. Marquet et al.
FULL PAPER
Table 1. NMR chemical shift differences of hydrogen and carbon atoms in
amiclenomycin (Acm) present in natural peptides,[2b] and in compounds 1
and 2. The spectra were recorded in D2O at 400 MHz (1H NMR) and
100 MHz (13C NMR), except for 1 and 2, which were recorded at 500 MHz
(1H NMR) and 125 MHz (13C NMR).
We chose a Diels Alder strategy to construct the cyclo-
hexadiene ring, with the use of trans-1,2-bis(phenylsulfonyl)-
ethylene, an acetylene dienophile equivalent described by
De Lucchi.[8] We expected that the mild conditions used to
regenerate the double bond, reductive elimination of the
phenylsulfinyl groups at room temperature with sodium
amalgam in methanol buffered with potassium dihydrogen-
phosphate, would preserve the 2,5-cyclohexadiene. Initial
attempts to prepare the oxygenated diene partner I of the
Diels Alder reaction from l-lysine according to Scheme 2
were not successful. We thus had to construct the cyclo-
hexadiene part first, and then introduce the amino acid
functionality.
Dd
Compounds
H-1' H-4'
C-1' C-4'
C-3 C-4
MeIle-Acm
Ile-Acm
1.47
1.49
1.48
1.47
1.47
1.47
1.37
1.46
10.3
10.4
10.4
10.4
10.3
10.3
10.15
10.46
0.9
1.1
1.5
1.7
1.6
1.2
2.39
1.45
MeVal-Acm
MeIle-Acm-Gln
Ile-Acm-Gln
Val-Acm-Gln
1
2
H
H
Results and Discussion
COOiPr
AllocHN
COOiPr
AllocHN
H
H
COOiPr
COOiPr
AllocHN
AllocHN
NH2
Our first targets were precur-
sors of the cyclohexadiene ring
with a functionalised side-chain
suitable for the introduction of
the amino acid moiety.
O
OTMS
I
O
A number of methods for the
(enantioselective) synthesis of
Scheme 2. Unsuccessful attempts to prepare Diels–Alder diene I.
amino acids are now available.[11] We first considered the
alkylation of glycine derivatives, for which many chiral
versions exist.[11] Preliminary experiments were carried out
with the anion of imine II[12] and the bromo derivatives III or
IV. No reaction occurred at low temperature, whilst at 08C III
and IV decomposed into aromatic products V and VI
(Scheme 3).
However, due to the expected sensitivity of the 1-amino-
2,5-cyclohexadiene ring to conjugation and/or aromatisation,
we first examined the synthetic routes to this moiety on a
simple model before the construction of the amino acid side-
chain. The synthesis of the two isomers VII and VIII and the
assignment of their stereochemistry have been described in
another paper.[9] In this work we report the preparation of the
two isomers 1 and 2.
We thus turned to application of the Strecker reaction to
aldehydes 16 and 42, and prepared their precursors 15 and 41,
OH
O
NH2, HCl
NH2, HCl
VII
VIII
NHAlloc
NHAlloc
Model compounds
16 : cis isomer
42 : trans isomer
15 : cis isomer
41 : trans isomer
The 5J values observed in the trans and cis compounds 1 and
2 are 5.6 and 8.1 Hz, respectively; in good agreement with the
corresponding values, 5.6 and 8.2 Hz, found in the model
compounds VII and VIII.[9] The reported value for natural
amiclenomycin was 7.5 Hz, very close to that of the cis
compound, and we concluded that the published stereo-
chemistry was very probably incorrect. Comparison of
chemical shift values supported this
which contain hydroxypropyl side-chains, by the same Diels
Alder cycloaddition-based strategy as used for the prepara-
tion of the trans and cis models VII and VIII.[9]
Synthesis of the cis isomer 2: The diene 13 was synthesised
from butane-1,4-diol as shown in Scheme 4. This symmetric
conclusion (Table 1). It would be
interesting to study inhibition of
Br
Br
DAPA aminotransferase, the crystal
structure of which has recently been
published,[10] by these two isomers.
Cl
SO2Ph
0°C
+
SO2Ph
N
COOCH3
SO2Ph
SO2Ph
We intend to examine whether one
or both isomers cocrystallise with
the protein, and we hope to obtain
the three-dimensional structure of
the complex(es).
OR
V
VI
II
III : R = H
IV : R = THP
Scheme 3. Tentative attempts to alkylate the glycine Schiff base II.
440
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Chem. Eur. J. 2002, 8, No. 2

Synthesis of Amiclenomycin
439 450
a
methanol under reflux. The N-
protected (1E,3E) diene 13 was
obtained from 12 by means of a
Curtius reaction[16] under the
same conditions as described
for the preparation of the cor-
responding diene in the model
series.
b
OH
OTBDMS
OTBDMS
HO
HO
O
4
5
Li
NtBu
c
Et2O(O)P
f
9
OTBDMS
e
d
EtOOC
OTBDMS
OTBDMS
O
HO
7
6
8
g
The Diels Alder reaction
between 13 and trans-1,2-di-
(phenylsulfonyl)ethylene (14)[8]
was performed in refluxing
ortho-xylene to afford, after
reductive elimination of the
phenylsulfinyl groups from the
mixture, cyclohexadiene 15.
To introduce the amino acid
functionality by a Strecker re-
action[17] (Scheme 5), alcohol 15
was oxidised to 16 by the Swern
method. This aldehyde was
treated with trimethylsilyl cya-
nide in the presence of a cata-
lytic amount of ZnI2 and then
with a saturated solution of
h
EtOOC
OTBDMS
EtOOC
OH
10
11
OH
OH
OH
i
SO2Ph
j
SO2Ph
SO2Ph
k
l
HOOC
OH
+
PhO2S
12
NHAlloc
NHAlloc
NHAlloc
15
13
14
Scheme 4. a) NaH, TBDMSCl, THF, 97%. b) (COCl)2, DM SO, CHCl2, À608C; NEt3, À208C, 94%. c) NaH,
(EtO)2P(O)CH2CO2Et, THF, À208C, 80%. d) DiBAH, CH2Cl2, À2608C, 84%. e) (COCl)2, DM SO, CHCl2,
2
‡
ˆ
À
À608C; NEt3, À208C, 94%. f) LDA, tBuN CH CH3, (EtO)2P(O)Cl, THF, À788C; H3O , 67%. g) NaH,
(EtO)2P(O)CH2CO2Et, THF, À208C, 70%. h) THF/H2O/CH3CO2H (1:1:3), 71%. i) NaOH, MeOH, 608C, 83%.
j) (PhO)2P(O)N3, allyl alcohol, NEt3, reflux, 70%. k) 14, ortho-xylene, reflux. l) Na(Hg), MeOH, KH2PO4, 37%.
diol was monosilylated in 90% yield with tert-butyldimethyl-
silyl (TBDMS) chloride according to a method described by
McDougal et al.,[13] who explained the selectivity of the
reaction by the insolubility of the monosodium salt in THF.
Alcohol 4 was then oxidised to aldehyde 5 by a Swern reaction
and converted into the a,b-unsaturated aldehyde 8. A Wittig
reaction carried out with triethyl phosphonoacetate enabled
aldehyde 5 to be transformed into the conjugated ester 6,
which was then reduced by diisobutyl aluminium hydride
(DiBAH) to the allylic alcohol 7. This was then oxidised to
give 8. This reaction could be performed more rapidly and
with an equivalent yield by means of the formylolefination
reaction developed by Meyers.[14] This conversion proceeds by
condensation of lithium en-
ammonia in methanol to give amino nitrile 17. The diconden-
sation product 18 and/or the aromatic compound 19 were
isolated in some experiments. We found that the quality of the
ammonia and the reaction temperature were important
parameters. To minimise the formation of 18 and 19, the
reaction has to be performed with very pure ammonia and at a
temperature not exceeding 508C for 15 min.
Cleavage of the allyloxycarbonyl group of 17 was carried
out with Pd(PPh3)4 in the presence of phenylsilane.[18] During
extraction of the resulting amine with an acidic aqueous
solution at 08C followed by lyophilisation, hydration of the
nitrile group took place, and the amide 20 was obtained as a
mixture containing 22% of the aromatic compound 21.
aminophosphonate 9 with alde-
H
O
OH
CN
hyde 5 at À788C, followed by
H2N
CN
NC
N
H2N
CN
hydrolysis of the intermediate
imine. Compound 9 was pre-
pared in situ from acetaldehyde
tert-butylimine,[15] by treatment
with lithium diisopropylamide
(LDA) and diethylchlorophos-
phate.
a
b
+
+
NHAlloc
NHAlloc
NHAlloc
NHAlloc
NHAlloc
18
16
15
17
19
c
Aldehyde 8 was then trans-
formed into the (1E,3E) conju-
gated ester 10 by means of a
Wittig reaction with the triethyl
phosphonoacetate anion. De-
protection of the alcohol moi-
ety in compound 10 under acid-
ic conditions afforded 11. Sap-
onification of the ester was
achieved by using an aqueous
sodium hydroxide solution in
H2N
CONH2
H2N
CONH2
+
,
HCl
NH2 , HCl
20
21
À
Scheme 5. a) (COCl)2, DMSO, CH2Cl2, À608C; NEt3, À208C, 95%. b) TMS CN, ZnI2, CH2Cl2, RT; NH3,
MeOH, 74%. c) Pd(PPh3)4, PhSiH3, CH2Cl2, RT,; HCl, 60%.
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441

A. Marquet et al.
FULL PAPER
The last step was the conversion of the
amino acid amide 20 into the amino acid
2. To conserve supplies of amide 20, the
reaction conditions were first examined
on the aromatic analogue, homophenyl-
alanine amide (22). This was prepared
from 3-phenylpropanal by a Strecker
reaction to provide 19, which was then
treated with a methanolic solution of
NaOH/H2O2 (Scheme 6). Hydrolysis of
22 with reasonable concentrations
H2N
CONH2
H2N
COOH
+
H2N
CONH2
H2N
CONH2
H2N
COX
+
+
,
HCl
NH2 , HCl
20
NH2
NH2
20
2
22 : X = NH2
23 : X = OH
21
Scheme 7. Conversion of d,l-amino acid amide 20 into l-amino acid 2 and d-amino acid amide 20
with the aid of immobilised pronase in a phosphate buffer (pH 9.6) at 378C.
(0.7m) of basic reagents (NaOH, LiOH, Na2O2[19]) was very
slow (over 24 h at room temperature) and therefore not
compatible with the amino-cyclohexadienyl moiety.
were separated on a Dowex column with ammonia solution as
eluant.
In order to measure the enantiomeric excesses of acid 2 and
amide 20, these compounds were converted by acidic treat-
ment into the corresponding aromatic amino acid 23, which
was derivatised into 27 by classical methods (Scheme 8) and
submitted to gas chromatography on a chiral column. The
retention times were compared with those of commercial
racemic homophenylalanine, also derivatised into 27. The
enantiomeric excesses of 2 and 20 were 74% and 80%,
respectively.
NH2
CN
NH2
CONH2 NH2
COOH
O
a
b
c
23
19
22
d
O
O
Boc
O
NH
N
Boc Boc
NH
Boc
N
HN
N
COOH
O
O
e
f
24
25
26
À
Scheme 6. a) TMS CN, ZnI2, CH2Cl2, RT; NH3, MeOH, 73%. b) H2O2,
NaOH, MeOH, RT, 76%. c) NaOH or LiOH or Na2O2, H2O, RT.
d) (NH4)2CO3, H2O, MeOH, 508C, 62%. e) Boc2O, DMAP, THF, RT,
65%. f) LiOH, THF/H2O (5:1), RT, 92%.
Scheme 8. a) 3n HCl, reflux. b) 2n iPrOH/HCl, 1008C; (CF3CO)2O,
CH2Cl2, RT. The same procedure was used for the derivatisation of 20.
Synthesis of the trans isomer 1: The diene 31 was synthesised
from pentane-1,5-diol as shown in Scheme 9. The diol was
successively monosilylated, oxidised and converted into a,b-
unsaturated aldehyde 30 by the methods described for the
synthesis of 8 (Scheme 4).
Dienes 31 and 32 were obtained by the Danishefsky
method.[22] Aldehyde 30, activated by ZnCl2, was treated
with bromotrimethylsilane in the presence of triethylamine
to afford a 35:65 mixture of 31 (1E,3E) and 32 (1E,3Z).
