Stereoselective synthesis of 3,6-disubstituted-3,6-dihydropyridin-2-ones as potential diketopiperazine mimetics using organocopper-mediated anti-S N2′ reactions and their use in the preparation of low-molecule CXCR4 antagonists

Article abstract of DOI:10.1021/jo060390t

Organocopper-mediated anti-S_N2′ reactions of γ-phosphoryloxy-α,β-unsaturated-δ-lactams were used to prepare highly functionalized diketopiperazine mimetics. The substrate phosphates 24, 32, and 47 were prepared from a-amino acid-derived allylic

Full text of DOI:10.1021/jo060390t

Stereoselective Synthesis of
3,6-Disubstituted-3,6-dihydropyridin-2-ones as Potential
Diketopiperazine Mimetics Using Organocopper-Mediated anti-SN2′
Reactions and Their Use in the Preparation of Low-Molecule
CXCR4 Antagonists
Ayumu Niida,† Hiroaki Tanigaki,† Eriko Inokuchi,† Yoshikazu Sasaki,† Shinya Oishi,†
Hiroaki Ohno,† Hirokazu Tamamura,† Zixuan Wang,‡ Stephen C. Peiper,‡ Kazuo Kitaura,†
Akira Otaka,*,†,§ and Nobutaka Fujii*,†
Graduate School of Pharmaceutical Sciences, Kyoto UniVersity, Sakyo-ku, Kyoto 606-8501, Japan,
Department of Pathology and Immunotherapy Center, Medical College of Georgia,
Augusta, Georgia 30912, and Graduate School of Pharmaceutical Sciences,
The UniVersity of Tokushima, Tokushima 770-8505, Japan
nfujii@pharm.kyoto-u.ac.jp; aotaka@ph.tokushima-u.ac.jp
ReceiVed February 24, 2006
Organocopper-mediated anti-SN2′ reactions of γ-phosphoryloxy-R,â-unsaturated-δ-lactams were used to
prepare highly functionalized diketopiperazine mimetics. The substrate phosphates 24, 32, and 47 were
prepared from R-amino acid-derived allylic alcohols 10 by a sequence of reactions that included ring-
closing metathesis. In the reactions of phosphates with organocopper reagents, the addition of LiCl
dramatically improved anti-SN2′ selectivity, indicating that an organocopper cluster containing lithium
chloride plays an important role in the determination of regioselectivity. This reaction system was applied
to the preparation of novel low molecular weight CXCR4-chemokine receptor antagonists.
Introduction
This well-organized structure is widely seen in compounds of
biological or medicinal interest. Therefore, it seemed logical
that the DKP nucleus could serve as a drug template with
appropriately arrayed pharmacophores (Figure 1).4 On the basis
of our studies on EADIs, we envisioned that the replacement
of a DKP cis-amide bond with structurally similar (Z)-alkene
units could provide DKP mimetics 2 as novel starting points
for creating drug-like structures (Figure 2).
The replacement of a peptide bond in biologically active
peptides with a non-hydrolyzable unit is a promising approach
for peptide-lead drug discovery. (E)-Alkene dipeptide isosteres
(EADIs) represent amide-bond mimetics that possess excellent
structural homology and resistance to proteases.1 Over the past
decade, we have engaged in the development of efficient
stereoselective methodology for the preparation of EADIs
utilizing organocopper-mediated transformations along with their
application to biologically active peptides.2,3 Piperazine-2,5-
dione (diketopiperazine: DKP) derivatives 1 represent the
smallest cyclic peptides consisting of two R-amino acid residues.
(1) For alkene dipeptide isosteres, see: (a) Christos, T. E.; Arvanitis,
A.; Cain, G. A.; Johnson, A. L.; Pottorf, R. S.; Tam, S. W.; Schmidt, W.
K. Bioorg. Med. Chem. Lett. 1993, 3, 1035. (b) Bohnstedt, A. C.; Prasad,
J. V. N. V.; Rich, D. H. Tetrahedron Lett. 1993, 34, 5217. (c) Wai, J. S.;
Bamberger, D. L.; Fisher, T. E.; Graham, S. L.; Smith, R. L.; Gibbs, J. B.;
Mosser, S. D.; Oliff, A. I.; Pompliano, D. L.; Rands, E.; Kohl, N. E. Bioorg.
Med. Chem. 1994, 2, 939. (d) Vasbinder, M. M.; Jarvo, E. R.; Miller, S. J.
Angew. Chem., Int. Ed. 2001, 40, 2824. (e) Wipf, P.; Xiao, J. Org. Lett.
2005, 7, 103. (f) Jenkins, C. L.; Vasbinder, M. M.; Miller, S. J.; Raines, R.
T. Org. Lett. 2005, 7, 2619.
* Corresponding Authors. Phone: +81-75-753-4551 (N.F.); +81-88-633-
7283 (A.O.). Fax: +81-75-753-4570 (N.F.); +81-88-633-9505 (A.O.).
