Formal enantiospecific synthesis of (+)-FR900482

Article abstract of DOI:10.1021/jo0206521

The enantiospecific synthesis of FK973, and thus a formal enantiospecific synthesis of the antitumor antibiotic (+)-FR900482, is reported. Addition of aniline 8 to chiral epoxide 9, prepared from L-vinylglycine, afforded amino alcohol 12. After protection of the aliphatic nitrogen with the 9-phenylfluoren-9-yl group, to preserve the acidic stereocenter from racemization, formation of the aziridine 14 and intramolecular condensation under basic conditions gave azocinone 15. Hydroxymethylation at the benzylic position was achieved by a process involving methylenation, epoxidation, and hydrogenolysis; the absolute stereochemistry of the resulting alcohol 23 was determined by X-ray crystallographic analysis. The hydroxyl group of 23 was carbamoylated, and the aromatic amine was deprotected electrochemically and then oxidized to give an unstable hydroxylamine that was immediately protected as acetate 26. Oxidation of 26 with DMP, followed by hydrazinolysis of the acetyl group led to spontaneous closure of the resulting N-hydroxyamino ketone to hemiketal 28, which can be considered as a fully protected precursor of FR900482 and derivatives. Acid treatment to remove the protecting groups and acetylation afforded the triacetate FK973.

Full text of DOI:10.1021/jo0206521

F or m a l En a n tiosp ecific Syn th esis of (+)-F R900482
M. Rita Paleo,*,‡ Natalia Aurrecoechea, Kang-Yeoun J ung, and Henry Rapoport†
Department of Chemistry, University of California, Berkeley, California 94720, and
Departamento de Quı´mica Orga´nica, Facultad de Qu´ımica, Universidad de Santiago de Compostela,
15782 Santiago de Compostela, Spain
qopaleo@usc.es
Received October 15, 2002
The enantiospecific synthesis of FK973, and thus a formal enantiospecific synthesis of the antitumor
antibiotic (+)-FR900482, is reported. Addition of aniline 8 to chiral epoxide 9, prepared from
L-vinylglycine, afforded amino alcohol 12. After protection of the aliphatic nitrogen with the
9-phenylfluoren-9-yl group, to preserve the acidic stereocenter from racemization, formation of the
aziridine 14 and intramolecular condensation under basic conditions gave azocinone 15. Hydroxy-
methylation at the benzylic position was achieved by a process involving methylenation, epoxidation,
and hydrogenolysis; the absolute stereochemistry of the resulting alcohol 23 was determined by
X-ray crystallographic analysis. The hydroxyl group of 23 was carbamoylated, and the aromatic
amine was deprotected electrochemically and then oxidized to give an unstable hydroxylamine
that was immediately protected as acetate 26. Oxidation of 26 with DMP, followed by hydrazinolysis
of the acetyl group led to spontaneous closure of the resulting N-hydroxyamino ketone to hemiketal
28, which can be considered as a fully protected precursor of FR900482 and derivatives. Acid
treatment to remove the protecting groups and acetylation afforded the triacetate FK973.
In tr od u ction
and stronger antitumor activity. The triacetate 3 is also
isolated as a mixture of isomers, but with form B
predominant (7:79 ratio). This derivative is less toxic and
approximately three times more potent than mitomycin
C against a variety of tumor cells in mice.6a Potent
antitumor activity has recently been reported for FK317
(4) as well, and successful phase I clinical trials make it
the most promising drug candidate in this family. These
semisynthetic derivatives also form interstrand DNA-
DNA and DNA-protein cross-links after being bioacti-
vated in cells.
FR900482 (1) and its dihydro derivative FR66979 (2)
are two potent antitumor agents isolated from Strepto-
myces sandaensis No. 6897.1,2 These compounds possess
an unusual hydroxylamine hemiketal functionality and
appear as a mixture of diastereoisomers in equilibrium
via 5. Form A is favored in neutral or acidic conditions,
probably as the result of an intramolecular hydrogen
bond between the aziridine NH and the bridging hy-
droxylamine oxygen. Both compounds show promising
antitumor activity,3 equal to or greater than that of the
structurally related mitomycin C (6), a compound widely
used in cancer therapy. Intensive studies to define the
mechanisms of their biological activity4 have shown that
reductive activation of FR900482 and FR66979 leads to
an electrophilic, mitosene-like intermediate that, like the
mitomycins, forms interstrand DNA-DNA cross-links.5
Other members of this family, FK973 (3)6 and FK317 (4),7
were obtained by chemical modification of FR900482 in
an effort to develop new drugs with reduced side effects
The unique structure and promising antitumor activi-
ties have made these compounds attractive synthetic
(4) (a) Masuda, K.; Nakamura, T.; Shimomura, K.; Shibata, T.;
Terano, H.; Kohsaka, M. J . Antibiot. 1988, 41, 1497. (b) Williams, R.
M.; Rajski, S. R. Tetrahedron Lett. 1992, 33, 2929. (c) Woo, J .;
Sigurdsson, S. Th.; Hopkins, P. B. J . Am. Chem. Soc. 1993, 115, 1199.
(d) Williams, R. M.; Rajski, S. R. Tetrahedron Lett. 1993, 34, 7023. (e)
Huang, H.; Pratum, T. K.; Hopkins, P. B. J . Am. Chem. Soc. 1994,
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1997, 4, 127. (g) Paz, M. M.; Hopkins, P. B. Tetrahedron Lett. 1997,
38, 343. (h) Paz, M. M.; Hopkins, P. B. J . Am. Chem. Soc. 1997, 119,
5999.
* Address correspondence to this author: qopaleo@usc.es
‡ Universidad de Santiago de Compostela.
(5) For an excellent review on DNA Cross-Linking Agents see:
Rajski, S. R.; Williams, R. M. Chem. Rev. 1998, 98, 2723.
† Deceased March 6, 2002.
(6) (a) Shimomura, K.; Manda, T.; Mukumoto, S.; Masuda, K.;
Nakamura, T.; Mizota, T.; Matsumoto, S.; Nishigaki, F.; Oku, T.; Mori,
J .; Shibayama, F. Cancer Res. 1988, 48, 1166. (b) Masuda, K.;
Nakamura, T.; Mizota, T.; Mori, J .; Shimomura, K. Cancer Res. 1988,
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Manda, T.; Mori, J .; Shimomura, K. J pn. J . Pharmacol. 1989, 49, 317.
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T.; Shimomura, K. J pn. J . Cancer Res. 1998, 89, 1306. (b) Naoe, Y.;
Kawamura, I.; Inami, M.; Matsumoto, S.; Nishigaki, F.; Tsujimoto, S.;
Manda, T.; Shimomura, K. J pn. J . Cancer Res. 1998, 89, 1318. (c) Naoe,
Y.; Inami, M.; Kawamura, I.; Nishigaki, F.; Tsujimoto, S.; Matsumoto,
S.; Manda, T.; Shimomura, K. J pn. J . Cancer Res. 1998, 89, 666.
(1) (a) Uchida, I.; Takase, S.; Kayakiri, H.; Kiyoto, S.; Hashimoto,
M.; Tada, T.; Koda, S.; Morimoto, Y. J . Am. Chem. Soc. 1987, 109,
4108. (b) Iwami, M.; Kiyoto, S.; Terano, H.; Kohsaka, M.; Aoki, H.;
Imanaka, H. J . Antibiot. 1987, 40, 589.
(2) Terano, H.; Takase, S.; Hosoda, J .; Kohsaka, M. J . Antibiot. 1989,
42, 145.
(3) (a) Kiyoto, S.; Shibata, T.; Yamashita, M.; Komori, T.; Okuhara,
M.; Terano, H.; Kohsaka, M.; Aoki, H.; Imanaka, H. J . Antibiot. 1987,
40, 594. (b) Shimomura, K.; Hirai, O.; Mizota, T.; Matsumoto, S.; Mori,
J .; Shibayama, F.; Kikuchi, H. J . Antibiot. 1987, 40, 600. (c) Hirai, O.;
Shimomura, K.; Mizota, T.; Matsumoto, S.; Mori, J .; Kikuchi, H. J .
Antibiot. 1987, 40, 607.
10.1021/jo0206521 CCC: $25.00 © 2003 American Chemical Society
Published on Web 11/26/2002
130
J . Org. Chem. 2003, 68, 130-138

Formal Enantiospecific Synthesis of (+)-FR900482
F IGURE 2.
ners. The aromatic precursor, 8, was easily prepared on
large scale from commercially available 3,5-dinitro-p-
toluic acid following literature procedures.9a,14 The pre-
cursor to the aliphatic portion of the molecule was
prepared from L-methionine methyl ester hydrochloride
following the published procedure for the synthesis of
N-Cbz-L-vinylglycine methyl ester (11).15 Epoxidation of
11 with an excess of m-CPBA gave a 1/4 ratio of anti and
syn isomers of epoxide 9.15a,16 Although complete separa-
tion of the two isomers of 9 can be achieved by prepara-
tive HPLC, we decided to carry the mixture on and
perform the separation by column chromatography at a
later stage.
F IGURE 1.
targets for many research groups;8 many approaches9
have been described, but only two total syntheses10 of
racemic FR900482, one of the enantiomerically pure
material,11 and a formal enantioselective synthesis12 have
been reported to date. We report herein our contribution
to this field by presenting the enantiospecific synthesis
of FK973, which can be considered a formal enantiospe-
cific synthesis of the natural product FR900482.13
The amino alcohol 12 (Scheme 1) was obtained in 90%
yield by regioselective ring-opening17 of epoxide 9 with
aniline 8 in CH3CN in the presence of Mg(ClO4)2. To
preserve the enantiomeric purity of the product through
the next steps in the synthesis, we needed a protecting
group on the aliphatic nitrogen able to inhibit deproto-
nation R to the carbonyl group; for this purpose 12 was
transformed in its N-(9-phenylfluoren-9-yl) derivative.18
Hydrogenolysis of the Cbz group to free the amine was
followed by treatment with PfBr in the presence of K3-
PO4 and Pb(NO3)2 to give a mixture of N,N-diPf (major
component) and N-monoPf (13); the mixture was con-
verted into 13 alone by refluxing in MeOH in the
presence of a catalytic amount of 1 M HCl in 82% overall
yield (1:5 mixture of epimers as determined by 1H NMR).