We have shown in the case of the model compounds that the
percentage of the desired (E,E) isomer could be improved by
isomerisation with iodine but that the yield of the subsequent
Diels Alder reaction is lower and that the overall yield is
identical with or without isomerisation.[9] Thus, the cyclo-
addition here was performed with the initial 35:65 mixture of
dienes 31 and 32 and with trans-1,2-bis(phenylsulfonyl)ethyl-
ene (14) as the dienophile.[8]
The protective groups in dienes 31 and 32 were chosen in
order to subsequently selectively hydrolyse the secondary
hydroxyl group of the Diels Alder adduct, but no selective
cleavage was observed under various conditions. With a dilute
solution of HCl in methanol (0.01 eq.) both silyl ethers were
removed. With oxalic or acetic acid (0.001 to 0.01 eq.), the
monoprotected compounds 34 was observed, but always in a
mixture with the diol 33. We thus had to isolate the
Another method, described as milder, is the hydrolysis of
N-protected hydantoins by lithium hydroxide at room tem-
perature.[20] Hydantoin 24 was prepared by condensation of
ammonium carbonate with amino nitrile 19. Protection of the
nitrogen atoms of 24 with tert-butyloxycarbonyl groups
afforded 25. However, hydrolysis of the latter with lithium
hydroxide gave compound 26 and homophenylalanine could
be identified only after a few days (Scheme 6).
The alternative route of enzymatic hydrolysis was then
considered. An enantioselective method for the conversion of
a-amino nitriles into l-a-amino acids under moderately basic
conditions (pH 10) has been described by Taillades et al.,[21]
who used immobilised pronase on a poly(N-acryloylpiperidin-
4-one) (80%) cross-linked with (1,4-bisacryloylpiperazine)
(20%). They showed that the hydration of d,l-amino nitriles
to d,l-amino acid amides is efficiently catalysed in phosphate
or borate buffers by ketonic sites in the polymer matrix.
Pronase, with its amidase activity, then effects the enantio-
selective transformation of the intermediate d,l-amino acid
amides into l-amino acids and d-amino acid amides. Under
these conditions, the d,l-mixture 20 (containing 27% of
aromatic compound 21) was converted into l-amino acid 2
and d-amino acid amide 20 (Scheme 7). Compounds 2 (28%)
and 20 (29%) and the aromatic compounds 22 and 23 (25%)
442
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Synthesis of Amiclenomycin
439 450
a
b
OTBDMS
HO
OH
HO
OTBDMS
O
28
29
Li
N
Et2O(O)P
tBu
c
OTBDMS
OTBDMS
+
9
d
SO2Ph
SO2Ph
e
OTBDMS
OTBDMS
O
30
OTMS
OTMS
OTMS
31
32
f
OH
OTBDMS
OTBDMS
OTBDMS
OH
OTBDMS
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
g
h
+
+
+
SO2PH
OH
N3
N3
37
OH
34a, b
OH
33a
35a, b
36
33b
ˆ
Scheme 9. a) NaH, TBDMSCl, THF, RT, 89%. b) (COCl)2, DM SO, CHCl2, À608C; NEt3, À208C, 90%. c) LDA, tBuN CH-CH3, (EtO)2P(O)Cl, THF,
2
‡
‡
À788C; H3O , RT, 56%. d) TMSBr, ZnCl2, NEt3, toluene, reflux, 75%. e) 14, ortho-xylene, 1208C. f) MeOH, H , RT, 66%. g) TBDMSCl, DMAP, CH2Cl2,
NEt3, 83%. h) PPh3, DIAD, (PhO)2P(O)N3, CH2Cl2, 08C, 35a,b: 52%.
deprotected compound 33 and then reprotect the primary
alcohol. From the similarity of the NMR spectra of the Diels
Alder adducts 33 to those of the model series (Table 2), we
were able to conclude that 33 was a 80:20 to 65:35 mixture of
33a and 33b. The reprotection of the primary alcohol was
achieved by treatment of the mixture of 33a and 33b with tert-
butyldimethylsilyl chloride in the presence of triethylamine
match those of 34a and 34b. The epimeric azide 37 was also
formed in 5 10% yield, as in the model series. The aromatic
compound 36 was similarly isolated in a reproducible yield of
30%.
Amine 38, obtained by reduction of azides 35a and 35b
under hydrogen (5 bars) in the presence of Lindlar catalyst,[25]
was then protected by an allyloxycarbonyl group to furnish
39a and 39b. Deprotection of the alcohol by acidic meth-
anolysis, followed by desulfonylation with sodium amalgam
gave the cyclohexadiene 41 (Scheme 10).
and
a catalytic amount of N,N-dimethylaminopyridine
(DMAP).[23] Alcohols 34 were transformed into azides 35a
and 35b by a Mitsunobu reaction, with diphenylphosphoryl
azide.[24] As in the case of the model compounds, the relative
proportions of 35a and 35b (75:25 to 60:40) did not exactly
The last steps of this synthesis were achieved as in the case
of the cis isomer (Scheme 11). Alcohol 41 was oxidised to 42,
Table 2. Comparison of chemical shifts in compounds 33a, 33b, 35a, 35b and models[9] (solvent: CDCl3, 1H NMR: 400 MHz, 13C NMR: 100 MHz).
d
Compounds
R
H-1
H-2
H-3
H-6
C-1
C-2
C-3
C-6
Et
4.15
4.10
4.37
4.22
4.88
4.81
2.58
2.61
61.59
61.55
61.59
61.50
65.15
64.58
33.60
31.40
(CH2)3OH
Et
4.16
4.10
3.96
3.83
4.55
4.52
2.96
2.87
58.94
58.96
66.34
66.46
61.73
61.45
37.04
34.82
(CH2)3OH
Et
4.14
4.13
4.21
4.20
4.42
4.46
2.70
2.82
57.89
58.50
60.10
61.30
50.91
51.21
33.78
32.10
(CH2)3OTBDMS
Et
4.67
4.66
4.46
4.43
4.88
4.88
3.02
3.12
62.40
62.53
60.39
60.45
54.99
54.95
37.07
35.03
(CH2)3OTBDMS
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443

A. Marquet et al.
FULL PAPER
cis isomers–5.6 and 8.1 Hz,
OTBDMS
OH
OH
OTBDMS
OTBDMS
respectively–are
in
good
agreement with the values
found in the model compounds
VII and VIII (5.6 and 8.2 Hz).
The observed value in the nat-
ural product was 7.5 Hz, close to
the value found in the cis com-
pound. The chemical shift dif-
ferences reported in Table 1 for
the amiclenomycin-containing
peptides are also more consis-
tent with those of isomer 2.
Thus, we conclude that the
stereochemistry originally at-
tributed to the natural product
should be corrected.
SO2Ph
SO2Ph
SO2Ph
SO2Ph
SO2Ph
a
SO2Ph
SO2Ph
b
d
c
SO2Ph
N3
NHAlloc
NHAlloc
NHAlloc
NH2
39a, b
40a, b
41
35a, b
38a, b
Scheme 10. a) H2 (5 bars), Pd(5%)/CaCO3-Pb(3.5%), THF/iPrOH (1:1), RT. b) ClCO2All, EtOH, NaHCO3,
sonication, RT, 76% from 35. c) MeOH, H , RT, 86%. d) Na(Hg), MeOH, KH2PO4, RT, 74%.
‡
OH
O
H2N
CN
H2N
CN
a
b
+
NHAlloc
NHAlloc
NHAlloc
As discussed for VII and
VIII,[9] the values of the cou-
pling constants are consistent
42
41
19
c
43
with
a
planar ring.[26] AM1
semiempirical calculations on
the most stable conformations
of 1 and 2 indeed indicated that
the ring was almost planar
H N
CN HCl,
CONH2
HCl,H2N
H2N
COOH
H2N
2
CONH2
HCl,H2N
X
H2N
COX
d
+
+
+
+
(acis ˆ 175.58
and
atrans
ˆ
178.78) (Figure 1). The calculat-
ed distance between the two
homoallylic hydrogens (4.05 ä
in the cis compound and 4.75 ä
in the trans) explains why no
NOEs were observed.
NH
2, HCl
NH2, HCl
44
NH2
NH2
45
19 : X = CN
1
45
21 : X = NH2
23 : X = OH
21 : X = CONH2
À
Scheme 11. a) (COCl)2, DMSO, CH2Cl2, À608C; NEt3, À208C, quantitative yield. b) TMS CN, ZnI2, CH2Cl2,
RT; NH3, MeOH, 51%. c) Pd(PPh3)4, PhSiH3, CH2Cl2, RT; HCl, 85%. d) immobilised pronase, phosphate
buffer, pH 9.6, 378C, 1: 20%, 45: 20%.
which was converted into amino nitrile 43 accompanied by the
aromatic compound 19. Deprotection of the amine followed
by a rapid extraction at 08C with 1n hydrochloric acid gave a
mixture of amino nitrile 44 and amino acid amide 45 (in a ratio
of 80:20 to 30:70), and their aromatic derivatives 19 and 21 (13
to 23%). This crude mixture, when treated with immobilised
pronase, afforded the l-amino acid 1 (20%) and the d-amino
acid amide 45 (20%). The enantiomeric excesses of these
products were 94% and 88%, respectively (determined by
chiral gas chromatography, as described above for 2 and 20).
Experimental Section
General procedures: Solvents were dried by distillation under argon over
CaH2 (CH2Cl2, toluene, ortho-xylene, NEt3), Mg (MeOH) or Na/benzo-
phenone (THF, Et2O). All other commercially available reagents were
used without further purification. Column chromatography was performed
with flash silica (Merck 230, 0.040 0.063 mm). 1H NMR (400 MHz) and
13C NMR (100 MHz) were recorded on a Bruker ARX400 at room
temperature for CDCl3 solutions unless otherwise stated (some spectra
were recorded on a Bruker AC200 or a DMX500). All chemical shifts are
reported as d values (ppm) relative to CDCl3 (or CD3OD): d ˆ 7.28 (3.34)
1
and d ˆ 77.16 (49.86) for H NMR and 13C NMR spectra, respectively. IR
spectra were recorded on a Perkin Elmer 1420 instrument. CI mass
spectra were obtained with
a NERMAG R30 10 apparatus. High-
5
Configuration of amiclenomycin: The J(H-1',H-4') coupling
resolution mass spectra were recorded on a JEOL MS700BE (CH4). MS-
MS spectra were recorded on a Micromass Quattro1 instrument with ESI
source. Melting points were measured with a Kofler bank and are
constants measured after irradiation of H-3' in the trans and
¬
uncorrected. Elemental analyses were performed by the Service Regional
de Microanalyse (SIAR-Jussieu).
Determination of the 5J coupling constant values: The 5J coupling constants
between H-1' and H-4' in compounds 1, 2, 20 and 45 were measured from
the 4' proton signal after irradiation of the 3' protons. The experiments were
carried out on a Bruker ARX400 apparatus at 400 MHz in D2O. For 2 and
20, 5J was 8.1 Hz and for 1 and 45, 5.6 Hz.
4-tert-Butyldimethylsilyloxybutan-1-ol
(4):
Butane-1,4-diol
(9.0 g,
Figure 1. Modeling of compounds 1 and 2 by AM1 semiempirical methods.
The dihedral angle a is defined by the intersection of the (C1, C2, C3, C4)
and the (C1, C6, C5, C4) planes.
100 mmol) was added to a vigorously stirred dispersion of NaH in mineral
oil (80%, 3.15 g) in dry THF (200 mL). After being stirred for 1 h, the
mixture was cooled in an ice bath, and tert-butyldimethylsilyl chloride
444
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
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Chem. Eur. J. 2002, 8, No. 2

Synthesis of Amiclenomycin
439 450
(16.5 g, 109 mmol) was added over 15 min. Stirring was continued at RT for
another hour, after which the reaction mixture was diluted with diethyl
ether (500 mL) and washed with saturated Na2CO3 solution (2 Â 100 mL),
followed by brine (2 Â 100 mL). The organic layer was dried over MgSO4
and concentrated to afford a yellow oil that was distilled (b.p. 578C,
0.07 mbar). Monosilylated diol 4 was obtained as a colourless oil. Yield:
19.7 g, 97%; 1H NM R:d ˆ 0.06 (s, 6H; SiCH3), 0.90 (s, 9H; tBu), 1.64 (m,
4H; H-2, H-3), 3.63 3.66 (m, 4H; H-1, H-4); 13C NM R:d ˆ À5.31
(SiCH3), 18.39 (C(CH3)3), 25.99 (C(CH3)3), 29.95, 30.28 (C-2, C-3), 62.81,
63.44 (C-1, C-4); elemental analysis calcd for C10H24O2Si: C 58.83, H 11.76;
found C 58.64, H 11.96.
(8.4 mL, 118 mmol) and triethylamine (33 mL, 237 mmol). Yield: 10.5 g,
94%.
