Total synthesis and biological evaluation of Amaryllidaceae alkaloids: narciclasine, ent-7-deoxypancratistatin, regioisomer of 7-deoxypancratistatin, 10b-epi-deoxypancratistatin, and truncated derivatives.

Article abstract of DOI:10.1021/jo020129m

Biocatalytic approaches have yielded efficient total syntheses of the major Amaryllidaceae alkaloids, all based on the key enzymatic dioxygenation of suitable aromatic precursors. This paper discusses the logic of general synthetic design for lycoricidine, narciclasine, pancratistatin, and 7-deoxypancratistatin. Experimental details are provided for the recently accomplished syntheses of narciclasine, ent-7-deoxypancratistatin, and 10b-epi-deoxypancratistatin via a new and selective opening of a cyclic sulfate over aziridines followed by aza-Payne rearrangement. The structural core of 7-deoxypancratistatin has also been degraded to a series of intermediates in which the amino inositol unit is cleaved and deoxygenated in a homologous fashion. These truncated derivatives and the compounds from the synthesis of the unnatural derivatives have been tested against six important human cancer cell lines in an effort to further develop the understanding of the mode of action for the most active congener in this group, pancratistatin. The results of the biological activity testing as well as experimental, spectral, and analytical data are provided in this manuscript for all relevant compounds.

Full text of DOI:10.1021/jo020129m

Tota l Syn th esis a n d Biologica l Eva lu a tion of Am a r yllid a cea e
Alk a loid s: Na r cicla sin e, en t-7-Deoxyp a n cr a tista tin , Regioisom er of
7-Deoxyp a n cr a tista tin , 10b-epi-Deoxyp a n cr a tista tin , a n d
Tr u n ca ted Der iva tives1
Tomas Hudlicky,*,† Uwe Rinner,† David Gonzalez,†,‡ Hulya Akgun,†,§ Stefan Schilling,†
Peter Siengalewicz,† Theodore A. Martinot,† and George R. Pettit|
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200,
and Department of Chemistry & Biochemistry and the Cancer Research Institute,
Arizona State University, Tempe, Arizona 85287
hudlicky@chem.ufl.edu
Received February 25, 2002
Biocatalytic approaches have yielded efficient total syntheses of the major Amaryllidaceae alkaloids,
all based on the key enzymatic dioxygenation of suitable aromatic precursors. This paper discusses
the logic of general synthetic design for lycoricidine, narciclasine, pancratistatin, and 7-deoxypan-
cratistatin. Experimental details are provided for the recently accomplished syntheses of narci-
clasine, ent-7-deoxypancratistatin, and 10b-epi-deoxypancratistatin via a new and selective opening
of a cyclic sulfate over aziridines followed by aza-Payne rearrangement. The structural core of
7-deoxypancratistatin has also been degraded to a series of intermediates in which the amino inositol
unit is cleaved and deoxygenated in a homologous fashion. These truncated derivatives and the
compounds from the synthesis of the unnatural derivatives have been tested against six important
human cancer cell lines in an effort to further develop the understanding of the mode of action for
the most active congener in this group, pancratistatin. The results of the biological activity testing
as well as experimental, spectral, and analytical data are provided in this manuscript for all relevant
compounds.
In tr od u ction
for antitumor activity,7 and synthesized8-10 by a number
of research groups. The history of the Amaryllidaceae
alkaloids, their structure elucidation, and their biological
profiles, as well as their syntheses, have been sum-
marized on several occasions.3 These alkaloids are avail-
able only in minute quantities from natural sources,6j and
their future as therapeutic agents depends on their
availability. Because isolation in larger quantity is not
Plants in the Amaryllidaceae family have been used
for thousands of years as herbal remedies; the ancient
Greeks knew their medicinal value.2 The alkaloids from
their extracts have been the object of active chemical
investigation for nearly 200 years.3 Lycorine (1), the first
alkaloid of this group to be isolated,4 was studied for its
antitumor properties long before more oxygenated con-
geners were identified.5 Over the past two decades,
lycoricidine (2), narciclasine (3), pancratistatin (5), and
7-deoxypancratistatin (4) have been isolated,6 screened
(6) Isolation and structure elucidation of Amaryllidaceae alkaloids:
Lycorine: (a) ref 4. Lycoricidine: (b) Okamoto, T.; Torii, Y.; Isogai, Y.
Chem. Pharm. Bull. 1968, 16, 1860. Narciclasine: (c) Piozzi, F.;
Fuganti, C.; Mondelli, R.; Ceriotti, G. Tetrahedron 1968, 24, 1119. (d)
See ref 6b. (e) Wakamiya, T.; Nakamoto, W. H.; Shiba, T. Tetrahedron
Lett. 1984, 25, 4411. (f) Trimino Ayllon, Z.; Ramos Martinez, I.; Iglesias
Perez, C.; Spengler Salabarria, I.; Velez Castro, H. Rev. Cubana Farm.
1989, 23, 155. (g) Abou-Donia, A. H.; De Giulio, A.; Evidente, A.; Gaber,
M.; Habib, A.; Lanzeta, R.; Seif El Din, A. Phytochemistry 1991, 30,
3445. 7-Deoxypancratistatin: (h) Ghosal, S.; Singh, S.; Kumar, Y.;
Srivastava, R. S. Phytochemistry 1989, 28, 611. Pancratistatin: (i)
Pettit, G. R.; Gaddamidi, V.; Cragg, G. M.; Herald, D. L.; Sagawa, Y.
J . Chem. Soc., Chem. Commun. 1984, 1693. (j) Pettit, G. R.; Backhaus,
R. A.; Boettner, F. E. J . Nat. Prod. 1995, 58, 37.
† University of Florida.
‡ Present address: Facultad de Quimica, C. C. 1157, Montevideo,
Uruguay.
§ Present address: Faculty of Pharmacy, Hacettepe University,
Hacettepe, 06100 Ankara, Turkey.
| Arizona State University.
(1) Preliminary disclosures for narciclasine, see ref 9l; for ent-7-
deoxypancratistatin, see ref 10n, and for epi-7-deoxypancratistatin, see
ref 50.
(2) Hartwell, J . L. Lloydia 1967, 30, 379.
(3) For reviews see: (a) Martin, S. F. In The Alkaloids; Brossi, A.
R., Ed.; Academic Press: New York, 1987; Vol. 40, p 251. (b) Polt, R.
In Organic Synthesis: Theory and Applications; Hudlicky, T., Ed.; J AI
Press: Greenwich, CT, 1997; Vol. 3, p 109. (c) Hoshino, O. In The
Alkaloids; Cordell, G. A., Ed.; Academic Press: New York, 1998; Vol.
51, p 323.
(4) Gorter, K. Bull. J ard. Bot. 1920, 1, 352 (CAN: 14: 3699). (b)
Gorter, K. Chem. Zentr. 1920, 846.
(5) Fitzgerald, R.; Hartwell, J . L.; Leiter, J . J . Nat. Cancer Inst.
1958, 20, 763.
(7) Biological activity of Amaryllidaceae alkaloids: (a) Fitzgerald,
D. B.; Hartwell, J . L.; Leiter, J . J . Nat. Cancer Inst. 1958, 20, 763. (b)
Ceriotti, G. Nature 1967, 595. (c) J imenez, A.; Santos, A.; Alonso, G.;
Vazquez, D. Biochim. Biophys. Acta 1976, 425, 342. (d) Pettit, G. R.;
Gaddamidi, V.; Herald, D. L.; Singh, S. B.; Cragg, G. M.; Schmidt, J .
M.; Boettner, F. E.; Williams, M.; Sagawa, Y. J . Nat. Prod. 1986, 49,
995. (e) Gabrielsen, B.; Monath, T. P.; Huggins, J . W.; Kefauver, D.
F.; Pettit, G. R.; Groszek, G.; Hollingshead, M.; Kirsi, J . J .; Shannon,
W. M.; Schubert, E. M.; Dare, J .; Ugarkar, B.; Ussery, M. A.; Phelan,
M. J . J . Nat. Prod. 1992, 55, 1569.
10.1021/jo020129m CCC: $22.00 © 2002 American Chemical Society
Published on Web 07/26/2002
8726
J . Org. Chem. 2002, 67, 8726-8743

Amaryllidaceae Alkaloids
pursued by 10 or more research groups, and at least three
of these groups have made substantial multigenerational
improvement of synthetic protocols toward these com-
pounds.
This paper describes the details of our most recent
syntheses of narciclasine (8 operations), ent-7-deoxypan-
cratistatin (12 operations), and epi-7-deoxypancratistatin
(12 operations) by three different approaches. All are
connected by a common motif: each synthesis begins with
the biooxidation of an aromatic compound. Some trun-
cated derivatives of 7-deoxypancratistatin have been
prepared for biological evaluation, and the results are
reported herein.
Syn th etic Str a tegy. We have proposed that 15 steps
be the limit for a practical synthesis for any desired
compound.13 Arguments for acceptance of this limit are
offered by basic algebraic considerations of “assumed”
yields of 90% in each stepsan optimistic projection at
best. The success of inventing a short synthesis of the
oxygenated phenanthridone nucleus is likely to be ham-
pered by the need of protective and deprotective opera-
tions required to preserve the integrity of the oxygenated
ring, which can be visualized as a C-substituted aminoi-
nositol.
The best strategy for an efficient synthesis of any of
these alkaloids is to attach the aryl fragment to an
electrophilic synthon that already contains most of the
oxygenated centers. Because enantiomeric alkaloids may
or may not be active, such a strategy should also
accommodate the preparation of both enantiomers. Sym-
metry arguments similar to those already applied to the
synthesis of inositols14-16 indicate that the enantiomeric
series of pancratistatin is related by the “switch of the
F IGURE 1. Representative members of the Amaryllidaceae
family of alkaloids.
practical, there is a strong case for development of
syntheses or semisyntheses of these alkaloids, their
derivatives, and potential prodrugs.11
Some of these alkaloids also display antiglycosidic (and
hence antiviral) activity because of the similarity of their
oxygenation pattern to that of natural sugars.12 This
additional biological spectrum of activities provides for
even stronger justification of synthetic effort toward these
alkaloids. The synthesis of Amaryllidaceae alkaloids is
(8) Lycorine: (a) Tsuda, Y.; Sano, T.; Taga, J . I.; Isobe, K.; Toda, J .;
Takagi, S.; Yamaki, M.; Murata, M.; Irie, H.; Tanaka, H. J . Chem.
Soc., Perkin Trans. 1 1979, 1358. (b) Sano, T.; Kashiwaba, N.; Toda,
J .; Tsuda, Y.; Irie, H. Heterocycles 1980, 14, 1097. (c) Martin, S. F.;
Tu, C. J . Org. Chem. 1981, 46, 3763. (d) Schultz, A. G.; Holoboski, M.
A.; Smyth, M. S. J . Am. Chem. Soc. 1993, 115, 7904. (e) Hoshino, O.;
Ishizaki, M.; Kamei, K.; Taguchi, M.; Nagao, T.; Iwaoka, K.; Sawaki,
S.; Umezawa, B.; Iitaka, Y. J . Chem. Soc., Perkin Trans. 1 1996, 571.
(9) Lycoricidine: (a) Ohta, S.; Kimoto, S. Chem. Pharm. Bull. 1976,
24, 2977. (b) Paulsen, H.; Stubbe, M. Tetrahedron Lett. 1982, 23, 3171.
(c) Paulsen, H.; Stubbe, M. Liebigs Ann. Chem. 1983, 535. (d) Chida,
N.; Ohtsuka, M.; Ogawa, S. Tetrahedron Lett. 1991, 32, 4525. (e)
Hudlicky, T.; Olivo, H. F. J . Am. Chem. Soc. 1992, 114, 9694. (f) Chida,
N.; Ohtsuka, M.; Ogawa, S. J . Org. Chem. 1993, 58, 4441. (g) Martin,
S. F.; Tso, H. H. Heterocycles 1993, 35, 85. (h) Hudlicky, T.; Olivo, H.
F.; McKibben, B. J . Am. Chem. Soc. 1994, 116, 5108. (i) Keck, G. E.;
Wager, T. T. J . Org. Chem. 1996, 61, 8366; Narciclasine: (j) Rigby, J .
H.; Mateo, M. E. J . Am. Chem. Soc. 1997, 119, 12655. (k) Keck, G. E.;
Wager, T. T.; Rodriquez, J . F. D. J . Am. Chem. Soc. 1999, 121, 5176.
(l) Gonzalez, D.; Martinot, T.; Hudlicky, T. Tetrahedron Lett. 1999,
40, 3077. (m) Rigby, J . H.; Maharoof, U. S. M.; Mateo, M. E. J . Am.
Chem. Soc. 2000, 122, 6624.
(10) Pancratistatin: (a) Danishefsky, S.; Lee, J . Y. J . Am. Chem.
Soc. 1989, 111, 4829. (b) Tian, X. R.; Hudlicky, T.; Ko¨nigsberger, K. J .
Am. Chem. Soc. 1995, 117, 3643. (c) Trost, B. M.; Pulley, S. R. J . Am.
Chem. Soc. 1995, 117, 10143. (d) Keck, G. E.; McHardy, S. F.; Murry,
J . A. J . Am. Chem. Soc. 1995, 117, 7289. (e) Hudlicky, T.; Tian, X. R.;
Ko¨nigsberger, K.; Maurya, R.; Rouden, J .; Fan, B. J . Am. Chem. Soc.
1996, 118, 10752. (f) Chida, N.; J itsuoka, M.; Yamamoto, Y.; Ohtsuka,
M.; Ogawa, S. Heterocycles 1996, 43, 1385. (g) Magnus, P.; Sebhat, I.
K. Tetrahedron 1998, 54, 15509. (h) Magnus, P.; Sebhat, I. K. J . Am.
Chem. Soc. 1998, 120, 5341; Kim, S.; Ko, H.; Kim, E.; Kim, D. Org.
Lett. 2002, 4, 1343. 7-Deoxypancratistatin: (j) Keck, G. E.; Wager, T.
T.; McHardy, S. F. J . Org. Chem. 1998, 63, 9164. (k) Tian, X. R.;
Maurya, R.; Ko¨nigsberger, K.; Hudlicky, T. Synlett 1995, 1125. (l) Keck,
G. E.; McHardy, S. F.; Murry, J . A. J . Org. Chem. 1999, 64, 4465. (m)
Acena, J . L.; Arjona, O.; Leon, M. L.; Plumet, J . Org. Lett. 2000, 2,
3683. ent-7-Deoxypancratistatin: (n) Akgun, H.; Hudlicky, T. Tetra-
hedron Lett. 1999, 40, 3081.
(13) Hudlicky, T. Chem. Rev. 1996, 96, 3.
(14) For physical and spectral properties see: Hudlicky, T.; Cebulak,
M. Cyclitols and their Derivatives. A Handbook of Physical, Spectral
and Synthetic Data; VCH: New York, 1993.
(15) (a) Hudlicky, T.; Price, J . D.; Rulin, F.; Tsunoda, T. J . Am.
Chem. Soc. 1990, 112, 9439. (b) Luna, H.; Olivo, H. F.; Andersen, C.;
Nugent, T.; Price, J . D. J . Chem. Soc., Perkin Trans. 1 1991, 2907. (c)
Mandel, M.; Hudlicky, T. J . Chem. Soc., Perkin Trans. 1 1993, 1537.
(d) Boyd, D. R.; Sharma, N. D.; Hand, M. V.; Groocock, M. R.; Kerley,
N. A.; Dalton, H.; Chima, J .; Sheldrake, G. N. J . Chem. Soc., Chem.
Commun. 1993, 974. (e) Mandel, M.; Hudlicky, T.; Kwart, L. D.;
Whited, G. M. J . Org. Chem. 1993, 58, 2331. (f) Mandel, M.; Hudlicky,
T. J . Chem. Soc., Perkin Trans. 1 1993, 741. (g) Hudlicky, T.; Thorpe,
A. J . Synlett 1994, 899. (h) Hudlicky, T. Pure Appl. Chem. 1994, 66,
2067. (i) Hudlicky, T.; Mandel, M.; Rouden, J .; Lee, R. S.; Bachmann,
B.; Dudding, T.; Yost, K. J .; Merola, J . S. J . Chem. Soc., Perkin Trans.
1 1994, 1553. (j) Hudlicky, T.; Abboud, K. A.; Entwistle, D. A.; Fan, R.
L.; Maurya, R.; Thorpe, A. J .; Bolonick, J .; Myers, B. Synthesis 1996,
897. (k) Hudlicky, T.; Abboud, K. A.; Bolonick, J .; Maurya, R.; Stanton,
M. L.; Thorpe, A. J . Chem. Commun. 1996, 1717. (l) Desjardins, M.;
Brammer, L. E.; Hudlicky, T. Carbohydr. Res. 1997, 304, 39. (m)
Nguyen, B. V.; York, C.; Hudlicky, T. Tetrahedron 1997, 53, 8807. (n)
Brammer, L. E.; Hudlicky, T. Tetrahedron: Asymmetry 1998, 9, 2011.
(o) Hudlicky, T.; Claeboe, C. D.; Brammer, L. E.; Koroniak, L.; Butora,
G.; Ghiviriga, I. J . Org. Chem. 1999, 64, 4909. (p) Oppong, K. A.;
Hudlicky, T.; Yan, F. Y.; York, C. T.; Nguyen, B. V. Tetrahedron 1999,
55, 2875.
(16) (a) Hoover, G. A.; Nicolosi, R. J .; Ellozy, M.; Hegsted, D. M.
Clin. Res. 1977, 25, A536. (b) Hoover, G. A.; Nicolosi, R. J .; Lozy, M.
E.; Heqsted, D. M. Am. J . Clin. Nutr. 1977, 30, 631. (c) Hoover, G. A.;
Nicolosi, R. J .; Corey, J . E.; Ellozy, M.; Hayes, K. C. J . Nutr. 1978,
108, 1588. (d) Hoover, G. A.; Nicolosi, R. J .; Lozy, M. E.; Hayes, K. C.
1978, 37, 258. (e) Carless, H. A. J .; Billinge, J . R.; Oak, O. Z.
Tetrahedron Lett. 1989, 30, 3113. (f) Carless, H. A. J .; Busia, K.
Tetrahedron Lett. 1990, 31, 1617. (g) Carless, H. A. J .; Oak, O. Z.