Cyclization to the aziridine ring and protection of the
aromatic amine occurred in the same step when 13 was
treated with freshly prepared benzenesulfonic anhydride
(Bs2O) in pyridine. At this point, we were able to separate
the syn isomer cleanly from the anti diastereomer,
isolating 14 in 76% yield. Deprotonation at the benzylic
position with KHMDS in THF and intramolecular con-
densation of the resulting carbanion with the aziridino
methyl ester afforded the eight-membered ring 15 in 72%
yield.
Resu lts a n d Discu ssion
Our synthetic approach involved intermolecular cou-
pling of a suitably protected aniline (8) with a chiral
epoxide (9) (see Figure 2) followed by intramolecular
condensation to form the aziridinobenzoazocinone ring
enantiospecifically. We considered compound 15 to be the
key intermediate for synthesis of FR900482 and conge-
(8) Coleman, R. S. Curr. Opin. Drug Discovery Dev. 2001, 4, 435.
(9) (a) J ones, R. J .; Rapoport, H. J . Org. Chem. 1990, 55, 1144 (b)
Yasuda, N.; Williams, R. M. Tetrahedron Lett. 1989, 30, 3397. (c)
Fukuyama, T.; Goto, S. Tetrahedron Lett. 1989, 30, 6491. (d) McClure,
K. F.; Danishefsky, S. J . J . Org. Chem. 1991, 56, 850. (e) McClure, K.
F.; Benbow, J . W.; Danishefsky, S. J . J . Am. Chem. Soc. 1991, 113,
8185. (f) Dmitrienko, G. I.; Denhart, D.; Mithani, S.; Prasad, G. K. B.;
Taylor, N. J . Tetrahedron Lett. 1992, 33, 5705. (g) McClure, K. F.;
Danishefsky, S. J . J . Am. Chem. Soc. 1993, 115, 6094. (h) Martin, S.
F.; Wagman, A. S. Tetrahedron Lett. 1995, 36, 1169. (i) Lim, H.-J .;
Sulikowski, G. A. Tetrahedron Lett. 1996, 37, 5243. (j) Ziegler, F. E.;
Belema, M. J . Org. Chem. 1997, 62, 1083. (k) Rollins, S. B.; Williams,
R. M. Tetrahedron Lett. 1997, 38, 4033. (l) Zhang, W.; Wang, C.;
J imenez, L. S. Synth. Commun. 2000, 30, 351. (m) Williams, R. M.;
Rollins, S. B.; J udd, T. C. Tetrahedron 2000, 56, 521.
(10) (a) Fukuyama, T.; Xu, L.; Goto, S. J . Am. Chem. Soc. 1992, 114,
383. (b) Schkeryantz, J . M.; Danishefsky, S. J . J . Am. Chem. Soc. 1995,
117, 4722.
(11) Total synthesis of natural (+)-FR900482: (a) Katoh, T.; Itoh,
E.; Yoshino, T.; Terashima, S. Tetrahedron Lett. 1996, 37, 3471. (b)
Yoshino, T.; Nagata, Y.; Itoh, E.; Hashimoto, M.; Katoh, T.; Terashima,
S. Tetrahedron Lett. 1996, 37, 3475. (c) Katoh, T.; Yoshino, T.; Nagata,
Y.; Nakatani, S.; Terashima, S. Tetrahedron Lett. 1996, 37, 3479. Total
synthesis of an enantiomeric pair of FR900482: (d) Katoh, T.; Itoh,
E.; Yoshino, T.; Terashima, S. Tetrahedron 1997, 53, 10229. (e)
Yoshino, T.; Nagata, Y.; Itoh, E.; Hashimoto, M.; Katoh, T.; Terashima,
S. Tetrahedron 1997, 53, 10239. (f) Katoh, T.; Nagata, Y.; Yoshino, T.;
Nakatani, S.; Terashima, S. Tetrahedron 1997, 53, 10253. (g) For the
enantioselective synthesis of FR900482 analogues see: Kambe, M.;
Arai, E.; Suzuki, M.; Tokuyama, H.; Fukuyama, T. Org. Lett. 2001, 3,
2575.
(14) (a) Nielsen, O. B. T.; Bruun, H.; Bretting, C.; Feit, P. W. J . Med.
Chem. 1975, 18, 41. (b) Phenol protection was performed in 98% yield
using H2C(OMe)2 and P2O5 in CH2Cl2 as described: Fuji, K.; Nakano,
S.; Fujita, E. Synthesis 1975, 276.
(15) (a) Shaw, K. J .; Luly, J . R.; Rapoport, H. J . Org. Chem. 1985,
50, 4515. (b) Afzali-Ardakani, A.; Rapoport, H. J . Org. Chem. 1980,
45, 4817. (c) Carrasco, M.; J ones, R. J .; Kamel, S.; Truong, T.; Rapoport,
H. Org. Synth. 1991, 70, 29.
(16) Truong, T.; Rapoport, H. J . Org. Chem. 1993, 58, 6090.
(17) Chini, M.; Crotti, P.; Macchia, F. Tetrahedron Lett. 1990, 31,
4661.
(12) Fellows, I. M.; Kaelin, D. E., J r.; Martin, S. F. J . Am. Chem.
Soc. 2000, 122, 10781.
(13) The conversion of FK973 to FR900482 by simple treatment with
aqueous NaHCO3 has been described; see ref 1a.
(18) (a) Christie, B. D.; Rapoport, H. J . Org. Chem. 1985, 50, 1239.
(b) Feldman, P. L.; Rapoport, H. J . Org. Chem. 1986, 51, 3882.
J . Org. Chem, Vol. 68, No. 1, 2003 131

Paleo et al.
SCHEME 1a
a
Reagents: (a) Mg(ClO4)2, CH3CN (90%). (b) (i) H2, Pd-C, (ii) PfBr, (iii) MeOH, cat. HCl (82%). (c) Bs2O (76%). (d) KHMDS (72%). (e)
LiAlH4, THF (97%). (f) (COCl)2, DMSO, Et3N (94%). (g) HC(OEt)3, p-TsOH (93%). (h) (H2CO)n, Triton B (97%). (i) H2O2, TBAF (80%, 19)
or TBHP, Triton B (77%, 22). (j) H2, Pd-C, Py (90%).
Hydroxymethylation of 15 was more difficult than
expected. Alkylation of the enolate generated by treat-
ment with bases such as KHMDS, LDA, NaH, or Triton
B followed by addition of an electrophile (SEMCl, BOMCl,
p-formaldehyde, or trioxane) afforded mainly O-alkylated
products. Trapping the enolate with TBSCl and then
treating it with TBAF followed by SEMCl failed, as did
aldol-type condensations of the enol silyl ether with
dibenzyloxymethane catalyzed by TMSOTf,19 or reactions
using Mukaiyama’s conditions.20 Also unsuccessful was
direct condensation with formaldehyde and LiOH in
THF/H2O.10a Nevertheless, when 15 was treated with
p-formaldehyde and Triton B,21 some hydroxymethylated
product 20 was isolated. Unfortunately, although a
number of variations in concentration, temperature, time,
and base were explored in attempts to increase the yield,
enone 18 was always the main product. When the
reaction was performed at 65 °C for 1 h using Triton B
as base, 18 was isolated in almost quantitative yield
(97%). Since elimination of water under the reaction
conditions proved to be so facile, we decided to investigate
the possibility of functionalizing the enone to obtain the
desired alcohol 20.
reduction of R,â-epoxyketones to â-hydroxyketones, sev-
eral methods and reagents have been reported. Although
treatment with PhSeNa25 or NaI/NaOAc26 were unsuc-
27
cessful, better results were obtained by using SmI2 in
a 2:1 mixture of THF:MeOH, which afforded alcohol 20
in 63% yield. Attempts to increase the yield of 20 were
fruitless, with the enone elimination product again
forming as the main side product. As an alternative, we
investigated catalytic hydrogenolysis for reduction of
epoxide 19 to the desired alcohol 20. Hydrogenation of
19 in MeOH with Pd/C as the catalyst gave a complex
mixture, but we observed that the addition of some
inorganic salts slowed the reduction process and made
it more selective. Finally, we found that by adding
pyridine to the reaction mixture, we could isolate the
hydroxymethyl derivative 20 in 92% yield.
At this point, we reconsidered our synthetic strategy
and thought it more convenient to reduce the aromatic
ester to the corresponding aldehyde oxidation level of the
final target before undertaking the hydroxymethylation
sequence. LAH reduction of 15 in THF gave a diol (97%),
which was oxidized to the keto aldehyde 16 under Swern
conditions28 in 94% yield. The aldehyde could be protected
selectively as the diethyl acetal 17 in 93% yield by
treatment with triethyl orthoformate in THF/ethanol in
the presence of p-TsOH. The diethyl acetal was chosen
over the dimethyl analogue since we encountered solubil-
ity problems with the latter derivative.
1,4-Addition of oxygenated nucleophiles22 (KOAc,
NaOBn) to the enone 18 and the alkoxymercuration
reaction23 with benzyl alcohol as the nucleophile both
failed to functionalize the enone at the 4-position. Ep-
oxidation of 18 with tert-butyl hydroperoxide (TBHP) or
H2O2 was then explored, with the best result obtained
with H2O2 and TBAF as the base in DMSO24 (80% yield
of 19, 89% based on recovered starting material). For the
Reaction of ketone 17 with p-formaldehyde and Triton
B afforded enone 21 in 97% yield. The best conditions
for the epoxidation of 18 did not apply to acetal 21,
(19) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron Lett. 1980, 21,
2527.
(20) Mukaiyama, T. Angew. Chem., Int. Ed. Engl. 1977, 16, 817.
(21) Avramoff, M.; Sprinzak, Y. J . Org. Chem. 1961, 26, 1284.