† Kyoto University.
‡ Medical College of Georgia.
§ The University of Tokushima.
10.1021/jo060390t CCC: $33.50 © 2006 American Chemical Society
Published on Web 04/21/2006
3942
J. Org. Chem. 2006, 71, 3942-3951

Synthesis of 3,6-Disubstituted-3,6-dihydropyridin-2-ones
SCHEME 1. Previous Synthetic Routes for the Preparation
of Diketopiperazine Mimetics
FIGURE 1. General structure of 2,5-diketopiperazine and biologically
active derivatives.
SCHEME 2. Retrosynthetic Analysis of Diketopiperazine
Mimetics Prepared by an Organocopper-Mediated anti-SN2′
Reactiona
FIGURE 2. Design of diketopiperazine mimetics.
However, to our knowledge, there have been only a few
reports in which 3,6-disubstituted-3,6-dihydropyridin-2-ones
(DKP mimetics 2) having side-chain functionalities have been
synthesized in stereoselective fashions. These include synthetic
protocols that employ the ring-closing metathesis or palladium-
catalyzed carbonylation as key reactions (Scheme 1). Ring-
closing metathesis of bisolefinic amide 5 with Grubbs’ ruthe-
nium alkylidene complexes yielded the desired DKP mimetics
2, where the stereochemical outcome depends on the stereo-
chemistry of the requisite metathesis substrate 5, which was
obtained by coupling between enantiomerically pure 1-substi-
tuted prop-2-enylamines 3 and 2-substituted but-3-enoic acids
4.5 Alternatively, Knight et al. have reported the enantioselective
synthesis of 3,6-dihydro-1H-pyridin-2-ones 7 by Pd-catalyzed
decarboxylative carbonylation of 5-vinyloxazolidin-2-ones 6,
a L ) leaving group.
which were synthesized from the corresponding R-amino
aldehydes.6 The stereochemistry at the 6-position was derived
from that of the precursor R-amino aldehyde. The stereoselective
introduction of substituents at the 3-position was achieved in
two ways. One way involves the Pd-catalyzed reaction of 5-(alk-
1-enyl)oxazolidinones 6a to provide 3,6-disubstituted analogues
7a;6a,b however, this requires long reaction times, and the product
yields were rather low. To circumvent these problems, a two-
step protocol consisting of the Pd-catalyzed synthesis of the
6-substituted pyridinones 7b followed by an enolate alkylation
(7b to 2) was developed.6c In this methodology, the nature of
both the electrophiles incoming to the enolate and the substituent
on the nitrogen affect the diastereoselection at the 3-position.
Our approach for the stereoselective preparation of DKP
mimetics 2 is shown in Scheme 2. We envisioned that the
γ-activated-R,â-unsaturated lactams 8 could be converted into
the corresponding dihydropyridinone derivatives 2 by an orga-
nocopper-mediated anti-SN2′ reaction. A Ru-catalyzed olefin
metathesis7 reaction is suitable for the synthesis of key substrates
(2) (a) Ibuka, T.; Habashita, H.; Funakoshi, S.; Fujii, N.; Oguchi, Y.;
Uyehara, T.; Yamamoto, Y. Angew. Chem., Int. Ed. Engl. 1990, 29, 801.
(b) Ibuka, T.; Habashita, H.; Otaka, A.; Fujii, N.; Oguchi, Y.; Uyehara, T.;
Yamamoto, Y. J. Org. Chem. 1991, 56, 4370. (c) Ibuka, T.; Nakai, K.;
Habashita, H.; Hotta, Y.; Fujii, N.; Mimura, N.; Miwa, Y.; Taga, T.;
Yamamoto, Y. Angew. Chem., Int. Ed. Engl. 1994, 33, 652. (d) Oishi, S.;
Tamamura, H.; Yamashita, M.; Odagaki, Y.; Hamanaka, N.; Otaka, A.;
Fujii, N. J. Chem. Soc., Perkin Trans. 1 2001, 2445. (e) Oishi, S.; Niida,
A.; Kamano, T.; Miwa, Y.; Taga, T.; Odagaki, Y.; Hamanaka, N.;
Yamamoto, M.; Ajito, K.; Tamamura, H.; Otaka, A.; Fujii, N. J. Chem.
Soc., Perkin Trans. 1 2002, 1786.
(3) (a) Fujimoto, K.; Doi, R.; Hosotani, R.; Wada, M.; Lee, J.-U.;
Koshiba, T.; Ibuka, T.; Habashita, H.; Nakai, K.; Fujii, N.; Imamura, M.
Life Sci. 1997, 60, 29. (b) Kawaguchi, M.; Hosotani, R.; Ohishi, S.; Fujii,
N.; Tulachan, S. S.; Koizumi, M.; Toyoda, E.; Masui, T.; Nakajima, S.;
Tsuji, S.; Ida, J.; Fujimoto, K.; Wada, M.; Doi, R.; Imamura, M. Biochem.