Preparation from 5: Acetaldehyde tert-butylimine: Acetaldehyde (20 mL,
360 mmol) was introduced dropwise at 08C into a flask containing tert-
butylamine (38 mL, 360 mmol). The mixture was stirred at this temperature
for 3 h, then solid KOH (800 mg, 14 mmol) was added. After 12 h at 48C,
the aqueous layer was removed, and the organic layer was distilled (bp 66
678C) to furnish the desired imine as a colourless oil. Yield: 23 g, 66%;
1H NMR (200 MHz): d ˆ 1.11 (s, 9H; tBu), 1.90 (d, 3H; J ˆ 4.8 Hz, CH3),
7.62 (q, 1H; J ˆ 4.8 Hz, CH ); 13C NMR (50MHz): d ˆ 22.77 (CH3), 29.61
ˆ
ˆ
(C(CH3)3), 56.66 (C(CH3)3), 155.00 (CH ).
Acetaldehyde tert-butylimine (3 g, 30 mmol) was added at À788C to a
solution of lithium diisopropylamide (30 mL, 2m in heptane) in anhydrous
THF (60 mL). The mixture was stirred at this temperature for 30 min, and
diethyl chlorophosphate (4.4 mL, 30 mmol) was added. The mixture was
then allowed to warm to À108C over 1 h, was stirred for 2 h at this
temperature and then for 5 min at À788C. Aldehyde 5 was added, and the
reaction mixture was allowed to warm to RT over 2 h. The reaction was
quenched by addition of a saturated oxalic acid solution (50 mL), and the
mixture was diluted with toluene (50 mL). The organic layer was extracted
with diethyl ether (3 Â 50 mL) and concentrated to furnish an orange oil,
which was flash chromatographed (cyclohexane/ethyl acetate 49:1 41:9).
a,b-Unsaturated aldehyde 8 was obtained as an orange oil. Yield: 3.06 g,
67%; 1H NMR (200 MHz): d ˆ 0.00 (s, 6H; SiCH3), 0.85 (s, 9H; tBu), 1.68
(tt, J ˆ 6.7, 6.7 Hz, 2H; H-5), 2.38 (tdd, J ˆ 7.2, 7.2, 1.4 Hz, 2H; H-4), 3.61 (t,
J ˆ 6.0 Hz, 2H; H-6), 6.08 (tdd, J ˆ 15.6, 7.9, 1.5 Hz, 1H; H-2), 6.85 (td, J ˆ
15.6, 6.7 Hz, 1H; H-3), 9.46 (d, J ˆ 7.9 Hz, 1H; H-1); 13C NMR (50 MHz):
d ˆ À5.34 (SiCH3), 18.28 (C(CH3)3), 25.92 (C(CH3)3), 29.37 (C-4), 30.89 (C-
5), 62.04 (C-6), 133.04 (C-2), 158.76 (C-3), 194.05 (C-1).
4-tert-Butyldimethylsilyloxybutanal (5):
A stirred solution of oxalyl
dichloride (8.8 mL, 100 mmol) in anhydrous dichloromethane (200 mL)
was cooled to À608C, and anhydrous dimethyl sulfoxide (14.3 mL,
201 mmol) was added dropwise. After 10 min, alcohol 4 (17.1 g, 84 mmol)
was added, and stirring was maintained for 30 min, during which the
solution was allowed to warm to À208C. Addition of triethylamine (54 mL,
390 mmol) then produced a white precipitate and, after an additional
20 min stirring at this temperature, the mixture was diluted with diethyl
ether (200 mL) and washed with a saturated NH4Cl solution (100 mL). The
organic layer was diluted with cyclohexane (1 L), washed with a saturated
Na2CO3 solution (100 mL) followed by brine (3 Â 150 mL) and dried over
MgSO4. Solvents were removed to deliver the desired aldehyde 5 smoothly.
The crude product was used without purification for the next step. Yield:
15.9 g, 94%; 1H NMR (200 MHz): d ˆ 0.01 (s, 6H; SiCH3), 0.85 (s, 9H;
tBu), 1.83 (tt, J ˆ 7.1, 6.5 Hz, 2H; H-3), 2.48 (td, J ˆ 7.1, 1.6 Hz, 2H; H-2),
3.62 (t, J ˆ 6.5 Hz, 2H; H-4), 9.76 (t, J ˆ 1.6 Hz, 1H; H-1); 13C NM R
(50 MHz): d ˆ À5.37 (SiCH3), 18.34 (C(CH3)3), 25.53 (C-3), 25.95
(C(CH3)3), 40.84 (C-2), 62.12 (C-4), 202.70 (C-1).
Ethyl (2E,4E)-8-tert-butyldimethylsilyloxyocta-2,4-dienoate (10): Com-
pound 10 was prepared as described for compound 6, from aldehyde 8
(3.06 g, 13.4 mmol), NaH (80%, 0.7 g) and triethyl phosphonoacetate
(4.7 mL, 23 mmol). It was obtained after chromatography (cyclohexane/
ethyl acetate 49:1) as a yellow oil. Yield: 2.82 g, 70%; 1H NM R:d ˆ 0.04 (s,
6H; SiCH3), 0.89 (s, 9H; tBu), 1.29 (t, J ˆ 7.1 Hz, 3H; CH2CH3), 1.64 (tt,
J ˆ 6.8, 6.8 Hz, 2H; H-7), 2.24 (td, J ˆ 6.9, 6.9 Hz, 2H; H-6), 3.61 (t, J ˆ
6.1 Hz, 2H; H-8), 4.19 (q, J ˆ 7.1 Hz, 2H; CH2CH3), 5.78 (d, J ˆ 15.3 Hz,
Ethyl (2E)-6-tert-butyldimethylsilyloxyhex-2-enoate (6): Triethyl phospho-
noacetate (23.5 mL, 117 mmol) was added dropwise, with vigorous stirring,
to a dispersion of NaH in mineral oil (80%, 3.52 g, 117 mmol) in dry THF
(100 mL) cooled to À208C. After the reaction mixture had been stirred at
this temperature for 30 min, aldehyde 5 (15.8 g, 78 mmol) was added, and
the mixture was kept for 20 min at À208C and then for 30 min at RT. The
solution was diluted in diethyl ether (500 mL), and the mixture was washed
with a saturated NH4Cl solution. The organic layer was washed with a
saturated Na2CO3 solution (2 Â 100 mL) followed by brine (2 Â 100 mL)
and dried over MgSO4. After concentration and flash chromatography
(cyclohexane/ethyl acetate 98:2), 6 was obtained as a colourless oil. Yield:
17 g, 80%; 1H NMR (200 MHz): d ˆ 0.00 (s, 6H; SiCH3), 0.84 (s, 9H; tBu),
1.23 (t, J ˆ 7.1 Hz, 3H; OCH2CH3), 1.62 (tt, J ˆ 6.8, 6.8 Hz, 2H; H-5), 2.23
(tdd, J ˆ 7.3, 7.3, 1.5 Hz, 2H; H-4), 3.58 (t, J ˆ 6.1 Hz, 2H; H-6), 4.13 (q, J ˆ
7.1 Hz, 2H; OCH2CH3), 5.78 (td, J ˆ 15.6, 1.5 Hz, 1H; H-2), 6.94 (td, J ˆ
15.7, 6.9 Hz, 1H; H-3); 13C NM R:d ˆ À5.34 (SiCH3), 14.28 (OCH2CH3),
18.38 (C(CH3)3), 25.92 (C(CH3)3), 28.67 (C-4), 31.12 (C-5), 60.09
(OCH2CH3), 62.14 (C-6), 121.48 (C-2), 148.92 (C-3), 166.64 (C-1);
elemental analysis calcd for C14H28O3Si: C 61.78, H 10.29; found C 61.77,
H 10.23.
1H; H-2), 6.09 6.22 (m, 2H; H-4, H-5), 7.25 (dd, J ˆ 15.2, 9.7 Hz, 1H;
13
À
H-3); C NM R:d ˆ À5.30 (Si CH3), 14.33 (CH2CH3), 18.34 (C(CH3)3),
25.96 (C(CH3)3), 29.38 (C-6), 31.76 (C-7), 60.16 (CH2CH3), 62.24 (C-8),
119.36 (C-2), 128.66, 144.01 (C-4, C-5), 144.95 (C-3), 167.27 (C-1);
elemental analysis calcd for C16H30O3Si: C 64.44, H 10.06; found C 64.45,
H 10.17.
Ethyl (2E,4E)-8-hydroxyocta-2,4-dienoate (11): Protected alcohol 10 (5 g,
16.8 mmol) dissolved in a THF/water/acetic acid (1:1:3; 75 mL) was stirred
for 4 h at RT. The solvents were evaporated, and the crude product was
purified by chromatography (cyclohexane/ethyl acetate 9:1 1:1) to give 11
as a colourless oil. Yield: 2.21 g, 71%; 1H NMR (200 MHz): d ˆ 1.20 (t, J ˆ
7.1 Hz, 3H; CH3), 1.61 (tt, J ˆ 7.0, 7.0 Hz, 2H; H-7), 2.18 (td, J ˆ 6.8, 6.8 Hz,
2H; H-6), 2.65 (m, 1H; OH), 3.55 (t, J ˆ 6.3 Hz, 2H; H-8), 4.10 (q, J ˆ
7.1 Hz, 2H; CH2CH3), 5.70 (d, J ˆ 15.4 Hz, 1H; H-2), 5.97 6.20 (m, 2H;
H-4, H-5), 7.17 (dd, J ˆ 15.3, 9.9 Hz, 1H; H-3); 13C NMR (50 MHz) : 14.19
(CH3), 29.22 (C-6), 31.47 (C-7), 60.21 (CH2CH3), 61.72 (C-8), 119.31 (C-2),
128.65, 143.74 (C-4, C-5), 144.90 (C-3), 167.37 (C-1); MS: m/z: 185
(2E)-6-tert-Butyldimethylsilyloxyhex-2-en-1-ol (7): Diisobutylaluminium
hydride (1m in hexane, 129 mL) was added at À608C to a solution of ester 6
(16 g, 59 mmol) in dry dichloromethane. After the mixture had been stirred
for 20 min at this temperature, the reaction was quenched with methanol
(50 mL). Aluminium salts were slowly hydrolysed with a hydrochloric acid
solution (1m). After dilution with diethyl ether (1 L) and water (200 mL),
the aqueous layer was extracted with diethyl ether (2 Â 300 mL). The
combined organic layers were dried over MgSO4 and concentrated to give
the desired alcohol 7 as a colourless oil after chromatography (cyclo-
hexane/ethyl acetate 8:2). Yield: 11.34 g, 84%; 1H NMR (200 MHz): d ˆ
0.00 (s, 6H; SiCH3), 0.84 (s, 9H; tBu), 1.55 (tt, J ˆ 6.9, 6.9 Hz, 2H; H-5),
2.05 (td, J ˆ 6.9, 6.9 Hz, 2H; H-4), 2.23 (m, 1H; OH), 3.56 (t, J ˆ 6.4 Hz,
2H; H-6), 4.01 (d, J ˆ 3.5 Hz, 2H; H-1), 5.50 5.72 (m, 2H; H-2, H-3);
13C NM R:d ˆ À5.28 (SiCH3), 18.32 (C(CH3)3), 25.95 (C(CH3)3), 28.51 (C-
4), 32.21 (C-5), 62.52 (C-6), 63.51 (C-1), 129.29 132.53 (C-2, C-3);
elemental analysis calcd for C12H26O2Si: C 62.62, H 11.30; found C 62.57,
H 11.44.
‡
‡
[M‡H] , 202 [M‡NH4] .
(2E,4E)-8-Hydroxyocta-2,4-dienoic acid (12): A sodium hydroxide solution
(0.8m, 60 mL) was added to a solution of ester 11 (2.21 g, 12 mmol) in
methanol (30 mL), and the mixture was stirred for 50 min at 608C.
Neutralisation with hydrochloric acid (12n) and evaporation of the solvents
gave a white solid; this was then flash chromatographed (dichloromethane/
ethanol/acetic acid 9:1:0.1). Acid 12 was obtained as a white solid. Yield:
1.56 g, 83%; 1H NMR (200 MHz, CD3OD): d ˆ 1.64 (tt, J ˆ 6.9, 6.9 Hz, 2H;
H-7), 2.24 (td, J ˆ 6.8, 6.8 Hz, 2H; H-6), 3.56 (t, J ˆ 6.5 Hz, 2H; H-8), 5.78
(d, J ˆ 15.3 Hz, 1H; H-2), 6.08 6.32 (m, 2H; H-4, H-5), 7.24 (dd, J ˆ 15.3,
9.8 Hz, 1H; H-3); 13C NMR (50 MHz, CD3OD) : 30.20 (C-6), 32.44 (C-7),
62.10 (C-8), 120.47 (C-2), 129.84, 145.18 (C-4, C-5), 146.84 (C-3), 170.79 (C-
1); elemental analysis calcd for C8H12O3: C 61.57, H 7.69; found C 61.50, H
7.73.