(22) Mulzer, J .; Kappert, M.; Huttner, G.; J ibril, I. Angew. Chem.,
Int. Ed. Engl. 1984, 23, 704.
(25) (a) Miyashita, M.; Suzuki, T.; Yoshikoshi, A. Tetrahedron Lett.
1987, 28, 4293. (b) Takano, S.; Shimazaki, Y.; Sekiguchi, Y.; Ogasawara,
K. Synthesis 1989, 539.
(26) Paulsen, H.; Eberstein, K.; Koebernick, W. Tetrahedron Lett.
1974, 271.
(23) Thaisrivongs, S.; Seebach, D. J . Am. Chem. Soc. 1983, 105,
7407.
(24) Miyashita, M.; Suzuki, T.; Yoshikoshi, A. Chem. Lett. 1987, 285.
(27) Molander, G. A.; Hahn, G. J . Org. Chem. 1986, 51, 2596.
(28) Mancuso, A. J .; Huang, S.-L.; Swern, D. J . Org. Chem. 1978,
43, 2480.
132 J . Org. Chem., Vol. 68, No. 1, 2003

Formal Enantiospecific Synthesis of (+)-FR900482
SCHEME 2a
a
Reagents: (a) (i) Cl3CCONCO, (ii) NaBH4 (80%). (b) 2e- (91%). (c) (i) Davis’ oxaziridine (63%), (ii) Ac2O, NaOAc (92%). (d) DMP
(91%). (e) NH2NH2 (97%). (f) (i) TFA, Et3SiH. (ii) Ac2O, Py (52%).
because the reaction became extremely slow. However,
upon treatment with TBHP and Triton B29 a mixture of
epoxides was obtained, the major one being isolated in
77% yield (22). The minor epoxide was easily recycled to
enone 21 by treatment with SmI2 in THF (82% yield).
Catalytic hydrogenation of 22 was again successfully
applied to give 23 in 90% isolated yield. Interestingly,
hydrogenolysis of the benzylic acetal was not observed
and the overreduction of the hydroxymethyl group to
yield acceptable (63%). Immediately, the unstable hy-
droxylamine was selectively protected with Ac2O/NaOAc
to give acetoxyamine 26 in 92% yield. Oxidation of the
hydroxyl group of 26 to the ketone under Swern condi-
tions, PDC or P2O5/DMSO failed, resulting mainly in the
recovery of starting material. The Dess-Martin perio-
dinane (DMP)38 in CH2Cl2 was much more effective,
affording keto-carbamate 27 in 91% yield.
Removal of the four different protecting groups was the
only task remaining. Hydrolysis of the N-OAc group was
easily accomplished with hydrazine in a 1:1 mixture of
CH2Cl2:MeOH to give spontaneously the hemiacetal 28
in almost quantitative yield. Finally, 28 was converted
into FK973 with TFA:CH2Cl2 in the presence of Et3SiH,
followed by acetylation with Ac2O in pyridine. The
product obtained was compared with a sample of au-
thentic FK973, prepared by treatment of natural FR90-
0482 with acetic anhydride/pyridine,1a showing identical
properties (TLC, spectroscopic data).
The utility of this synthetic route rests on the relevance
of 28 as a precursor to every member of the FR900482
family by careful manipulation of the protected functional
groups. Several selective deprotection methods were also
investigated with acetate 29, obtained from 28 by treat-
ment with Ac2O and DMAP in pyridine. The most
interesting result was the selective removal of the phen-
ylfluorenyl group, which was cleanly achieved by reduc-
tion of 29 with sodium naphthalenide in DME to give 30
(95% yield after column chromatography). This result
suggests that this synthetic protocol could also be applied
to the synthesis of FK317, starting with an aniline in
which the phenolic hydroxyl is protected as a methyl39
instead of methoxymethyl ether. In summary, a formal
enantiospecific synthesis of the antitumor antibiotic (+)-
30
methyl (observed when NaHCO3 was added to the
reaction mixture) was again avoided by using pyridine.
The stereochemistry of 23 was determined unambigu-
ously by X-ray crystallography.31
Carbamoylation of 23 was achieved by treatment with
trichloroacetyl isocyanate32 at 0 °C, followed by addition
of a solution of NH3 in methanol (65% yield). When
electrolysis was applied to remove the benzenesulfonyl
group of the resulting ketocarbamate, the main product
isolated was enone 21. To prevent base-induced33 elimi-
nation of the carbamate, the ketone was reduced first,
to give alcohol 24 (Scheme 2) in which there is no center
sensitive to base. Treatment of 23 with trichloroacetyl
isocyanate32,34 in THF followed by reduction with NaBH4
in EtOH gave 24 in 80% yield. The benzenesulfonyl group
was now reduced electrochemically35 and 25 was isolated
in 91% yield. Oxidation of the amine to hydroxylamine
was attempted with m-CPBA and MMPP36 under differ-
ent conditions, but only with Davis’ oxaziridine37 was the
(29) Yang, N. C.; Finnegan, R. A. J . Am. Chem. Soc. 1958, 80, 5845.
(30) Corey, E. J .; Nicolau, K. C.; Melvin, L. S., J r. J . Am. Chem.
Soc. 1975, 97, 654.
(31) The authors have deposited the crystallographic data for this
structure with the Cambridge Crystallographic Data Centre, deposition
number CCDC 192884. These data can be obtained free of charge via
www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12
Union Road, Cambridge CB2 1EZ, UK; fax +44 1223 336033; e-mail
deposit@ccdc.cam.ac.uk).
(32) Deng, M.-Z.; Caubere, P.; Senet, J . P.; Lecolier, S. Tetrahedron
1988, 44, 6079.
(33) Phenol is normally added to the electrolysis medium as a proton
source and bromine scavenger.
(36) Brougham, P.; Cooper, M. S.; Cummerson, D. A.; Heaney, H.;
Thompson, N. Synthesis 1987, 1015.
(37) (a) Zajac, W. W., J r.; Walters, T. R.; Darcy, M. G. J . Org. Chem.
1988, 53, 5856. (b) Davis. F. A.; Sheppard, A. C. Tetrahedron 1989,
45, 5703.
(34) Weygand, F.; Frauendorfer, E. Chem. Ber. 1970, 103, 2437.
(35) (a) Roemmele, R. C.; Rapoport, H. J . Org. Chem. 1988, 53, 2367.
(b) Civitello, E. R.; Rapoport, H. J . Org. Chem. 1992, 57, 834. (c) Peterli-
Roth, P.; Maguire, M. P.; Leo´n, E.; Rapoport, H. J . Org. Chem. 1994,
59, 4186.
(38) (a) Dess, D. B.; Martin, J . C. J . Am. Chem. Soc. 1991, 113, 7277.
(b) Ireland, R. E.; Liu, L. J . Org. Chem. 1993, 58, 2899. (c) Meyer, S.
D.; Schreiber, S. L. J . Org. Chem. 1994, 59, 7549.
(39) Harris, C. M.; Kibby, J . J .; Fehlner, J . R.; Raabe, A. B.; Barber,
T. A.; Harris, T. M. J . Am. Chem. Soc. 1979, 101, 437.
J . Org. Chem, Vol. 68, No. 1, 2003 133

Paleo et al.
1
3480 cm-1; H NMR δ 7.16 (d, J ) 1.3 Hz, 1H), 7.09 (d, J )
1.3 Hz, 1H), 5.21 (s, 2H), 3.86 (s, 3H), 3.77 (br s, 2H), 3.49 (s,
3H), 2.10 (s, 3H); 13C NMR δ 167.1, 155.4, 145.6, 128.5, 116.7,
110.2, 105.3, 94.6, 56.1, 51.9, 9.5. Anal. Calcd for C11H15NO4:
C, 58.66; H, 6.71; N, 6.22. Found: C, 58.40; H, 6.71; N, 6.16.
FR900482 has been developed13 in a convergent manner
from aniline 8 and methyl (2S,3S)-2-[(benzyloxycarbo-
nyl)amino]-3,4-epoxybutanoate.
Exp er im en ta l Section
Meth yl (2R,3S)-3-[N-[3-[N-(Ben zyloxyca r bon yl)a m in o]-
2-h y d r o x y -4-m e t h o x y -4-o x o b u t y l]a m i n o ]-5-m e t h -
oxym eth oxy-4-m eth ylben zoa te (12). Mg(ClO4)2 (9.0 g, 0.04
mol) was added to a stirred solution of aniline 8 (9.0 g, 0.04
mol) in freshly distilled CH3CN (40 mL) at room temperature.
When the mixture became homogeneous, a 0.33 M solution of
9 (12.7 g, 0.048 mol) in CH3CN (145 mL) was added via
cannula. The reaction mixture was stirred under argon for 46
h. The solvent was evaporated, the residue was dissolved in
EtOAc (400 mL), and the solution was washed with water (200
mL) and brine (100 mL). The aqueous layers were back-
extracted with EtOAc (2 × 50 mL) and the combined organic
phase was dried and evaporated. The residue was chromato-
graphed (EtOAc-hexane, 1:2) to give 17.6 g of 12 (90% yield):
mp (EtOAc-hexane) 112-113 °C; IR 1720, 1750, 3420, 3600
cm-1; 1H NMR (CDCl3-D2O, main isomer) δ 7.33 (m, 5H), 7.16
(s, 1H), 7.05 (s, 1H), 5.93 (d, J ) 9.1, 1H), 5.20 (s, 2H), 5.14 (s,
2H), 4.60 (br d, J ) 9.1, 1H), 4.38 (br t, J ) 6.1, 1H), 3.85 (s,
3H), 3.71 (s, 3H), 3.48 (s, 3H), 3.40 (dd, J ) 14.0, 6.1, 1H),
3.26 (dd, J ) 14.0, 7.6, 1H), 2.10 (s, 3H); 13C NMR δ 171.4,
167.7, 156.9, 155.1, 146.5, 135.9, 128.44, 128.38, 128.1, 127.9,
116.6, 104.9, 104.8, 94.6, 69.4, 67.2, 56.2, 56.0, 52.6, 51.9, 45.7,
9.3. Anal. Calcd for C24H30N2O9: C, 58.77; H, 6.16; N, 5.71.
Found: C, 59.12; H, 6.40; N, 5.89.