Biophys. Res. Commun. 2001, 288, 711. (c) Tamamura, H.; Hiramatsu, K.;
Miyamoto, K.; Omagari, A.; Oishi, S.; Nakashima, H.; Yamamoto, N.;
Kuroda, Y.; Nakagawa, T.; Otaka, A.; Fujii, N. Bioorg. Med. Chem. Lett.
2002, 12, 923. (d) Oishi, S.; Kamano, T.; Niida, A.; Odagaki, Y.; Hamanaka,
N.; Yamamoto, M.; Ajito, K.; Tamamura, H.; Otaka, A.; Fujii, N. J. Org.
Chem. 2002, 67, 6162. (e) Tamamura, H.; Koh, Y.; Ueda, S.; Sasaki, Y.;
Yamasaki, T.; Aoki, M.; Maeda, K.; Watai, Y.; Arikuni, H.; Otaka, A.;
Mitsuya, H.; Fujii, N. J. Med. Chem. 2003, 46, 1764. (f) Tamamura, H.;
Hiramatsu, K.; Ueda, S.; Wang, Z.; Kusano, S.; Terakubo, S.; Trent, J. O.;
Peiper, S. C.; Yamamoto, N.; Nakashima, H.; Otaka, A.; Fujii, N. J. Med.
Chem. 2005, 48, 380.
(4) (a) Kanoh, K.; Kohno, S.; Katada, J.; Takahashi, J.; Uno, I.; Hayashi,
Y. Bioorg. Med. Chem. 1999, 7, 1451. (b) Donkor, I. O.; Sanders, M. L.
Bioorg. Med. Chem. Lett. 2001, 11, 2647. (c) Maeda, K.; Nakata, H.; Koh,
Y.; Miyakawa, T.; Ogata, H.; Takeoka, Y.; Shibayama, S.; Sagawa, K.;
Fukushima, D.; Moravek, J.; Koyanagi, Y.; Mitsuya, H. J. Virol. 2004, 78,
8654. (d) Nam, N.-H.; Ye, G.; Sun, G.; Parang, K. J. Med. Chem. 2004,
47, 3131. (e) Borthwick, A. D.; Davies, D. E.; Exall, A. M.; Livermore, D.
G.; Sollis, S. L.; Nerozzi, F.; Allen, M. J.; Perren, M.; Shabbir, S. S.;
Woollard, P. M.; Wyatt, P. G. J. Med. Chem. 2005, 48, 6956.
(5) (a) Boucard, V.; Sauriat-Dorizon, H.; Guibe´, F. Tetrahedron 2002,
58, 7275. (b) Humphries, M. E.; Murphy, J.; Phillips, A. J.; Abell, A. D. J.
Org. Chem. 2003, 68, 2432.
(6) (a) Knight, J. G.; Ainge, S. W.; Harm, A. M.; Harwood, S. J.;
Maughan, H. I.; Armour, D. R.; Hollinshead, D. M.; Jaxa-Chamiec, A. A.
J. Am. Chem. Soc. 2000, 122, 2944. (b) Knight, J. G.; Tchabanenko, K.
Tetrahedron 2002, 58, 6659. (c) Anderson, T. F.; Knight, J. G.; Tcha-
banenko, K. Tetrahedron Lett. 2003, 44, 757.
J. Org. Chem, Vol. 71, No. 10, 2006 3943

Niida et al.
8, in terms of compatibility with various functional groups.8
The amide nitrogen should be appropriately protected by a group
such as Me or dimethoxybenzyl (DMB) to raise the proportion
of conformers with cis-amide geometry, which is necessary for
facile olefin metathesis.9 We present herein the efficient
conversion of γ-oxygenated-R,â-unsaturated-δ-lactams 8 to
DKP mimetics 2 using organocopper-mediated anti-SN2′ reac-
tions. This novel methodology was applied to the synthesis of
low molecular weight CXCR4 antagonists on the basis of the
DKP mimetic structure.10
SCHEME 3. Synthesis of Requisite Substrates for
Ring-Closing Metathesisa
Results and Discussion
Our synthesis started from the known N-Ns-O-TBS protected
syn-1,2-amino alcohol syn-1111 (Ns: 2-nitrobenzenesulfonyl;
TBS: tert-butyldimethylsilyl) derived from allylic alcohol syn-
1012 (Scheme 3). The silyl ether syn-11 was subjected to
N-modification either with MeI, K2CO3, or with DMB-OH,
Ph3P, and DEAD (Mitsunobu conditions) to afford N-Me 12a
and N-DMB 12b derivatives, respectively.13 After removal of
the Ns group of 12 by treatment with thiolate anion under basic
conditions, the resulting secondary amines were acylated with
acryloyl chloride to yield the metathesis substrates 13. The
corresponding diastereomer 13c was synthesized from N-Boc
protected anti-1,2-amino alcohol anti-1012 by a sequence of
reactions identical to those used for the preparation of 13a.