(2E)-6-tert-Butyldimethylsilyloxyhex-2-enal (8):
Preparation from 7: Compound 8 was prepared as described for 5, from 7
Allyl (1E,3E)-7-hydroxy-hepta-1,3-dienyl-carbamate (13): Diphenylphos-
(11.3 g, 49 mmol), oxalyl dichloride (5.2 mL, 59 mmol), dimethyl sulfoxide
phoryl azide (5.2 mL, 24 mmol) and triethylamine (3.3 mL, 24 mmol) were
Chem. Eur. J. 2002, 8, No. 2
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0445 $ 17.50+.50/0
445

A. Marquet et al.
FULL PAPER
added to a solution of acid 12 (2.66 mg, 17 mmol) in allyl alcohol (80 mL).
The mixture was stirred under reflux for 2.5 h, and after cooling to RT, the
solvents were evaporated. The resulting oil was purified by flash
chromatography (cyclohexane/ethyl acetate 8:2 4:6) to afford the desired
for which two signals in a 55:45 ratio are observed. This product is probably
a mixture of meso and (RR,SS) compounds. 18: 1H NM R:d ˆ 1.58 1.78
(m, 8H; H-1', H-2'), 2.81 (m, 2H; H-4), 3.59 3.63 (m, 1H; H-3'a), 3.75
3.76 (m, 1H; H-3'b), 4.53 (d, J ˆ 5.5 Hz, 4H; COOCH2), 4.68 4.70 (m, 2H;
1
ˆ
H-1), 4.89 4.95 (m, 2H; NH), 5.17 (d, J ˆ 10.5 Hz, 2H; CH2), 5.26 (dd,
diene 13 as a yellow oil. Yield: 2.51 g, 70%; H NM R:d ˆ 1.62 (tt, J ˆ 7.0,
ˆ
7.0 Hz, 2H; H-6), 1.98 (m, 1H; OH), 2.12 (td, J ˆ 7.0, 7.0 Hz, 2H; H-5), 3.61
(t, J ˆ 6.4 Hz, 2H; H-7), 4.58 (d, J ˆ 5.4 Hz, 2H; COOCH2), 5.20 (d, J ˆ
J ˆ 17.2, 1.2 Hz, 2H; CH2), 5.68 5.76 (m, 8H; H-2, H-3, H-5, H-6), 5.83
5.92 (m, 2H; CH CH2); 13C NMR (50MHz): d ˆ 29.64, 29.90 (C-1', C-2'),
ˆ
ˆ
ˆ
10.4 Hz, 1H; CH2), 5.28 (d, J ˆ 17.3 Hz, 1H; CH2), 5.47 (td, J ˆ 14.7,
34.07 (C-4), 44.70 (C-1), 48.66 (C-3'a), 49.23 (C-3'b), 65.56 (COOCH2),
ˆ
7.3 Hz, 1H; H-4), 5.64 (dd, J ˆ 10.8, 13.7 Hz, 1H; H-2), 5.83 5.90 (m, 1H;
117.65 ( CH2), 118.91 (CN), 119.25 (CN), 126.78 (C-2, C-6), 130.17 (C-3,
‡
ˆ
ˆ
ˆ
CH CH2), 5.95 (dd, J ˆ 15.0, 10.6 Hz, 1H; H-3), 6.59 (dd, J ˆ 13.8, 10.6 Hz,
C-5), 132.74 (CH CH2), 155.56 (C O); MS (CI): m/z: 506 [M‡H] , 479
1H; H-1), 6.84 (d, J ˆ 10.6 Hz, 1H; NH); 13C NM R:d ˆ 29.02 (C-5), 32.33
[M‡H À HCN] . 19: 1H NM R:d ˆ 1.65 (m, 2H; NH2), 2.08 (dt, J ˆ 7.5,
‡
ˆ
(C-6), 62.30 (C-7), 66.08 (COOCH2), 111.72 (C-2), 118.25 ( CH2), 124.94
7.5 Hz, 2H; H-3), 2.79 2.94 (m, 2H; H-4), 3.63 (t, J ˆ 7.2 Hz, 1H; H-2),
7.22 7.35 (m, 5H; Ph); 13C NM R:d ˆ 31.60 (C-4), 36.83 (C-3), 42.62 (C-2),
ˆ
ˆ
(C-1), 127.96 (C-3), 130.15 (C-4), 132.28 (CH CH2), 153.44 (C O).
‡
‡
122.07 (CN), 126.52 139.81 (Ph); MS: m/z: 161 [M‡H] , 178 [M‡NH4] ,
3.5% Sodium amalgam:[27] Clean sodium (27 g) was placed in a 500 mL
round-bottomed flask, fitted with a dropping funnel containing 750 g of
mercury in the central sockets. The air was displaced by dry nitrogen
between two side sockets. Mercury was added slowly enough to control the
temperature of the exothermic reaction. After cooling the mixture to RT, a
solid was obtained and powdered.
‡
134 [M‡H À HCN] .
2-Amino-4-(4c-aminocyclohexa-2,5-dien-1r-yl)-butanamide hydrochloride
(20): Phenylsilane (110 mL, 0.9 mmol ) and a solution of Pd(Ph3)4 (10 mg,
0.009 mmol) in dry dichloromethane (1 mL) were added under argon to a
solution of aminonitrile 17 (116 mg, 0.4 mmol) in dry dichloromethane
(1 mL). The mixture was stirred for 30 min at RT and extracted with a
hydrochloric acid solution (1n) at 08C (5 Â 1 mL). The combined aqueous
layers were lyophilised to afford a mixture of 20 (60%) and 21 (22%) as a
yellow oil. Yield: 82 mg. 20: 1H NMR (200 MHz, CD3OD): d ˆ 1.72 (dt, J ˆ
5.6, 5.6 Hz, 2H; H-3), 1.95 (td, J ˆ 5.6, 5.6 Hz, 2H; H-4), 2.90 (m, 1H; H-1'),
3.98 (m, 1H; H-2), 4.33 (m, 1H; H-4'), 5.87 5.91 (m, 2H; H-3', H-5'),
6.10 6.15 (m, 2H; H-2', H-6'); 13C NMR (50 MHz, CD3OD): d ˆ 30.02 (C-
3), 29.35 (C-4), 36.02 (C-1'), 54.16 (C-2), 46.10 (C-4'), 122.49 (C-3', C-5'),
Allyl [4c-(3-hydroxypropyl)cyclohexa-2,5-dien-1r-yl]-carbamate (15): A
solution of diene 13 (880 mg, 4.2 mmol) in anhydrous ortho-xylene
(5 mL) was added to trans-1,2-bis(phenylsulfonyl)ethylene (14; 1.28 g,
4.2 mmol). The mixture was heated at reflux overnight. After evaporation
of the solvent, the residual oil was diluted in anhydrous methanol (150 mL)
buffered with KH2PO4 (17.2 g, 126 mmol). The solution was vigorously
stirred with 3.5% sodium amalgam (2.15 g, 3.04 mmol) under argon for 3 h
at RT. The salts and mercury were then removed by filtration and washed
with dichloromethane (100 mL). The organic layer was concentrated and
purified by flash chromatography (cyclohexane/ethyl acetate 9:1 4:6) to
furnish the cyclohexa-1,4-diene 15. Yield: 363 mg, 37%; 1H NM R:d ˆ
1.46 1.58 (m, 4H; H-1', H-2'), 2.06 (m, 1H; OH), 2.70 2.72 (m, 1H; H-4),
3.59 (t, J ˆ 6.0 Hz, 2H; H-3'), 4.53 (d, J ˆ 5.5 Hz, 2H; COOCH2), 4.68 (m,
‡
135.71 (C-2', C-6'), 172.21 (C-1); MS: m/z (%): 196 [M‡H] , 179
‡
‡
ˆ
(30)[Ph(CH2)2CH(NH2)CONH2‡H] , 134 (100) [Ph(CH2)2CH NH2] ,
‡
‡
ˆ
117 (7) [PhCH2CH CH] , 91 (35) [PhCH2] ; MS-MS: m/z (%) 179
‡
‡
ˆ
ˆ
(100), 134 (75) [Ph(CH2)2CH NH2] , 117 (10) [PhCH2CH CH] , 91 (60)
‡
[PhCH2] .
ˆ
1H; H-1), 4.79 (d, J ˆ 8.8 Hz, 1H; NH), 5.18 (d, J ˆ 10.5 Hz, 1H; CH2),
2-Amino-4-phenyl-butanenitrile (19): A solution of 3-phenylpropanal
ˆ
5.27 (dd, J ˆ 17.2, 1.2 Hz, 1H; CH2), 5.67 5.77 (m, 4H; H-2, H-3, H-5,
(5.07 g, 37.8 mmol) and trimethylsilyl cyanide (6 mL, 46.6 mmol) in the
presence of a catalytic amount of ZnI2 was stirred at RT for 15 min. Then, a
saturated solution of ammonia in methanol (38 mL) was added, and stirring
was maintained for 3 h at 408C. The crude product was concentrated and
chromatographed (cyclohexane/ethyl acetate 9:1 1:9) to give amino nitrile
19 as a yellow oil. Yield: 4.39 g, 73%; 1H and 13C NMR: see above. MS:
H-6), 5.80 5.93 (m, 1H; CH CH2); 13C NMR (50 MHz): d ˆ 29.18, 30.70
ˆ
(C-1', C-2'), 34.74 (C-4), 44.86 (C-1), 62.75 (C-3'), 65.58 (COOCH2), 117.72
ˆ
ˆ
( CH2), 125.63 (C-2, C-6), 131.47 (C-3, C-5), 132.82 (CH CH2), 155.62
‡
‡
ˆ
(C O); MS: m/z: 238 [M‡H] , 255 [M‡NH4] .
Allyl [4c-(3-oxopropyl)-cyclohexa-2,5-dien-1r-yl]-carbamate (16): Alcohol
15 (418 mg, 1.8 mmol) was converted into the aldehyde 16 by means of a
‡
‡
‡
m/z: 161 [M‡H] , 178 [M‡NH4] , 134 [M‡H À HCN] .
Swern reaction as described for 5. Yield: 393 mg, 95%; 1H NM
(200 MHz) : 1.81 (td, J ˆ 6.8, 6.8 Hz, 2H; H-1'), 2.37 (td, J ˆ 7.5, 1.6 Hz,
2H; H-2'), 2.80 2.83 (m, 1H; H-4), 4.53 (d, J ˆ 5.6 Hz, 2H; COOCH2),
4.58 4.72 (m, 1H; H-1), 4.85 (d, J ˆ 9.0 Hz, 1H; NH), 5.17 (ddt, J ˆ 10.4,
R
2-Amino-4-phenyl-butanamide (22): A sodium hydroxide solution (1n,
27 mL) and a hydrogen peroxide solution (35%, 5 mL) were added to a
solution of nitrile 19 (2.1 g, 13.15 mmol) in methanol (14 mL). After 1 h of
stirring at RT, the mixture was extracted with dichloromethane, and the
organic layer was dried over MgSO4 to give 22 as yellow crystals. Yield:
1.78 g (76%); m.p. 898C; 1H NM R:d ˆ 1.57 (m, 2H; NH2), 1.80 1.90 (m,
1H; H-3), 2.16 2.25 (m, 1H; H-3), 2.70 2.83 (m, 2H; H-4), 3.40 (m, 1H;
H-2), 5.84 (m, 1H; CONH2), 7.07 (m, 1H; CONH2), 7.19 7.32 (m, 5H; Ph);
13C NM R:d ˆ 32.19 (C-4), 36.71 (C-3), 54.79 (C-2), 126.21 141.21 (Ph),
178.16 (C-1); elemental analysis calcd for C10H14ON2: C 67.39, H 7.91, N
15.72; found C 67.36, H 7.81, N 15.69.
ˆ
ˆ
1.3, 1.3 Hz, 1H; CH2), 5.27 (ddt, J ˆ 17.2, 1.5, 1.5 Hz, 1H; CH2), 5.64
ˆ
5.78 (m, 4H; H-2, H-3, H-5, H-6), 5.79 5.98 (m, 1H; CH CH2), 9.70 (t, J ˆ
1.7 Hz, 1H; H-3'); 13C NMR (50 MHz): d ˆ 25.88 (C-1'), 34.07 (C-4), 40.26
ˆ
(C-2'), 44.69 (C-1), 65.60 (COOCH2), 117.60 ( CH2), 126.80 (C-2, C-6),
ˆ
À ˆ
130.35 (C-3, C-5), 132.83 (CH CH2), 155.58 (N C O), 202.54 (C-3'); MS:
‡
‡
m/z: 236 [M‡H] , 253 [M‡NH4] .