Meth od s a n d Ma ter ia ls. All reactions requiring anhydrous
conditions were conducted in flame-dried glassware under an
atmosphere of argon. Solvents were distilled immediately
before use: THF and Et2O from Na/benzophenone; CH2Cl2,
DMSO, benzene, pyridine, and Et3N from CaH2; and MeOH
from Mg(OCH3)2. CH3CN was distilled first from P2O5 and then
from CaH2. K3PO4 and Pb(NO3)2 were dried in a muffle furnace
at 250 °C and cooled in a desiccator under nitrogen before use.
Tetraethylammonium bromide (TEAB) was recrystallized four
times from absolute EtOH and dried overnight in a Kugelrohr
oven at 100 °C under vacuum. Phenol was distilled (80 °C at
20 mmHg) and kept in the dark under nitrogen. 3-Hydroxy-
4-methyl-5-nitrobenzoic acid was prepared as described.14
Final reaction mixtures were dried over anhydrous Na2SO4
before filtration and evaporation under reduced pressure.
Column chromatography was performed with 230-400 mesh
silica gel. Melting points (open-ended capillary tubes) are
uncorrected. IR spectra were obtained in CH2Cl2, and NMR
spectra were obtained in CDCl3 at room temperature unless
otherwise stated. NMR chemical shifts are reported in ppm
(δ) downfield from internal TMS; coupling constants are given
in hertz. Elemental analyses were determined by the Mi-
croanalytical Laboratories, and X-ray crystallography was
carried out by the CHEXRAY Facility, College of Chemistry,
University of California, Berkeley.
Meth yl (2R,3S)-3-[N-[2-Hyd r oxy-4-m eth oxy-4-oxo-3-[N-
(9-p h e n y lflu o r e n -9-y l)a m in o ]b u t y l]a m in o ]-5-m e t h -
oxym eth oxy-4-m eth ylben zoa te (13). A mixture of 12 (16.3
g, 33.3 mmol) in distilled MeOH (220 mL) and 3.25 g of 10%
Pd-C was stirred under hydrogen atmosphere overnight at
room temperature. The mixture was filtered through Celite
and the pad was washed thoroughly with MeOH and CH2Cl2.
The solvent was evaporated, toluene (10 mL) was added and
evaporated, and the solid residue obtained was vacuum-dried,
kept under nitrogen, and dissolved in anhydrous CH3CN (60
mL). This solution was transferred via cannula to a Morton
flask, and K3PO4 (14.1 g, 0.066 mol) and Pb(NO3)2 (11.02 g,
0.033 mol) were added, followed by a solution of PfBr (21.36
g, 0.066 mmol) in CH3CN (50 mL). The resulting suspension
was stirred under argon at room temperature for 36 h, and
the supernatant was transferred via cannula to a flask. The
solid residue was triturated with CH2Cl2 (100 mL) for 15 min
and the mixture was filtered through a glass frit funnel (10-
15 size pore), and the process was repeated several times.
Evaporation of the solvents gave a solid that was purified
through a short silica gel column (CH2Cl2) to eliminate the
excess of PfBr. The mixture of N,N-diPf and N-monoPf
products was suspended in 500 mL of MeOH and treated with
1 M HCl (2.5 mL). The reaction mixture was heated at reflux
for 1 h, the solvent was evaporated, and the residue column
was chromatographed (CH2Cl2 to 10% Et2O/CH2Cl2) to yield
the product as a white solid (16.26 g, 82% yield): mp 92-93
Meth yl 3-Hyd r oxy-4-m eth yl-5-n itr oben zoa te. A solution
of 3-hydroxy-4-methyl-5-nitrobenzoic acid (12.0 g, 0.061 mol)
and concentrated H2SO4 (1.5 mL) in MeOH (250 mL) was
refluxed for 20 h and cooled to room temperature and the
solvent was evaporated. The residue was dissolved in (3:1)
CHCl3-iPrOH (150 mL) and washed with water (3 × 100 mL).
The aqueous layers were extracted with (3:1) CHCl3-iPrOH
(100 mL), and the combined organic phase was dried and
evaporated. The residue was recrystallyzed from CH2Cl2-
hexane or column chromatographed (5%Et2O in CH2Cl2) to
yield 12.3 g (96% yield): mp 159-160 °C; IR 1530, 1720, 3565
1
cm-1; H NMR (MeOD) δ 7.79 (d, J ) 1.4, 1H), 7.55 (d, J )
1.4, 1H), 4.92 (br s, 1H), 3.91 (s, 3H), 2.32 (s, 3H); 13C NMR
(MeOD) δ 166.5, 158.2, 152.1, 129.8, 126.0, 119.2, 116.4, 52.9,
12.0. Anal. Calcd for C9H9NO5: C, 51.19; H, 4.30; N, 6.63.
Found: C, 50.82; H, 4.33; N, 6.46.
Meth yl 3-Meth oxym eth oxy-4-m eth yl-5-n itr oben zoa te.
To a stirred solution of methyl 3-hydroxy-4-methyl-5-nitroben-
zoate (12.0 g, 57.0 mmol) in a 1:1 mixture of distilled CH2Cl2
(150 mL) and dimethoxymethane (150 mL) under argon was
added P2O5 (16.2 g, 114 mmol) in small portions over a period
of 1 h. The mixture was stirred overnight at room temperature,
poured into an ice-cooled 10% Na2CO3 solution (150 mL), and
extracted with ether (400 mL). The organic layer was washed
with water (2 × 100 mL), dried, and evaporated, and the
residue was chromatographed (CH2Cl2) to give 14.2 g of
product as a white solid (98% yield): mp 66-67 °C; IR 1525,
1
°C; IR 1710, 3440, 3680 cm-1; H NMR (CDCl3-D2O) δ 7.69
(t, J ) 7.9, 2H), 7.42-7.13 (m, 12 H), 6.84 (s, 1H), 5.18 (s, 2H),
3.84 (s, 3H), 3.69 (dd, J ) 11.2, 5.6, 1H), 3.47 (s, 3H), 3.31 (s,
3H), 3.14 (dd, J ) 12.7, 4.5, 1H), 2.97 (dd, J ) 12.7, 5.6, 1H),
2.71 (d, J ) 6.7, 1H), 1.86 (s, 3H); 13C NMR δ 174.6, 167.4,
154.8, 148.0, 147.8, 146.8, 143.4, 141.0, 140.1, 128.8, 128.6,
128.4, 128.2, 127.5, 127.4, 126.1, 125.8, 125.1, 120.2, 120.1,
116.6, 105.3, 105.1, 94.7, 72.5, 70.1, 57.5, 56.1, 52.0, 51.9, 45.7,
9.4. Anal. Calcd for C35H36N2O7: C, 70.45; H, 6.08; N, 4.69.
Found: C, 70.61; H, 6.15; N, 4.77.
1
1720 cm-1; H NMR δ 8.12 (d, J ) 1.4, 1H), 7.92 (d, J ) 1.4,
1H), 5.32 (s, 2H), 3.95 (s, 3H), 3.51 (s, 3H), 2.44 (s, 3H); 13C
NMR δ 165.0, 156.1, 150.9, 129.2, 127.6, 118.1, 117.6, 94.8,
56.4, 52.6, 12.1. Anal. Calcd for C11H13NO6: C, 51.77; H, 5.13;
N, 5.49. Found: C, 51.47; H, 5.21; N, 5.48.
Meth yl 3-Am in o-5-m eth oxym eth oxy-4-m eth ylben zoa te
(8). A mixture of 10.0 g of the nitrobenzoate (0.04 mol) and
2.0 g of 10% Pd/C catalyst in 175 mL of distilled MeOH was
shaken under hydrogen (60 psi) for 2 h at room temperature.
The mixture was filtered through a Celite pad, which was
washed thoroughly with MeOH and CH2Cl2, and the combined
fractions were evaporated. The residue was chromatographed
(3% MeOH in CH2Cl2) to yield 8.4 g of 8 (95%) which should
be kept under argon in the fridge: mp 98-99 °C; IR 1710,
P r ep a r a tion of Ben zen esu lfon ic An h yd r id e (Bs2O).
Benzenesulfonic acid monohydrate (40 g, 0.25 mol) was
suspended in benzene (100 mL) and thionyl chloride (64 mL,
0.88 mol) was added slowly. The reaction mixture was heated
at reflux for 3 h, then the excess of SOCl2 and benzene was
distilled off under argon, the brown residual solution was
134 J . Org. Chem., Vol. 68, No. 1, 2003

Formal Enantiospecific Synthesis of (+)-FR900482
allowed to cool, dry Et2O (30 mL) and hexane (15 mL) were
added, and the solution was kept in the refrigerator overnight.
The white crystals were filtered under nitrogen and dried (75%
yield).
mL) was added, followed by sat. Na2CO3 (5 mL), CHCl3 (150
mL), KH2PO4, and Na2SO4. The resulting mixture was stirred
at room temperature for 1 h and then filtered. The precipitate
was washed with CHCl3, the combined clear filtrate and
washings were evaporated, and the residue was chromato-
graphed (10% Et2O-CH2Cl2) to give 31 as a white solid (5.13
Meth yl (2S,3S)-3-[N-[1-Ben zen esu lfon yl-4-m eth oxy-4-
oxo-(2,3)-[N-(9-ph en ylflu or en -9-yl)azir idin o]bu tyl]am in o]-
5-m eth oxym eth oxy-4-m eth ylben zoa te (14). To a solution
of 13 (15.0 g, 25.1 mmol) in 120 mL of pyridine was added
freshly prepared Bs2O (18.75 g, 62.9 mmol). The reaction
mixture was heated at 65 °C for 14 h, then cooled to room
temperature, and the pyridine was removed under vacuum.