Nonalkylated derivative 13d was also synthesized.
The attempted olefin metathesis of 13a-c with Grubbs’ Ru
catalyst A14 resulted in low cyclization yields (Table 1, entries
1-4). The use of the second-generation catalyst B15 improved
the yields (entries 5-7), although long reaction times under
reflux were required. Ring-closing metathesis of 13 with catalyst
B gave the benzylidene derivative 15 as a side product. This
prompted us to postulate that the low reactivity of the substrates
may be partly attributed to the presence of the bulky TBS group.
Therefore, TBS-deprotected derivatives 16a-c, obtained in high
yields by the treatment of 13a-c with TBAF (88-99%), were
subjected to the metathesis reaction with catalyst A or B (Table
2). Although the reaction with catalyst A did not afford
satisfactory results (entries 1 and 2), ring-closure with catalyst
a Reagents and conditions: (i) MeI, K2CO3, DMF; (ii) DMB-OH, PPh3,
DEAD, THF; (iii) HSCH2CO2H, LiOH, DMF; (iv) CH2dCHCOCl, Et3N,
CH2Cl2; (v) 4 M HCl in dioxane; (vi) Ns-Cl, 2,4,6-collidine, CHCl3; (vii)
TBSOTf, 2,6-lutidine, CH2Cl2.
TABLE 1. Ring-Closing Metathesis of O-TBS-Protected
Acrylamide Derivatives
(7) (a) Yet, L. Chem. ReV. 2000, 100, 2963. (b) Trnka, T. M.; Grubbs,
R. H. Acc. Chem. Res. 2001, 34, 18. (c) Deiters, A.; Martin, S. F. Chem.
ReV. 2004, 104, 2199.
(8) (a) Gao, Y.; Wei, C.-Q.; Burke, T. R., Jr. Org. Lett. 2001, 3, 1617.
(b) Stymiest, J. L.; Mitchell, B. F.; Wong, S.; Vederas, J. C. Org. Lett.
2003, 5, 47. (c) Walensky, L. D.; Kung, A. L.; Escher, I.; Malia, T. J.;
Barbuto, S.; Wright, R. D.; Wagner, G.; Verdine, G. L.; Korsmeyer, S. J.
Science 2004, 305, 1466. (d) Tamamura, H.; Araki, T.; Ueda, S.; Wang,
Z.; Oishi, S.; Esaka, A.; Trent, J. O.; Nakashima, H.; Yamamoto, N.; Peiper,
S. C.; Otaka, A.; Fujii, N. J. Med. Chem. 2005, 48, 3280.
(9) Rutjes, F. P. J. T.; Schoemaker, H. E. Tetrahedron Lett. 1997, 38,
677.
(10) A portion of this work has appeared in preliminary communica-
tions: (a) Niida, A.; Mizumoto, M.; Sasaki, Y.; Tamamura, H.; Otaka, A.;
Fujii, N. In Peptide Science; Shimohigashi, Y., Ed.; The Japanese Peptide
Society: Osaka, 2004; p 169. (b) Niida, A.; Oishi, S.; Sasaki, Y.; Mizumoto,
M.; Tamamura, H.; Fujii, N.; Otaka, A. Tetrahedron Lett. 2005, 46, 4183.
(11) Niida, A.; Tomita, K.; Mizumoto, M.; Tanigaki, H.; Terada, T.;
Oishi, S.; Otaka, A.; Inui, K.; Fujii, N. Org. Lett. 2006, 8, 616.
(12) Hanson, G. J.; Lindberg, T. J. Org. Chem. 1985, 50, 5399.
(13) (a) Fukuyama, T.; Jow, C.-K.; Cheung, M. Tetrahedron Lett. 1995,
36, 6373. (b) Hidai, Y.; Kan, T.; Fukuyama, T. Chem. Pharm. Bull. 2000,
48, 1570. (c) Lin, X.; Dorr, H.; Nuss, J. M. Tetrahedron Lett. 2000, 41,
3309.
cat.
(equiv)
productb,c
(yield, %)
entry
substrate
conditionsa
1
2
3
4
5
6
7
13a
13a
13b
13c
13a
13a
13b
A (0.6)
A (0.6)
A (0.1)
A (0.6)
B (0.6)
B (0.6)
B (0.6)
rt, 48 h
14a (trace)
14a (37)
14b (10)
14c (30)
14a (57)
14a (61)
14b (29)
reflux, 36 h
reflux, 36 h
reflux, 36 h
rt, 36 h
reflux, 48 h
reflux, 36 h
a CH2Cl2 was used as solvent. b Isolated yield. c Starting materials were
recovered, except for entry 6.
B proceeded smoothly at room temperature to yield the desired
cyclized compounds 17a-c in good yields (entries 3-6). Even
for substrate 13d, which lacked an N-alkyl substituent, the
catalyst B afforded the cyclized product 17d in a moderate yield
(entry 7).