Allyl [4c-(3-Amino-3-cyano-propyl)-cyclohexa-2,5-dien-1r-yl]-carbamate
(17): Aldehyde 16 (423 mg, 1.8 mmol) and trimethylsilyl cyanide (300 mL,
2.25 mmol) in the presence of a catalytic amount of ZnI2 were stirred for
15 min at RT. A saturated solution of ammonia in methanol (2 mL) at
À408C was added, and the mixture was heated at 508C for 15 min. After
solvent removal and chromatography (cyclohexane/ethyl acetate 9:1 0:1),
amino nitrile 17 was obtained as a yellow powder. Yield: 346 mg, 74%;
1H NM R:d ˆ 1.60 1.68 (m, 4H; H-1', H-2'), 1.71 (m, 2H; NH2), 2.76 2.77
(m, 1H; H-4), 3.62 (t, J ˆ 6.3 Hz, 1H; H-3'), 4.51 (d, J ˆ 5.4 Hz, 2H;
COOCH2), 4.65 4.69 (m, 1H; H-1), 4.88 (d, J ˆ 9.0 Hz, 1H; NH), 5.16 (d,
5-Phenethyl-imidazolidine-2,4-dione (24): Amino nitrile 19 (2.62 g,
14.15 mmol) and ammonium carbonate (15.6 g, 198 mmol) in a methanol/
water 1:1 solution were stirred for 6 h at 508C. After concentration and
recrystallisation from water, hydantoin 24 was obtained as white crystals.
Yield: 1.78 g, 62%; m.p. 1668C; 1H NMR (CD3OD): d ˆ 1.91 2.00 (m, 1H;
CH2CH2Ph), 2.06 2.15 (m, 1H; CH2CH2Ph), 2.69 2.76 (m, 2H; CH2Ph),
4.08 (dd, J ˆ 7.2, 4.2 Hz, 1H; N-CH), 7.17 7.31 (m, 5H; Ph); 13C NM R
À
(CD3OD): d ˆ 28.41 (CH2Ph), 31.30 (CH2CH2Ph), 55.76 (CH N), 124.69,
ˆ
126.93, 127.01, 139.46 (Ph), 157.43, 175.55 (C O); elemental analysis calcd
ˆ
ˆ
J ˆ 10.4 Hz, 1H; CH2), 5.25 (dd, J ˆ 17.2, 1.4 Hz, 1H; CH2), 5.68 5.74
for C11H12O2N2: C 64.69, H 5.92, N 13.72; found C 65.10, H 5.85, N 13.68.
(m, 4H; H-2, H-3, H-5, H-6), 5.81 5.91 (m, 1H; CH CH2); 13C NM R
ˆ
N,N'-Bis-tert-butyloxycarbonyl-5-phenethyl-imidazolidine-2,4-dione (25):
Di-tert-butyldicarbonate (806 mg, 3.67 mmol) was added to a solution of
hydantoin 24 (250 mg, 1.23 mmol) in THF (20 mL) in the presence of a
catalytic amount of DMAP, and the mixture was stirred under argon at RT
for 45 min. The crude product was concentrated and filtered on silica gel
(cyclohexane/ethyl acetate 7:3) to give a yellow oil. Recrystallisation from
pentane afforded 25 as white crystals. Yield: 323 mg, 65%; m.p. 978C;
1H NM R:d ˆ 1.53 (s, 9H; tBu), 1.56 (s, 9H; tBu), 2.34 2.41 (m, 2H;
CH2Ph), 2.63 2.67 (m, 1H; CH2CH2Ph), 2.71 2.76 (m, 1H; CH2CH2Ph),
(50 MHz): d ˆ 29.86, 31.59 (C-1', C-2'), 34.13 (C-4), 43.38 (C-3'), 44.65 (C-
ˆ
1), 65.49 (COOCH2), 117.63 ( CH2), 121.94 (CN), 126.45 (C-2, C-6), 130.38
‡
ˆ
ˆ
(C-3, C-5), 132.74 (CH CH2), 155.48 (C O); MS: m/z: 262 [M‡H] , 279
‡
[M‡NH4] .
The double condensation by-product 18 and the aromatic compound 19
may be isolated in sizeable yields if the ammonia concentration in the
methanolic solution is insufficient or if the ammonia is not sufficiently pure.
A single d value is found for each proton in compound 18, except for H-3'
446
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0446 $ 17.50+.50/0
Chem. Eur. J. 2002, 8, No. 2

Synthesis of Amiclenomycin
439 450
‡
‡
4.46 (dd, J ˆ 6.6, 3.3 Hz, 1H; N-CH), 7.16 7.29 (m, 5H; Ph); 13C NM R
(50 MHz): d ˆ 27.76, 27.99 (C(CH3)3), 29.70, 31.60 (CH2CH2Ph), 58.51
[M‡H] ,
180
ˆ
(30)
[Ph(CH2)2CH(NH2)CO2H‡H] ,
134
(60)
‡
‡
‡
ˆ
[Ph(CH2)2CH NH2] , 117 (18) [PhCH2CH CH] , 91 (100) [PhCH2] .
À
(N CH), 84.83 86.53 (C(CH3)3), 126.50 139.70 (Ph), 145.10, 147.60,
Derivatisation into compound 27: A solution of amino acid 2 in hydro-
chloric acid (3n, 1 mL) was heated at reflux for 2.5 h. After evaporation of
solvent, a solution of 2n isopropanol in HCl was added, and the mixture
was heated at 1008C for 30 min under argon. The solvent was evaporated
under draught, and CH2Cl2 (1 mL) followed by trifluoroacetic anhydride
(10 drops) were added. After 30 min at RT, the solvent was evaporated, and
27 was injected onto a CHIRASYL-VAL 0.20 m G.C. column (length 50 m,
internal diameter 0.32 mm). The same procedure was used for amino acid
amide 20 and for the racemic homophenylalanine reference.
ˆ
148.20, 167.30 (C O); elemental analysis calcd for C21H28O6N2: C 62.36,
H 6.98, N 6.93; found C 62.30, H 7.02, N 7.03.
2-(1,3-di-tert-butyloxycarbonyl)urea-4-phenyl-butanoic acid (26): A solu-
tion of N-protected hydantoin 25 (0.49 mmol, 197 mg) in THF (10 mL) and
water (2 mL) was stirred in the presence of lithium hydroxide monohydrate
(41 mg, 0.97 mmol) for 2 h at RT. After concentration, dilution in water
(3 mL) and acidification with hydrochloric acid (1n, pH 6), the solution was
filtered to afford 26 as a white powder. Yield: 189 mg, 92%; m.p. 1528C;
1H NM R:d ˆ 1.48 (s, 9H; tBu), 1.52 (s, 9H; tBu), 2.17 2.22 (m, 1H;
CH2CH2Ph), 2.74 2.78 (m, 1H; CH2CH2Ph), 2.51 2.62 (m, 2H; CH2Ph),
5.40 5.50 (m, 1H; N-CH), 7.18 7.30 (m, 5H; Ph), 10.28 (m, 1H; NH),
10.97 (m, 1H; COOH); 13C NM R:d ˆ 28.24, 28.43 (C(CH3)3), 31.65
5-tert-Butyldimethylsilyloxypentan-1-ol (28): Pentane-1,5-diol (27.1 g,
0.27 mol) was transformed into the colourless oil 28 as described for the
preparation of 4. Yield: 50.4 g, 89%; b.p. 1228C (0.1 mbar); 1H NM R:d ˆ
0.00 (s, 6H; SiCH3), 0.85 (s, 9H; tBu), 1.31 1.38 (m, 2H; H-3), 1.46 1.56
(m, 4H; H-2, H-4), 2.33 (s, 1H; OH), 3.54 3.58 (m, 4H; H-1, H-5);
13C NM R:d ˆ À5.28 (SiCH3), 18.38 (C(CH3)3), 22.04 (C-3), 25.98
(C(CH3)3), 32.45 32.51 (C-2, C-4), 62.66 63.19 (C-1, C-5); elemental
analysis calcd for C11H26O2Si: C 60.56, H 11.92; found C 60.51, H 12.07.
À
(CH2CH2Ph), 32.90 (CH2Ph), 56.00 (CH N), 82.59 86.41 (C(CH3)3),
ˆ
126.15, 128.36, 128.57, 141.30 (Ph), 150.16, 151.18, 154.03 (C O), 175.79
‡
‡
(COOH); MS: m/z: 423 [M‡H] , 440 [M‡NH4] .
Synthesis of the polyacrylamide resin:
5-Tert-butyldimethylsilyloxypentanal (29): Alcohol 28 (21.8 g, 100 mmol)
was transformed into the yellow oil 29 as described for the preparation of 5.
Yield: 19.5 g, 90%; 1H NMR (200 MHz): d ˆ À0.02 (s, 6H; SiCH3), 0.82 (s,
9H; tBu), 1.40 1.57 (m, 2H; H-4), 1.57 1.68 (m, 2H; H-3), 2.39 (td, J ˆ 7.1,
1.7 Hz, 2H; H-2), 3.56 (t, J ˆ 6.0 Hz, 2H; H-5), 9.70 (t, J ˆ 1.8 Hz, 1H;
H-1); 13C NMR (50 MHz): d ˆ À5.37 (SiCH3), 18.34 (C(CH3)3), 18.58 (C-
3), 25.92 (C(CH3)3), 32.07 (C-4), 43.59 (C-2), 62.55 (C-5), 202.48 (C-1).
1-acryloylpiperidin-4-one: 4-Piperidone monohydrate hydrochloride (15 g,
98 mmol) was added to NaHCO3 (24.7 g, 290 mmol) in water (75 mL)
cooled to 08C. Acryloyl chloride (9.4 mL, 120 mmol) was added dropwise
at this temperature, with efficient mechanical stirring, over 30 min. The
solution was kept at 08C for 1 h and further stirred for 1 h 15 min at RT.
Excess NaHCO3 was removed by filtration, and acryloylpiperidone was
extracted with chloroform (5 Â 100 mL). The organic layer was washed
with 2m hydrochloric acid (2 Â 20 mL) and dried over MgSO4. After
concentration, pure 1-acryloylpiperidin-4-one was obtained. Yield: 13.28 g,
65%; 1H NM R:d ˆ 2.37 (t, J ˆ 6.3 Hz, 4H; NCH2CH2), 3.75 3.80 (m, 4H;
(2E)-7-tert-Butyldimethylsilyloxyhept-2-enal (30): a,b-Unsaturated alde-
hyde 30 was obtained as an orange oil from aldehyde 29 in one step as
described for the preparation of 8. Yield: 12.1 g, 56%; 1H NM
(200 MHz): d ˆ 0.00 (s, 6H; SiCH3), 0.84 (s, 9H; tBu), 1.49 1.58 (m, 4H;
H-5, H-6), 2.27 2.33 (m, 2H; H-4), 3.58 (t, J ˆ 5.8 Hz, 2H; H-7), 6.07 (tdd,
J ˆ 15.5, 7.9, 1.3 Hz, 1H; H-2), 6.81 (td, J ˆ 15.6, 6.7 Hz, 1H; H-3), 9.45 (d,
J ˆ 7.9 Hz, 1H; H-1); 13C NMR (50 MHz): d ˆ À5.34 (SiCH3), 18.31
(C(CH3)3), 24.22, 32.13 (C-5, C-6), 25.92 (C(CH3)3), 32.46 (C-4), 62.58 (C-
7), 133.01 (C-2), 158.75 (C-3), 194.05 (C-1).
R
ˆ
NCH2CH2), 5.63 (dd, J ˆ 10.5, 1.8 Hz, 1H; CH2), 6.20 (dd, J ˆ 16.8, 1.8 Hz,
1H; CH2), 6.54 (dd, J ˆ 16.8, 10.5 Hz, 1H; CH CH2); 13C NM R:d ˆ
ˆ
ˆ
ˆ
ˆ
41.42, 41.47, 41.65, 44.06 (NCH2CH2), 127.38 (CH CH2), 129.26 ( CH2),
À ˆ
ˆ
166.05 (N C O), 206.95 (C O).
1,4-Bisacryloyl-piperazine: Acryloyl chloride (8.1 mL, 100 mmol) was
added dropwise over 30 min to a stirred mixture of piperazine (4.3 g,
50 mmol) and triethylamine (14 mL, 100 mmol) in dry dichloromethane
(350 mL) cooled to 08C. After 45 min of stirring at this temperature, the
mixture was allowed to warm to RTover 1 h. The organic layer was washed
with water (2 Â 100 mL) and with hydrochloric acid (0.5m, 2 Â 40 mL).