Tetrahedron Lett. 1991, 32, 1671. (h) Carless, H. A. J .; Oak, O. Z. J .
Chem. Soc., Chem. Commun. 1991, 61. (i) Carless, H. A. J .; Busia, K.
Carbohydr. Res. 1992, 234, 207. (j) Carless, H. A. J .; Busia, K.; Oak,
O. Z. Synlett 1993, 672. (g) Sanfilippo, C.; Patti, A.; Piattelli, M.;
Nicolosi, G. Tetrahedron: Asymmetry 1998, 9, 2809.
(11) Pettit, G. R.; Freeman, S.; Simpson, M. J .; Thompson, M. A.;
Boyd, M. R.; Williams, M. D.; Pettit, G. R., III; Doubek, D. L. Anti-
Cancer Drug Des. 1995, 10, 243.
(12) Gabrielsen, B.; Monath, T. P.; Huggins, J . W.; Kefauver, D. F.;
Pettit, G. R.; Groszek, G.; Hollingshead, M.; Kirsi, J . J .; Shannon, W.
M.; Schubert, E. M.; Dare, J .; Ugarkar, B.; Ussery, M. A.; Phelan, M.
J . J . Nat. Prod. 1992, 55, 1569.
J . Org. Chem, Vol. 67, No. 25, 2002 8727

Hudlicky et al.
SCHEME 1
Discu ssion
Na r cicla sin e. Two possible disconnections were con-
sidered, both leading to amino enone 14, via a nitroso
Diels-Alder reaction, Scheme 2. On the basis of our
experience in the synthesis of lycoricidine and various
conduramines, we anticipated that the conduramine unit
of narciclasine (3) would be formed by a regio- and
stereospecific nitroso Diels-Alder addition to the diol
derived from 1,3-dibromobenzene (7).
o-Vanillin (11) serves to furnish the aromatic fragment
of narciclasine in the form of borate 10,20 and 1,3-
dibromobenzene (6) provides the asymmetric portion of
the molecule by means of toluene dioxygenase oxidation
to the corresponding cis-cyclohexadiene diol 7. The two
bromine atoms are located in different proenantiotopic
spaces by virtue of the particular symmetry present in
the cis-cyclohexadiene diols, which we have exploited
extensively in several preparations.15a,17a,21,22
1,3-Dibromobenzene was subjected to whole-cell fer-
mentation with E. coli J M109 (pDTG601A), an organism
developed by Gibson23 for the overexpression of toluene
dioxygenase (TDO). Biooxidation yielded the new me-
tabolite 7 (4 g/L, >99% ee), a compound that possesses
unique latent symmetry and two chemically different
vinylic bromine atoms. Diol 7 was transformed in a one-
pot operation to bicyclic oxazine 9 in 70% yield (Scheme
3). The acetonide is prepared in neat 2,2-dimethoxypro-
pane (DMP), which is also a suitable solvent for the
Diels-Alder cycloaddition. Thus, after verification of
complete conversion of diol 7 into acetonide 8, the
periodate and the hydroxamic acid were added. In this
way, we were able to shorten the preparation and avoid
isolating acetonide 8 which tends to dimerize in its pure
state.24
Oxazines such as 9 were formed according to ample
precedents for the reactions of cis-cyclohexadienediols
with nitroso dienophiles.25,26 Our synthesis of cyclitols25,27
and the alkaloid lycoricidine were based on these
reactions.9h,e,25b, Reduction of 9 under Keck’s conditions28
yielded the conduramine oxidation state as previously
reported,25a but gave predominantly the fully dehaloge-
nated conduramine derivative (-)-15. This result, al-
though unfavorable for the narciclasine synthesis, pro-
trans-disposed functionalities” as indicated in Scheme 1.
If one considers that the trans diol and the â-arylamine
are interchangeable across the enantiotopic plane15a
shown, then a common strategy can be devised for both
enantiomers by two identical routes from a single enan-
tiomer of the material which contains the cis-diol unit
“protected” from symmetrization by the presence of a
removable group.
Such a strategy is implemented by performing two
sequences of identical functionalizations in a different
order, as shown in Scheme 1. Successful applications of
this kind of strategy to sugar and inositol syntheses have
been reported.13,15 The creation of either an electrophilic
aziridine or an electrophilic oxirane at the more electron-
rich olefin allows the rest of the synthesis to be completed
by a series of identical chemical steps, executed in
different order, as demonstrated for the first time in our
enantiodivergent synthesis of (+)- and (-)-pinitol.15a
Several reviews offer an expanded version of this argu-
ment.13,17
Other solutions for the enantiodivergent synthesis of
arene cis-diols have been reported. Boyd’s strategy18 is
based on the directing effects in the enzymatic oxidation
and the greater rate of reduction of the directing group
(iodine) by chemical means (R3SnH). Because toluene
dioxygenase-mediated oxidation of para-substituted di-
halobenzenes produces mixtures of poor enantiomeric
enrichment, J ohnson’s19 lipase resolution of intermedi-
ates derived from such mixtures must be used to enrich
the optical purity of the desired ent-diols. We have used
both strategies in the synthesis of ent-7-deoxypancrat-
istatin.
(20) Dallacker, F.; Sanders, J . Chem. Ztg. 1984, 108, 186. (b)
Shirasaka, T.; Takuma, Y.; Imaki, N. Synth. Commun. 1990, 20, 1223.
(21) Hudlicky, T.; Luna, H.; Price, J . D.; Rulin, F. Tetrahedron Lett.
1989, 30, 4053.
(22) Hudlicky, T.; Fan, R. L.; Tsunoda, T.; Luna, H.; Andersen, C.;
Price, J . D. Isr. J . Chem. 1991, 31, 229.
(23) Gibson, D. T.; Koch, J . R.; Kallio, R. E. Biochemistry 1968, 7,
2653. (b) Hudlicky, T.; Stabile, M. R.; Gibson, D. T.; Whited, G. M.
Org. Synth. 1999, 76, 77.
(24) Pittol, C. A.; Pryce, R. J .; Roberts, S. M.; Ryback, G.; Sik, V.;
Williams, J . O. J . Chem. Soc., Perkin Trans. 1 1989, 1160. (b) Ley, S.
V.; Redgrave, A. J .; Taylor, S. C.; Ahmed, S.; Ribbons, D. W. Synlett
1991, 741. (c) Hudlicky, T.; Boros, E. E.; Olivo, H. F.; Merola, J . S. J .
Org. Chem. 1992, 57, 1026. (d) Hudlicky, T.; Boros, C. H. Tetrahedron
Lett. 1993, 34, 2557.
(25) (a) Hudlicky, T.; Olivo, H. F. Tetrahedron Lett. 1991, 32, 6077.
(b) Olivo, H. F. Ph.D. Dissertation, Virginia Polytechnic Institute and
State University, 1992.
(26) Weinreb, S. M.; Boger, D. L. Hetero Diels-Alder Methodology
in Organic Synthesis; Harcourt Brace J ovanovich: San Diego, 1987;
Vol. 47.
(17) (a) Hudlicky, T.; Gonzalez, D.; Gibson, D. T. Aldrichimica Acta
1999, 31, 35. (b) Boyd, D. R.; Sheldrake, G. N. Nat. Prod. Rep. 1998,
309. (c) Brown, S. M.; Hudlicky, T. In Organic Synthesis: Theory and
Applications; Hudlicky, T., Ed.; J AI Press: Greenwich, CT, 1993; Vol.
2, p 113. (d) Hudlicky, T.; Reed, J . W. In Advances in Asymmetric
Synthesis; Hassner, A., Ed.; J AI Press: Greenwich, CT, 1995; p 271.
(18) Allen, C. C. R.; Boyd, D. R.; Dalton, H.; Sharma, N. D.;
Brannigan, I.; Kerley, N. A.; Sheldrake, G. N.; Taylor, S. C. J . Chem.
Soc., Chem. Commun. 1995, 117.
(27) Hudlicky, T.; Fan, R.; Luna, H.; Olivo, H.; Price, J . Pure Appl.
Chem. 1992, 64, 1109.
(19) J ohnson, C. R.; Adams, J . P.; Collins, M. A. J . Chem. Soc.,
Perkin Trans. 1 1993, 1.
(28) Keck, G. E.; Fleming, S.; Nickell, D.; Weider, P. Synth.
Commun. 1979, 9, 281.
8728 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
SCHEME 2
SCHEME 3
SCHEME 4
vided conclusive proof of the absolute stereochemistry of
diol 7. Conduramine derivative (-)-15 was independently
prepared from bromodiol (+)-16, whose absolute stereo-
chemistry is well established (Scheme 3).9e,25a This struc-
ture proof also confirmed the assumption that the
polarized halodiene would undergo regiospecific nitroso
Diels-Alder reaction.25,27,28
We studied the reduction of the oxazine in some detail.
Our initial plan was to follow the previous reports by
Keck et al.28 by opening the oxazine bridge by reduction
with aluminum amalgam in order to obtain a brominated
amino conduritol derivative such as 17. However, we
found the same type of overreduction problems that we
had observed in the synthesis of lycoricidine.9e The vinylic
bromine on C10a (narciclasine numbering) was reduced
under these conditions, and we isolated the fully debro-
minated conduramine derivative (-)-15 and the desired
17 in a 99:1 ratio (HPLC).
29
ever, Mo(CO)6 cleanly reduced dibrominated oxazine 9
to the corresponding bromo enone 19 with concomitant
cleavage of the acetonide protecting group (Scheme 4).
Because the mechanism of the cleavage with Mo(CO)6
does not involve radical formation but is rather a metal
insertion process,29a it can be performed successfully in
the presence of vinylic halides.
Both tributyltin hydride and tris-trimethylsilylsilane
(TTMSS), normally suited for reduction of oxazine 9 to
unsaturated ketone 19 cannot be applied here as deha-
logenation is unavoidable under such conditions. How-
(29) (a) Cicchi, S.; Goti, A.; Brandi, A.; Guarna, A.; Desarlo, F.
Tetrahedron Lett. 1990, 31, 3351. (b) Ritter, A. R.; Miller, M. J . J . Org.
Chem. 1994, 59, 4602. (c) Geneste, F.; Racelma, N.; Moradpour, A.
Synth. Commun. 1997, 27, 957. (d) Olivo, H. F.; Hemenway, M. S.;
Hartwig, A. C.; Chan, R. Synlett 1998, 247.
J . Org. Chem, Vol. 67, No. 25, 2002 8729

Hudlicky et al.
SCHEME 5
We explored directed hydride reduction by means of
Zn(BH4)2
inversion as reported by Chida in his preparation of
lycoricidine. This procedure gave the desired R-benzoate
23 cleanly in 60% yield from ketone 14 (Scheme 6).
A modification of the Bischler-Napieralski reaction
reported by Banwell35 and applied with success in simpli-
fied models of phenanthridone alkaloids36 was chosen for
the last steps of the synthesis. This interesting variation
uses a 5:3 mixture of trifluoromethanesulfonic anhydride
and DMAP instead of POCl3 to attain cyclization. The
reaction has been applied successfully to sensitive mol-
ecules not only by Banwell36 but also by us in the
preparation of both enantiomers of 7-deoxypancratistatin,
as described below and as previously reported.10b,e The
acetonide protecting group in 23 was removed by an
acidic resin in methanol. This method is convenient
because the diols are generally very soluble in methanol
and simple filtration of the resin yields a solution of
essentially pure product which was treated with acetic
anhydride and pyridine. The resulting diacetate 24 was
obtained in 90% yield over the two steps (performed as
a single operation).
Compound 24 was subjected to Banwell’s conditions
and afforded phenanthridone 25 in 40% yield. The
particular ratio of Tf2O and DMAP (5:3) was empirically
determined by Banwell.35 With an equimolar mixture, no
cyclization is observed. The application of this reaction
to other substrates (including acetonides 22 and 23, and
ketone 14) afforded only phenolic material. Although the
closure could result in two isomers (phenanthridones 25
and 26), we never observed the formation of the latter
product. A different result was obtained by Magnus in
his synthesis of pancratistatin where a 3:1 ratio of
isomers was detected in a related closure.10h
30,31
or NaB(AcO)3H.32 Because of the strong
chelating properties of the zinc cation, the reagent has
been used to attain anti selectivity in the reduction of
acyclic R-hydroxy ketones33 and has been also exploited
for the reduction of â-hydroxy ketones with high selectiv-
ity.32 However, in our hands only a disappointing 20%
diasteromeric excess has been observed in these reduc-
tions (Scheme 4).
To circumvent the problem of overreduction34 of the
bromine atom at C10a, we decided to couple the aromatic
portion of the alkaloid (borate 10) directly to oxazine 9
and postpone the bridge opening to a later stage in the
synthesis. The coupling was performed under the stan-
dard Suzuki-Miyaura conditions34 and proceeded only
in fair yield (30%). Oxazine 13 was isolated along with
10-15% of ketone 14 (Scheme 5) and 20-25% of substi-
tuted biphenyls formed by homocoupling. Enone 14 was
formed also through a palladium insertion mechanism
similar to the regular cleavage of the nitrogen-oxygen
bond in oxazine 9 by Mo(CO)6 as discussed above. To the
best of our knowledge, this is the first example of Suzuki
coupling of a halo-oxazine and a phenyl borate.
Because 13 was resistant to aluminum amalgam
reduction under Keck’s conditions, and stronger reducing
agents (sodium amalgam or H2/Pd) led to fully saturated
products we transformed 13 into unsaturated ketone 14
instead with tris-trimethylsilyl silane (TTMSS). Further
improvement was obtained by adding acetonitrile and
Mo(CO)6 directly to the Suzuki reaction mixture after the
coupling of 9 and 10 was completed. Heating this mixture
for 12 h afforded ketone 14 in 45% yield. In this fashion
we were able to optimize a preparation of the advanced
intermediate 14 in only three operations from 1,3-dibro-
mobenzene (Scheme 5).
The esters in 25 were removed with a basic Amberlyst
resin in methanol. The reaction worked efficiently to form
1
a polar fluorescent solid whose H NMR spectrum and
To set the stereochemistry at C2 (narciclasine number-
ing), we applied a Luche reduction followed by Mitsunobu
optical rotation ([R]26 ) +204 (c 0.3, DMSO)) matched
D
those of the compound prepared by methylation of
natural narciclasine using Piozzi’s procedure6c (diaz-
(30) Narasimhan, S.; Balakumar, R. Aldrichimica Acta 1998, 31,
omethane in ethanol, 5 days, 50%) ([R]26 ) +219 (c 1.0,
D
19.
(31) Paquette, L. A. Encyclopedia of Reagents for Organic Synthesis;
DMSO)).
J . Wiley: New York, 1995; Vol. 8.
(32) Hoveyda, A. H.; Evans, D. A.; Fu, G. C. Chem. Rev. 1993, 93,
1307.
(35) Banwell, M. G.; Bissett, B. D.; Busato, S.; Cowden, C. J .;
Hockless, D. C. R.; Holman, J . W.; Read, R. W.; Wu, A. W. J . Chem.
Soc., Chem. Commun. 1995, 2551.
(33) Nakata, T.; Tanaka, T.; Oishi, T. Tetrahedron Lett. 1983, 24,
2653.
(34) Miyaura, N.; Yanagi, T.; Suzuki, A. Synth. Commun. 1981, 11,
513.
(36) Banwell, M. G.; Cowden, C. J .; Gable, R. W. J . Chem. Soc.,
Perkin Trans. 1 1994, 3515.
8730 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
SCHEME 6
Cleavage of the methyl ether on the C7-OH of 27
proved to be problematic. After several trials under the
conditions reported by Trost and Pulley (LiI, DMF, 80
°C, several hours) for the deprotection of 7-O-methyl-
pancratistatin,10c we observed only degradation products.
An improved and updated procedure37 performed on 1.0
( 0.1 mg of 7-O-methylnarciclasine (27) afforded a polar
compound with strong yellow-green fluorescence. Puri-
fication of this material afforded 0.3 ( 0.1 mg of a
of Olivo,38 reporting an improved route to aziridine
synthons of this type. The Mitsunobu protocol is greatly
superior to the previously used aziridination by the
Evans-J acobsen-Yamada method,39 which we used dur-
ing all of our previous syntheses of pancratistatin and
7-deoxypancratistatin.
Recent studies by Boyd18 have shown that the iodine
atom present in dihalogenated cis-diols such as 29
(obtained by biooxidation with toluene dioxygenase ex-
pressed in the blocked mutant P. putida UV4) can be
selectively removed by catalytic hydrogenolysis (H2, Pd/
C), a procedure which leads to a mixture of (2S,3S) and
(2R,3R) enantiomers of bromodiol 16. Boyd used a second
fermentation step with a nonblocked strain of Pseudomo-
nas (P. putida NCIB 8819) to metabolize the “normal”
(2S,3S) isomer to increase its optical purity. Boyd’s
method provides a route to (2R,3R) enantiomers of
monosubstituted cis-dihydrodiols; however, the valuable
(2S,3S) isomer is destroyed in this procedure. As we were
interested in both enantiomers of amino alcohol 15, we
developed an alternative route that would provide both
enantiomers in high enantiomeric excess. In addition
since the hydrogenolysis of 29 did not provide good
results in our hands, the iodine atom was instead
removed with Bu3SnH /AIBN21 to yield (-)-16 (55%, 20%
ee).
1
compound that showed an identical H NMR spectrum
and a matching optical rotation with the literature data
for narciclasine ([R]23 ) +130 (c 0.03, DMSO), lit.9j
D
+141.8). The TOCSY spectrum was fully consistent with
structure 3.
The total synthesis of narciclasine was completed from
1,3-dibromobenzene in 12 steps (14 from o-vanillin) and
only eight individual operations. This was the second
synthesis of narciclasine to be published,1 and it is 11
steps shorter than the first preparation.9j Keck has
reported the completion of the third total synthesis of this
alkaloid in 12 steps.9k
en t-7-Deoxyp a n cr a tista tin . In a preliminary com-
munication,10m we reported a 12-step synthesis of this
compound prepared for biological evaluation. The only
other Amaryllidaceae alkaloid prepared in the ent-series
is ent-lycoricidine, reported by Keck.9k For our approach
to the ent-alkaloid, we chose the corresponding ent-
conduramine A, which would be manipulated to the
required vinylaziridine by the recently published protocol
(38) Olivo, H. F.; Hemenway, M. S.; Hartwig, A. C.; Chan, R. Synlett
1998, 247.