(14) Grubbs, R. H.; Chang, S. Tetrahedron 1998, 54, 4413.
(15) (a) Scholl, M.; Ding, S.; Lee, C. W.; Grubbs, R. H. Org. Lett. 1999,
1, 953. (b) Arisawa, M.; Theeraladanon, C.; Nishida, A.; Nakagawa, M.
Tetrahedron Lett. 2001, 42, 8029.
3944 J. Org. Chem., Vol. 71, No. 10, 2006

Synthesis of 3,6-Disubstituted-3,6-dihydropyridin-2-ones
TABLE 2. Ring-Closing Metathesis of Acrylamides Containing
Allylic Alcohol Moieties
TABLE 3. Organocopper-mediated Reactions of
γ-Phosphoryloxy-r,â-unsaturated-δ-lactam 24
cat.
(equiv)
productb
(yield, %)
entry
substrate
conditionsa
1
2
3
4
5
6
7
16a
16b
16a
16a
16b
16c
13d
A (0.15)
A (0.15)
B (0.15)
B (0.05)
B (0.15)
B (0.15)
B (0.15)
rt, 12 h
reflux, 12 h
rt, 12 h
rt, 6 h
rt, 12 h
rt, 12 h
rt, 12 h
17a (trace)c
17b (31)c
17a (74)
17a (84)
17b (74)
17c (84)
17d (53)
product(s)
(isolated yield, %)
entry
1
organocopper reagenta,b,c
Me3CuLi2‚LiI‚3LiBr
25 (35), SN2-25 (10),
31 (3), 23 (23)
2
Me2CuLi‚LiI‚2LiBr
25 (67), SN2-25 (8),
31 (5), 23 (5)
25 (83)
25 (24), SN2-25 (40)
25 (93)
25 (77), SN2-25 (trace)
25 (55), SN2-25 (7)
SN2-25 (11), 23 (17)
26 (63), SN2-26 (13)
26 (82)
a CH2Cl2 was used as solvent. b Isolated yield. c Starting materials were
recovered.
3
4
5
6
7
8
9
10
11
MeCu‚LiI‚LiBr
MeCuI‚MgCl
SCHEME 4. Attempted Conversion of 17a to γ-Activated
MeCuI‚MgCl‚2LiCl
MeCu(CN)‚MgCl‚2LiCl
MeCu(CN)‚MgCl‚2LiCl‚BF3
Me2Cu(CN)‚(MgCl)2‚2LiCl‚BF3
i-BuCu‚2LiId
Derivatives Followed by Organocopper-Mediated Reactionsa
i-BuCu‚2LiI‚2LiCld
i-PrCuI‚MgCl‚2LiCle
27 (trace),
SN2-27 (trace), 18 (62)
27 (84), SN2-27 (8)
27 (59), SN2-27 (12)
27 (36), SN2-27 (45)
12
13
14
i-PrCu(CN)‚MgCl‚2LiCl
i-PrCu(CN)‚MgCl‚2LiCl‚BF3
i-PrCu(CN)‚MgCl‚2LiCl‚5BF3
a Two equivalents of reagents were used, except for entry 8 (4 equiv).
b THF or a mixed solvent consisting of THF and Et2O (or Et2O-n-pentane)
was used. c Reactions were carried out at -78 °C for 20 min, except for
entry 11. d Alkyllithium for the preparation of the organocopper reagent
was obtained from the reaction of the corresponding alkyl iodide and a
pentane solution of tert-butyllithium (See the Supporting Information).
e Reaction at -78 °C for 20 min then at 0 °C for 40 min.
a Reagents and conditions: (i) MsCl, pyridine, CH2Cl2; (ii) ClCO2Me,
DMAP, pyridine, CH2Cl2; (iii) PhNCO, BF3‚Et2O, Et2O; (iv) Ac2O, DMAP,
pyridine, CHCl3. RCuLn: see text.
(CN)(MgCl)2‚BF3‚2LiCl]2e for the preparation of SN2′ alkylation
product 22 led to the recovery of starting materials along with
the formation of the undesired reduced product 23. The treatment
of the easily obtainable acetate 21 with Gilman-type (Me2-
CuLi2‚LiI‚2LiBr) and “higher-order” (Me3CuLi2‚LiI‚3LiBr)
cuprate gave the reduction product 23 in 42 and 82% yields,
respectively, without the formation of the desired anti-SN2′
product. The use of “lower-order” organocopper reagent (MeCu‚
LiI‚LiBr) resulted in 86% recovery of the starting material.
Because allylic phosphates have also been documented to
undergo highly stereoselective anti-SN2′ reactions with orga-
nocopper reagents,19 we next examined the feasibility of using
γ-phosphoryloxy-R,â-unsaturated-δ-lactams for the preparation
of disubstituted DKP mimetics (Table 3). The reaction of 17a
with diphenylphosphoryl chloride in the presence of pyridine
proceeded smoothly to give the phosphate derivative 24 in 85%
yield as an activated compound, which was stable below 4 °C.