After concentration, 1,4-bisacryloyl-piperazine was crystallised from
methanol/diethyl ether (15:85), to give of white crystals. Yield: 5.55 g,
57%; m.p. 95 968C; 1H NM R:d ˆ 3.60 (s, 4H; NCH2), 3.71 (s, 4H;
(1E,3E)-7-tert-Butyldimethylsilyloxy-1-trimethylsilyloxyhepta-1,3-diene
(31) and (1E,3Z)-7-tert-butyldimethylsilyloxy-1-trimethylsilyloxyhepta-
1,3-diene (32):
A solution of a,b-unsaturated aldehyde 30 (4.53 g,
18.7 mmol) in toluene (21 mL) was added to a stirred suspension of ZnCl2
(200 mg) in triethylamine (8.6 mL, 62.7 mmol). Trimethylsilyl bromide
(5.4 mL, 41.1 mmol) was added dropwise with stirring, and the mixture was
heated under reflux overnight. After having cooled to RT, the solution was
filtered on a Celite pad, concentrated, diluted with cyclohexane (400 mL)
and cooled for 1 h at 48C. After concentration, another filtration through a
Celite pad afforded a crude oil, which was distilled to give a colourless oil as
a mixture of the (1E,3E) and (1E,3Z) isomers 31 and 32 in 35:65 ratio.
Yield: 75%; b.p. 1108C (0.5 mbar). 31: 1H NM R:d ˆ 0.03 (s, 6H; Si(CH3)2),
0.19 (s, 9H; Si(CH3)3), 0.88 (s, 9H; tBu), 1.57 (tt, J ˆ 7.0, 7.0 Hz, 2H; H-6),
2.06 2.16 (m, 2H; H-5), 3.59 (t, J ˆ 6.5 Hz, 2H; H-7), 5.44 (dt, J ˆ 14.7,
7.2 Hz, 1H; H-4), 5.66 (dd, J ˆ 11.3, 11.3 Hz, 1H; H-2), 5.83 5.97 (m, 1H;
H-3), 6.43 (d, J ˆ 11.8 Hz, 1H; H-1); 13C NM R:d ˆ À5.20 (Si(CH3)2),
À0.39 (Si(CH3)3), 18.42 (C(CH3)3), 26.06 (C(CH3)3), 29.15 (C-5), 32.73 (C-
6), 62.67 (C-7), 113.94 (C-2), 126.22 (C-3), 129.11 (C-4), 142.29 (C-1). 32:
1H NM R:d ˆ 0.03 (s, 6H; Si(CH3)2), 0.20 (s, 9H; Si(CH3)3), 0.88 (s, 9H;
tBu), 1.57 (tt, J ˆ 7.0, 7.0 Hz, 2H; H-6), 2.06 2.16 (m, 2H; H-5), 3.59
(t, J ˆ 6.4 Hz, 2H; H-7), 5.19 (dt, J ˆ 10.4, 7.5 Hz, 1H; H-4), 5.83 5.97 (m,
2H; H-2, H-3), 6.49 (d, J ˆ 11.4 Hz, 1H; H-1); 13C NM R:d ˆ À5.20
(Si(CH3)2), À0.39 (Si(CH3)3), 18.42 (C(CH3)3), 24.08 (C-5), 26.06
(C(CH3)3), 32.94 (C-6), 62.67 (C-7), 109.73 (C-2), 124.66 (C-3), 126.99
(C-4), 144.01 (C-1).
ˆ
NCH2), 5.75 (dd, J ˆ 10.7, 1.5 Hz, 2H; CH2), 6.33 (dd, J ˆ 16.7, 1.5 Hz, 2H;
CH2), 6.57 (dd, J ˆ 10.7, 16.6 Hz, 2H; CH CH2); 13C NM R:d ˆ 42.32,
ˆ
ˆ
ˆ
ˆ
ˆ
45.78 (NCH2), 127.36 (CH CH2), 129.15 ( CH2), 165.95 (C O).
Immobilisation of pronase on poly(N-acryloylpiperidin-4-one): A solution
of 1-acryloylpiperidin-4-one (5 g, 24 mmol), 1,4-bisacryloyl-piperazine (1 g,
5 mmol) and pronase (100 mg) in water (6 mL) was deoxygenated by
bubbling argon through it for 1 h. N,N,N',N'-tetramethyl ethylene diamine
(40 mL) and a deoxygenated ammonium persulfate solution (0,175m,
1 mL) were added quickly. The flask was transferred to an ice bath and
left there for 1 h, and then at RT for 1 h. The solid was recovered, crushed,
and washed with water. The immobilised pronase can be stored at 48C.
(2R)-2-Amino-4-(4c-amino-cyclohexa-2,5-dien-1r-yl)-butanoic acid (2): Im-
mobilised pronase (2 g) and (d,l)-amino acid amide 20 (in the presence of
aromatic compound 21) (94 mg, 0.35 mmol) were added to a phosphate
buffer (0.1m, 20 mL, pH 9.6). After 7.5 h stirring at 378C, the mixture was
filtered, and the resin was washed with water. The combined aqueous layers
were acidified to pH 6 with acetic acid and then lyophilised and purified on
‡
a Dowex-SO3ÀNH4 column (H2O/NH4OH (0.2 m) 1:0 0:1) to give l-
3c-Hydroxy-6c-(3-hydroxypropyl)-1r,2t-bis(phenylsulfonyl)-cyclohex-4-
ene (33a) and 3t-hydroxy-6t-(3-hydroxypropyl)-1r,2t-bis(phenylsulfonyl)-
cyclohex-4-ene (33b): Trans-1,2-bis(phenylsulfonyl)ethylene (14; 2.12 g,
6.88 mmol) was added to the above 65:35 mixture of the dienes 32 and 31
(6.17 g) in anhydrous ortho-xylene (7 mL). The mixture was stirred at
1208C until complete disappearance of sulfone (24 h). After concentration
under high vacuum, the crude product was dissolved in methanol (7 mL)
with one drop of 12n hydrochloric acid and stirred for 30 min. Concen-
tration followed by purification of the resulting oil by chromatography
(cyclohexane/ethyl acetate 95:5 0:1) afforded a white foam as a mixture of
amino acid 2 (20 mg, 28%) contaminated with 21 (27%) and d-amino acid
amide 20 (21 mg, 29%). A pure sample of 2 could be obtained after
additional DOWEX chromatography; the enantiomeric excess was deter-
mined on this sample. 1H NMR (500 MHz, D2O): d ˆ 1.56 1.62 (m, 1H;
H-4), 1.65 1.71 (m, 1H; H-4), 1.84 1.91 (m, 2H; H-3), 2.96 (m, 1H; H-1'),
3.75 (t, J ˆ 6.0 Hz, 1H; H-2), 4.41 (m, 1H; H-4'), 5.87 (d, J ˆ 10.4 Hz, 2H;
H-3', H-5'), 6.13 (d, J ˆ 10.4 Hz, 2H; H-2', H-6'); 13C NMR (125 MHz,
D2O): d ˆ 27.83, 29.29 (C-3, C-4), 35.10 (C-1'), 55.50 (C-2), 45.56 (C-4'),
121.52 (C-3', C-5'), 135.75 (C-2', C-6'), 175.32 (C-1); MS-MS: m/z (%): 197
Chem. Eur. J. 2002, 8, No. 2
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0447 $ 17.50+.50/0
447

A. Marquet et al.
FULL PAPER
two diastereoisomers 33a and 33b in a ratio of 80:20 to 65:35. Yield: 1.98 g,
66%. 33a: 1H NM R:d ˆ 1.42 1.51 (m, 1H; H-2'), 1.53 1.64 (m, 1H;
H-2'), 1.73 1.81 (m, 1H; H-1'), 1.83 1.91 (m, 1H; H-1'), 2.45 (m, 1H; OH-
3'), 2.87 (m, 1H; H-6), 3.49 (t, J ˆ 6.3 Hz, 2H; H-3'), 3.60 (d, J ˆ 9.7 Hz, 1H;
OH-3), 3.83 (m, 1H; H-2), 4.10 (m, 1H; H-1), 4.52 (m, 1H; H-3), 5.74 5.88
(m, 2H; H-4, H-5), 7.33 7.84 (m, 10H; Ph); 13C NM R:d ˆ 28.16 (C-1'),
30.61 (C-2'), 34.82 (C-6), 58.96 (C-1), 61.45 (C-3), 61.80 (C-3'), 66.46 (C-2),
127.41 129.70 (C-4, C-5), 127.83 141.71 (Ph). 33b: 1H NM R:d ˆ 1.22
1.26 (m, 1H; H-2'), 1.31 1.39 (m, 1H; H-2'), 1.54 1.64 (m, 2H; H-1'), 2.45
(m, 1H; OH-3'), 2.61 (m, 1H; H-6), 3.36 (t, J ˆ 6.3 Hz, 2H; H-3'), 3.54 (m,
1H; OH-3), 4.10 (m, 1H; H-1), 4.22 (m, 1H; H-2), 4.81 (m, 1H; H-3), 5.64
(d, J ˆ 10.5 Hz, 1H; H-4), 5.74 5.88 (m, 1H; H-5), 7.33 7.84 (m, 10H; Ph);
13C NM R:d ˆ 29.60 (C-1'), 30.86 (C-2'), 31.40 (C-6), 61.50 (C-2), 61.55 (C-
1), 61.70 (C-3'), 64.58 (C-3), 127.83 141.71 (Ph), 128.16 (C-4), 128.76 (C-5);
33a ‡ 33b: elemental analysis calcd for C21H24O6S2: C 57.40, H 5.80; found
C 57.78, H 5.54.
2.3 Hz, 1H; H-6), 7.79 (m, 1H; H-2), 7.96 (dd, J ˆ 8.3, 1.1 Hz, 2H; H-2'),
7.50 7.60 (m, 3H; H-3', H-4'); 13C NMR (50 MHz): d ˆ À5.22 (SiCH3),
18.80 (C(CH3)3), 26.04 (C(CH3)3), 29.95 (CH2CH2O), 32.04 (CH2Ph), 61.96
(CH2O), 125.23 144.20 (Ph).
Compound 37: This compound was also isolated by chromatography, in a
yield of 10%, and was characterised by its NMR spectra. 1H NM R:d ˆ 0.06
(s, 6H; SiCH3), 0.91 (s, 9H; tBu), 1.33 1.36 (m, 2H; H-2'), 1.74 1.83 (m,
1H; H-1'), 1.93 1.98 (m, 1H; H-1'), 2.28 2.33 (m, 1H; H-6), 3.44 3.50
(m, 2H; H-3'), 4.12 (d, J ˆ 4.1 Hz, 1H; H-2), 4.28 (s, 1H; H-1), 4.31 (m, 1H;
H-3), 5.84 (m, 1H; H-4), 6.28 (m, 1H; H-5), 7.55 7.77 (m, 10H; Ph);
13C NM R:d ˆ À4.89 (SiCH3), 18.70 (C(CH3)3), 25.30 (C-1'), 26.34
(C(CH3)3), 30.32 (C-2'), 38.99 (C-6), 59.49 (C-2), 59.64 60.64 (C-1, C-3),
62.72 (C-3'), 118.94 (C-4), 128.40 139.98 (Ph), 135.84 (C-5); IR (CDCl3):
‡
nÄ ˆ 2100 cmÀ1 (N3); HRMS: m/z: found 576.2027 [M‡H] ; C27H38O5N3S2Si
calcd 576.2022.
Allyl
[6c-(3-tert-butyldimethylsilyloxypropyl)-1r,2t-bis(phenylsulfonyl)-
6c-(3-tert-Butyldimethylsilyloxypropyl)-3c-hydroxy-1r,2t-bis(phenylsulfo-
nyl)cyclohex-4-ene (34a) and 6t-(3-tert-butyldimethylsilyloxypropyl)-3t-
hydroxy-1r,2t-bis(phenylsulfonyl)cyclohex-4-ene (34b): Anhydrous tri-
ethylamine (140 mL, 1.01 mmol) and tert-butyldimethylsilyl chloride
(280 mg, 1.84 mmol) were added to a stirred solution of diols 33a and
33b (400 mg, 0.92 mmol) in anhydrous dichloromethane (10 mL) in the
presence of a catalytic amount of DMAP (0.2 eq). After 5.5 h of stirring,
the mixture was concentrated and purified by chromatography (cyclo-
hexane/ethyl acetate 95:5 5:5), to afford a yellow oil as a mixture of the
two diastereoisomers 34a and 34b in a ratio of 80:20 to 65:35. Yield: 83%.