Toluene was added and evaporated to remove traces of
pyridine. The residue was washed with water (250 mL) and
extracted with ether (3 × 200 mL). The combined organic
phase was dried and concentrated, and the crude product was
chromatographed (20 to 30% EtOAc in hexane) to give 14 as
a white solid (13.73 g, 76% yield): mp 82-86 °C; [R]20D -14.3°
1
g, 97% yield). 31a : mp (EtOH) 204-207 °C dec; H NMR δ
7.64-7.13 (m, 19 H), 6.96 (s, 1H), 6.89 (br s, 1H), 5.07 (m, 2H),
4.57 (d, J ) 5.5, 2H), 4.48 (dd, J ) 12.6, 4.3, 1H), 3.81 (br m,
1H), 3.40 (br m, 1H), 3.35 (s, 3H), 2.90 (d, J ) 4.3, 1H, OH),
2.63 (br s, 1H), 2.05 (br s, 1H), 1.78 (br s, 1H, OH), 1.24 (br s,
1H); 13C NMR δ 154.7, 147.9, 144.8, 142.7, 141.3, 140.4, 139.5,
138.2, 132.8, 128.9, 128.8, 128.7, 128.3, 128.0, 127.5, 127.2,
127.1, 126.4, 126.1, 125.0, 122.7, 120.0, 119.9, 111.7, 94.2, 75.1,
64.2, 63.7, 56.0, 53.3, 51.7, 38.6, 30.2. Anal. Calcd for
C
39H36N2O6S: C, 70.89; H, 5.49; N, 4.24. Found: C, 70.56; H,
1
5.52; N, 4.14. 31b: mp (CH2Cl2-EtOH) 202-204 °C dec; H
NMR δ 7.5-6.98 (m, 20 H), 6.22 (br s, 1H), 5.09 (br s, 2H),
4.66 (br s, 1H), 4.44 (br s, 2H), 4.19 (br m, 1H), 3.65 (br m,
1H), 3.38 (s, 3H), 2.80 (br m, 1H), 2.73 (br m, 1H), 1.24 (br s,
2H), 1.16 (br s, 1H); 13C NMR δ 155.7, 148.5, 145.7, 143.3,
141.2, 140.3, 140.1, 138.8, 138.2, 132.8, 129.3, 128.9, 128.8,
128.3, 127.9, 127.4, 127.2, 126.8, 126.0, 125.4, 120.3, 120.1,
112.8, 94.7, 75.5, 70.9, 64.3, 56.2, 52.1, 43.2, 34.9, 30.6. Anal.
Calcd for C39H36N2O6S: C, 70.89; H, 5.49; N, 4.24. Found: C,
71.09; H, 5.45; N, 4.20.
1
(c 1.0, CHCl3); IR 1720 cm-1; H NMR (2 rotamers) δ 7.70-
7.05 (m, 38 H), 6.92 (d, J ) 1.2, 1H), 6.76 (d, J ) 1.2, 1H),
5.26-5.18 (m, 4H), 3.82 (s, 3H), 3.81 (m, 1H), 3.79 (s, 3H), 3.64
(m, 2H), 3.48 (s, 3H), 3.46 (s, 3H), 3.39 (s, 3H), 3.33 (dd, J )
14.8, 8.7, 1H), 3.19 (s, 3H), 2.20 (d, J ) 6.1, 1H), 2.15 (d, J )
6.1, 1H), 2.09 (m, 1H), 2.07 (s, 3H), 1.98 (s, 3H), 1.77 (m, 1H);
13C NMR (2 rotamers) δ 169.3 and 169.1, 165.9 and 165.8,
155.9, 147.0 and 146.9, 145.2 and 145.0, 142.4 and 142.3, 141.1
and 141.0, 140.2 and 139.9, 139.7 and 139.1, 138.9 and 137.9,
135.3 and 134.7, 132.9 and 132.7, 129.0 and 128.9, 128.87 and
128.85, 128.78 and 128.4, 128.2, 127.8 and 127.7, 127.62 and
127.58, 127.4, 127.2 and 127.1, 126.8 and 126.7, 126.1 and
126.0, 125.7 and 125.6, 123.7 and 123.0, 120.1, 119.9 and 119.8,
114.0 and 113.8, 94.3, 75.4, 56.2, 52.1 and 52.0, 51.8 and 51.5,
50.6 and 49.1, 39.6 and 38.9, 37.7 and 37.4, 12.3 and 11.9.
Anal. Calcd for C41H38N2O8S: C, 68.51; H, 5.33; N, 3.90.
Found: C, 68.24; H, 5.32; N, 3.97.
(3S,4S)-1-Ben zen esu lfon yl-7-m et h oxym et h oxy-5-oxo-
(3,4)-[N-(9-ph en ylflu or en -9-yl)azir idin o]-1,2,3,4,5,6-h exah y-
d r oben zo[b]a zocin e-9-ca r ba ld eh yd e (16). DMSO (2.4 mL,
33.8 mmol) was added to a solution of (COCl)2 (1.4 mL, 16.0
mmol) in CH2Cl2 (75 mL) at -78 °C. After 15 min, diol 31 (5.0
g, 7.57 mmol) in 75 mL of CH2Cl2 was added and the mixture
was stirred for 3 h at -78 °C. Triethylamine (10.5 mL, 75.7
mmol) was added slowly and the mixture was stirred for 10
min at -78 °C and then warmed to room temperature. Ice
water (100 mL) was added, the layers were separated, and
the aqueous phase was extracted with CH2Cl2 (3 × 100 mL).
The combined organic layer was washed with brine, dried, and
evaporated to give a residue that was chromatographed (30%
EtOAc-hexane) to yield 4.67 g of 16 (94%): mp 137-140 °C;
Meth yl (3S,4S)-1-Ben zen esu lfon yl-7-m eth oxym eth oxy-
5-oxo-(3,4)-[N-(9-p h en ylflu or en -9-yl)a zir id in o]-1,2,3,4,5,6-
h exa h yd r oben zo[1,2-b]a zocin -9-ca r boxyla te (15). To a
-20 °C solution of 14 (12.0 g, 16.7 mmol) in 300 mL of THF
was added KHMDS (76 mL, 83.5 mmol, 1.1 M in THF). The
resulting orange solution was stirred for 2 h as the tempera-
ture warmed from -20 to 3 °C, then poured over a cold mixture
of 1 M KH2PO4 (400 mL) and ether (500 mL). After being
stirred for 10 min, the organic phase was separated and
washed with brine, and the aqueous phase was back extracted
with Et2O (2 × 100 mL). The combined organic phase was
dried and evaporated, and the residue was dissolved in CH2-
Cl2 (∼10 mL) with stirring. EtOH (100 mL) was then added
and the solution was heated at reflux for 10 min; after standing
overnight, a white powder was filtered off and dried. The
mother liquors were concentrated and the residue was chro-
matographed (CH2Cl2) to provide additional product. The solids
from the column and the crystallization were combined to yield
a total of 8.2 g of product as a white solid (72% yield): mp
[R]20 +87.9° (c 1.0, CHCl3); IR 1685 cm-1; 1H NMR δ 9.90 (s,
D
1H), 7.79-7.49 (m, 8H), 7.38-7.05 (m, 5H), 6.95-6.83 (m, 4H),
6.72 (d, J ) 7.5, 1H), 6.61 (d, J ) 7.3, 2H), 5.49 (d, J ) 6.7,
1H), 5.33 (d, J ) 6.7, 1H), 4.32 (dd, J ) 14.3, 3.3, 1H), 3.83 (d,
J ) 18.3, 1H), 3.57 (s, 3H), 3.55 (d, J ) 18.3, 1H), 3.53 (d, J )
14.3, 1H), 2.48 (dd, J ) 6.6, 3.3, 1H), 1.99 (d, J ) 6.6, 1H); 13
C
NMR δ 203.7, 190.2, 155.1, 147.6, 142.6, 142.1, 142.0, 141.3,
139.2, 138.2, 138.0, 135.9, 133.5, 129.3, 129.1, 128.0, 127.7,
127.2, 127.1, 126.4, 126.3, 124.8, 121.2, 120.3, 120.2, 115.1,
95.2, 75.5, 56.7, 48.1, 45.4, 42.7, 42.4. Anal. Calcd for
C
39H32N2O6S: C, 71.33; H, 4.91; N, 4.27. Found: C, 71.16; H,
4.98; N, 4.38.
(3S,4S)-1-Ben zen esu lfon yl-9-d iet h oxym et h yl-7-m et h -
oxym et h oxy-(3,4)-[N-(9-p h en ylflu or en -9-yl)a zir id in o]-
2,3,4,6-tetr a h yd r o-1H-ben zo[1,2-b]a zocin -5-on e (17). To a
solution of aldehyde 16 (4.5 g, 6.86 mmol) in a 1:2 mixture of
EtOH:THF (30 mL) was added p-TsOH (325 mg, 1.71 mmol)
and triethyl orthoformate (10 mL), and the resulting solution
was stirred for 5 h at room temperature. The solvents were
evaporated, the residue was dissolved in CH2Cl2 (200 mL), and
the solution was washed with aq NaHCO3 (100 mL). The
aqueous phase was extracted with CH2Cl2 (2 × 50 mL), the
combined organic phase was washed with H2O (2 × 75 mL),
dried, and evaporated, and the residue was chromatographed
(5% Et2O-CH2Cl2) to yield 4.66 g (93%) of the acetal 17: mp
(CH2Cl2-EtOH) 220-222 °C; [R]20 +89.0° (c 1.0, CHCl3); IR
D
1690, 1720 cm-1
;
1H NMR δ 7.91 (d, J ) 1.4, 1H), 7.64 (m,
5H), 7.51 (t, J ) 7.7, 2H), 7.39-7.30 (m, 2H), 7.17-6.89 (m,
7H), 6.73 (d, J ) 7.5, 1H), 6.62 (d, J ) 7.8, 2H), 5.47 (d, J )
6.6, 1H), 5.30 (d, J ) 6.6, 1H), 4.29 (dd, J ) 14.3, 3.4, 1H),
3.94 (s, 3H), 3.80 (d, J ) 18.1, 1H), 3.56 (s, 3H), 3.51 (d, J )
18.1, 1H), 3.50 (d, J ) 14.3, 1H), 2.47 (dd, J ) 6.6, 3.3, 1H),
1.96 (d, J ) 6.6, 1H); 13C NMR δ 204.1, 165.8, 154.3, 147.7,
142.6, 142.2, 142.1, 140.5, 139.2, 138.1, 136.4, 133.3, 129.4,
129.3, 129.0, 128.7, 128.0, 127.9, 127.8, 127.2, 127.0, 126.4,
126.3, 124.9, 121.5, 120.3, 120.1, 115.3, 95.1, 75.4, 56.6, 52.4,
48.0, 45.3, 42.5, 42.4. Anal. Calcd for C40H34N2O7S: C, 69.96;
H, 4.99; N, 4.08. Found: C, 69.61; H, 5.22; N, 4.06.