(39) Evans, D. A.; Faul, M. M.; Bilodeau, M. T. J . Org. Chem. 1991,
56, 6744. (b) Li, Z.; Conser, K. R.; J acobsen, E. N. J . Am. Chem. Soc.
1993, 115, 5326. (c) Yamada, Y.; Yamamoto, T.; Okawara, M. Chem.
Lett. 1975, 361.
(37) After a personal communication with Dr. Pulley, we obtained
the correct procedure that used LiCl in DMF at 120 °C for 2 h, not LiI
as reported in ref 10c.
J . Org. Chem, Vol. 67, No. 25, 2002 8731

Hudlicky et al.
SCHEME 7
SCHEME 8
Enantiomerically impure diol (-)-16 was converted to
amino alcohol 15 via oxazine 30 as described in Scheme
7. Alcohol 15 was acetylated with acetic anhydride and
pyridine to give 31. To obtain the optically pure enanti-
omers, a method similar to that employed by J ohnson
was used.19 Under carefully controlled conditions, crude
porcine pancreatic lipase (PPL, Sigma type II crude)
catalyzed the hydrolysis of optically impure 31 to afford
(+)-amino alcohol (+)-15 and acetate 33 with high
enantiomeric purity (99% ee) for a 35-45% conversion
of 31.19,40 The optical purity of (+)-15 was determined
by comparing the optical rotation value ([R]26 ) +29.1
D
(c 1.0, CHCl3) to the corresponding value of the enanti-
omer (-)-15 prepared from the “natural” bromocyclo-
hexadiene cis-diol: [R]25 ) -30.1. (c 1.1, CHCl3),25a (see
D
Scheme 7).
After the conversion of (+)-15 to the corresponding ent-
aziridine (+)-32, the synthesis of ent-7-deoxypancratista-
tin was completed exactly as previously published for the
natural isomer (Scheme 8),10b and the compound was
submitted for biological evaluation (see the section on
biological activity for a discussion of results).
Regioisom er of 7-Deoxyp a n cr a tista tin . This alka-
loid has served a number of investigators as a somewhat
easier model on which to base approaches to the more
complex pancratistatin, as the presence of the phenolic
hydroxyl in pancratistatin makes for a more difficult
synthesis.
plan called for benzylic oxidation and recyclization of
the “Danishefsky lactone” intermediate following the
installation of an amine at C4a. However, the oxidation
was not reported in the original disclosure, nor has a
subsequent report appeared. The second report involved
the intramolecular opening of aziridines, first reported
by the Rapoport group42 with studies continued by
Bergmeier.43
After the first and second generation syntheses of the
title compound, we turned to a completely new strategy
inspired by two reports in the literature. The first was
that of Gauthier and Bender, who reported successful
intramolecular opening of an epoxide in 41 with a
transmetalated arene as shown below.41 Their ultimate
(40) Schoffers, E.; Golebiowski, A.; J ohnson, C. R. Tetrahedron 1996,
52, 3769.
(41) Gauthier, D. R., J r.; Bender, S. L. Tetrahedron Lett. 1996, 37,
13.
In a model study directed at the synthesis of ent-7-
deoxypancratistatin by a strategy similar to Bender’s, we
were also able to cyclize aryl bromide 43 onto the
8732 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
SCHEME 9
aziridine with t-BuLi/Et2O to produce conduramine 44,
which possesses the ent-configuration required for the
alkaloid.44 However, extension of this model study to the
piperonyl derivative of 43 was not successful.
With these precedents, we formulated the strategy
outlined in Scheme 9. Protection of the diol in 16 as the
acetonide followed by aziridination under Evans’s and
J acobsen’s protocol39 generated the tosyl aziridine 45 in
63% yield. Dehalogenation of vinyl bromide 45 under
radical conditions followed by epoxidation at elevated
temperature produced an inseparable mixture of epoxides
47 (R:â ) 2.6:1).45 Because of the redundant outcome [for
definitions of redundant operations see ref 13] of the
nucleophilic opening of epoxide 47, we assumed that
either trans diol 48 or trans piperonyl ethers 49 or 50
would be obtained from the isomeric mixture of epoxides
47 upon selective trans-diaxial opening of the oxirane
with oxygen nucleophiles. Either transmetalation (50) or
acid-catalyzed treatment (49) would then be used to open
the aziridine.
the literature, to our knowledge. To this end, the cyclic
sulfate 55 was prepared as shown in Scheme 10. The
tosylaziridine 46 was synthesized as previouslyreported.10e,j
Dihydroxylation of 46 provided cis diol 54 in 85% yield.
This material was converted to the cyclic sulfate 55 in
93% yield with sulfuryl chloride in CH2Cl2.
As reported in a recent publication,46a the outcome of
this approach led to the synthesis of an isomer of
7-deoxypancratistatin, 53, via the initial opening of the
aziridine with the oxygen nucleophile and the subsequent
acid-catalyzed cyclization of epoxy ether 52.
We were pleased to find that ammonium salts of
several benzoic acid derivatives cleanly differentiated
between the aziridine and the cyclic sulfate and led
chemoselectively to the trans-disposed ester-alcohols
56a -c in 60-90% yield.48 In contrast, when epoxides 47,
sulfate 55 and the corresponding sulfite (prepared by
reaction of diol 54 with thionyl chloride in CH2Cl2) were
allowed to react with sodium or potassium salts of
piperonol, decomposition or opening of the aziridine
rather than the epoxide was observed. Only ammonium
salts of carboxylic acids were found to differentiate clearly
between these functional groups. Several benzoate de-
rivatives were prepared by this method, namely piperonyl
and o-bromopiperonyl esters, to study the possibility of
intramolecular opening of the aziridine ring by either a
epi-7-Deoxyp a n cr a tista tin . The inability to open the
oxirane selectively in 47 ultimately led to our investiga-
tion of the selectivity of nucleophilic opening of cyclic
sulfates or sulfites47 over aziridines contained in the same
molecule. Such investigations have not been reported in
(46) (a) Schilling, S.; Rinner, U.; Chan, C.; Ghiviriga, I.; Hudlicky,
T. Can J . Chem. 2001, 79, 1659. (b) We have reported the synthesis of
7-deoxypancratistatin by the intramolecular aziridine opening at many
occasions at conferences. The proceedings of the Heterocyclic Congress
in Vienna, August 1999, were published before the erroneous assign-
ment was observed: Hudlicky, T. J . Heterocycl. Chem. 2000, 37, 535.
The incorrectly assigned structure as well as reasons for not detecting
this error has been reported as a full paper (ref 46a). The major lesson
learned from these endeavor was the recognition that structure
assignment of highly similar compounds is very difficult by NMR
techniques alone.
(42) Bergmeier, S. C.; Lee, W. K.; Rapoport, H. J . Org. Chem. 1993,
58, 5019.
(43) Bergmeier, S. C.; Seth, P. P. J . Org. Chem. 1999, 64, 3237. (b)
Bergmeier, S. C.; Fundy, S. L.; Seth, P. P. Tetrahedron 1999, 55, 8025.
(c) Bergmeier, S. C.; Seth, P. P. Tetrahedron Lett. 1995, 36, 3793.
(44) McLamore, S. D. Ph.D. Dissertation, University of Florida,
1997.
(45) (a) Viehe, H. G.; Vaerman, J . L. Tetrahedron 1989, 45, 3183.
(b) Viehe, H. G.; Vaerman, J . L.; Schmidtchen, F. P.; Kresze, G.; Burger,
W.; Braun, H. Tetrahedron: Asymmetry 1990, 1, 403.
(47) (a) Lohray, B. B. Synthesis 1992, 1035. (b) Byun, H. S.; He, L.
L.; Bittman, R. Tetrahedron 2000, 56, 7051.
(48) Kim, B. M.; Sharpless, K. B. Tetrahedron Lett. 1989, 30, 655.
J . Org. Chem, Vol. 67, No. 25, 2002 8733

Hudlicky et al.
SCHEME 10
completion of the synthesis of the cis epimer of 7-deoxy-
pancratistatin validated the strategy proposed originally
by Haseltine.51
Tr u n ca ted Der iva tives of 7-Deoxyp a n cr a tista tin .
Little information is available concerning the mode of
action of pancratistatin although a number of derivatives
have been made and tested.52 It seems likely, though,
that the aminocyclitol portion is involved in the antiviral
function whereas the anthramide portion plays a role in
DNA interactions. We decided to provide truncated
derivatives of 7-deoxypancratistatin in order to see at
which point the activity of the parent compound would
fall off. The synthesis of these compounds is straightfor-
ward and is outlined in Scheme 12.
Coupling of a higher order cyanocuprate, derived from
4-bromo-(1,2-methylenedioxy)benzene, with vinyl aziri-
dine 46 or (-)-32 under Lewis acid catalysis10d,10f gave
the functionalized cyclohexenes 71/72 in yields of 21%
and 18% respectively. Oxidation of the olefinic bond was
achieved with ruthenium tetroxide, produced in situ,
which provided diols 73/74 in good yields. A sequence
involving deprotection of the acetonide under acidic
conditions, oxidative degradation of all vicinal hydroxyl
groups in the resulting tetrol, and reduction afforded diols
75/76 in 60% and 45% overall yields. Several reported
methods for removal of the tosyl group were attempted
on diol 75, all of which were unsucessful. To facilitate
removal of the tosyl group, diol 75 was acylated under
conditions using excess base as well as excess di-tert-butyl
dicarbonate which produced alcohol 77; nevertheless,
detosylation attempts still failed. Finally, deprotection
of carbamate 76 was achieved by base hydrolysis (10%
aq KOH) furnishing the free amine, which was subse-
quently isolated as the hydrochloride salt 78 as shown
in Scheme 12.
Lewis acid-mediated process or by an organometallic
species derived from 56c. Unfortunately all attempts to
close the ring failed.
Therefore, we decided to return to our original idea of
intramolecular aziridine opening in an ether such as 49.
When ester 57 was treated with sodium methoxide in
THF, migration of the TBS group took place and alcohols
59 and 60 were obtained, as shown in Scheme 11. We
found that increasing the reaction time of the ester
cleavage also increased the percentage of alcohol 60 in
the reaction mixture. Eventually, we succeeded in pre-
paring the free alcohol 59 without observing silyl migra-
tion when ester 57 was treated with excess sodium
methoxide for a reaction time of less than 1 min.
Any attempts to alkylate the hydroxyl function in 59
to produce ether 65 failed, but instead gave the epoxide
64 via an aza-Payne rearrangement as shown in Scheme
11. Even deprotonation of the alcohol using tert-butyl-
lithium at -30 °C followed by quenching of the alkoxide
with excess piperonyl bromide only yielded compound 64.
Interestingly, alkylation of alcohol 60 by means of the
same procedure also afforded epoxy amide 64, which
indicates that the reaction sequence involves silyl migra-
tion followed by an aza-Payne rearrangement yielding
intermediate 63, which is subsequently alkylated by
piperonyl bromide.
Biologica l Activity P r ofile
Synthesis of the truncated derivatives, and especially
of 7-deoxypancratistatin (4) and ent-7-deoxypancratista-
tin (ent-4), as well as the positional regioisomer of
7-deoxypancratistatin, 53, and the 10b-epimer or cis-7-
deoxypancratistain 70 provided the basis for an impor-
tant extension of prior SAR11,53-55 cancer cell growth
inhibition studies of (+)-pancratistatin (5).6i,j Against a
minipanel of six human cancer cell lines and the marine
P388 lymphocytic leukemia cell line, the following results
were obtained. Evaluation of 7-deoxypancratistatin (4)
led to good cancer cell growth inhibition (GI50, µg/mL):
Epoxy amide 64 smoothly cyclized to 66 with Me2AlCl
in CH2Cl2 in good yield (68%). Prior to RuCl3/NaIO4
oxidation of the benzylic position, the free hydroxyl group
of alcohol 66 was protected as a methoxy methyl ether
(67). Cleavage of the tosyl group in phenanthridone 69
under reductive conditions using Na/naphthalene in
DME at -50 °C afforded amide 69 in 75% yield. Final
deprotection of the acetonide, TBS- and MOM-ether with
HCl/MeOH in one step49 provided the cis-C10b epimer
(50) Rinner, U.; Siengalewicz, P.; Hudlicky, T. Org. Lett. 2002, 4,
115.
(51) Doyle, T. J .; Hendrix, M.; Haseltine, J . Tetrahedron Lett. 1994,
35, 8295.
(52) (a) McNulty, J .; Mao, J .; Gibe, R.; Mo, R. W.; Wolf, S.; Pettit,
G. R.; Herald, D. L.; Boyd, M, R. Bioorg. Med. Chem. Lett. 2001, 11,
169. (b) Pettit, G. R.; McNulty, J .; Herald, D. L.; Doubek, D. L.;
Chapuis, J . C.; Schmidt, J . M.; Tackett, L. P.; Boyd, M. R. J . Nat. Prod.
1997, 60, 180.
(53) (a) Pettit, G. R.; Cragg, G. M.; Singh, S. B.; Duke, J . A.; Doubek,
D. L. J . Nat. Prod. 1990, 53, 176. (b) Pettit, G. R.; Pettit, G. R., III;
Backhaus, R. A. J . Nat. Prod. 1993, 56, 1682. (c) Pettit, G. R.; Melody,
N.; O’Sullivan, M.; Thompson, M. A.; Herald, D. L.; Coates, B. J . Chem.
Soc., Chem. Commun. 1994, 2725.
of 7-deoxypancratistatin, 70 ([R]25 ) +5.8 (c 0.49, CH3-
D
OH), mp >280 °C, Rf 0.1 CHCl3/MeOH 4:1).50 The
(49) Mandel, M.; Hudlicky, T. J . Org. Chem. 1993, 58, 2331. (b)
Hudlicky, T.; Mandel, M.; Rouden, J .; Lee, R. S.; Bachmann, B.;
Dubbing, T.; Yost, K. J .; Merola, J . S. J . Chem. Soc., Perkin Trans. 1
1994, 1553.
(54) Pettit, G. R.; Melody, N.; Herald, D. L. J . Org. Chem. 2001, 66,
2583.
(55) Kojima, K.; Mutsuga, M.; Inoue, M.; Ogihara, Y. Phytochemistry
1998, 48, 1199.
8734 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
SCHEME 11
SCHEME 12
CNS SF-295 (0.29), colon KM 20L2 (0.22), lung NCI-
H460 (0.29), melanoma SK-MEL-5 (0.23), ovary OVCAR-3
(0.24), renal A498 (0.47), and leukemia P388 (0.44), but
the enantiomer with the opposite absolute configuration,
ent-7-deoxypancratistatin (ent-4), was about 10-fold less
active exhibiting GI50 values of 2.0-3.4 µg/mL. Among
the truncated substances, only alcohol 77 (shown in
Scheme 12) gave any indication of cancer cell line
inhibition with GI50 5.3 µg/mL against pancreas-a BX-
PG-3 and 8.5 µg/mL with lung NCI-H460. The evalua-
tion of the cis epimer 70 against the six major human
cell lines found this compound to be inactive. This finding
is interesting from the viewpoint of providing useful
information about the precise stereochemical require-
ments for activity. Note for example that the opposite
configuration (in 7-deoxypancratistatin) provides for
moderate activity as does the sp2 hybridization found in
lycoricidine and narciclasine. Several derivatives related
to the positional isomer 5346 have been tested against
the same cell lines. Of these compounds, two were found
to be moderately active 79 and 80, which showed GI50
values of less than 10 (µg/mL) against the breast cancer
cell line MCF-7. Of the compounds related to the cis-fused
phenanthridine nucleus of cis-7-deoxypancratistatin 70
only 66 showed similar levels of activity against the cell
line MCF-7. These results again emphasize the impor-
J . Org. Chem, Vol. 67, No. 25, 2002 8735

Hudlicky et al.
a 12-L fermentor containing 8 L of medium adjusted to pH
7.0 (60.0 g of KH2PO4, 16.0 g of citric acid, 40.0 g of MgSO4,
9.6 mL of concentrated H2SO4, 9.6 mL of a 270.0 g/L solution
of ferric ammonium citrate, 16.0 mL of a trace metal solution,
0.7 mL of antifoam, 2.69 g of thiamine hydrochloride, and 800
mg of ampicillin), and the cells were grown for approximately
26 h to an OD ) 70 (λ ) 660 nm). 1,3-Dibromobenzene (50.0
g, 0.32 mol) was added in portions to the culture, and the diol
production was checked every 20 min by measuring a char-
acteristic adsorbance peak in the UV region (λ ) 282 nm). After
all metabolic activity ceased (or no more diol formation was
observed by UV), the fermentation was stopped, and the pH
was adjusted to 7.5 with NH4OH. The cells were separated
from the broth by centrifugation at 7000 rpm for 20 min, and
the resulting clear solution was saturated with sodium chloride
and extracted with ethyl acetate. The organic layer was dried
over anhydrous MgSO4, and the solvent was removed under
reduced pressure. The crude diol was purified by recrystalli-
zation (methylene chloride/pentane) to yield 7 as a yellowish
solid. Because of its instability to storage this material has to
be used quickly following its isolation. Yield: 3-4 g/L; Rf 0.4
(hexanes/ethyl acetate, 1:1); mp 80-81 °C; [R]25D +21.3 (c 1.1,
tance of a nearly intact pancratistatin (5) molecule
including the phenolic hydroxyl for retaining maximum
(e.g., P388 leukemia, GI50, 0.03 µg/mL) cancer cell inhibi-
tory properties.11,53,54
Con clu sion
It appears that major improvements in the synthesis
of important antitumor alkaloids of the Amaryllidaceae
group have been attained. Our results provide for a
synthesis of narciclasine that is only 12 steps and 8
operations. Certainly this brevity begins to support a case
for total synthesis as a solution to a supply for natural
sources. On the other hand, the several generations of
syntheses of 7-deoxypancratistatin, its enantiomer and
its 10b-epimer have witnessed only slight improvements
over the first generation disclosure of a 14-step prepara-
tion of the most important member of this class, pan-
cratistatin. Our 1995 disclosure of the first asymmetric
synthesis of this alkaloid still stands as the shortest on
record, due in no small part to the incorporation of
enzymatic dioxygenation of aromatics into the synthetic
strategy. Such oxygenation not only introduces the
required asymmetry but plays a key role in all subse-
quent stereochemical events that are necessary for the
attainment of the target. This strategy is at the core of
all of our approaches to these compounds and is one of
the major reasons for their brevity.