34a: 1H NM R:d ˆ 0.06 (s, 6H; SiCH3), 0.90 (s, 9H; tBu), 1.43 1.58 (m,
1H; H-2'), 1.64 1.70 (m, 1H; H-2'), 1.81 1.88 (m, 2H; H-1'), 2.94 (m, 1H;
H-6), 3.41 (d, J ˆ 10.2 Hz, 1H; OH), 3.56 3.63 (m, 2H; H-3'), 3.97 (s, 1H;
H-2), 4.16 (d, J ˆ 5.4 Hz, 1H; H-1), 4.55 (m, 1H; H-3), 5.88 5.94 (m, 2H;
H-4, H-5), 7.54 5.77 (m, 10H; Ph); 13C NM R:d ˆ À5.17 (SiCH3), 18.51
(C(CH3)3), 26.08 (C(CH3)3), 28.46 (C-1'), 31.31 (C-2'), 35.21 (C-6), 59.45 (C-
1), 61.90 (C-3), 62.55 (C-3'), 66.45 (C-2), 127.85 141.70 (C-4, C-5, Ph); 34b:
1H NM R:d ˆ 0.01 (s, 6H; SiCH3), 0.87 (s, 9H; tBu), 1.23 1.26 (m, 2H;
H-2'), 1.55 1.60 (m, 2H; H-1'), 2.65 (m, 1H; H-6), 3.46 (s, 1H; OH), 3.45 (t,
J ˆ 6.2 Hz, 2H; H-3'), 4.10 (m, 1H; H-1), 4.36 (m, 1H; H-2), 4.88 (m, 1H;
H-3), 5.71 5.75 (m, 1H; H-4), 5.83 5.91 (m, 1H; H-5), 7.54 7.77 (m, 10H;
Ph); 13C NM R:d ˆ À5.17 (SiCH3), 18.51 (C(CH3)3), 26.08 (C(CH3)3), 30.38
(C-2'), 31.31 (C-1'), 32.00 (C-6), 61.50 61.55 (C-1, C-2), 62.65 (C-3'), 65.11
(C-3), 127.85 141.70 (C-4, C-5, Ph); 34a ‡ 34b: elemental analysis calcd
(%) for C27H38O6S2Si: C 58.77, H 7.24; found C 58.88, H 6.95.
cyclohex-4-en-3t-yl]carbamate (39a) and allyl [6t-(3-tert-butyldimethyl-
silyloxypropyl)-1r,2t-bis(phenylsulfonyl)-cyclohex-4-en-3c-yl]carbamate
(39b): A solution of azides 35a and 35b (70:30, 335 mg, 0.58 mmol) in
THF/isopropyl alcohol (1:1, 14 mL) was introduced into a reactor with a
Lindlar catalyst (300 mg). After the mixture had been stirred overnight
under hydrogen (5 bars), the catalyst was removed by centrifugation and
washed with dichloromethane (2 Â 20 mL). After evaporation of the
combined layers, a yellow oil containing the two diastereoisomers 38a
and 38b was obtained. This crude product was directly used in the following
step without purification.
The oil was dissolved in absolute ethanol (14 mL) buffered with NaHCO3
(489 mg, 5.82 mmol), and allyloxycarbonyl chloride (111 mL, 1.05 mmol)
was added. The solution was sonicated at RT for 1.5 h and then
concentrated. Purification by chromatography (cyclohexane/ethyl acetate
9:1 7:3) afforded the two diastereoisomers 39a and 39b in a 65:35 ratio as
a yellow oil. Yield: 281 mg, 76% over two steps. 39a: 1H NM R:d ˆ 0.00 (s,
6H; SiCH3), 0.84 (s, 9H; tBu), 1.47 1.56 (m, 1H; H-2'), 1.59 1.65 (m, 1H;
H-2'), 1.75 1.81 (m, 1H; H-1'), 1.86 1.92 (m, 1H; H-1'), 3.10 (m, 1H;
H-6), 3.51 3.57 (m, 2H; H-3'), 3.78 3.83 (ddd, J ˆ 13.2, 5.6, 1.5 Hz, 1H;
COOCH2), 4.15 4.19 (m, 2H; COOCH2, H-2), 4.39 (m, 1H; H-1), 5.06 (m,
ˆ
1H; H-3), 5.07 (m, 1H; NH), 5.12 (dd, J ˆ 10.2, 1.5 Hz, 1H; CH2), 5.14
ˆ
(dd, J ˆ 17.3, 1.5 Hz, 1H; CH2), 5.54 (d, J ˆ 10.2 Hz, 1H; H-4), 5.63 5.71
ˆ
(m, 1H; CH CH2), 5.85 (d, J ˆ 10.7 Hz, 1H; H-5), 7.35 7.96 (m, 10H; Ph);
13C NM R:d ˆ À4.90 (SiCH3), 18.73 (C(CH3)3), 26.38 (C(CH3)3), 28.55 (C-
1'), 31.33 (C-2'), 35.26 (C-6), 46.40 (C-3), 60.64 (C-2), 62.13 (C-1), 62.93 (C-
3t-Azido-6c-(3-tert-butyldimethylsilyloxypropyl)-1r,2t-di(phenylsulfonyl)-
cyclohex-4-ene (35a) and 3c-azido-6t-(3-tert-butyldimethylsilyloxypropyl)-
1r,2t-di(phenylsulfonyl)cyclohex-4-ene (35b): A mixture of alcohols 34a
and 34b (420 mg, 0.76 mmol) and triphenylphosphine (280 mg, 1.06 mmol)
in anhydrous dichloromethane (2 mL) was stirred at 08C. After 10 min,
diisopropylazodicarboxylate (210 mL, 1.07 mmol) and diphenylphosphoryl
azide (230 mL, 1.06 mmol) were added. The solution was kept at 08C for
1.5 h. Purification of the crude product by chromatography (cyclohexane/
ethyl acetate 95:5 7:3) afforded the desired azide as a yellow oil as a 80:20
to 60:40 mixture of the two diastereoisomers 35a and 35b. Yield: 52%.
35a: 1H NM R:d ˆ 0.01 (s, 6H; SiCH3), 0.88 (s, 9H; tBu), 1.42 1.49 (m,
2H; H-2'), 1.70 1.75 (m, 2H; H-1'), 3.12 (m, 1H; H-6), 3.40 3.46 (m, 2H;
H-3'), 4.43 (m, 1H; H-2), 4.66 (m, 1H; H-1), 4.88 (m, 1H; H-3), 5.81 (d, J ˆ
10.4 Hz, 1H; H-5), 5.98 (d, J ˆ 10.4 Hz, 1H; H-4), 7.58 7.97 (m, 10H; Ph);
13C NM R:d ˆ À5.24 (SiCH3), 18.38 (C(CH3)3), 26.05 (C(CH3)3), 29.80,
30.67 (C-1', C-2'), 35.03 (C-6), 54.95 (C-3), 60.45 (C-2), 62.21 (C-3'), 62.53
(C-1), 122.16 (C-5), 128.23 141.47 (C-4, Ph); 35b: 1H NM R:d ˆ 0.00 (s,
6H; SiCH3), 0.87 (s, 9H; tBu), 1.42 1.49 (m, 2H; H-2'), 1.54 1.70 (m, 2H;
H-1'), 2.82 (m, 1H; H-6), 3.40 3.46 (m, 2H; H-3'), 4.13 (s, 1H; H-1), 4.20
(s, 1H; H-2), 4.46 (s, 1H; H-3), 5.86 (d, J ˆ 10.5 Hz, 1H; H-4), 6.15 (d, J ˆ
10.5 Hz, 1H; H-5), 7.58 7.97 (m, 10H; Ph); 13C NM R:d ˆ À5.24 (SiCH3),
18.38 (C(CH3)3), 26.05 (C(CH3)3), 26.95, 29.75 (C-1', C-2'), 32.10 (C-6),
51.21 (C-3), 58.50 (C-1), 61.30 (C-2), 62.21 (C-3'), 120.88 (C-4), 128.23
141.47 (Ph), 133.41 (C-5); 35a ‡ 35b: IR (CDCl3): nÄ ˆ 2100 cmÀ1 (N3); MS:
ˆ
3'), 65.98 (COOCH2), 118.23 ( CH2), 125.04 (C-4), 127.68 141.59 (Ph),
1
ˆ
ˆ
131.24 (C-5), 132.62 (CH CH2), 154.92 (C O). 39b: H NM R:d ˆ 0.00 (s,
6H; SiCH3), 0.86 (s, 9H; tBu), 1.29 1.36 (m, 2H; H-2'), 1.49 1.59 (m, 1H;
H-1'), 1.62 1.70 (mm, 1H; H-1'), 2.64 (m, 1H; H-6), 3.39 3.42 (s, 2H;
H-3'), 4.10 4.24 (s, 2H; H-1, H-2), 4.40 (m, 1H; COOCH2), 4.69 (m, 1H;
ˆ
ˆ
H-3), 5.15 (dd, J ˆ 10.7, 1.6 Hz, 1H; CH2), 5.22 (d, J ˆ 17.3 Hz, 1H; CH2),
ˆ
5.69 (d, J ˆ 9.7 Hz, 1H; NH), 5.76 5.86 (m, 1H; CH CH2), 5.80 5.84 (m,
1H; H-4), 5.94 (dd, J ˆ 10.2, 3.6 Hz, 1H; H-5), 7.58 7.94 (m, 10H; Ph);
13C NM R:d ˆ À4.92 (SiCH3), 18.65 (C(CH3)3), 26.31 (C(CH3)3), 29.92,
30.33 (C-1', C-2'), 31.53 (C-6), 41.50 (C-3), 58.08, 60.49 (C-1, C-2), 62.41 (C-
ˆ
3'), 65.72 (COOCH2), 117.63 ( CH2), 122.63 (C-4), 128.91 137.90 (Ph),
ˆ
ˆ
130.39 (C-5), 132.71 (CH CH2), 155.12 (C O); 39a ‡ 39b: HRMS: m/z:
‡
found 634.2335 [M‡H] ; C31H43O7NS2Si calcd 634.2328.
Allyl [6c-(3-hydroxypropyl)-1r,2t-di(phenylsulfonyl)cyclohex-4-en-3t-yl]-
carbamate (40a) and allyl [6t-(3-hydroxypropyl)-1r,2t-di(phenylsulfonyl)-
cyclohex-4-en-3c-yl]carbamate (40b): Silylated alcohols 39a and 39b
(280 mg, 0.44 mmol) solubilised in methanol (5 mL) in the presence of
hydrochloric acid (12n, 1 mL), were stirred for 15 min. After concentration,
the mixture was purified by flash chromatography (cyclohexane/ethyl
acetate 9:1 3:7) to give a white foam consisting of a mixture of the two
diastereoisomers 40a and 40b. Yield: 197 mg, 86%. 40a: 1H NM R:d ˆ 1.54
(s, 1H; OH), 1.70 1.80 (m, 2H; H-2'), 1.90 1.96 (m, 1H; H-1'), 2.08 2.18
(m, 1H; H-1'), 3.20 (m, 1H; H-6), 3.67 (m, 2H; H-3'), 3.88 (dd, J ˆ 13.2,
5.6 Hz, 1H; COOCH2), 4.12 4.46 (m, 2H; H-1, H-2), 4.23 (dd, J ˆ 13.2,
5.6 Hz, 2H; COOCH2), 5.12 (m, 1H; H-3), 5.12 (m, 1H; NH), 5.18 5.23
‡
‡
m/z: 576 [M‡H] , 593 [M‡NH4] .
ˆ
3-tert-Butyldimethylsilyloxypropyl-1-(phenylsulfonyl)benzene (36): This
compound was also isolated by chromatography as a yellow oil in a yield
of 30%. 1H NM R:d ˆ 0.05 (s, 6H; SiCH3), 0.31 (s, 9H; tBu), 1.81 1.87 (m,
2H; CH2CH2O), 2.75 (t, J ˆ 7.7 Hz, 2H; CH2Ph), 3.62 (t, J ˆ 6.1 Hz, 2H;
CH2O), 7.41 (m, 2H; H-4), 7.41 7.45 (m, 1H; H-5), 7.77 (ddd, J ˆ 6.1, 2.3,
(m, 2H; CH2), 5.63 (d, J ˆ 10.6 Hz, 1H; H-4), 5.68 5.75 (m, 1H;
ˆ
CH CH2), 5.91 (d, J ˆ 10.6 Hz, 1H; H-5), 7.40 8.04 (m, 10H; Ph);
13C NM R:d ˆ 28.43, 30.86 (C-1', C-2'), 35.06 (C-6), 46.06 (C-3), 60.38, 61.57
ˆ
(C-1, C-2), 62.06 (C-3'), 65.70 (COOCH2), 117.93 ( CH2), 124.90 (C-4),
1
ˆ
ˆ
127.33 141.16 (C-5, Ph), 132.61 (CH CH2), 154.67 (C O). 40b: H NM R:
448
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0448 $ 17.50+.50/0
Chem. Eur. J. 2002, 8, No. 2

Synthesis of Amiclenomycin
439 450
d ˆ 1.10 1.20 (m, 2H; H-2'), 1.40 1.50 (m, 1H; H-1'), 1.60 (s, 1H; OH),
1.65 1.75 (m, 1H; H-1'), 2.69 (m, 1H; H-6), 3.47 (t, J ˆ 5.8 Hz, 2H; H-3'),
4.09 4.29 (m, 2H; H-1, H-2), 4.10 (m, 2H; COOCH2), 4.71 (m, 1H; H-3),
30.37 (C-4), 35.79 (C-1'), 46.10 (C-4'), 54.16 (C-2), 122.95 (C-3', C-5'),
136.61 (C-2', C-6'), 172.20 (C-1).