Upon standing at room temperature, the phosphates were
gradually converted to the pyridinone derivative 18.
Next, we examined the activation of the γ-hydroxyl group
of 17a (Scheme 4). Generally, the use of γ-mesyloxy groups is
suitable for the organocopper-mediated reaction of acyclic (E)-
R,â-enoates to prepare EADIs in satisfactory yield.2 However,
the reaction of 17a with Ms-Cl-pyridine resulted in the formation
of the pyridinone derivative 18. Thus, we examined alternative
substrates having a less electron-withdrawing O-activating
group, including carbonate,16 carbamate,17 and acetate18 deriva-
tives. These compounds were obtained in low to excellent yields
(carbamate 19, 10%; carbonate 20, 65%; acetate 21, 91%).
However, attempted reactions of these compounds with orga-
nocopper reagents [i-PrCu(CN)MgCl‚BF3‚2LiCl or i-Pr2Cu-
(16) (a) Boquel, P.; Chapleur, Y. Tetrahedron Lett. 1990, 31, 1869. (b)
Kang, S.-K.; Park, Y.-W.; Lee, D.-H.; Sim, H.-S.; Jeon, J.-H. Tetrahe-
dron: Asymmetry 1992, 3, 705. (c) Spino, C.; Tremblay, M.-C.; Gobdout,
C. Org. Lett. 2004, 6, 2801. (d) Spino, C.; Allan, M. Can. J. Chem. 2004,
82, 177.
(17) (a) Gallina, C.; Ciattini, P. G. J. Am. Chem. Soc. 1979, 101, 1035.
(b) Denmark, S. E.; Marble, L. K. J. Org. Chem. 1990, 55, 1984. (c)
Smitrovich, J. H.; Woerpel, K. A. J. Org. Chem. 2000, 65, 1601. (d) Peng,
Z.-H.; Woerpel, K. A. Org. Lett. 2001, 3, 675.
First, the reaction of phosphate 24 with MeLi‚LiBr complex-
derived organocopper-reagents was investigated. Contrary to the
finding that the reaction of acetate 21 with MeLi‚LiBr-derived
reagents did not afford any SN2′ alkylated product, the phosphate
24 was converted into mixtures containing the desired anti-
(18) (a) Goering, H. L.; Singleton, V. D., Jr. J. Am. Chem. Soc. 1976,
98, 7854. (b) Goering, H. L.; Singleton, V. D., Jr. J. Org. Chem. 1983, 48,
1531. (c) Belelie, J. L.; Chong, J. M. J. Org. Chem. 2002, 67, 3000.
J. Org. Chem, Vol. 71, No. 10, 2006 3945

Niida et al.
SCHEME 5. Organocopper-Mediated anti-SN2′ Reaction of
5,6-trans-Phosphate 32
SN2′ product in varying ratios, depending on the organocopper
reagents employed (Table 3, entries 1 and 2). It should be noted
that the reaction of 24 with MeCu‚LiI‚LiBr in THF-Et2O at
-78 °C for 20 min proceeded smoothly to afford 25 in 83%
isolated yield, without other accompanying products (Table 3,
entry 3).20
On the basis of these results, we speculated that “lower-order”
reagent systems such as MeCu‚MX, prepared from a 1:1 mixture
of organometallic reagent and copper salt, affected the anti-
SN2′ conversion of the phosphate. Being encouraged by these
results, we next examined Grignard reagent (MeMgCl) as an
alkyl source for the organocopper reagents. Unexpectedly, the
treatment of phosphate 24 with MeCuI‚MgCl, formed from
equimolar amounts of MeMgCl and CuI, gave a mixture of SN2
(SN2-25: 40%) and anti-SN2′(25: 24%) products (Table 3, entry
4). In contrast, the addition of the lithium salts (LiCl) dramati-
cally improved the selectivity to produce the desired anti-SN2′
compound 25 in 93% isolated yield (Table 3, entry 5). This
indicated that using “lower-order” reagents in the presence of
lithium salts provides a suitable system for the anti-SN2′ reaction
of γ-phosphoryloxy-R,â-unsaturated-δ-lactams. Recently, a
mixture of CuCN and LiCl (1:2, mole ratio), which is a soluble
copper complex in THF, was successfully applied to a wide
range of organocopper-mediated transformations.21 In our
present work, the use of a CuCN‚2LiCl complex gave the
desired compound 25 in 77% yield with an accompanying small
amount of SN2 product (Table 3, entry 6). It is well-documented
that the addition of Lewis acids such as BF3‚Et2O or TMSCl to
organocopper-mediated reactions improves the chemical yields
or regioselectivity.22 However, inclusion of BF3‚Et2O in the
CuCN-mediated reaction of the phosphate 24 led to an increase
in SN2 product (Table 3, entry 7). The corresponding reaction
with “higher order” cyanocuprate-BF3 [Me2Cu(CN)‚(MgCl)2‚
2LiCl‚BF3] was unsuccessful, resulting in a complex mixture
without formation of the desired anti-SN2′ product (Table 3,
entry 8).
yield) along with a small amount of SN2-26 (13%; Table 3,
entry 9). As expected, the addition of LiCl to i-BuCu‚2LiI
completely suppressed the formation of SN2-26 (Table 3, entry
10). In sharp contrast, the reaction with the copper reagent
derived from i-PrMgCl and CuI did not proceed at -78 °C.