If major improvements in brevity and yields are to
materialize, the synthetic strategy that is utilized must
lead to the target in 6-8 steps. The experimental
difficulties with such a goal are resident in the function-
ality at C1 and C10b in the fully functionalized alkaloid.
By contrast, narciclasine, which bears unsaturation at
these two centers, is attainable more easily.
Perhaps the solution to the brevity issue could be
achieved by the discovery of a new method for the regio-
and steroselective hydration of narciclasine, a strategy
attended to by many recent investigatons55 with no
simple solution in sight.
acetone); IR (KBr) ν 3255, 1588 cm-1 1H NMR (CDCl3, 300
;
MHz) δ 6.43 (dd, J ) 1.5, 0.9 Hz, 1 H), 6.25 (dd, J ) 4.2, 1.5
Hz, 1 H), 4.41 (dd, J ) 6.3, 4.2 Hz, 1 H), 4.29 (dd, J ) 6.3, 0.9
Hz, 1 H), 2.80 (bs, 2 H); 13C NMR (acetone-d6 75.4 MHz) δ
131.7, 130.3, 129.9, 114.9, 72.1, 71.0; MS (-)ESI CH3COO-
m/z 271(81Br + 81Br (M - H)-) 269(81Br + 79Br (M - H)-), 267-
(79Br + 79Br (M - H)-). Anal. Calcd for C6H6Br2O2‚H2O
(phenol) C, 28.61; H 1.60. Found: C, 28.22; H 1.89.
1 , 8 -D i b r o m o -1 1 -c a r b o m e t h o x y -4 , 4 -d i m e t h y l -
(1R,2S,6S,7S)-3,5,10,11-tr ioxa a za tr icyclo[5.2.2.02,6]-8-u n -
d ecen e (9). To a solution of diol 7 (1.5 g, 5.6 mmol) in 2,2-
dimethoxypropane (72 mL) was added a catalytic amount of
p-toluenesulfonic acid. After complete consumption of starting
material (TLC analysis), the solution was cooled to 0 °C before
water (6 mL) was added. On a preparative scale, the inter-
mediate acetonide was not isolated (analytical samples of 4,6-
d ibr om o-2,2-d im eth yl-(3a S,7a S)-ben zo[d ](1,3)-d ioxole (8)
were purified by flash column chromatography). Data for the
intermediate are as follows: Rf 0.5 (hexanes/ethyl acetate 4:1);
[R]26D +23.3 (c 1.0, C2H5OH); 1H NMR (DMSO-d6, 500 MHz) δ
6.56 (m, 1 H), 6.40 (dd, J ) 4.4, 1.2 Hz, 1 H), 4.80 (d, J ) 8.8
Hz, 1 H), 4.76 (dd, J ) 8.7, 4.4 Hz, 1 H), 1.33 (s, 3 H), 1.30 (s,
3 H); 13C NMR (DMSO, 125 MHz) δ 129.3, 127.2, 125.8, 117.4,
106.3, 74.3, 73.5, 27.0, 25.2.
NaIO4 (1.2 g, 5.6 mmol) was added to the reaction vessel
before methyl carbamate (0.59 g, 5.6 mmol, in 10 mL of
methanol) was added dropwise. After addition, the solution
was allowed to warm to room temperature and stirred for 16
h. Upon completion of the reaction (TLC analysis), an excess
of saturated aqueous sodium bisulfite was added carefully until
a light straw color was obtained. The mixture was extracted
with Et2O (3 × 100 mL), the organic phase was washed with
brine (2 × 15 mL) and dried over MgSO4, and the solvent was
removed in vacuo. The reaction product was isolated by flash
column chromatography (hexanes/ethyl acetate 7:3) affording
1.3 g (60%) of 9 as a colorless solid. Rf 0.3 (hexanes/ethyl
In the area of structure-activity relationships, we have
provided additional results and evidences that a full
structural core, with the natural stereochemical relation-
ship is required for high level of activity. Our efforts will
now be focused solely on further improvements in the
brevity of synthetic approaches to these fascinating
compounds. We look forward to reporting new results in
due course.
acetate 7:3); mp 150-152 °C; [R]25 +36.4 (c 1.1, CHCl3); IR
D
(KBr) ν 1724, 1601 cm-1; 1H NMR (C6D6, 500 MHz) δ 6.37 (dd,
J ) 2.3, 0.9 Hz, 1 H), 5.13 (dd, J ) 4.4, 2.3 Hz, 1 H), 4.24 (dd,
J ) 6.9, 1.0 Hz, 1 H), 4.07 (dd, J ) 6.9, 4.3 Hz, 1 H), 3.26 (s,
(56) All nonhydrolytic reactions were carried out under an argon
atmosphere. Glassware used for moisture sensitive reactions was
flame-dried with an internal inert gas sweep. THF was distilled from
sodium benzophenone. Analytical TLC was performed on silica gel 60-F
Exp er im en ta l Section
3,5-Dibr om o-(1S,2S)-3,5-cycloh exa d ien e-1,2-d iol (7).56
Escherichia coli J M109 (pDTG601A) was grown overnight at
35 °C with continuous shaking (150 rpm) in an enriched
medium (9.6 g of K2HPO4, 8.4 g of KH2PO4, 3.0 g of (NH4)2-
SO4, 9.0 g of yeast extract, 60 mg of ampicillin, dissolved in
600 mL of tap water). The preculture was then transferred to
plates. Flash chromatography was performed using Kieselgel 60
254
(230-400 mesh). IR spectra were recorded as neat samples on a Perkin-
Elmer 1600 Series FT spectrometer. 1H and 13C NMR spectra were
obtained on a Varian 300 or 500 MHz instrument. Proton and carbon
chemical shifts are reported in ppm, relative to chloroform (7.24 and
77.23 ppm), respectively. Mass spectra were recorded on a Finnigan-
Matt 95 instrument.
8736 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
3 H), 1.20 (s, 3 H), 0.88 (s, 3 H); 13C NMR (C6D6, 125 MHz) δ
158.2, 132.9, 121.2, 111.5, 87.9, 81.2, 74.6, 61.7, 53.4, 25.5, 24.9;
MS (FAB) m/z 401 (81Br + 81Br, [M + H]+), 400 (81Br + 79Br,
56.6, 52.7, 47.9, 27.4, 25.9; MS (CI): 392 ([M + H]+, 100), 391
(M+, 92), 291 (18), 187 (7); HRMS Calcd for C19H22NO8:
392.1345. Found: 392.1320. Anal. Calcd for C19H21NO8: C,
58.31; H, 5.41; N 3.58. Found: C, 58.61; H, 5.56; N, 3.29.
[M + H]+), 399 (79Br + 79Br, [M + H]+); HRMS calcd for C11H14
-
-
NBr2O5: 399.9219; Found: 399.9195. Anal. Calcd for C11H13
NBr2O5: C 33.11, H 3.28, N 3.51. Found: C, 33.23; H 3.29; N,
3.43.
Ta n d em Su zu k i Cou p lin g-Oxa zin e Red u ction . To a
solution of Pd(PPh3)4 (290 mg, 0.25 mmol) of benzene (45 mL)
were added bromide 9 (2.0 g, 5.0 mmol), aq 2 M Na2CO3 (5
mL), and borate 10 (1.2 g, 6.0 mmol) in ethanol (2 mL). The
reaction mixture was stirred at reflux for 8 h (total consump-
tion of starting material) then Mo(CO)6 (1.0 g, 3.8 mmol) was
added. After 12 h, the resulting heterogeneous reaction
mixture was allowed to cool to room temperature, and the
mixture was filtered through a pad of silica gel. The layers
were separated, and the aqueous phase was extracted with
ethyl acetate. The organic phase was dried over MgSO4, the
solvent removed under reduced pressure, and the residue
purified by flash column chromatography affording 600 mg
(31%) of product 14.
4-Meth oxyben zo[d ][1,3]d ioxole-6-bor on ic Acid (10). To
a solution of 6-bromo-4-methoxybenzo[d][1,3]dioxole (3.0 g,
13.0 mmol) in anhydrous THF (55 mL) cooled to -78 °C was
added dropwise 0.7 M tert-butyllithium in hexane (10.0 mL).
During the addition the solution turned dark purple. After 15
min, triethyl borate (3.1 mL, 18.2 mmol) was added dropwise.
The dark purple color vanished 5 min after addition of the
reagent was complete. After 2 h at -78 °C, the reaction was
quenched with saturated aq NH4Cl. Ethyl acetate (50 mL) and
water (30 mL) were added, the layers were separated, and the
aqueous phase was extracted with EtOAc (4 × 30 mL). The
combined organic layer was washed with brine (2 × 15 mL),
dried over MgSO4, and concentrated to afford 2.5 g (97%) of
10 as a white-gray solid which decomposed on silica gel
chromatography but was pure enough to be used for the next
7 -A m i n o c a r b o m e t h y o x y -2 , 2 -d i m e t h y l -6 -( 7 -
m et h oxyb en zo[d ][1,3]d ioxol-5-yl)-(3a R,4R,7R,7a S)-4,7-
d ih yd r oben zo[d ][1,3]d ioxol-4-ol (22). To a stirred solution
of ketone 14 (1.30 g, 3.32 mmol) in methanol (22 mL) was
added cerium chloride (1.23 g, 4.98 mmol). After 5 min, the
mixture was cooled to 0 °C, and NaBH4 (138 mg, 3.65 mmol)
was added. The reaction mixture was stirred at 0 °C until total
consumption of starting material (30 min). The reaction was
quenched by adding a few drops of 50% acetic acid to neutral
pH. Water (50 mL) and methylene chloride (50 mL) were
added, and the heterogeneous mixture was extracted with
methylene chloride (4 × 20 mL). The organic layer was washed
with water (3 × 15 mL) and brine (2 × 15 mL). The combined
organic layer was dried over MgSO4, and the solvent was
removed under reduced pressure. The residue was purified by
flash column chromatography using gradient mixtures of ethyl
acetate and hexanes affording 22 (400 mg, 50%) as colorless
solid. (Note: On a smaller scale, 200 mg (0.511 mmol) of
starting material 14, 174 mg of 23 (80%) was isolated); Rf 0.2
1
step. Mp > 200 °C; H NMR (CD3OD, 300 MHz) δ 6.96 (s, 1
H), 6.81 (s, 1 H), 5.82 (s, 2 H), 3.79 (s, 3 H); 13C NMR (CD3OD,
75 MHz) δ 115.4, 108.2, 103.1 (3 C), 102.3, 57.3.
1 -B r o m o -1 1 -c a r b o m e t h y o x y -4 ,4 -d i m e t h y l -8 -(7 -
m eth oxyben zo[d ][1,3]d ioxol-5-yl)-(1R,2S,6S,7S)-3,5,10,11-
tr ioxa a za tr icyclo[5.2.2.02,6]-8-u n d ecen e (13). To a solution
of Pd(PPh3)4 (14.5 mg, 0.05 mmol) in benzene (3 mL) were
added bromide 9 (100 mg, 0.26 mmol) and aq 2 M Na2CO3 (1
mL). Borate 10 (64 mg, 0.30 mmol) in ethanol (2 mL) was
added, and the mixture was stirred at reflux until total
consumption of the starting material (12 h). The product was
extracted with Et2O (3 × 25 mL), and the organic phase was
washed with 5% hydrochloric acid (10 mL) and brine (3 × 10
mL) and then dried over MgSO4 before the solvent was
removed under reduced pressure. The residue was purified by
flash column chromatography (hexanes/ethyl acetate) affording
13 (52 mg, 44%). Rf 0.7 (hexanes/ethyl, acetate 7:3); mp 158-
160 °C; [R]25D +37.1 (c 1.0, CHCl3); IR (KBr) ν 4214, 3019, 2400,
1214 cm-1; 1H NMR (C6D6, 500 MHz) δ 6.82 (d, J ) 1.3 Hz, 1
H), 6.73 (d, J ) 1.4 Hz, 1 H), 6.48 (dd, J ) 2.1, 1.1 Hz, 1 H),
5.45 (dd, J ) 4.1, 2.0 Hz, 1 H), 5.23 (m, 1), 4.52 (dd, J ) 7.0,
1.0 Hz, 1 H), 4.31 (dd, J ) 7.1, 4.3 Hz, 1 H), 3.43 (s, 3 H), 3.24
(s, 3 H), 1.12 (s, 3 H), 0.95 (s, 3 H); 13C NMR (CDCl3, 75 MHz)
δ 158.3, 149.4, 143.8, 143.7, 136.4, 129.7, 124.0, 111.7, 106.1,
101.8, 100.3, 87.8, 81.2, 74.2, 56.6, 55.9, 54.1, 25.8, 25.3; FAB
MS m/z 472 (81Br [M + H]+), 470 (79Br [M + H]+), 332, 290,
154; HRMS: Calcd for C19H21N81BrO8: 472.0434. Found:
472.0423; Calcd for C19H21N79BrO8: 470.0451. Found: 470.0360.
Anal. Calcd for C19H20NBrO8: C, 48.53; H, 4.29; N, 2.98.
Found: C, 48.52; H, 4.33; N, 2.90.
(ethyl acetate); mp: 91-94 °C; [R]25 -14.4 (c 0.8, CHCl3); IR
D
(KBr) ν 2820, 2660, 1955, 1460 cm-1
;
1H NMR (CDCl3, 300
MHz) δ 6.54 (s, 1 H), 6.53 (s, 1 H), 6.05 (s, 1 H), 5.92 (s, 2 H),
4.65 (m, 4 H), 4.40 (d, J ) 9 Hz, 1 H), 3.85 (s, 3 H), 3.64 (s, 3
H), 2.88 (d, J ) 10 Hz, 1 H), 1.30 (s, 3 H), 1.27 (s, 3 H); 13C
NMR (CDCl3, 75 MHz) δ 156.5, 149.1, 143.5, 137.0, 135.2,
133.6, 130.6, 109.2, 105.6, 101.5, 99.8, 66.5, 56.8, 52.3, 51.0,
26.1, 24.5; MS (CI) 392 ([M - H]+), 334, 259, 173; HRMS Calcd
for C19H24NO8: 394.1502. Found: 394.1478. Anal. Calcd for
C
19H23NO8: C, 58.01; H 5.89. Found: C, 58.07; H, 6.29.
7 -A m i n o c a r b o m e t h y o x y -2 , 2 -d i m e t h y l -6 -( 7 -
m et h oxyb en zo[d ][1,3]d ioxol-5-yl)-(3a R,4S,7R,7a S)-4,7-
Dih yd r oben zo[d ][1,3]d ioxol-4-yl Ben zoa te (23). To a so-
lution of alcohol 22 (200 mg, 0.51 mmol) in anhydrous THF
(10 mL) were added tributylphosphine (0.26 mL, 1.02 mmol),
benzoic acid (125 mg, 1.02 mmol), and DEAD (0.16 mL, 1.02
mmol) at 25 °C, and the solution was stirred until total
consumption of starting material (2 h). The mixture was
concentrated, and the residue was purified by flash column
chromatography using hexanes/ethyl acetate (6:4) affording
ester 23 as an oil (133 mg, 52%). Rf 0.5 (hexanes/ethyl acetate,
6:4); [R]25D -12.22 (c 1.0, CHCl3); IR (solution in CHCl3) ν 3420,
1745, 1720, 1492 cm-1; 1H NMR (C6D6, 300 MHz) δ 8.08 (d, J
) 6.6 Hz, 2 H), 7.75 (d, J ) 5.5 Hz, 1 H), 6.89 (s, 1 H), 6.80 (d,
J ) 1.1 Hz, 1 H), 6.28 (d, J ) 6.6 Hz, 1 H), 5.85 (dd, J ) 6.6,
1.4 Hz, 1 H), 5.40 (s, 2 H), 5.28 (s, 2 H), 4.58 (d, J ) 6.9 Hz, 1
H), 4.37 (d, J ) 6.9 Hz, 1 H), 3.92 (q, J ) 7.1 Hz, 1 H), 3.80 (q,
J ) 7.1 Hz, 1 H), 3.50 (s, 3 H), 3.40 (s, 3 H), 1.29 (s, 3 H), 1.13
(s, 3 H); 13C NMR (C6D6, 75 MHz) δ 165.0, 156.2, 149.9, 145.4,
144.3, 133.6, 133.4, 131.6, 129.9, 121.3, 108.7, 107.1, 101.43,
100.4, 78.0, 74.9, 69.0, 63.5, 62.4, 56.3, 52.1, 50.5, 26.5, 24.4,
14.2, 13.6; MS (CI): 497 (M+), 480, 376, 318, 281, 215, 105;
HRMS Calcd for C26H27NO9 ([M]+): 497.1686, Found: 497.1716;
HRMS Calcd for C26H28NO9 ([M + H]+): 498.1764, Found:
498.1752.
7 -A m i n o c a r b o m e t h y o x y -2 , 2 -d i m e t h y l -6 -( 7 -
m e t h o x y b e n zo [d ][1,3]d io x o l-5-y l)-(3a S ,7R ,7a S )-4,7-
d ih yd r oben zo[d ][1,3]d ioxol-4-on e (14). To a degassed so-
lution of oxazine 13 (370 mg, 0.78 mmol) in benzene (16 mL)
was added tris(trimethylsilyl)silane (39 mg, 1.57 mmol). The
reaction mixture was heated to reflux, and a catalytic amount
of AIBN was added. Heating and stirring was continued for
90 min (total consumption of starting material) before the
reaction mixture was allowed to cool to room temperature. The
solvent was removed under reduced pressure and the residue
purified by flash column chromatography using a gradient of
hexanes and ethyl acetate affording 14 (200 mg, 65%); Rf 0.50
(ethyl acetate); mp 81-84 °C; [R]26 -26.8 (c 1.1 CHCl3); IR
D
(neat on NaCl plates) ν 2806, 2706, 1980, 1750 cm-1; 1H NMR
(CDCl3, 300 MHz) δ 6.83 (s, 1 H), 6.74 (d, J ) 2.2 Hz, 1 H),
6.38 (s, 1 H), 5.99 (s, 2 H), 5.47 (d, J ) 8.2 Hz, 1 H), 5.24 (d,
J ) 8.2 Hz, 1 H), 4.63 (dd, J ) 5.0, 2.2 Hz, 1 H), 4.42 (d, J )
5.1 Hz, 1 H), 3.87 (s, 3 H), 3.65 (s, 3 H), 1.37 (s, 3 H), 1.28 (s,
3 H); 13C NMR (CDCl3, 75 MHz) 195.7, 156.2, 153.2, 149.6,
143.8, 138.0, 129.9, 123.6, 110.4, 107.5, 102.2, 100.9, 77.1, 73.4,
J . Org. Chem, Vol. 67, No. 25, 2002 8737

Hudlicky et al.