Aromatic compounds 19 and 21 were also identified, in a yield of 15%.
ˆ
ˆ
5.16 (dd, J ˆ 10.6, 1.1 Hz, 1H; CH2), 5.23 (d, J ˆ 17.1 Hz, 1H; CH2), 5.69
(2R)-2-Amino-4-(4t-amino-cyclohexa-2,5-dien-1r-yl)butanoic acid (1):
Amino acid 1 was prepared as described for 2, from a mixture of 44 and
ˆ
(d, J ˆ 9.9 Hz, 1H; NH), 5.78 5.88 (m, 1H; CH CH2), 5.84 (m, 1H; H-4),
5.95 (dd, J ˆ 10.6, 3.0 Hz, 1H; H-5), 7.59 7.97 (m, 10H; Ph); 13C NM R:d ˆ
29.58, 30.23 (C-1', C-2'), 31.34 (C-6), 41.50 (C-3), 58.08, 60.50 (C-1, C-2),
45 (40 mg, 0.149 mmol) and pronase (1 g). Yield: 20%; 1H NM
(500 MHz, D2O): d ˆ 1.46 1.52 (m, 1H; H-4), 1.55 1.61 (m, 1H; H-4),
1.74 1.81 (m, 2H; H-3), 2.91 (m, 1H; H-1'), 3.62 (t, J ˆ 5.9 Hz, 1H; H-2),
4.28 (m, 1H; H-4'), 5.80 (d, J ˆ 10.4 Hz, 2H; H-3', H-5'), 6.01 (d, J ˆ
10.4 Hz, 2H; H-2', H-6'); 13C NMR (125 MHz, D2O): d ˆ 27.10, 29.49 (C-
3, C-4), 35.10 (C-1'), 45.25 (C-4'), 55.50 (C-2), 121.79 (C-3', C-5'), 135.80 (C-
R
ˆ
62.44 (C-3'), 65.70 (COOCH2), 117.67 ( CH2), 122.80 (C-4), 128.91 141.60
ˆ
(Ph), 130.85 (C-5), 132.67 (CH CH2), 154.81 (C ˆ O); 40a
‡
40b:
elemental analysis calcd for C25H29O7NS2: C 57.78, H 5.62, N 2.69; found
C 57.51, H 5.85, N 2.62.
ˆ
Allyl [4t-(3-hydroxypropyl)-cyclohexa-2,5-dien-1r-yl]carbamate (41):
A
2', C-6'), 175.32 (C O).
solution of disulfones 40a and 40b (253 mg, 0.49 mmol) in dry methanol
(11 mL) buffered with KH2PO4 (2.56 g, 18 mmol) was vigorously stirred
with 3.5% sodium amalgam (2.56 g, 3.9 mmol) under argon atmosphere for
45 min at RT. The salts and mercury were removed by filtration and washed
with dichloromethane (10 mL), and the filtrate was concentrated and
chromatographed (cyclohexane/ethyl acetate 5:5 4:6). After recrystalli-
sation from ethyl acetate, 41 was obtained as white needles. Yield: 152 mg,
74%; m.p. 918C; 1H NM R:d ˆ 1.45 1.47 (m, 4H; H-1', H-2'), 2.02 (s, 1H;
OH), 2.72 (m, 1H; H-4), 3.60 (t, J ˆ 5.8 Hz, 2H; H-3'), 4.56 (d, J ˆ 5.6 Hz,
2H; COOCH2), 4.67 (m, 1H; H-1), 4.88 (d, J ˆ 9.2 Hz, 1H; NH), 5.23 (d,
The d-amino acid amide 45 was isolated in a yield of 20%. MS of 45: no
molecular peak was observed when an ESI or APCI source was used, but a
peak at m/z 179 was identified as corresponding to the elimination of NH3.
MS-MS: m/z (%) 179: 134 (90) [Ph(CH2)2CH NH2] , 117 (10)
[PhCH2CH CH] , 91 (45) [PhCH2] , identical to those observed for the
‡
ˆ
‡
‡
ˆ
cis isomer. Compound 1 shows the same behavior in the MS.
Acknowledgement
ˆ
ˆ
J ˆ 10.9 Hz, 1H; CH2), 5.32 (d, J ˆ 17.2 Hz, 1H; CH2), 5.78 (d, J ˆ
10.2 Hz, 2H; H-2, H-6), 5.85 (d, J ˆ 10.2, 2.4 Hz, 2H; H-3, H-5), 5.91
We thank Dominique Florentin for fruitful discussions, Denis Lesage,
FranÁoise Fournier and Nicole Morin for the mass spectrometry measure-
ments, Francine Acher and Didier Buisson for the chiral chromatography
experiments and Louis Hamon for the molecular modeling. We are grateful
to Aventis CropScience for financial support to O.B. and S.C.
5.98 (m, 1H; CH CH2); 13C NM R:d ˆ 29.25, 30.09 (C-1', C-2'), 35.29 (C-4),
ˆ
ˆ
44.90 (C-1), 63.36 (C-3'), 65.95 (COOCH2), 118.04 ( CH2), 126.27 (C-2,
ˆ
ˆ
C-6), 131.74 (C-3, C-5), 133.25 (CH CH2), 155.70 (C O); elemental
analysis calcd for C13H19O3N: C 65.80, H 8.07, N 5.90; found C 65.77, H 8.05,
N 5.91.
Allyl [4t-(3-oxopropyl)-cyclohexa-2,5-dien-1r-yl]-carbamate (42): Alde-
hyde 42 was prepared, as described for 5, from alcohol 41 (140 mg,
0.59 mmol), oxalyl dichloride (65 mL, 0.71 mmol) and DMSO (100 mL,
1.42 mmol) in dichloromethane (2 mL); quantitative yield. 1H NM R:d ˆ
1.74 (m, 2H; H-1'), 2.33 (m, 2H; H-2'), 2.77 (m, 1H; H-4), 4.50 (d, 2H;
COOCH2), 4.62 (m, 1H; H-1), 4.96 (d, J ˆ 8.6 Hz, 1H; NH), 5.14 (d, J ˆ
[1] Y. Okami, T. Kitahara, M. Hamada, H. Naganawa, S. Kondo, K.
Maeda, T. Takeuchi, H. Umezawa, J. Antibiot. 1974, 27, 656 664.
[2] a) K. H. Baggaley, B. Blessington, C. P. Falshaw, W. D. Ollis, J. Chem.
Soc. Chem. Commun. 1969, 101 102; b) A. Kern, U. Kabatek, G.
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[3] T. Yamada, T. Osawa, S. Kawakishi, S. Udaka, T. Ohta, Mutat. Res.
1993, 286, 293 297.
[4] T. Kitahara, K. Hotta, M. Yoshida, Y. Okami, J. Antibiot. 1975, 28,
215 221.
ˆ
ˆ
10.5 Hz, 1H; CH2), 5.24 (d, J ˆ 17.3 Hz, 1H; CH2), 5.68 5.76 (m, 4H;
ˆ
H-2, H-3, H-5, H-6), 5.85 5.95 (m, 1H; CH CH2), 9.69 (t, J ˆ 1.4 Hz, 1H;
H-3'); 13C NMR: 26.93 (C-1'), 34.22 (C-4), 39.73 (C-2'), 44.51 (C-1), 65.57
ˆ
(COOCH2), 117.63 ( CH2), 127.02 130.33 (C-2, C-3, C-5, C-6), 132.94
ˆ
À ˆ
(CH CH2), 155.56 (N C O), 202.22 (C-3').
Allyl
[4t-(3-amino-3-cyano-propyl)cyclohexa-2,5-dien-1r-yl]-carbamate
[5] K. Hotta, T. Kitahara, Y. Okami, J. Antibiot. 1975, 28, 222 228.
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(43): Amino acid amide 43 was prepared as described for 17, from 42
(140 mg, 0.59 mmol) and trimethylsilyl cyanide (120 mL, 0.89 mmol) in the
presence of a catalytic amount of ZnI2 and a saturated methanolic
ammonia solution (2.5 mL). Chromatography (cyclohexane/ethyl acetate
9:1 0:1) gave 43 as a yellow powder. Yield: 74 mg, 51%; 1H NM R:
d ˆ 1.60 1.70 (m, 4H; H-1', H-2'), 1.80 (m, 2H; NH2), 2.79 2.81 (m, 1H;
H-4), 3.63 (t, J ˆ 7.2 Hz, 1H; H-3'), 4.54 (d, J ˆ 5.5 Hz, 2H; COOCH2), 4.65
(m, 1H; H-1), 4.93 (d, J ˆ 9.2 Hz, 1H; NH), 5.19 (d, J ˆ 10.3 Hz, 1H;
ˆ
ˆ
CH2), 5.27 (d, J ˆ 17.2 Hz, 1H; CH2), 5.77 (m, 4H; H-2, H-3, H-5,
H-6), 5.84 5.94 (m, 1H; CH CH2); 13C NM R:d ˆ 30.62, 31.31 (C-1', C-2'),
ˆ
ˆ
34.47 (C-4), 43.56 (C-3'), 43.56 (COOCH2), 65.68 (C-1), 117.79 ( CH2),
ˆ
122.00 (CN), 126.89, 130.51 (C-2, C-3, C-5, C-6), 132.92 (CH CH2), 155.57
ˆ
(C O).
Aromatic compound 19 was also isolated as a yellow oil in a yield of 40%.
2-Amino-4-(4t-amino-cyclohexa-2,5-dien-1r-yl)-butanenitrile hydrochlor-
ide (44) and 2-Amino-4-(4t-amino-cyclohexa-2,5-dien-1r-yl)-butanamide
hydrochloride (45): Amino nitrile 44 and amide 45 were prepared as
described for 17, from 43 (35 mg, 0.13 mmol), phenylsilane (60 mL,
0.50 mmol) and a solution of Pd(PPh3)4 (10 mg, 0.009 mmol) in dry
dichloromethane (1 mL). Yield: 31 mg (85%) of the mixture of amine
1
hydrochlorides 44 and 45. 44: H NMR (CD3OD): d ˆ 1.77 1.82 (m, 2H;
H-4'), 1.92 1.99 (m, 2H; H-3), 3.09 (m, 1H; H-1'), 4.36 (m, 1H; H-4'), 4.57
(dd, J ˆ 8.7, 5.9 Hz, 1H; H-2), 5.97 6.00 (m, 2H; H-3', H-5'), 6.17 6.21 (m,
2H; H-2', H-6'); 13C NMR (50 MHz, CD3OD): d ˆ 28.35 (C-3), 30.70 (C-4),
35.79 (C-1'), 42.71 (C-4'), 45.68 (C-2), 116.75 (CN), 123.33 (C-3', C-5'),
135.78 (C-2', C-6'). 45: 1H NMR (CD3OD): d ˆ 1.63 1.70 (m, 2H; H-4),
1.80 1.89 (m, 2H; H-3), 3.02 (m, 1H; H-1'), 3.92 (t, J ˆ 6.2 Hz, 1H; H-2),
4.32 (m, 1H; H-4'), 5.93 (d, J ˆ 10.4 Hz, 1H; H-3', H-5'), 6.18 (d, J ˆ
10.4 Hz, 1H; H-2', H-6'); 13C NMR (50 MHz, CD3OD) : 28.70 (C-3),
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¬
[18] N. Thieriet, J. Alsina, E. Giralt, F. Guibe, F. Albericio, Tetrahedron
Lett. 1997, 41, 7275 7278.
Chem. Eur. J. 2002, 8, No. 2
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0449 $ 17.50+.50/0
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A. Marquet et al.
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Received: May 30, 2001 [F3302]
450
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0802-0450 $ 17.50+.50/0
Chem. Eur. J. 2002, 8, No. 2