When the reaction was conducted at room temperature, pyri-
dinone derivative 18 was obtained in 62% isolated yield (Table
3, entry 11). This was probably due both to steric hindrance
and to higher basicity of the reagent having a secondary carbon
center. On the other hand, use of CuCN‚2LiCl in combination
with i-PrMgCl afforded the desired anti-SN2′ product 27 (Table
3, entry 12). Generally, CuCN-based reagents have been
reported to exhibit higher soft nucleophilic character than
reagents prepared using other copper salts including CuI.23 These
may be more suitable for SN2′ reactions of 24 with the copper
reagents having an i-Pr group. An increased formation of the
SN2 product was observed when the reaction with i-PrCu(CN)‚
MgCl‚2LiCl was conducted in the presence of BF3‚Et2O (Table
3, entries 13 and 14), as in the case of MeCu(CN)‚MgCl‚2LiCl.
Other diketopiperazine mimetics 28-30, containing phenyl,
hydroxyl, and ester functional groups, respectively, were also
synthesized by use of organocopper-mediated anti-SN2′ reac-
tions.10 We have confirmed that organocopper-mediated reac-
tions of 5,6-trans-phosphate 32 derived from lactam 17c
proceeded smoothly in an anti-SN2′ manner to yield 3,6-cis-
diketopiperazine mimetics 33-38 (Scheme 5).10,24 In all cases,
no detectable amounts of SN2 products were observed. This is
probably due to the presence of a benzyl group, which
effectively prevents the access of organocopper reagent to the
γ-position from the opposite side of the leaving group.
Next, the introduction of other alkyl groups using various
organometallic reagents was investigated. The reaction of
phosphate 24 with organocopper reagents prepared from i-BuLi
and CuI (1:1 ratio) gave the desired anti-SN2′ product 26 (63%
(19) (a) Yanagisawa, A.; Noritake, Y.; Nomura, N.; Yamamoto, H. Synlett
1991, 251. (b) Yanagisawa, A.; Nomura, N.; Yamamoto, H. Synlett 1991,
513. (c) Arai, M.; Lipshutz, B. H.; Nakamura, E. Tetrahedron 1992, 48,
5709. (d) Yanagisawa, A.; Nomura, N.; Yamamoto, H. Tetrahedron 1994,
50, 6017. (e) Torneiro, M.; Fall, Y.; Castedo, L.; Mourin˜o, A. J. Org. Chem.
1997, 62, 6344. (f) Belelie, J. L.; Chong, J. M. J. Org. Chem. 2001, 66,
5552. (g) Calaza, M. I.; Hupe, E.; Knochel, P. Org. Lett. 2003, 5, 1059. (h)
Dieter, R. K.; Gore, V. K.; Chen, N. Org. Lett. 2004, 6, 763. (i) Soorukram,
D.; Knochel, P. Org. Lett. 2004, 6, 2409.
(20) Generally, an increase in MeLi, a copper salt ratio, improved the
electron-donating activity of the reagents. The reactivity of MeLi-derived
organocopper reagents toward the acetate 21 reflects this nature. Organo-
copper reagents possessing highly reducing potency proved to be unsuitable
for the anti-SN2′ reaction of the phosphate 24. See: Chounan, Y.; Horino,
H.; Ibuka, T.; Yamamoto, Y. Bull. Chem. Soc. Jpn. 1997, 70, 1953.
(21) (a) Swenson, R. E.; Sowin, T. J.; Zhang, H. Q. J. Org. Chem. 2002,
67, 9182. (b) Harrington-Frost, N.; Leuser, H.; Calaza, M. I.; Kneisel, F.
F.; Knochel, P. Org. Lett. 2003, 5, 2111. (c) Hupe, E.; Calaza, M. I.;
Knochel, P. Chem.sEur. J. 2003, 9, 2789. (d) Kobayashi, Y.; Nakata, K.;
Ainai, T. Org. Lett. 2005, 7, 183.
The involvement of lithium salts is likely to be crucial for
the preferential formation of anti-SN2′ products (e.g., Table 3,
entry 4 vs 5). We hypothesized that cluster-like structures
consisting of organocopper and lithium salts were responsible
for determining regioselectivity. The importance of cluster
structures of organocopper and lithium salts is well-documented
in organocopper chemistry.25 Of note, in conjugate additions
to R,â-unsaturated carbonyl compounds using organocuprates,
including Me2CuLi‚LiX (X ) I or CN), a “trap and bite”
mechanism has been postulated and supported by theoretical
investigations (Figure 3).26 According to this mechanism,
organocuprate cluster reagent 39 traps the substrate by coordi-
nating with a carbonyl group, followed by the opening of the
cluster to form the “biting” structure 40. This results in C-C
bond formation by subsequent reductive elimination. It has been
(22) (a) Yamamoto, Y.; Yamamoto, S.; Yatagai, H.; Maruyama, K. J.