6-Am in oca r b om et h oxy-1,2-d ih yd r oxy-5-(7-m et h oxy-
ben zo-[d ][1,3]d ioxol-5-yl)-4-cycloh exen e-1-yl Ben zoa t e
(24). To a solution of benzoate 23 (120 mg, 0.241 mmol) in
methanol (7 mL) was added a catalytic amount of Dowex 50
× 8-100 ion-exchange resin. After the mixture was stirred
for 12 h at room temperature (until no more starting material
could be detected by TLC), the resin was removed by filtration.
The solvent was evaporated under reduced pressure to afford
the intermediate diol. The crude product was dissolved in
pyridine (1 mL, 12.5 mmol) and cooled to 0 °C. Acetic
anhydride (0.5 mL, 5.3 mmol) and a catalytic amount of DMAP
were added. The reaction mixture was stirred at room tem-
perature until total consumption of the starting material (3
h). Ether (5 mL) and water (2 mL) were added, and the organic
phase washed with 2 mL aliquots of 10% aq copper(II) sulfate
and then 2 mL of brine. The organic layer was dried over
MgSO4, the solvent removed under reduced pressure, and the
residue purified by flash column chromatography (hexanes/
ethyl acetate) affording benzoate 24 as colorless solid (44.8 mg,
total consumption of starting material (TLC analysis), The
resin was removed by filtration and the solvent removed under
reduced pressure affording 6 mg (80%) of the known derivative
of narciclasine 27;6c Rf 0.40 (4:1 CH2Cl2-MeOH); [R]26 +204
D
(c 0.3, DMSO); IR (KBr) ν 3423 (br.), 2952, 2366, 1631, 1465
1
cm-1; H NMR (CD3OD, 300 MHz) δ 6.91 (s, 1 H), 6.17 (m, 1
H), 6.08 (d, J ) 1.1 Hz, 1 H), 6.02 (d, J ) 1.1 Hz, 1 H), 4.24
(m, 2 H), 3.98 (s, 3 H), 3.90 (m, 2 H); 13C NMR (CD3OD, 75
MHz) δ 154.1, 145.5, 140.2, 135.2, 133.7, 123.7, 115.0, 103.6,
100.5, 74.2, 71.0, 70.8, 61.1, 53.6; MS (LC/ESI MS): 653.5 ([M
+ H + M]+), 322 ([M + H]+).
2,3,4-Tr ih yd r oxy-7-m e t h oxy-(2S ,3R ,4S ,4a R )-2,3,4,6-
tetr a h yd r o[1,3]d ioxolo[4,5-j]p h en a n th r id in -6-on e (7-Me-
th yln a r cicla sin e) (27). This derivative of (+)-narciclasine
was prepared as described in the literature.6c A pure sample
of natural narciclasine (3) (15 mg) was dissolved in excess
freshly prepared diazomethane in ethanol/acetonitrile. The
reaction mixture was stirred for several hours until the yellow
color disappeared. The extent of the reaction was determined
by TLC, and the product was purified by flash column
chromatography using a mixture of methylene chloride and
methanol. All data obtained for this compound matched the
synthetic product, including 1H NMR and optical rotation.
34%); Rf 0.3 (hexanes/ethyl acetate 2:1); mp 112-115 °C; [R]26
D
-11.5 (c 1.0, CHCl3); IR (KBr) ν 3368 (br), 1750, 1720, 1602,
1
1521, 1447 cm-1; H NMR (CDCl3, 300 MHz) δ 8.04 (dd, J )
8.5, 1.7 Hz, 2 H), 7.57 (tt, J ) 7.4, 1.4 Hz, 1 H), 7.44 (t, J )
7.7 Hz, 2 H), 6.58 (s, 1 H), 6.57 (s, 1 H), 6.10 (d, J ) 3.0 Hz, 1
H), 5.94 (s, 2 H), 5.82 (dd, J ) 6.9, 3.0 Hz, 2 H), 5.54 (dd, J )
4.4, 2.5 Hz, 1 H), 5.49 (dd, J ) 7.1, 2.5 Hz, 1 H), 4.90 (m, 1 H),
4.80 (d, J ) 8.8 Hz, 1 H), 3.86 (s, 3 H), 3.64 (s, 3 H), 2.12 (s, 3
H), 2.03 (s, 3 H); 13C NMR (CDCl3, 75 MHz) δ 170.2, 169.9,
165.9, 149.2, 143.5, 133.4, 131.2, 129.8, 129.5, 128.5, 123.2,
106.2, 101.7, 100.6, 70.9, 69.6, 69.0, 56.6, 52.6, 51.0, 20.9, 20.8
(3 quaternary carbons below noise level); MS (FAB) 541 (M+,
2), 391 (60), 149 (100); HRMS Calcd for C27H27NO11: 541.1584.
Found: 541.1627.
[R]26 +219 (c 1.0, DMSO).
D
2,3,4,7-Tetr ah ydr oxy-(2S,3R,4S,4aR)-2,3,4,6-tetr ah ydr o-
[1,3]d ioxolo[4,5-j]p h en a n th r id in -6-on e (Na r cicla sin e) (3).
To a solution of crude triol 27 (15 mg, 0.047 mmol) in
anhydrous DMF (2 mL) was added anhydrous LiCl (10 mg,
0.24 mmol) under a stream of argon. The mixture was heated
to 120 °C until total consumption of starting material (4 h).
After the solvent was removed under reduced pressure, the
residue was adsorbed on silica gel and purified by flash column
chromatography (methylene chloride/methanol 4:1) affording
3 mg of narciclasine (20%). For a detailed study of the NMR
spectra of narciclasine see ref 6g. Rf 0.6 (CH2Cl2/MeOH, 4:1);
1H NMR (DMSO-d6, 500 MHz) δ 13.25 (s, 1 H), 7.88 (s, 1 H),
6.85 (s, 1 H), 6.15 (dd, J ) 4.5, 2.8 Hz, 1 H), 6.08 (m, 2 H),
5.19 (d, J ) 6.3 Hz, 1 H), 5.16 (d, J ) 5.6 Hz, 1 H), 5.01 (d, J
) 3.8 Hz, 1 H), 4.18 (ddd, J ) 8.6, 2.4, 1.4 Hz, 1 H), 4.01 (m,
1 H), 3.79 (ddd, J ) 8.0, 5.5, 2.2 Hz, 1 H), 3.69 (m, 1 H). Signals
at 13.25, 7.88, 5.19, 5.16, and 5.01 can exchange with deute-
rium on addition of deuterium oxide. A TOCSY experiment
confirmed the assigned structure. Optical rotation of this
compound matched that obtained by Rigby as well as the value
for the natural product.
3-(Meth oxyca r bon yl)-1-br om o-5,6-O-isop r op ylid en e-2-
oxa -3-a zobicyclo[2.2.2]oct-7-en e-5,6-d iol (30). To a solution
of the acetonide of (-)-(16) (9.6 g, 0.042 mol) in MeOH/H2O
(16:4, 150 mL) at 0 °C were added NaIO4 (8.9 g, 42 mmol) and
N-hydroxymethyl carbamate (3.8 g, 42 mmol). The reaction
mixture was allowed to warm to room temperature, and the
solution was stirred until total consumption of the starting
material (18 h). Water (100 mL) and concentrated aqueous
NaHSO3 (100 mL) were then added, and the resulting mixture
was extracted with CH2Cl2 (2 × 75 mL). The combined organic
layer was washed with brine and dried over MgSO4, and the
solvent was removed under reduced pressure The residue was
purified by flash column chromatography (hexane/ethyl ac-
etate, 4:1) to yield 30 as colorless solid (7.7 g, 70%). Rf 0.23
(hexanes/ethyl acetate, 4:1); [R]28D -8.3 (c 1.19 CHCl3);1H NMR
(300 MHz, CDCl3) δ 6.51 (dd, J ) 9.0, 1.5 Hz, 1H), 6.41 (m,
1H), 5.05 (m, 1H), 4.60 (d, J ) 2.0 Hz, 2H), 3.77 (s, 3H), 1.35
(s, 3H), 1.32 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 158.0, 134.0,
131.7, 111.5, 81.2, 74.1, 54.0, 53.0, 25.6, 25.4.
Data for the intermediate diol: 6-Am in oca r bom eth oxy-
1,2-d ih yd r oxy-5-(7-m eth oxyben zo-[d ][1,3]d ioxol-5-yl)-4-
cycloh exen e-1-yl Ben zoa te. 1H NMR (CDCl3, 300 MHz) δ
8.04 (d, J ) 8.0 Hz, 2 H), 7.75 (t, J ) 7.7 Hz, 1 H), 7.41 (t, J
) 7.7 Hz, 2 H), 6.58 (d, J ) 4.1 Hz, 2 H), 6.04 (d, J ) 2.8 Hz,
1 H), 5.93 (s, 2 H), 5.75 (dd, J ) 6.3, 3.6 Hz, 1 H), 4.85 (bs, 2
H), 4.20 (s, 1 H), 4.13 (s, 1 H), 3.84 (s, 3 H), 3.60 (s, 3 H), 2.02
(s, 1 H).
3,4-D i a c e t o x y -7-m e t h o x y -(2S ,3R ,4S ,4a R )-2,3,4,6-
t et r a h yd r o[1,3]d ioxolo[4,5-j]p h en a n t h r id in -6-on e-2-yl
Ben zoa te (25). To a solution of diacetate 24 (42 mg 0.08
mmol) and DMAP (28.4 mg, 0.23 mmol) in CH2Cl2 (2 mL)
cooled to -10 °C was added trifluoromethanesulfonic anhy-
dride (70 mL, 0.39 mmol). The reaction mixture was stirred
for 5 h at -10 °C to -5 °C and for 12 h at 0 °C. After total
consumption of starting material (TLC analysis), the solvents
were removed under reduced pressure, and THF (2 mL) was
added. The reaction mixture was cooled to 0 °C and two drops
of 2 M aq HCl was added. The mixture was stirred for 2 h,
and solid sodium bicarbonate was added. The solvent was
removed under reduced pressure and the residue purified by
flash column chromatography (hexanes/ethyl acetate, 6:4),
affording ester 25 as a yellow oil (13.8 mg, 41%); Rf 0.1
(hexanes/ethyl acetate, 2:1); [R]26 +22.4 (c 1.1, CHCl3); IR ν
D
3490 (br), 2940, 2858, 1660, 1613 cm-1; H NMR (CDCl3, 300
1
MHz) δ 8.04 (dd, J ) 1.5, 7.0 Hz, 2 H), 7.56 (tt, J ) 1.2, 7.3
Hz, 1 H), 7.43 (t, J ) 7.8 Hz, 2 H), 6.79 (s, 1 H), 6.25 (m, 1 H),
6.11 (s, 1H), 6.08 (bs, 1H), 6.05 (d, J ) 1.2 Hz, 1 H), 6.00 (d, J
) 1.2 Hz, 1 H), 5.57 (m, 2 H), 5.35 (dd, J ) 2.2, 8.9 Hz, 1 H),
4.57 (d, J ) 9.1 Hz, 1 H), 4.03 (s, 3 H), 2.13 (s, 3 H), 2.09 (s, 3
H); 13C NMR (CDCl3, 75 MHz) δ 133.6, 129.9, 128.6, 117.6,
102.0, 99.6, 71.6, 68.89, 68.2, 61.0, 50.0, 20.9, 20.8; HRMS
calcd. for C26H24NO10: 510.1400. Found: 510.1419.
2,3,4-Tr ih yd r oxy-7-m e t h oxy-(2S ,3R ,4S ,4a R )-2,3,4,6-
tetr a h yd r o[1,3]d ioxolo[4,5-j]p h en a n th r id in -6-on e (7-Me-
th yln a r cicla sin e) (27). To a solution of phenanthridone 25
(10 mg, 0.024 mmol) in methanol (2 mL) was added a caralytic
amount of Amberlyst A-21 weakly basic ion-exchange resin.
The mixture was stirred for 2 h at room temperature until
6-(N-Meth oxycar bon yl)am in o)-1,2-O-isopr opyliden ecy-
cloh ex-4-en -1,2,3-t r iol (15). To a solution of 30 (7.0 g, 22
mmol) in a mixture of THF (500 mL) and H2O (50 mL) was
added 4.15 g of Al (Hg) at 0 °C. The reaction mixture was
stirred at for 3 h 0 °C and then at room temperature until
total consumption of the starting material (12 h). The reaction
mixture was diluted with THF (250 mL) and stirred for 10
min, filtered through Celite, and concentrated in vacuo. The
8738 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
residue was purified by flash column chromatography (hex-
tion of 35 (300 mg, 9.74 mmol) in 20 mL of methanol was added
a spatula tip of Dowex-50W. The reaction mixture was allowed
to stir at room temperature for 20 h (total consumption of
starting material), the resin was removed by filtration, and
the solvent was removed under reduced pressure affording 260
mg of compound 36 (95%) as white solid. Rf 0.34 (chloroform/
anes/ethyl acetate, 1:2) to yield alcohol 15 (3.7 g, 65%); Rf: 0.57
(hexanes/ethyl acetate, 1:2); [R]28 +7.6 (c 1.20, CHCl3); 1H
D
NMR (300 MHz,CDCl3) δ 5.86 (dd, J ) 10.0, 2.7 Hz, 1 H), 5.74
(dd J ) 10.0, 1.6 Hz, 1 H), 5.50 (d, J ) 8.0 Hz, 1 H), 4.15 (m,
3 H), 4.02 (m, 1H), 3.60 (m, 4 H), 1.38 (s, 3 H), 1.28 (s, 3 H);
13C NMR (75 MHz, CDCl3) δ 157.1, 131.6, 130.0, 109.4, 79.60,
methanol, 8:1). Mp 190-202 °C (ethyl acetate/methanol); [R]28
D
8.0, 69.2, 52.6, 51.4, 27.2, 25.0; HMRS (CI) calcd for C11H19
-
-105.3 (c 0.8, MeOH); 1H NMR (300 MHz, CD3OD) δ 6.70 (m,
NO5: 244.1184; Found 244.1145. Anal. Calcd for C11H18NO5‚
1/2H2O: C; 52.17; H, 7.11; N, 5.53. Found: C, 52.10; H, 6.78;
N, 5.33.
3 H), 5.98 (m, 3 H), 5.70 (dd, J ) 9.5, 2.1 Hz, 1 H), 4.61 (s, 1
H), 4.27 (s, 1 H), 3.81 (m, 1 H), 3.60 (s, 3 H), 3.27 (m, 1 H); 13
C
NMR (75 MHz, CD3OD) δ 159.8, 149.0, 147.8, 137.2, 134.9,
127.8, 122.7, 109.6, 108.8, 102.1, 73.4, 67.9, 56.1, 52.3, 50.2.
(1R ,2R ,3R ,6S )-6-(N -C a r b o m e t h o x y )a m in o )-1,2-O -
isop r op ylid en ecycloh ex-4-en e-1,2,3-t r iol ((+)-17) a n d
(1S,2S,3S,6R)-6-(N-Ca r ebom eth oxy)a m in o-1,2-O-isop r o-
p ylid en e-3-a cetylcycloh ex-4-en e-1,2-d iol (33). Acetylation
product 31 (2.0 g, 7.0 mol) was suspended in 0.1 M phosphate
buffer (50 mL, pH ) 7.0, T ) 25 °C) and treated with PPL
Sigma Type II crude lipase (200 mg). The mixture was stirred
at room temperature, keeping the pH of the solution constant
by addition of 1 N aq NaOH (4.5 mL of 1 N NaOH was added
over 9 h). The reaction mixture was purified by flash chroma-
tography (hexanes/ethyl acetate 2:1), affording 0.60 g (35%)
of (+)-15 and 0.80 g of 33 (40%). mp: 98-100 °C; Rf 0.68
(hexanes/ethyl acetate, 1:2) [R]25D +25 (c 1.02, CHCl3); 1H NMR
(CDCl3) δ 5.86 (d, J ) 7.0 Hz, 1 H), 5.80 (d J ) 7.0 Hz, 1 H),
5.22 (m, 1 H), 5.00 (bs, 1 H), 4.28 (m, 1 H), 4.19 (m, 2 H), 3.65
(s, 3 H), 2.02 (s, 3 H), 1.42 (s, 3 H), 1.30 (s, 3 H)13C NMR (75
MHz, CDCl3) δ 170.0, 158.0, 131.0, 127.8, 109.3, 76.3, 76.0,
70.8, 52.3, 50.5, 26.9, 24.9, 21.1; HRMS calcd for C13H20NO6
286.1290, found 286.1292. Anal. Calcd for C13H20NO6: C,
54.54; H, 6.66; N, 4.89. Found: C, 54.41; H, 6.45; N, 4.83.
Met h yl N-[(1S,2S,3S,4S,5R,6R)-2-(1,3-Ben zod ioxol-5-
yl)-5,6-d ih yd r oxy-3,4-ep oxycycloh ex-1-yl]ca r ba m a te (37).