(CH2Cl2-EtOH) 142-144 °C; [R]20 +80.0° (c 0.6, CHCl3); IR
D
(3 S ,4 S )-1 -B e n z e n e s u l fo n y l -5 -h y d r o x y -7 -m e t h -
oxym et h oxy-(3,4)-[N-(9-p h en ylflu or en -9-yl)a zir id in o]-
1,2,3,4,5,6-h exa h yd r oben zo[1,2-b]a zocin -9-m eth a n ol (31).
Ketone 15 (5.5 g, 8.0 mmol) in 50 mL of THF was added to a
suspension of LiAlH4 (910 mg, 24.0 mmol) in THF (50 mL) at
0 °C. The reaction mixture was stirred for 20 min, EtOAc (15
1690 cm-1; 1H NMR δ 7.67-7.29 (m, 10H), 7.19-6.96 (m, 6H),
6.78 (d, J ) 7.5, 1H), 6.70 (d, J ) 7.2, 2H), 6.43 (s, 1H), 5.43
(s, 1H), 5.40 (d, J ) 6.5, 1H), 5.26 (d, J ) 6.5, 1H), 4.31 (dd, J
) 14.3, 3.5, 1H), 3.78 (d, J ) 17.7, 1H), 3.55 (s, 3H), 3.62-
3.47 (m, 6H), 2.49 (dd, J ) 6.6, 3.4, 1H), 1.97 (d, J ) 6.6, 1H),
1.25 (t, J ) 7.0, 3H), 1.24 (t, J ) 7.0, 3H); 13C NMR δ 205.0,
J . Org. Chem, Vol. 68, No. 1, 2003 135

Paleo et al.
154.3, 147.8, 142.8, 142.3, 142.1, 139.7, 139.2, 139.1, 138.7,
132.9, 130.7, 129.1, 128.8, 128.6, 128.0, 127.9, 127.8, 127.0,
126.9, 126.5, 126.3, 125.1, 120.2, 120.0, 118.2, 113.0, 100.7,
95.1, 75.5, 61.2, 61.1, 56.4, 48.2, 45.3, 42.5, 42.4, 15.2 (2C).
Anal. Calcd for C43H42N2O7S: C, 70.67; H, 5.79; N, 3.83.
Found: C, 70.32; H, 5.87; N, 3.80.
aqueous phase was extracted four times with Et2O and the
combined organic layer was dried and evaporated. The residue
was purified by column chromatography (EtOAc:hexane, 2:3)
to yield 1.77 g of enone 21 (82% yield). A very little amount of
â-hydroxy ketone was isolated (12%).
(3S ,4S )-1-Be n ze n e su lfon yl-9-d ie t h oxym e t h yl-6-h y-
d r oxym eth yl-7-m eth oxym eth oxy-(3,4)-[N-(9-p h en ylflu o-
r en -9-yl)a zir idin o]-2,3,4,6-tetr a h ydr o-1H-ben zo[b]a zocin -
5-on e (23). A suspension of 22 (1.0 g, 1.32 mmol) and 10%
Pd-C (200 mg) in anhydrous methanol (60 mL) and pyridine
(55 µL, 0.68 mmol) was stirred under hydrogen for 3.5 d at 60
psi. The catalyst was removed by filtration and washed
thoroughly with methanol, and the combined filtrate and
washings were evaporated. The residue was chromatographed
(EtOAc-hexane, 2:3) to give 23 as a white foam (905 mg, 90%
yield): mp (EtOAc-hexane) 172-175 °C (softens) 203-206 °C
(3S,4S)-1-Ben zen esu lfon yl-9-d iet h oxym et h yl-7-m et h -
oxym eth oxy-6-m eth ylen e-(3,4)-[N-(9-p h en ylflu or en -9-yl)-
a zir id in o]-2,3,4,6-t et r a h yd r o-1H -b en zo[1,2-b]a zocin -5-
on e (21). Paraformaldehyde (185 mg, 6.16 mmol) was
suspended in DMSO (20 mL) and Triton B (1M solution in
DMSO-MeOH, 820 µL, 0.82 mmol) was added; a homogeneous
solution was obtained after stirring at room temperature for
a couple of minutes. A solution of 17 (3.0 g, 4.1 mmol) in DMSO
(10 mL) was added, and the mixture was heated at 65 °C for
1.5 h. After cooling to room temperature, water was added,
and the mixture was extracted with EtOAc (2 × 100 mL). The
combined organic phase was washed with brine (50 mL), dried,
and evaporated to a white residue that was purified by column
chromatography (5% Et2O-CH2Cl2) to give 21 as a white solid
dec; [R]20 +59.8° (c 1.0, CHCl3); IR 1680 cm-1 1H NMR δ
;
D
7.74-7.31 (m, 10H), 7.20-6.94 (m, 6H), 6.78 (d, J ) 7.5, 1H),
6.66 (m, 2H), 6.40 (d, J ) 1.0, 1H), 5.52 (d, J ) 6.6, 1H), 5.43
(s, 1H), 5.34 (d, J ) 6.6, 1H), 4.50 (m, 1H), 4.23 (dd, J ) 14.1,
3.7, 1H), 3.89 (dd, J ) 8.9, 3.0, 1H), 3.69-3.51 (m, 5H), 3.57
(s, 3H), 3.42 (d, J ) 14.1, 1H), 2.97 (dd, J ) 11.0, 3.6, 1H),
2.51 (dd, J ) 6.7, 3.6, 1H), 2.00 (d, J ) 6.7, 1H), 1.25 (t, J )
7.0, 6H); 13C NMR δ 207.8, 154.8, 147.6, 142.7, 142.3, 142.2,
140.2, 139.9, 139.0, 138.3, 133.3, 130.6, 129.2, 129.1, 128.9,
128.4, 128.1, 127.9, 127.1, 126.9, 126.5, 126.4, 125.1, 120.3,
120.1, 117.7, 112.8, 100.7, 94.7, 75.5, 62.4, 61.34, 61.30, 56.6,
53.2, 48.7, 44.7, 42.6, 15.24, 15.21. Anal. Calcd for
(2.96 g, 97% yield): mp 107-110 °C; [R]20 +11.6° (c 1.0,
D
CHCl3); IR 1680 cm-1; H NMR δ 7.63-7.07 (m, 15 H), 6.85
1
(m, 3H), 6.51 (br m, 2H), 6.37 (br s, 1H), 6.13 (br s, 1H), 5.32-
5.26 (m, 3H), 4.07 (br d, J ) 12.4, 1H), 3.57 (br m, 7H), 3.29
(br d, J ) 13.7, 1H), 2.43 (d, J ) 6.4, 1H), 2.03 (br s, 1H), 1.24
(br m, 6H); 13C NMR δ 197.2, 154.8, 145.9, 145.5, 142.3, 140.6,
140.4, 140.3, 139.8, 137.9, 132.9, 129.7, 128.7, 128.6, 128.1,
127.9, 127.4, 126.8, 126.6, 125.8, 119.8, 117.9, 113.3, 100.5,
95.0, 75.5, 61.1 (2C), 56.5, 48.0, 44.4, 44.1, 15.15, 15.12. Anal.
Calcd for C44H42N2O7S: C, 71.14; H, 5.70; N, 3.77. Found: C,
70.79; H, 5.66; N, 3.66.
C
44H44N2O8S: C, 69.46; H, 5.83; N, 3.68. Found: C, 69.11; H,
5.93; N, 3.67.