To a solution of olefin 36 (250 mg, 0.81 mmol) in benzene (20
mL) were added VO(acac)2 (18 mg, 0.065 mmol) and 5 M
t-BuOOH (1.0 mL). The reaction mixture was heated at 70 °C
for 5 h (total consumption of starting material). After the
solution was cooled to room temperature, the solvent was
removed under reduced pressure and the residue purified by
flash column chromatography (chloroform/methanol, 8:1) to
afford epoxide 37 (175 mg, 67%) as white solid. Rf 0.28
(chloroform/methanol, 8:1); mp 193-195 °C (chloroform/
methanol); [R]28 -65.8 (c 0.8, MeOH); 1H NMR (300 MHz,
D
CD3OD); 6.96 (d, J ) 8.0 Hz, 1 H), 6.80 (d, J ) 8.1 Hz, 1 H),
6.72 (d, J ) 8.0 Hz, 1 H) 5.90 (s, 2 H), 4.25 (t, J ) 5.0 Hz, 1
H), 3.78 (t, J ) 10.0 Hz,), 3.46 (s, 3 H), 3.38 (m, 3 H), 3.08 (d,
J ) 10.9 Hz, 1 H); 13C NMR (75 MHz, CD3OD) δ 160.0, 150.0,
148.3, 135.2, 123.5, 109.0, 108.7, 102.3, 73.2, 68.0, 60.0, 54.4,
52.3, 51.9, 48.3.
Met h yl N-[(1S,2S,3S,4R,5R,6R)-2-(1,3-Ben zod ioxol-5-
yl)-3,4,5,6-tetr a h yd r oxycycloh exyl]ca r ba m a te (38). To a
solution of epoxide 37 (170 mg, 0.49 mmol) in 5 mL of water
was added sodium benzoate (5 mg, 0.034 mmol). The mixture
was heated at 100 °C until total consumption of the starting
material (8 d). The solution was cooled to room temperature,
the water was removed in vacuo, and the residue was purified
by flash column chromatography (chloroform/methanol, 6:1),
affording aryl aminocyclitol 38 (130 mg, 80%) as white solid:
Rf 0.20 (chloroform/methanol, 8:1); mp 190-202 °C (ethyl
acetate/methanol); [R]28D +1.69 (c 0.95, MeOH); 1H NMR (300
MHz, CD3OD) δ 6.90 (s, 1 H), 6.77 (dd, J ) 8.0, 1.8 Hz, 1 H),
6.70 (d, J ) 8.0 Hz, 1 H), 5.85 (m, 2 H) 4.30 (m, 1 H), 4.00 (m,
2 H) 3.75 (m, 2 H), 3.50 (s, 3 H), 3.30 (s, 1 H), 3.18 (dd, J )
12.0, 2.0 Hz, 1 H); 13C NMR (75 MHz, CD3OD) δ 159.9, 148.6,
147.5, 134.9, 123.7, 110.9, 108.6, 102.0, 76.0, 73.5, 73.4, 71.8,
52.3, 51.3, 48.3.
Met h yl
(1S,4S,5R,6S)-4,5-(Isop r op ylid en ed ioxy)-7-
a zobicyclo[4.1.0]h ep t-2-en e-7-ca r boxyla te (32). To a solu-
tion of alcohol (+)-15 (2.22 g, 9.0 mmol) in freshly distilled
THF (100 mL) was added PPh3 (4.74 g) followed by DEAD (2.35
g, 13.5 mmol). The reaction mixture was stirred at room
temperature until total consumption of starting material (20
h). The solvent was removed under reduced pressure, and the
residue was purified by flash column chromatography (hex-
anes/ethyl acetate 3:2), affording compound 32 (1.24 g, 60%);
Rf 0.57 (hexanes/ethyl acetate, 3:2). [R]28 +92 (c 0.9, CHCl3);
D
1H NMR (300 MHz CDCl3) δ 6.07 (m, 1 H), 5.74 (dd, J ) 10.0,
1.6 Hz, 1 H), 4.82 (d, J ) 7.0 Hz, 1 H), 4.45 (t, J ) 7.0 Hz, 1
H), 3.74 (s, 3 H), 3.05 (d, J ) 4.9 Hz, 1H), 2.98 (t, J ) 5.0 Hz,
1 H), 1.41 (s, 6 H); 13C NMR (75 MHz, CDCl3) δ 163.0, 130.9,
122.5, 110.4, 70.9, 70.0, 53.8, 34.5, 33.1, 27.8, 26.1.
Meth yl N-[(1S,2S,5S,6R)-2-(1,3)-Ben zod ioxol-5-yl)-5,6-
(isop r op ylid en ed ioxy)cycloh ex-3-en -1-yl]ca r ba m a te (35).
To a solution of 5-bromo-1,3-benzodioxole 34 (12.3 mL, 53.2
mmol) in freshly distilled THF (500 mL) was added 2.5M
n-BuLi in hexanes (21.3 mL) at -78 °C. The reaction mixture
was stirred for 60 min at -78 °C before CuCN (2.39 g, 26
mmol) was added. After 90 min at -78 °C, aziridine 32 (3.0 g,
13 mmol) in THF (50 mL) was added followed by BF3‚Et2O
(0.8 mL). After 3 h, the mixture was allowed to warm to room
temperature. Saturated aq NH4Cl (150 mL) was added, the
layers were separated, and the aqueous phase was extracted
with ethyl acetate (4 × 100 mL). The combined organic layers
were dried over MgSO4, the solvent was removed under
reduced pressure, and the residue was purified by flash column
chromatography (hexanes/ethyl acetate, 4:1) to give carbamate
35 (0.936 g, 20%) as a white solid. Rf 0.31 (hexanes/ethyl
Met h yl N-[(1S,2S,3S,4R,5R,6R)-2-(1,3-Ben zod ioxol-5-
yl)-3,4,5,6-tetr a a cetoxycycloh exyl]ca r ba m a te (39). To a
solution of aryl aminocyclitol 38 (50 mg, 0.15 mmol) in pyridine
(1.0 mL) was added acetic anhydride (1.0 mL). The reaction
mixture was stirred at room temperature for 16 h (total
consumption of starting material). The solvent was removed
in vacuo and the residue purified by flash column chromatog-
raphy (hexanes/ethyl acetate, 1:1) to afford tetraacetate 39 (60
mg, 82%) as white solid; Rf 0.41 (hexanes/ethyl acetate 2:3);
mp 108-111 °C (hexanes/ethyl acetate); [R]28 -13.9 (c 0.95,
D
CHCl3); 1H NMR (300 MHz, CDCl3) δ 6.72 (m, 3H), 5.93 (s,
2H), 5.35 (s, 1H), 5.09 (m, 2H), 4.70 (m, 1H), 4.40 (bd, J ) 9.0
Hz, 1H), 3.54 (s, 3H), 3.22 (d, J ) 11.4 Hz, 1H), 2.18 (s, 6H),
2.02 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 170.5, 169.3, 168.8,
168.3, 156.6, 147.7, 147.0, 129.6, 122.2, 109.1, 108.2, 101.0,
72.1, 71.1, 68.7, 68.1, 52.2, 48.1, 47.2, 20.8, 20.6.
acetate, 3:2); mp 189-190 °C (hexanes/ethyl acetate); [R]28
D
1
-81.7 (c 0.8, CHCl3); H NMR (300 MHz, CDCl3) δ 6.74 (d, J
(1S,2R,3R,4R,4a S,11S)-1,2,3,4-Tetr a a cetoxy-1,2,3,4,4a ,-
11-h e xa h yd r o-1,3-d ioxolo[4,5-j]p h e n a n t h r id in -6(2H )-
on e (40). To a solution of tetraacetate 39 (33 mg, 0.65 mmol)
in CH2Cl2 (3 mL) were added trifluoromethanesulfonic anhy-
dride (60 mg, 0.216 mmol) and DMAP (24 mg, 0.195 mmol).
The reaction mixture was stirred at 5 °C for 18 h (total
consumption of starting material), and then the solvent was
removed in vacuo. THF (2 mL) and 2 N aq HCl (0.2 mL) were
added, and the mixture was stirred at room temperature for
) 8.0 Hz, 1 H), 6.67 (d, J ) 1.8 Hz, 1 H), 6.62 (dd, J ) 8.0, 2.0
Hz, 1 H), 5.97 (m, 1 H), 5.94 (m, 1 H), 5.90 (m, 1 H), 4.68 (t, J
) 5.0 Hz, 1 H), 4.60 (bs, 1 H), 4.40 (bs, 1 H), 3.54 (s, 3 H), 3.40
(m, 1 H), 1.54 (s, 3 H), 1.41 (s, 3 H); 13C NMR (75 MHz, CDCl3)
δ 156.0, 147.0, 146.0, 136.0, 132.0, 123.5, 121.5, 109.0, 108.4,
108.2, 101.0, 76.4, 72.4, 57.0, 51.0, 45.0, 28.2, 25.9.
Met h yl N-[(1S,2R,5S,6R)-2-(1,3-Ben zod ioxol-5-yl)-5,6-
d ih yd r oxycycloh ex-3-en -1-yl]ca r ba m a te (36). To a solu-
J . Org. Chem, Vol. 67, No. 25, 2002 8739

Hudlicky et al.
6 h. The mixture was quenched with saturated NaHCO3, and
the aqueous layer was extracted with ethyl acetate (3 × 5 mL).
The combined organic layer was dried over MgSO4, the solvent
removed under reduced pressure, and the residue purified by
flash column chromatography (hexanes/ethyl acetate, 1:1) to
afford the desired compound 40 (20 mg, 61%) as white solid.
Rf 0.48 (hexanes/ethyl acetate, 1:2) mp 231-237 °C (hexanes/
ethyl acetate); [R]28D -73.4 (c 0.8, CHCl3); 1H NMR (500 MHz,
CDCl3) δ 7.60 (s, 1 H), 6.56 (s, 1 H), 6.3 (bs, 1 H) 6.02 (d, J )
8.8 Hz, 2 H), 5.57 (t, J ) 2.9 Hz, 1 H), 5.47 (t, J ) 2.9 Hz, 1
H), 5.22 (t, J ) 2.9 Hz, 1 H), 5.19 (d, J ) 3.1 Hz, 1 H), 4.29
(dd, J ) 12.8, 11.1 Hz, 1 H), 3.45 (dd, J ) 13.4, 2.7 Hz, 1 H)
2.15 (s, 3 H), 2.09 (s, 3 H), 2.07 (s, 3 H), 2.03 (s, 3 H); 13C NMR
(125 MHz, CD3OD) δ 170.0, 165.0, 151.7, 147.0, 131.0, 123.3,
108.5, 103.7, 101.9, 71.3 67.7, 66.4, 66.3, 48.2, 39.7, 20.8, 20.7,
20.6.
en t-7-Deoxyp a n cr a tista tin (en t-4). To a suspension of K2-
CO3 (50 mg) in methanol (5 mL) was added compound 40 (10
mg, 0.014 mmol). The reaction mixture was stirred at room
temperature until total consumption of the starting material
(15 h), and then the precipitate was removed by filtration. The
solvent was removed in vacuo affording ent-deoxypancratista-
tin (12 mg, 72%) as white solid; Rf 0.29; (chloroform/methanol,
4:1); mp 304-307 °C. [R]28D -75.7 (c 0.8, DMF); 1H NMR (500
MHz,DMSO-d6) δ 7.31 (s, 1 H), 6.90 (s, 1 H), 6.83 (s, 1 H),
6.04 (s, 2 H), 5.36 (d, J ) 4 Hz, 1 H), 5.05 (m, 2 H), 4.77 (d, J
) 7.5 Hz, 1 H), 4.31 (m, 1H), 3.97 (q, J ) 4.0 Hz, 1 H), 3.84
(m, 1 H), 3.73 (m, 2 H), 2.98 (d, J ) 12.0 Hz, 1H).
41.7, 38.0, 27.5, 25.2, 22.0; HRMS (CI) calcd for C16H20O8NS2:
418.0630. Found: 418.0639. Anal. Calcd for C16H19NO8S2: C,
46.04; H, 4.59. Found: C, 46.18; H. 4.49.
(1S,2R,3R,4S,5S,6S)-3,4-(Isop r op ylid en ed ioxy)-5-h y-
dr oxy-6-ben zoyl-7-(4′-m eth ylph en ylsu lfon yl)-7-azabicyclo-
[4.1.0]h ep ta n e (56a ). To a solution of cyclic sulfate 55 (3.20
g, 7.66 mmol) in dry DMF (20 mL) was added ammonium
benzoate (2.69 g, 19.2 mmol). The reaction mixture was heated
at 70 °C for 2 h (total consumption of starting material). The
reaction mixture was cooled to 40 °C, and the DMF was
removed under reduced pressure. The residue was suspended
in THF (100 mL), and 4 drops of H2O and H2SO4 was added.
The resulting mixture was stirred for 1 h before it was
quenched with saturated aq NaHCO3 (150 mL) and then
diluted with CH2Cl2 (100 mL). The organic phase was ex-
tracted with CH2Cl2 (3 × 100 mL), the combined organic layer
was dried over Na2SO4, the solvent was removed in vacuo, and
the compound was purified by flash column chromatography
(hexanes/ethyl acetate, 5:1), affording ester 56a (3.16 g, 90%).
Rf 0.26 (hexanes/ethyl acetate, 3:1); [R]30 +41.6 (c 0.98,
D
CHCl3); IR ν 3494, 1723, 1599 cm-1
;
1H NMR (500 MHz,
CDCl3) δ 8.06 (d, J ) 8.0 Hz, 2 H), 7.85 (d, J ) 8.3 Hz, 2 H),
7.59 (t, J ) 7.4 Hz, 1 H), 7.45 (t, J ) 7.7 Hz, 2 H), 7.40 (d, J
) 7.9 Hz, 2 H), 5.12 (d, J ) 5.4 Hz, 1 H), 4.56 (d, J ) 6.1 Hz,
1 H), 4.19 (t, J ) 5.7 Hz, 1 H), 3.96 (dd, J ) 8.1, 5.4 Hz, 1 H),
3.33 (s, 1 H), 2.73 (d, J ) 8.4 Hz, 1 H), 2.48 (s, 3 H), 1.52 (s, 3
H), 1.36 (s, 3 H); 13C NMR (125 MHz, CDCl3) δ 165.6, 145.7,
134.0, 133.7, 130.4, 130.1, 129.4, 128.7, 128.3, 110.2, 75.2, 70.5,
68.4, 68.1, 41.5, 39.7, 27.7, 25.3, 21.9; HRMS (FAB) calcd for
(1S,2R,3R,4R,5S,6S)-3,4-(Isop r op ylid en ed ioxy)-5,6-d i-
h yd r oxy-7-(4′-m eth ylp h en ylsu lfon yl)-7-a za bicyclo[4.1.0]-
h ep ta n e (54). To a solution of aziridine 46 (500 mg, 1.56
mmol) in a mixture of ethyl acetate (7 mL) and acetonitrile (7
mL) was added a solution of NaIO4 (500 mg, 2.34 mmol) and
RuCl3‚H2O (32 mg, 0.16 mmol) in water (5 mL) at 0-5 °C.
After 15 s, the reaction was quenched by addition of 30% aq
Na2S2O3 (15 mL). The phases were separated, and the aqueous
layer was extracted with ethyl acetate (3 × 30 mL). The
combined organic phase was dried over Na2SO4 and filtered
through a plug of silica gel before the solvent was removed
under reduced pressure. The residue was purified by flash
column chromatography (hexanes/ethyl acetate 3:1), affording
diol 54 (472 mg, 85%) as white crystals. Rf 0.28 (hexanes/ethyl
C
23H26O7NS 460.1430, found 460.1441. Anal. Calcd for C23H25
-
NO7S: C, 60.12; H 5.48. Found: C, 60.54; H, 5.59.
(1S,2R,3R,4S,5S,6S)-3,4-(Isop r op ylid en ed ioxy)-5-[(ter t-
b u t yld im et h ylsilyl)oxy]-6-b en zoyl-7-(4′-m et h ylp h en yl-
su lfon yl)-7-a za bicyclo[4.1.0]h ep ta n e (57). To a solution of
alcohol 56a (1.66 g, 3.35 mmol) in dry DMF (8 mL) were added
imidazole (1.14 g, 16.8 mmol) and TBSCl (2.53 g, 16.8 mmol).
The solution was stirred at room temperature for 12 h (total
consumption of starting material). The reaction was quenched
with water (10 mL), and the mixture was extracted with CH2-
Cl2 (3 × 50 mL). The combined organic layer was dried over
Na2SO4, the solvent was removed under reduced pressure, and
the product was isolated by flash column chromatography
(hexanes/ethyl acetate, 9:1), yielding 57 (1.63 g, 85%) as
acetate, 1:1); mp 166-168 °C (hexanes/ethyl acetate); [R]26
D
+6.6 (c 1.1, CHCl3); IR ν 3367, cm-1
;
1H NMR (300 MHz,
colorless oil. Rf 0.47 (hexanes/ethyl acetate, 5:1); [R]26 +20.9
D
1
CDCl3) δ 7.82 (d, J ) 8.4 Hz, 2 H), 7.39 (d, J ) 8.4 Hz, 2 H),
4.42 (s, 2 H), 4.13 (m, 1 H), 3.98 (m, 1 H), 3.34 (dt, J ) 6.9, 1.5
Hz, 1 H), 3.28 (dt, J ) 6.9, 1.1 Hz, 1 H), 2.47 (s, 3 H), 1.42 (s,
3 H), 1.32 (s, 1 H); 13C NMR (75 MHz, CDCl3) δ 145.8, 133.8,
130.4, 128.2, 110.2, 69.5, 68.4, 62.1, 45.5, 43.4, 27.5, 25.1, 22.0;
HRMS (FAB) calcd for C16H22NO6S 356.1168, found 356.1166.
Anal. Calcd for C16H21NO6S: C, 54.07; H, 5.96. Found: C,
54.04; H, 5.97.
(c 1.2, CHCl3); IR ν 1725 cm-1; H NMR (300 MHz, CDCl3) δ
8.03 (d, J ) 7.3 Hz, 2 H), 7.85 (d, J ) 8.3 Hz, 2 H), 7.59 (t, J
) 7.4 Hz, 1 H), 7.45 (t, J ) 7.7 Hz, 2 H), 7.37 (d, J ) 8.5 Hz,
2 H), 4.92 (m, 1 H), 4.52 (m, 1 H), 3.91 (d, J ) 5.9 Hz, 1 H),
3.33 (d, J ) 6.4 Hz, 1 H), 3.10 (d, J ) 6.4 Hz, 1 H), 2.46 (s, 3
H), 1.54 (s, 3 H), 1.36 (s, 3 H), 0.91 (s, 9 H), 0.74 (s, 6 H), 0.09
(s, 3 H), 0.01 (s, 3 H); 13C NMR (75 MHz, CDCl3) δ 165.6, 145.2,
134.7, 133.7, 130.2, 130.0, 129.7, 128.7, 128.3, 110.0, 77.5, 71.7,
71.2, 70.5, 43.1, 39.1, 28.3, 26.1, 26.0, 25.9, 25.8, 22.0, 18.2,
-4.4, -4.7; HRMS (FAB) calcd for C29H40O7NSSi 574.2295,
found 574.2293. Anal. Calcd for C29H39NO7SSi: C, 60.71; H
6.85. Found: C, 60.63; H, 6.98.
(1S,2R,3R,4S,5R,6S)-3,4-(Isop r op ylid en ed ioxy)-5,6-O-
su lfu r yl-7-(4′-m eth ylp h en ylsu lfon yl)-7-a za bicyclo[4.1.0]-
h ep ta n e (55). To a solution of diol 54 (100 mg, 0.28 mmol) in
dry CH2Cl2 (5 mL) were added triethylamine (317 mL, 228
mg; 2.25 mmol) and 1.0 M sulfuryl chloride in methylene
chloride (0.85 mL, 0.85 mmol) at 0-5 °C. After addition, the
reaction mixture was warmed to room temperature and stirred
until total consumption of the starting material (2 h). The
mixture was diluted with CH2Cl2 (30 mL) and extracted with
water (2 × 20 mL). The organic layer was dried over Na2SO4
and the solvent removed under reduced pressure. The crude
product 55 was sufficiently pure for the next reaction. Rf 0.45
(hexanes/ethyl acetate, 3:1); mp 208-210 °C (hexanes/ethyl
(1S,2R,3R,4S,5S,6S)-3,4-(Isop r op ylid en ed ioxy)-5-[(ter t-
b u t yld im et h ylsilyl)oxy]-6-h yd r oxy-7-(4′-m et h ylp h en yl-
su lfon yl)-7-a za bicyclo[4.1.0]h ep ta n e (59). To a solution of
benzyl ester 57 (2.12 g, 3.70 mmol) in THF (80 mL) was added
5.5 M methanolic sodium methoxide (3.36 mL, 18.5 mmol). The
reaction mixture was stirred for 10 min (total consumption of
starting material) before it was quenched with aqueous NH4-
Cl (200 mL) and extracted with ethyl acetate (3 × 150 mL).
The combined organic phase was dried over Na2SO4, the
solvent was removed under reduced pressure, and the residue
was purifed by flash column chromatogaphy (hexanes/ethyl
acetate, 7:1), affording 1.28 g of alcohol 59 (74%) as colorless
acetate); [R]24 -51.8 (c 1.0, CHCl3); IR ν 1597, 1212, 1165
D
cm-1; H NMR (300 MHz, CDCl3) δ 7.83 (d, J ) 8.2 Hz, 2 H),
1
7.35 (d, J ) 8.2 Hz, 2 H), 5.25 (dd, J ) 6.1, 3.8 Hz, 1 H), 5.01
(d, J ) 6.1 Hz, 1 H), 4.62 (d, J ) 5.6 Hz, 1 H), 4.54 (d, J ) 4.1
Hz, 1 H), 3.53 (d, 6.4 Hz, 1 H), 3.38 (dd, J ) 5.8, 4.1 Hz, 1 H),
2.46 (s, 3 H), 1.43 (s, 3 H), 1.36 (s, 3 H); 13C NMR (75 MHz,
CDCl3) δ 145.8, 133.5, 130.0, 128.7, 110.8, 76.7, 76.0, 72.7, 69.1,
oil. Rf 0.23 (hexanes/ethyl acetate, 5:1); [R]26 -5.76 (c 1.1,
D
CHCl3); IR ν 3515, 1463, 1382, cm-1
;
1H NMR (300 MHz,
CDCl3) δ 0.80 (d, J ) 8.4 Hz, 2 H), 7.32 (dd, J ) 8.5, 0.6 Hz,
2 H), 4.35 (d, J ) 5.3 Hz, 1 H), 3.97 (t, J ) 5.3 Hz, 1 H), 3.89
8740 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
(dt, J ) 4.8, 0.8 Hz, 1 H), 3.69 (ddd, J ) 9.2, 4.3, 1.6 Hz, 1 H),
3.19 (d, J ) 6.7 Hz, 1 H), 3.04 (d, J ) 6.7 Hz, 1 H), 2.75 (d, J
) 9.0 Hz, 1 H), 2.44 (s, 3 H), 1.49 (s, 3 H), 1.33 (s, 3 H), 0.82
(s, 9 H), 0.05 (s, 3 H), 0.02 (s, 3 H); 13C NMR (75 MHz, CDCl3)
δ 44.9, 134.9, 129.9, 128.2, 109.7, 76.1, 71.2, 70.3, 68.0, 42.3,
39.2, 28.1, 25.8, 25.8, 21.9, 18.1, -4.7, -4.8; HRMS (FAB) calcd
for C22H36O6NSSi 470.2033, found 470.2020. Anal. Calcd for
of starting material). The reaction was quenched with water
(20 mL) and extracted with CH2Cl2 (3 × 20 mL), the combined
organic phase was dried over Na2SO4, the solvent was removed
in vacuo, and the residue was purified by flash column
chromatography (hexanes/ethyl acetate, 5:1), affording com-
pound 67 as colorless oil (21 mg, 97%). Rf 0.35 (hexanes/ethyl
acetate, 3:1); [R]25D +5.9 (c 0.85, CHCl3); IR ν 1487, 1244 cm-1
;
1H NMR (500 MHz, CDCl3) δ 7.71 (d, J ) 8.2 Hz, 2 H), 7.20
(d, J ) 7.9 Hz, 2 H), 7.11 (s, 1 H), 6.40 (s, 1 H), 5.88 (s, 2 H),
4.92 (d, J ) 7.0 Hz, 1 H), 4.63 (d, J ) 7.0 Hz, 1 H), 4.59 (d, J
) 17.0 Hz, 1 H), 4.38 (m, 1 H), 4.30 (d, J ) 18.4 Hz, 1 H), 4.23
(d, J ) 7.9 Hz, 1 H), 3.95 (m, 2 H), 3.79 (t, J ) 6.7 Hz, 1 H),
3.24 (s, 3 H), 3.16 (t, J ) 5.7 Hz, 1 H), 2.24(s, 3H), 1.50 (s, 3
H), 1.26 (s, 3 H), 0.88 (s, 9 H), 0.15 (s, 3 H), 0.12 (s, 3 H);13C
NMR (75 MHz, CDCl3) δ 147.1, 146.4, 143.4, 137.0, 129.5,
128.3, 127.9, 124.9, 109.5, 108.4, 106.0, 101.2, 97.9, 79.8, 78.5,
75.4, 72.9, 56.0, 53.0, 43.0, 41.4, 27.7, 26.1, 25.4, 21.7, 18.3,
-4.1, -4.2; HRMS (FAB) calcd for C32H46O9NSiS 648.2663,
found 648.2668.
C
22H35NO6SSi: C, 56.26; H 7.51. Found: C, 56.19; H, 7.42.
(1R,2R,3S,4S,5S,6R)-4,5-(Isop r op ylid en ed ioxy)-3-[(ter t-
bu tyldim eth ylsil)oxy]-6-N-(3′,4′-dim eth oxym eth ylben zyl)-
N(4′-m eth ylp h en ylsu lfon yl)-7-oxa bicyclo[4.1.0]h ep ta n e
(64). To a solution of alcohol 59 (100 mg, 0.21 mmol) in dry
THF (15 mL) at -78 °C was added t-BuLi (1.6 M in hexanes;
133 mL, 0.21 mmol). The solution was stirred for 10 min before
it was slowly warmed to -30 °C. Piperonyl bromide (55 mg;
0.26 mmol) and a catalytic amount of NBu4I were added, and
two-thirds of the solvent was removed under reduced pressure.
The solution was stirred for additional 2 h and slowly warmed
to room temperature. After 48 h the reaction was quenched
with 20 mL saturated aqueous NH4Cl and extracted with CH2-
Cl2 (3 × 50 mL). The combined organic phases were dried over
Na2SO4, the solvent was removed under reduced pressure, and
the residue was purified by flash column chromatography
affording ether 64 (84 mg, 0.14 mmol, 68%). Rf 0.53 (hexanes/
(1R,2S,3S,4S,4aR,10bS)-1,3,4,4a,11b-Hexah ydr o-1-m eth -
o x y m e t h y l-2[(t er t -b u t y ld i m e t h y ls i ly l)o x y ]-3,4-i s o -
p r oylid en ed ioxy-5-N-(4′m et h ylp h en ylsu lfon yl)-[1,3]d i-
oxolo[4,5-j]p h en a n th r id in -6(2H)-on e (68). To a suspension
of 67 (25 mg, 0.039 mmol) in CH3CN/CCl4/H2O (2:2:3) were
added NaIO4 (66 mg;0.31 mmol) and a catalytic amount of
RuCl3‚H2O. The reaction mixture was stirred at room tem-
perature until total consumption of the starting material (30
min). The heterogeneous mixture was diluted with CH2Cl2 (40
mL) and filtered through a plug of silica gel before it was
extracted with water (3 × 30 mL). The combined organic phase
was dried over Na2SO4, the slightly greenish solution was
filtered through silica, and the solvent was removed under
reduced pressure. Flash column chromatography (hexanes/
ethyl acetate, 5:1) of the residue provided 68 (14 mg, 50%) as
pale yellow oil. Rf 0.30 (hexanes/ethyl acetate, 3:1); [R]25D +5.0
ethyl acetate, 3:1); [R]30 -9.3 (c 2.2, CHCl3); IR ν, 1598 cm-1
;
D
1H NMR (300 MHz, CDCl3) δ 7.76 (d, J ) 8.3 Hz, 2 H), 7.28
(d, J ) 8.06 Hz, 2 H), 6.89 (d, J ) 1.7 Hz, 1 H), 6.81 (dd, J )
8.1, 1.7 Hz, 1 H), 6.70 (d, J ) 7.8 Hz, 1 H), 5.93 (s, 2 H), 4.42
(d, J ) 15.9 Hz, 1 H), 4.26 (d, J ) 15.6 Hz, 1 H), 4.20 (dd, J )
7.9, 5.5 Hz, 1 H), 4.01 (dt, J ) 5.1, 2.3 Hz, 1 H), 3.88 (dd, J )
4.7, 2.7 Hz, 1 H), 3.10 (t, J ) 3.5 Hz, 1 H), 3.02 (t, J ) 3.2 Hz,
1 H), 2.43 (s, 3 H), 1.33 (s, 3 H), 1.16 (s, 3 H), 0.86 (s, 9 H),
0.10 (s, 3H), 0.06 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 48.1,
147.3, 143.8, 137.5, 131.1, 129.8, 127.7, 121.8, 109.0, 109.0,
108.2, 101.3, 78.7, 77.4, 74.1, 70.6, 58.9, 55.5, 53.3, 50.2, 29.9,
26.9, 26.0, 24.4, 21.8, 18.3, 1.2, -4.6, -4.8; HRMS (FAB) calcd
for C30H42O8NSSi 604.2400, found 604.2392. Anal. Calcd for
(c 1.0, CHCl3); IR ν 1683, 1486, cm-1 1H NMR (300 MHz,
;
CDCl3) δ 8.14 (d, J ) 8.3 Hz, 2 H), 7.42 (s, 1 H), 7.29 (d, J )
8.1 Hz, 2 H), 7.19 (s, 1 H), 6.00 (dd, J ) 4.9, 1.2 Hz, 2 H), 5.09
(dd, J ) 9.5, 5.6 Hz, 1 H), 4.98 (d, J ) 7.1 Hz, 1 H), 4.77 (d, J
) 7.3 Hz, 1 H), 4.18 (dd, J ) 6.6, 2.4 Hz, 1 H), 4.10 (m, 1 H),
3.80 (t, J ) 7.0 Hz, 1 H), 3.69 (d, J ) 3.9 Hz, 1 H), 3.44 (s, 3
H), 2.41 (s, 3 H), 1.63 (s, 3 H), 1.19 (s, 3 H), 0.88 (s, 9 H), 0.14
(s, 3 H), 0.13 (s, 3 H); 13C NMR (75 MHz, CDCl3) δ 161.7, 152.8,
147.3, 144.6, 137.0, 135.1, 130.0, 129.0, 122.2, 109.9, 108.8,
106.4, 102.3, 97.6, 79.4, 78.3, 75.4, 73.9, 56.1, 54.9, 43.4, 27.4,
C
30H41NO8SSi: C, 59.68; H 6.84. Found: C, 59.78; H, 6.84.
(1R,2S,3S,4S,4a R,10b S)-1,3,4,4a ,11b -H exa h yd r o-1-h y-
d r oxy-2-[(ter t-bu tyld im eth ylsilyl)oxy]-3,4-isop r oylid en e-
d ioxy-5-N-(4′m eth yl-p h en ylsu lfon yl)-[1,3]d ioxolo[4,5-j]-
p h en a n th r id in (66). To a solution of epoxide 64 (58.7 mg,
0.10 mmol) in dry CH2Cl2 (10 mL) at -30 °C were added a 1.0
M solution of (CH3)2AlCl (100 mL, 0.10 mmol). The reaction
mixture was stirred at -30 °C for 1 h before it was allowed to
warm to 0 °C over about a period of 1 h and then quenched
with water (20 mL). The mixture was extracted with CH2Cl2
(3 × 50 mL), the combined organic phase was dried over Na2-
SO4, the solvent was removed in vacuo, and the residue
subjected to flash column chromatography (hexanes/ethyl
acetate, 9:1), affording 66 (40.2 mg, 68%) as colorless oil. Rf
26.1, 25.2, 21.9, 18.4, -4.3; HRMS (FAB) calcd for C32H44O10
NSSi: 662.2455. Found 662.2495.
-
(1R,2S,3S,4S,4aR,10bS)-1,3,4,4a,11b-Hexah ydr o-1-m eth -
o x y m e t h y l-2[(t er t -b u t y ld i m e t h y ls i ly l)o x y ]-3,4-i s o -
p r oylid en ed ioxy-[1,3]d ioxolo[4,5-j]p h en a n th r id in -6(2H)-
on e (69). To a solution of 70 (30 mg, 0.045 mmol) in dry DME
(5 mL) at -50 °C was added a 0.5 M Na/naphthalene in DME
until a green color persisted (total sonsumption of starting
material according to TLC). The solution was stirred for 10
min before the reaction was quenched with saturated aq NH4-
Cl. The mixture was warmed to room temperature, diluted
with water, and extracted with Et2O (3 × 30 mL). The
combined organic phase was dried over Na2SO4, the solvent
was removed in vacuo, and the residue was purified by flash
column chromatography affording compound 69 (12 mg, 0.024
mol, 52%) as pale yellow oil. Rf 0.35 (hexanes/ethyl acetate,
0.57 (hexanes/ethyl acetate, 2:1); [R]26 -33.5 (c 1.1, CHCl3);
D
IR ν 3561, 1486 cm-1; 1H NMR (500 MHz, CDCl3) δ 7.60 (d, J
) 8.3 Hz, 2 H), 7.09 (d, J ) 8.0 Hz, 2 H), 7.06 (s, 1 H), 6.34 (s,
1 H), 5.81 (dd, J ) 8.7, 1.4 Hz, 2 H), 4.49 (d, J ) 17.3 Hz, 1
H), 4.30 (dd, J ) 10.5, 7.9 Hz, 1 H), 4.21 (d, J ) 17.4 Hz, 1 H),
4.11 (dd, J ) 10.3, 6.9 Hz, 1 H), 3.93 (t, J ) 6.7 Hz, 1 H), 3.82
(dd, J ) 10.7, 6.4 Hz, 1 H), 3.37 (dd, J ) 10.8, 7.7 Hz, 1H),
2.95 (t, J ) 7.7 Hz, 1H), 2.28 (s, 3H), 1.45 (s, 3 H), 1.22 (s, 3
H), 0.85 (s, 9 H), 0.20 (s, 3 H), 0.19 (s, 3 H); 13C NMR (75 MHz,
CDCl3) δ 147.5, 146.5, 143.4, 137.6, 129.6, 129.1, 127.5, 124.1,
110.6, 108.6, 105.3, 101.2, 79.0, 75.1, 74.7, 71.8, 52.2, 42.6, 39.9,
27.5, 26.1, 25.3, 21.7, 18.3, -4.0, -4.8; HRMS (EI) calcd for
2:1); [R]25D +7.8 (1.0, CHCl3); IR ν 3206, 1671, 1464, 1381 cm-1
;
1H NMR (500 MHz, CDCl3) δ 7.51 (s, 1 H), 6.88 (s, 1 H), 6.43
(bs, 1 H), 6.01 (dd, J ) 2.8, 1.2 Hz, 2 H), 4.55 (d, J ) 6.2 Hz,
1 H), 4.39 (d, J ) 6.4 Hz, 1 H), 4.20 (m, 3 H), 3.80 (dd, J ) 8.9,
6.1 Hz, 1 H), 3.72 (t, J ) 9.8 Hz, 1 H), 2.98 (d, J ) 8.5 Hz, 1
H), 2.84 (s, 3 H), 1.57 (s, 3 H), 1.40 (s, 3 H), 0.89 (s, 9 H), 0.18
(s, 3 H), 0.11 (s, 3 H); 13C NMR (75 MHz, CDCl3) δ 183.3, 151.1,
147.6, 135.4, 110.5, 109.4, 108.1, 101.9, 98.8, 80.6, 78.9, 76.4,
76.3, 56.4, 52.8, 41.3, 28.4, 26.5, 26.2, 18.4, -3.8, -4.2; HRMS
(FAB) calcd for C25H37O8NSi: 508.2367. Found 508.2348.
C
C
30H42O8NSSi 604.2400, found 604.2409. Anal. Calcd for
30H41NO8SSi: C, 59.68; H 6.84. Found: C, 60.36; H, 6.98.