(3S,4S)-1-Ben zen esu lfon yl-6-ca r b a m oyloxym et h yl-9-
dieth oxym eth yl-7-m eth oxym eth oxy-(3,4)-[N-(9-ph en ylflu -
or en -9-yl)azir idin o]-1,2,3,4,5,6-h exah ydr oben zo[b]azocin -
5-ol (24). A solution of hydroxyketone 23 (500 mg, 0.66 mmol)
in THF (5 mL) was cooled at 0 °C and treated with trichloro-
acetyl isocyanate (90 µL, 0.75 mmol). The cooling bath was
removed and the solution stirred for 20 min. EtOH was then
added (0.5 mL), the solvents were evaporated, and the residue
was dissolved in EtOH (25 mL), cooled to 0 °C, and treated
with NaBH4 (380 mg, 9.9 mmol). The cooling bath was removed
and the reaction mixture was stirred at room temperature for
22 h. The solution was poured into a 3:1 mixture of CH2Cl2-
pH 7 phosphate buffer (200 mL), the aqueous layer was
neutralized with 1 M KH2PO4, and the organic layer was
separated. The aqueous layer was extracted with CH2Cl2 (2 ×
25 mL), and the combined organic layer was washed with brine
(50 mL), dried, and evaporated. The residue was chromato-
graphed (60% EtOAc-hexane + 1% Et3N) to yield the product
as a white foam (423 mg, 80% yield): mp 118-120 °C; IR 1720,
P r ep a r a tion of Ep oxy Keton e 22. To a stirred solution
of enone 21 (1.7 g, 2.3 mmol) in THF (30 mL) was added 70%
t-BuOOH (350 µL, 2.5 mmol) followed by Triton B (40% in
MeOH, 160 µL, 0.35 mmol). The resulting solution was stirred
for 20 min at room temperature, then partitioned between
water and EtOAc. The organic phase was dried and evapo-
rated, and the residue was chromatographed (2:3 EtOAc-
hexane) to give 1.34 g of the main epoxide 22a (77% yield):
mp (Et2O-CH2Cl2-hexane) 118-121 °C; [R]20 +83.3° (c 1.0,
D
CHCl3); IR 1700 cm-1; 1H NMR δ 7.75 (d, J ) 7.4, 2H), 7.66-
7.59 (m, 3H), 7.49 (m, 2H), 7.34 (m, 3H), 7.15-6.97 (m, 6H),
6.76 (m, 3H), 6.63 (s, 1H), 5.44 (s, 1H), 5.23 (m, 2H), 4.32 (br
d, J ) 4.9, 1H), 4.15 (br d, J ) 13.7, 1H), 3.61-3.45 (m, 8H),
2.57 (br d, J ) 4.8, 1H), 2.42 (br s, 1H), 2.12 (br d, J ) 5.6,
1H), 1.24 (br s, 6H); 13C NMR δ 199.6, 156.1, 147.3, 143.8,
143.4, 142.1, 141.9, 141.6, 139.4, 137.7, 133.2, 129.1, 128.9,
128.7, 128.6, 128.0, 127.6, 127.1, 127.0, 126.5, 126.2, 125.3,
120.2, 120.0, 118.8, 114.4, 100.2, 95.4, 75.4, 61.2, 61.1, 59.3,
56.7, 55.3, 48.8, 45.4, 41.4, 15.1, 15.1. Anal. Calcd for
1
3420, 3525 cm-1. H NMR (∼2:1 mixture of epimers) δ 7.88-
C
44H42N2O8S: C, 69.64; H, 5.58; N, 3.69. Found: C, 69.45; H,
6.98 (m, 40H), 5.28 (s, 1H), 5.27 (s, 1H), 5.12 (s, 2H), 5.03 (d,
J ) 6.9, 1H), 5.01 (d, J ) 6.9, 1H), 4.88 (br t, J ) 10.5, 2H),
4.68 (m, 4H), 4.58-4.26 (m, 3H), 4.19-4.01 (m, 2H), 3.81 (m,
1H), 3.59-3.14 (m, 16H), 2. 90 (m, 1H), 2.68 (m, 1H), 2.49 (m,
1H), 2.35 (m, 1H), 1.81 (br s, 1H), 1.76 (m, 1H), 1.49 (m, 2H),
1.18 (m, 12H). Anal. Calcd for C45H47N3O9S: C, 67.06; H, 5.88;
N, 5.21 Found: C, 67.02; H, 6.08; N, 5.03.
(3S,4S)-6-Ca r b a m oyloxym et h yl-9-d iet h oxym et h yl-7-
m eth oxym eth oxy-(3,4)-[N-(9-p h en ylflu or en -9-yl)a zir id i-
n o]-1,2,3,4,5,6-h exa h yd r oben zo[b]a zocin -5-ol (25). A stan-
dard electrochemical H-cell was assembled using an extra
course frit and rubber seals. The cell was equipped with a
platinum-foil anode, mercury-pool cathode, silver wire refer-
ence electrode, and nitrogen bubbler. Both chambers were
charged with a total 100 mL of a 0.1-0.2 M TEAB solution
and, in addition, solid TEAB was added to the anode chamber
5.87; N, 3.71. Minor epoxide 22b (17%): white crystals, mp
117-119 °C (CH2Cl2-hexane); [R]20D +28.0° (c 1.0, CHCl3); 1H
NMR (CDCl3, 55 °C) δ 7.68 (d, J ) 7.6, 2H), 7.60-7.07 (m,
15H), 6.96 (d, J ) 7.5, 1H), 6.85 (br s, 1H), 6.74 (br s, 1H),
5.37 (s, 1H), 5.15 (d, J ) 6.5, 1H), 5.09 (d, J ) 6.5, 1H), 4.01
(br d, J ) 10.4, 1H), 3.50 (m, 6H), 3.43 (s, 3H), 3.26 (m, 2H),
2.44 (d, J ) 6.4, 1H), 1.18 (q, J ) 7.0, 6H, 1H); 13C NMR
(CDCl3, 55 °C) δ 198.0, 156.1, 147.0, 145.1, 142.4, 141.5, 141.3,
140.8, 140.3, 138.1, 133.0, 128.8, 128.7, 128.4, 128.0, 127.6,
127.4, 126.9, 126.8, 126.4, 125.7, 119.83, 119.81, 114.7, 100.4,
95.7, 75.6, 61.2, 61.16, 58.4, 56.3, 54.1, 49.1, 44.7, 15.1. Anal.
Calcd for C44H42N2O8S: C, 69.64; H, 5.58; N, 3.69. Found: C,
69.30; H, 5.71; N, 3.72.
Recyclin g of 22b (m in or p r od u ct in th e ep oxid a tion
of th e en on e 21 w ith TBHP a n d Tr iton B in THF ). A
solution of epoxide 22b (2.2 g, 2.9 mmol) in a 2:1 mixture of
THF:MeOH at -78 °C was treated with a 0.1 M solution of
SmI2 in THF (Aldrich, 58 mL, 5.8 mmol). The resulting
solution was stirred for 10 min at -78 °C; excess reagent was
quenched by addition of pH 8.0 phosphate buffer (100 mL),
and the mixture was warmed to room temperature. The
to form
a saturated solution. The cathode solution was
deoxygenated with nitrogen for 10 min. Pre-electrolysis at -1.6
V was performed for 5-10 min to achieve a background
current of 0.2 mA. Current to the cell was shut off, phenol
(142 mg, 1.5 mmol) was added and, after degassing for 5 min,
pre-electrolyzed again at -1.6 V to a background current of
136 J . Org. Chem., Vol. 68, No. 1, 2003

Formal Enantiospecific Synthesis of (+)-FR900482
0.5 mA. Current was again turned off and compound 24 (405
mg, 0.5 mmol) was added. After degassing for 5 min, elec-
trolysis was conducted at -1.5 V for 8 h, when no more starting
material was detected by TLC and with the background
current measuring 1.1 mA. The contents of both chambers
were simultaneously poured into two 250-mL Erlenmeyer
flasks positioned side-by-side. The cathode solution was de-
canted from the Hg which was then washed with reagent grade
acetonitrile (25 mL). The combined solution was partitioned
between a 4:1 mixture of CH2Cl2:H2O (300 mL), and the
organic layer was washed with water (2 × 50 mL), dried, and
evaporated. Column chromatography (3% MeOH-CH2Cl2) of
the residue afforded the product as a white solid (305 mg, 91%
yield): mp 113-116 °C; 1H NMR (∼2:1 mixture of epimers) δ
7.64 (m, 4H), 7.39-7.12 (m, 21H), 7.04 (d, J ) 7.4, 1H), 6.69
(s, 1H), 6.56 (s, 1H), 6.41 (s, 1H), 6.34 (s, 1H), 5.28 (s, 1H),
5.26 (s, 1H), 5.17 (t, J ) 6.6, 2H), 5.06 (d, J ) 6.6, 1H), 5.03
(d, J ) 6.6, 1H), 4.75-4.53 (m, 8H), 4.34 (dd, J ) 10.5, 4.9,
1H), 4.03 (m, 1H), 3.71 (m, 6H), 3.61-3.40 (m, 10H), 3.47 (s,
3H), 3.36 (s, 3H), 3.25 (m, 1H), 3.09 (m, 1H), 1.81 (m, 3H),
1.48 (t, J ) 6.6, 1H), 1.19 (t, J ) 7.0, 6H), 1.18 (t, J ) 6.9,
6H); 13C NMR δ 157.1, 157.0, 156.4, 156.1, 149.0, 148.8, 147.9,
145.4, 143.8, 143.1, 141.5, 140.7, 140.5, 139.5, 138.9, 138.5,
128.8, 128.6, 128.4, 128.3, 128.3, 128.1, 127.6, 127.4, 127.1,
127.0, 126.8, 126.6, 126.5, 126.4, 126.1, 125.6, 125.2, 120.0,
119.9, 119.8, 119.6, 115.2, 111.5, 104.3, 101.3, 101.1, 94.9, 94.1,
75.6, 74.9, 73.3, 67.4, 64.3, 61.2, 61.1, 56.6, 56.1, 49.7, 48.7,
44.6, 41.6, 39.1, 39.0, 15.1 (4C). Anal. Calcd for C39H43N3O7:
C, 70.36; H, 6.51; N, 6.31. Found: C, 70.26; H, 6.71; N, 5.94.
7.5, 1H), 7.20-7.04 (m, 6H), 6.83 (d, J ) 7.5, 1H), 6.67 (d, J )
7.0, 2H), 5.60 (s, 1H), 5.45 (d, J ) 6.5, 1H), 5.32 (d, J ) 6.5,
1H), 4.67 (dd, J ) 10.7, 7.2, 1H), 4.47 (br s, 2H), 4.27 (dd, J )
10.7, 2.9, 1H), 3.81-3.63 (m, 6H), 3.57 (m, 1H), 3.56 (s, 3H),
2.50 (dd, J ) 6.7, 4.3, 1H), 1.94 (d, J ) 6.7, 1H), 1.93 (s, 3H),
1.34 (t, J ) 7.0, 6H); 13C NMR δ 201.3, 167.4, 156.8, 153.9,
150.0, 148.2, 142.5, 142.4, 142.3, 140.6, 138.9, 129.1, 128.6,
128.0, 127.8, 126.9, 126.8, 126.5, 125.2, 124.9, 120.2, 119.9,
113.9, 111.8, 101.3, 95.1, 75.4, 63.3, 61.6, 61.5, 56.5, 56.4, 48.4,
41.9, 41.6, 19.3, 15.2 (2C). Anal. Calcd for C41H43N3O9: C,
68.22; H, 6.00; N, 5.82. Found: C, 68.10; H, 6.11; N, 5.87.