(1R,2S,3S,4S,4aR,10bS)-1,3,4,4a,11b-Hexah ydr o-1-m eth -
o x y m e t h y l-2[(t er t -b u t y ld i m e t h y ls i ly l)o x y ]-3,4-i s o -
p r oylid en ed ioxy-5-N-(4′m et h yl-p h en ylsu lfon yl)-[1,3]d i-
oxolo[4,5-j]p h en a n th r id in (67). To a solution of alcohol 66
(20 mg, 0.033 mmol) in 0.5 mL of Hu¨nig’s base was added at
room temperature methoxymethyl chloride (100 mL, 0.85
mmol). The solution was stirred for 12 h (total consumption
J . Org. Chem, Vol. 67, No. 25, 2002 8741

Hudlicky et al.
epi-7-Deoxyp a n cr a tista tin (70). To a solution of 69 (15
mg; 0.03 mmol) in methanol (1.5 mL) was added 3% HCl in
methanol (0.5 mL). The reaction mixture was stirred until total
consumption of the starting material (2 d). The solvent was
removed under reduced pressure, and the residue was purified
by flash column chromatography affording 7 mg of the epimer
of the natural product (70%). Rf 0.1 (chloroform/methanol, 4:1);
A solution of diol 73 (1.72 g, 3.60 mmol) in THF/H2O/TFA (4:
1:1, 30 mL) was stirred at room temperature for 17 h. After
removal of the solvents by Kugelrohr distillation, the residue
was dissolved in acetone/H2O (3:2, 30 mL) and subsequently
treated with NaIO4 (2.13 g, 9.97 mmol) in H2O (13 mL). The
solution was stirred at room temperature for 4 h and then
diluted with water (5 mL). Excess acetone was removed under
reduced pressure, and the remaining solution was extracted
with EtOAc (2 × 50 mL). The combined organic extract was
dried over Na2SO4 and concentrated in vacuo. The solution in
CH3OH (120 mL) at 0 °C was treated with NaBH4 (1.60 g, 42.3
mmol) and slowly warmed to room temperature. After stirring
for 14 h, the solution was diluted with H2O (20 mL) and excess
methanol was removed under reduced pressure. The concen-
trate was extracted with EtOAc (2 × 60 mL), and the combined
organic extract was dried over Na2SO4. Removal of the solvent
under reduced pressure and purification of the residue by flash
column chromatography (methylene chloride/acetone 3:2) gave
tosylamide 75 (820 mg, 60%) as a white solid: Rf 0.61
[R]25 +5.9 (0.49, MeOH); IR ν 3328, 1648, 1468, 1254 cm-1
;
D
1H NMR (500 MHz, C5D5N) δ 9.09 (s, 1 H), 7.95 (s, 1 H), 7.24
(s, 1 H), 5.95 (s, 1 H), 5.86 (s, 1 H), 4.95 (t, J ) 2.6 Hz, 1 H),
4.74 (t, J ) 9.3 Hz, 1 H), 4.64 (dd, J ) 9.6, 2.8 Hz, 1 H), 4.52
(t, J ) 3.3 Hz, 1 H), 4.30 (t, J ) 9.6 Hz, 1H), 3.65 (dd, J )
10.2, 3.7 Hz, 1 H); 13C NMR (125 MHz, C5D5N) δ 164.6, 149.1,
146.3, 136.8, 122.8, 109.9, 106.6, 100.6, 74.2, 73.9, 71.6, 70.9,
55.6, 41.7; HRMS (EI pos) calcd. for C14H15O7N 309.0849, found
309.0875.
N-[(1R,2R,3S,4S,5S,6S)-2-(1,3-Ben zod ioxol-5-yl)-3,4-d i-
h yd r oxy-5,6-(isop r op ylid en ed ioxy)cycloh ex-1-yl]-4-m e-
th ylben zen esu lfon a m id e (73). A solution of 7110b (2.30 g,
5.19 mmol) in CH3CN/EtOAc (1:1, 65 mL) at 0 °C was treated
with a solution of RuCl3‚H2O (81 mg, 0.39 mmol) and NaIO4
(1.66 g, 7.76 mmol) in H2O (11 mL) and allowed to stir at 0 °C
for 3 min. The reaction was quenched with 50% aq Na2S2O3
(100 mL) and then warmed to room temperature. The organic
and aqueous phases were separated, and the aqueous phase
was extracted with ethyl acetate (3 × 100 mL). The combined
organic extracts were dried over Na2SO4 and concentrated in
vacuo. The residue was purified by flash column chromatog-
raphy (hexanes/ethyl acetate, 1:2) to afford diol 73 (1.87 g, 75%)
as a white solid: Rf 0.14 (hexanes/ethyl acetate, 1:2); mp: 103-
(methylene chloride/acetone, 1:1); mp: 137-139 °C; [R]25
D
+50.7 (c 1.0, CHCl3); IR (KBr) ν 3464, 3303, 2886, 1501 cm-1
;
1H NMR (300 MHz, CDCl3) δ 7.68 (d, J ) 8.4 Hz, 2 H), 7.28
(d, J ) 9.0 Hz, 2 H), 6.71 (d, J ) 7.8 Hz, 1 H), 6.61-6.58 (m,
2 H), 5.94 (s, 2 H), 4.90 (d, J ) 8.4 Hz, 1 H), 3.95 (dt, J ) 9.9,
4.2 Hz, 1 H), 3.71-3.59 (m, 2 H), 3.53-3.40 (m, 2 H), 3.16 (m,
1 H), 2.92 (dt, J ) 8.6, 5.0 Hz, 1 H), 2.63 (bs, 1 H), 2.41 (s, 3
H); 13C NMR (75 MHz, CDCl3) δ 147.8, 146.8, 143.5, 137.0,
131.6, 129.6, 126.9, 121.6, 108.5, 108.4, 101.0, 62.9, 62.8, 55.9,
48.8, 21.5; HRMS (CI) calcd for C18H22NO6S 380.1168, found
380.1166. Anal. Calcd for C18H21NO6S: C, 56.98; H, 5.58; N,
3.69. Found: C, 56.83; H, 5.52; N, 3.66.
105 °C; [R]29 -27.1 (c 1.1, CH3OH); IR (KBr) ν 3482, 1734,
D
1
1599, 1490 cm-1; H NMR (500 MHz, acetone) δ 7.49 (d, J )
Meth yl N-[(1R,2R)-2-(1,3-Ben zod ioxol-5-yl)-3-h yd r oxy-
1-(h yd r oxym eth yl)p r op yl]ca r ba m a te (76). A solution of
diol 74 (1.97 g, 5.17 mmol) in THF/H2O/TFA (4:1:1, 45 mL)
was stirred at room temperature for 16 h. The residue after
removal of the solvents via Kugelrohr distillation was dissolved
in acetone/H2O (3:2, 40 mL) and the stirred mixture treated
with a solution of NaIO4 (3.73 g, 17.4 mmol) in H2O (20 mL).
After 4 h, the reaction mixture was diluted with H2O (5 mL),
and excess acetone was removed under reduced pressure. The
concentrate was extracted with EtOAc (3 × 60 mL), dried over
Na2SO4, and concentrated in vacuo. The residue in CH3OH
(175 mL) at 0 °C was treated with NaBH4 (2.43 g, 64.2 mmol)
and was allowed to warm slowly to room temperature. After
20 h, the solution was diluted with H2O (25 mL), and excess
methanol was removed under reduced pressure. The concen-
trate was extracted with EtOAc (2 × 70 mL) and then dried
over Na2SO4. Removal of the solvent under reduced pressure
and purification of the residue by flash column chromatogra-
phy (methylene chloride/acetone, 3:2) provided carbamate 76
(654 mg, 45%) as oil: Rf 0.36 (3:2 CH2Cl2/acetone) [R]26D -55.2
8.2 Hz, 2 H), 7.21 (d, J ) 8.2 Hz, 2 H), 6.59 (d, J ) 1.7 Hz, 1
H), 6.58 (d, J ) 8.0 Hz, 1 H), 6.52 (dd, J ) 8.0, 1.6 Hz, 1 H),
6.34 (d, J ) 9.6 Hz, 1 H), 5.94 (m, 2 H), 4.51 (m, 1 H), 4.32
(dd, J ) 5.9, 2.9 Hz, 1 H), 4.21 (t, J ) 6.1 Hz, 1 H), 4.02 (m, 1
H), 3.94 (ddd, J ) 8.5, 6.0, 2.4 Hz, 1 H), 3.77 (td, J ) 8.8, 6.3
Hz, 1 H), 3.67 (d, J ) 5.8 Hz, 1 H), 2.83 (t, J ) 8.8 Hz, 1 H),
2.40 (s, 3 H), 1.49 (s, 3 H), 1.28 (s, 3 H); 13C NMR (125 MHz,
CDCl3) δ 147.5, 146.2, 142.3, 140.3, 135.4, 129.1, 126.8, 122.3,
109.2, 108.6, 107.7, 100.9, 77.9, 77.5, 71.7, 71.0, 58.2, 50.1, 26.8,
24.7, 20.5; HRMS (FAB) calcd for C23H28NO8S 478.1536, found
478.1516. Anal. Calcd for C23H27NO8S: C, 57.85; H, 5.70; N,
2.93. Found: C, 57.76; H, 5.79; N, 2.83.
Met h yl N-[(1R,2R,3S,4S,5S,6S)-2-(1,3-Ben zod ioxol-5-
yl)-3,4-d ih yd r oxy-5,6-(isop r op ylid en ed ioxy)cycloh ex-1-
yl]ca r ba m a te (74). A solution of RuCl3‚H2O (81 mg, 0.39
mmol) and NaIO4 (1.65 g, 7.71 mmol) in H2O (10 mL) was
added to a solution of 7210b (1.79 g, 5.14 mmol) in CH3CN/
EtOAc (1:1, 50 mL) at 0 °C. The resulting solution was allowed
to stir at 0 °C for 3 min before it was quenched with 50% aq
Na2S2O3 (50 mL). After separation of the organic and aqeous
layers, the aqueous phase was extracted with ethyl acetate (3
× 75 mL). The combined organic extracts were dried over Na2-
SO4, and the solvent was removed under reduced pressure.
The resulting residue was purified by flash column chroma-
tography (hexanes/ethyl acetate, 1:4) to furnish diol 74 (1.35
g, 69%) as a white solid: Rf 0.27 (hexanes/ethyl acetate, 1:4);
mp: 115-117 °C; [R]29D -47.7 (c 1.0, CHCl3); IR (KBr) ν 3398,
1702, cm-1; 1H NMR (500 MHz, CDCl3) δ 6.78 (d, J ) 7.8 Hz,
1 H), 6.77 (d, J ) 1.7 Hz, 1H), 6.70 (dd, J ) 8.2, 1.4 Hz, 1 H),
5.96 (s, 2 H), 4.64 (bs, 1 H), 4.37 (dd, J ) 5.3, 2.7 Hz, 1 H),
4.34 (q, J ) 2.3 Hz, 1 H), 4.19 (m, 1 H), 4.02 (dt, J ) 10.2, 2.9
Hz, 1 H), 3.90 (q, J ) 9.7 Hz, 1 H), 3.53 (s, 3 H), 2.95 (t, J )
9.5 Hz, 1 H), 2.76 (m, 1 H), 1.87 (m, 1 H), 1.60 (s, 3 H), 1.39 (s,
3 H); 13C NMR (75 MHz, CDCl3) δ 156.5, 148.0, 146.9, 131.8,
122.2, 109.2, 108.6, 108.4, 101.0, 77.3, 76.7, 72.3, 69.5, 55.5,
52.0, 47.9, 27.8, 25.8; HRMS (FAB) calcd for C18H24NO8
383.1502, found 383.1500. Anal. Calcd for C18H23NO8: C,
56.69; H, 6.08; N, 3.67. Found: C, 56.42; H, 6.18; N, 3.53.
(c 1.0, CHCl3); IR (neat) ν 3392, 1694, 1505 cm-1 1H NMR
;
(500 MHz, CDCl3) δ 6.77 (d, J ) 8.0 Hz, 1 H), 6.69 (d, J ) 1.1
Hz, 1 H), 6.64 (dd, J ) 8.0, 1.5 Hz, 1 H), 5.95 (s, 2 H), 5.02 (d,
J ) 9.1 Hz, 1 H), 4.16 (sx, J ) 4.7 Hz, 1 H), 3.82 (t, J ) 4.8
Hz, 1 H), 3.75 (m, 1 H), 3.71 (s, 3 H), 3.68-3.61 (m, 2 H), 3.55
(dd, J ) 11.6, 5.4 Hz, 1 H), 3.03 (dt, J ) 9.6, 2.5 Hz, 1 H), 2.19
(bs, 1 H); 13C NMR (75 MHz, CDCl3) δ 158.2, 147.8, 146.7,
131.8, 121.6, 108.7, 108.4, 101.0, 63.4, 63.0, 52.9, 52.5, 48.8;
HRMS (FAB) calcd for C13H18NO6 284.1134, found 284.1138.
Anal. Calcd for C13H17NO6: C, 55.12; H, 6.05. Found: C, 54.96;
H, 5.99.
N-[(1R,2R)-2-(1,3-Ben zod ioxol-5-yl)-3-(ter t-bu toxyca r -
bon yloxy)-1-(h yd r oxym eth yl)p r op yl]-N-(ter t-bu toxyca r -
bon yl)-4-m eth ylben zen esu lfon a m id e (77). To a stirred
suspension of NaH (87 mg, 3.63 mmol) in THF (7 mL) at 0 °C
was added diol 75 (425 mg, 1.12 mmol) in THF (7 mL). After
20 min di-tert-butyl dicarbonate (783 mg, 3.58 mmol) in THF
(5 mL) was added dropwise, and the solution was allowed to
warm slowly to room temperature. After 20 h, the reaction
was quenched with H2O, and the reaction mixture was
extracted with ethyl acetate (3 × 35 mL). The combined
N-[(1R,2R)-2-(1,3-Ben zod ioxol-5-yl)-3-h yd r oxy-1-(h y-
d r oxym eth yl)p r op yl]-4-m eth ylben zen esu lfon a m id e (75).
8742 J . Org. Chem., Vol. 67, No. 25, 2002

Amaryllidaceae Alkaloids
1
organic extracts were dried over MgSO4, and solvent removed
under reduced pressure. The remaining residue was purified
via flash column chromatography (hexanes/ethyl acetate, 2:1)
to afford 77 (540 mg, 83%) as a white solid: Rf 0.62 (hexanes/
OH); IR (neat) ν 3416, 1631, 1504, 1490, cm-1; H NMR (300
MHz, CD3OD) δ 6.79 (s, 1 H), 6.73 (m, 2 H), 5.86 (s, 2 H), 4.24
(t, J ) 8.5 Hz, 1 H), 4.13 (dd, J ) 10.4, 6.3 Hz, 1 H), 3.85-
3.78 (m, 2 H), 3.31 (td, J ) 7.4, 4.6 Hz, 1 H); 13C NMR (75
MHz, CD3OD) d149.8, 148.6, 133.7, 122.1, 109.5, 108.7, 102.6,
75.8, 72.2, 59.8, 51.5; HRMS (CI) calcd for C11H16NO4 (M + H
- Cl) 226.1079, found 226.1082.
ethyl acetate, 1:1); mp 67-69 °C; [R]25 +18.1 (c 1.0, CHCl3);
D
IR (KBr) ν 3284, 1744, 1492 cm-1; 1H NMR (500 MHz, CDCl3)
δ 7.67 (d, J ) 8.2 Hz, 2 H), 7.25 (d, J ) 8.5 Hz, 2 H), 6.68 (d,
J ) 7.7 Hz, 1 H); 6.55-6.56 (m, 2 H), 5.90 (s, 2 H), 4.52 (bs, 1
H), 4.21 (dd, J ) 11.0, 7.6 Hz, 1 H), 4.15 (dd, J ) 11.0, 6.0 Hz,
1 H), 3.93-3.81 (m, 3 H); 3.13 (dd, J ) 10.7, 7.1 Hz, 1 H); 2.40
Ack n ow led gm en t. The authors thank Prof. J ames
Rigby (Wayne State) for a sample and NMR data of
narciclasine. We are grateful to the National Science
Foundation (CHE-9615112 and CHE-9910412), the U.S.
Environmental Protection Agency (R 826113), TDC
Research, Inc., and the University of Florida (Alumni
fellowship for T.M.) for financial support of this work.
We want to thank Prof. David Gibson (U. Iowa) for the
gift of organisms used in this study. The biological
evaluation was carried out by the Pettit group, sup-
ported by the Outstanding Investigator grants CA44344-
08-12 and grant CA90441-01 awarded by the division
of Cancer Treatment and Diagnosis, NCI, DHHS, the
Arizona Disease Control Research Commision, and
Robert B. Dalton Endowment Fund. For other helpful
assistance, Prof. J ean M. Schmidt, Dr. J ean-Charles
Chapuis, and Mr. Lee Williams are gratefully acknowl-
edged.
13
(s, 3 H); 1.42 (s, 18 H); C NMR (125 MHz, CDCl3) δ 153.0,
152.8, 147.9, 147.1, 143.4, 137.4, 129.6, 129.5, 127.0, 121.9,
108.8, 108.5, 101.1, 82.6, 82.2, 66.4, 66.2, 52.7, 44.9, 27.7, 27.6,
21.5; HRMS (EI) calcd. for C28H37NO10S 579.2138, found
579.2128. Anal. Calcd for C28H37NO10S: C, 58.02; H, 6.43; N,
2.42. Found: C, 57.75; H, 6.43; N, 2.33.
(2R,3R)-2-Am in o-3-(1,3-Ben zod ioxol-5-yl)-b u t a n e-1,4-
d iol Hyd r och lor id e (78). To a solution of diol 76 (198 mg,
0.70 mmol) in CH3OH (6 mL) was added 10% aq KOH (4.5
mL), and the mixture was heated at reflux for 14 h. The
reaction was allowed to cool to room temperature, and the
reaction mixture was extracted with Et2O (3 × 20 mL). The
combined organic extract was dried over Na2SO4 and concen-
trated in vacuo. A solution of the remaining residue in CH3-
OH (5 mL) was added to CH3OH saturated with HCl at 0 °C,
with stirring. After 5 min, the solvent was removed under
reduced pressure. The residue was dissolved in 2-propanol and
filtered into chilled Et2O to precipitate amine hydrochloride
78 (149 mg, 82%) as a pale tan solid: [R]25D +59.0 (c 1.0, CH3-
J O020129M
J . Org. Chem, Vol. 67, No. 25, 2002 8743