P r ep a r a tion of 28. A solution of 27 (60 mg, 0.08 mmol) in
a 1:1 mixture of CH2Cl2:MeOH (3 mL) was cooled to 0 °C,
hydrazine monohydrate was added (2 drops), and the solution
was stirred for 30 min, The solvent was evaporated, the residue
was dissolved in CH2Cl2 (10 mL), and the solution was washed
with water (4 × 5 mL), dried, and concentrated, and the
residue was chromatographed (40% EtOAc:hexane) to afford
the product in 97% yield (55 mg): mp 110-112 °C; [R]20
D
+90.5° (c 1.4, CHCl3); 1H NMR δ 7.68 (d, J ) 7.5, 1H), 7.62 (d,
J ) 7.5, 1H), 7.37 (t, J ) 7.5, 1H), 7.31 (t, J ) 7.5, 1H), 7.17-
7.01 (m, 6H), 6.90 (d, J ) 7.5, 1H), 6.85 (d, J ) 7.5, 1H), 6.77
(m, 3H), 6.36 (br s, 1H), 5.56 (s, 1H), 5.50 (d, J ) 6.3, 1H),
5.27 (d, J ) 6.3, 1H), 4.79 (dd, J ) 12.2, 1.0, 1H), 4.69 (br s,
2H), 4.41 (dd, J ) 12.4, 4.4, 1H), 3.82-3.63 (m, 6H), 3.54 (s,
3H), 2.61 (d, J ) 3.4, 1H), 2.13 (dd, J ) 6.7, 1.8, 1H), 1.71 (d,
J ) 6.7, 1H), 1.33 (t, J ) 7.0, 3H), 1.32 (t, J ) 7.0, 3H); 13C
NMR δ 158.5, 154.3, 150.7, 149.0, 143.1, 142.5, 139.2, 138.9,
129.0, 128.3, 128.0, 127.6, 126.9, 126.8, 126.5, 125.2, 120.2,
119.9, 115.5, 110.2, 105.7, 101.7, 94.3, 93.2, 75.4, 61.7, 61.4,
56.5, 53.2, 41.2, 39.0, 30.3, 15.3. Anal. Calcd for C39H41N3O8:
C, 68.91; H, 6.08; N, 6.18. Found: C, 68.78; H, 6.16; N, 6.12.
(3S,4S)-6-Ca r b a m oyloxym et h yl-9-d iet h oxym et h yl-5-
h yd r oxy-7-m eth oxym eth oxy-(3,4)-[N-(9-p h en ylflu or en -9-
yl)azir idin o]-3,4,5,6-tetr ah ydr o-2H-ben zo[b]azocin -1-yl Ac-
eta te (26). Compound 25 (70 mg, 0.1 mmol) was dissolved in
THF (2 mL), Davis’ oxaziridine (35 mg, 0.13 mmol) was added
at once, and the resulting solution was stirred at room
temperature under nitrogen. More aziridine was added twice
at intervals of 1 h (2 × 27 mg). After a total reaction time of
3 h, the solvent was removed, the residue was chromato-
graphed, and 45 mg of hydroxylamine were collected (63%
yield). This material was dissolved in Ac2O (0.5 mL) and
NaOAc (10 mg, 0.12 mml) was added. The mixture was stirred
at room temperature for 1 h, then CH2Cl2 (10 mL) and EtOH
(0.5 mL) were added. The solution was stirred for 5 min, then
washed with sat NaHCO3 (2 × 10 mL), H2O (10 mL), and
brine, dried, and concentrated. The residue was chromato-
graphed (2:1 EtOAc:hexane to EtOAc) to yield 48 mg of 26
(92%): mp 111-114 °C; 1H NMR δ 7.66 (d, J ) 7.6, 1H), 7.63
(d, J ) 7.6, 1H), 7.39-7.26 (m, 4H), 7.20-7.02 (m, 6H), 6.74
(br m, 3H), 5.61 (br s, 1H), 5.56 (s, 1H), 5.37 (d, J ) 6.4, 1H),
5.27 (d, J ) 6.5, 1H), 4.68 (br s, 2H), 4.30-4.22 (m, 3H), 3.74-
3.56 (m, 7H), 3.52 (s, 3H), 2.03 (s, 3H), 1.86 (br s, 1H), 1.81 (t,
J ) 7.0, 1H), 1.32 (t, J ) 7.0, 6H); 13C NMR δ 168.8, 157.0,
154.8, 149.6, 148.2, 144.7, 143.1, 141.8, 139.5, 128.7, 128.4,
127.9, 127.6, 126.9, 126.8, 126.3, 125.5, 119.9, 119.7, 113.0,
111.1, 101.5, 95.1, 75.9, 67.3, 64.7, 61.6, 61.5, 58.8, 56.4, 40.0,
39.4, 35.8, 19.2, 15.2 (2C). Anal. Calcd for C41H45N3O9: C,
68.03; H, 6.27; N, 5.81. Found: C, 67.92; H, 6.40; N, 5.62.
P r ep a r a tion of 29. A solution of 28 (35 mg, 0.05 mmol)
and acetic anhydride (140 µL, 1.5 mmol) in pyridine (0.5 mL)
containing DMAP (6 mg, 0.05 mmol) was stirred at room
temperature for 12 h. Et2O was added (5 mL) and the organic
phase was washed with 1% HCl (3 mL), sat NaHCO3 (5 mL),
and brine (5 mL), dried, and concentrated, and the residue
was chromatographed (2:1, EtOAc:hexane) to yield the product
as a white foam in 88% yield (33 mg): [R]20 +116.0° (c 0.8,
D
CHCl3); 1H NMR δ 7.69 (d, J ) 7.7, 1H), 7.67 (d, J ) 7.7, 1H),
7.36 (dd, J ) 7.2, 13.6, 2H), 7.20-6.76 (m, 11H), 5.56 (s, 1H),
5.45 (d, J ) 6.3, 1H), 5.27 (d, J ) 6.3, 1H), 4.59 (br s, 2H),
4.28 (m, 2H), 3.85-3.62 (m, 6H), 3.59 (s, 3H), 3.39 (d, J ) 5.8,
1H), 2.11 (d, J ) 6.6, 1H), 2.02 (d, J ) 6.6, 1H), 1.99 (s, 3H),
1.31 (t, J ) 6.9, 3H), 1.30 (t, J ) 6.9, 3H); 13C NMR δ 168.0,
156.4, 154.4, 149.7, 148.1, 143.6, 143.0, 142.3, 139.6, 139.2,
128.9, 128.4, 128.0, 127.8, 126.9, 126.8, 126.7, 126.3, 125.5,
120.1, 119.7, 114.6, 109.6, 106.0, 101.4, 98.8, 94.4, 75.4, 63.4,
61.4, 61.2, 56.5, 53.1, 38.9, 37.8, 29.2, 21.7, 15.3, 15.2. Anal.
Calcd for C41H43N3O9: C, 68.22; H, 6.00; N, 5.82. Found: C,
68.13; H, 6.14; N, 5.73.
P r ep a r a tion of F K973. Compound 28 (10 mg, 0,014 mmol)
was cooled at 0 °C under an argon atmosphere and treated
with a cooled solution of Et3SiH in TFA (105 mol %, 1 mL from
a previously prepared solution of 25 µL of Et3SiH in 5 mL of
TFA). The resulting mixture, which became heterogeneous in
15 min, was stirred at 0-5 °C for 20 h. Ice water (3 mL) and
CH2Cl2 (5 mL) were added, the aqueous layer was extracted
with CH2Cl2 (3 mL), and the combined organic phase was
dried, filtered, and evaporated to give phenylfluorene. The
aqueous phase was evaporated and dried under vacuum, and
the crude product was dissolved in pyridine (0.5 mL) and
treated with Ac2O (60 µL). The resulting solution was stirred
at room temperature for 18 h. The solvent was removed under
vacuum, and toluene was added and evaporated to remove
traces of pyridine. The residue was partitioned between CH2-
Cl2 (5 mL) and water (5 mL), the aqueous phase was extracted
with CH2Cl2 (3 × 3 mL), and the combined organic phase was
dried and concentrated. The crude product was chromato-
graphed (EtOAc) to give FK973 (52% yield).
(3S,4S)-6-Ca r b a m oyloxym et h yl-9-d iet h oxym et h yl-7-
m et h oxym et h oxy-5-oxo-(3,4)-[N-(9-p h en ylflu or en -9-yl)-
a zir id in o]-3,4,5,6-tetr a h yd r o-2H-ben zo[b]a zocin -1-yl Ac-
eta te (27). A solution of alcohol 26 (73 mg, 0.1 mmol) in 2 mL
of CH2Cl2 was added to a stirred solution of DMP (64 mg, 0.15
mmol) in CH2Cl2 (5 mL), and the resulting solution was stirred
at room temperature for 20 min. Et2O (10 mL) was added and
the mixture was poured into 20 mL of sat aq NaHCO3
containing 2.5 g of Na2S2O3. The mixture was stirred for 5 min,
more Et2O (25 mL) was added, and the organic layer was
washed with sat NaHCO3 (10 mL) and H2O (10 mL), dried,
and concentrated. Column chromatography of the residue (3:2
EtOAc:hexane) afforded 67 mg of product (91% yield): mp
114-117 °C; [R]20 +102.4° (c 0.9, CHCl3); 1H NMR δ 7.68 (d,
D
J ) 7.5, 1H), 7.61 (d, J ) 7.5, 1H), 7.38 (m, 3H), 7.31 (t, J )
J . Org. Chem, Vol. 68, No. 1, 2003 137

Paleo et al.
Ack n ow led gm en t. We thank Fujisawa for provid-
ing us with an authentical sample of FR900482, Dr. F.
J . Hollander of the CHEXRAY facility at the University
of California, Berkeley for the X-ray crystallographic
determination, and the Spanish Ministerio de Educacio´n
y Cultura and CICYT (Spain, Grant SAF99-0127) for
financial support. We also thank Prof. Paul A. Bartlett,
Department of Chemistry, University of California at
Berkeley, for assistance with preparation of the manu-
script.
J O0206521
138 J . Org. Chem., Vol. 68, No. 1, 2003