Am. Chem. Soc. 1980, 102, 2318. (b) Yamamoto, Y.; Yamamoto, S.;
Yatagai, H.; Ishihara, Y.; Maruyama, K. J. Org. Chem. 1982, 47, 119. (c)
Lipshutz, B. H.; Ellsworth, E. L.; Siahaan, T. J. J. Am. Chem. Soc. 1989,
111, 1351. (d) Ibuka, T.; Tanaka, M.; Nishii, S.; Yamamoto, Y. J. Am.
Chem. Soc. 1989, 111, 4864. (e) Horiguchi, Y.; Komatsu, M.; Kuwajima,
I. Tetrahedron Lett. 1989, 30, 7087. (f) Cardillo, G.; Gentilucci, L.;
Tolomelli, A.; Tomasini, C. Tetrahedron 1999, 55, 6231.
(23) Ibuka, T.; Tanaka, M.; Nemoto, H.; Yamamoto, Y. Tetrahedron
1989, 45, 435.
(24) Relative configurations of the resulting DKP mimetics 25-30 and
32-37 were determined based on X-ray and 1H NMR analyses. In 1H NMR
measurements, upfield shifts of R-protons of 3,6-trans derivatives, which
were probably caused by an anisotropic effect of the side-chain phenyl ring,
were observed (see the Supporting Information).
3946 J. Org. Chem., Vol. 71, No. 10, 2006

Synthesis of 3,6-Disubstituted-3,6-dihydropyridin-2-ones
FIGURE 3. Conjugate addition of organocuprates to R,â-unsaturated
carbonyl compounds via a “trap and bite” mechanism.
FIGURE 5. Optimized geometries of complex 43, TS (45) and PD
(46) in the gas phase at the B3LYP/631A level. The energy changes
in kcal/mol are given above the arrows.
a reaction product in a theoretical study on the SN2 reaction of
organocuprates by Nakamura et al.27 The cluster 41 approaches
the phosphate 24 while coordinating the carbonyl oxygen with
a lithium atom to form complex 42. The resulting complex 42
is then preferentially converted to the Cu(III) complex 43 with
an anti-SN2′ interaction of the intramolecular organocopper
moiety. Rapid reductive elimination of 43 results predominantly
in the formation of the anti-SN2′ product 25. It is hypothesized
that magnesium salts cannot induce the formation of the cluster
structure such as 41 for electrostatic and structural reasons.
Therefore, both the R- and γ-carbons would be attacked by
“MeCu” without coordination between the organocopper species
and the carbonyl oxygen, leading to a mixture of anti-SN2′ and
SN2 products (Figure 4, 44). The reactivity of CN-containing
organocopper cluster reagents may differ from that of cluster
41. Decreased regioselectivity induced by BF3‚Et2O may result
from decomposition of the organocopper cluster or disruption
of interactions between the organocopper species and the
carbonyl oxygen.
FIGURE 4. Potential mechanism for anti-SN2′ selectivity induced by
the inclusion of LiCl in the reaction of MeCuI‚MgCl.
proposed that similar reaction mechanisms are involved in SN2
reactions of organocuprates.27
We performed density functional theory (DFT)28 calculations
on the basis of the plausible route from 43 to 25 (Figure 5). As
shown in Figure 5, these calculations confirm that reductive
elimination of complex 43 proceeds smoothly via transition state
45 with a reasonable activation energy (3.11 kcal/mol) to yield
complex 46, which leads to the anti-SN2′ product 25. These
results support the above explanation for the improvement of
anti-SN2′ selectivity induced by LiCl.
Next, organocopper-mediated anti-SN2′ reactions of N-DMB-
phosphate derivative 47 were carried out. (Scheme 6). All
reactions proceeded smoothly to afford the anti-SN2′ products
48-50.29 After removal of the DMB group under acidic
conditions, the resulting lactams were converted into the
corresponding (Z)-alkene dipeptide isosteres using Guibe´’s
methodology.5a These represent cis-peptide bond equivalents,11
indicating that our novel synthetic methodology for the prepara-
tion of DKP mimetics may also afford a potential strategy for
the stereoselective synthesis of (Z)-alkene dipeptide isosteres.
Encouraged by this methodology for the stereoselective
preparation of diketopiperazine mimetics, we conducted the
It is tempting to envisage the reaction mechanism of lithium-
induced anti-SN2′ selectivity, as shown in Figure 4. According
to this model, MeCuI‚MgCl is initially converted to the cluster
41 by the addition of lithium chloride. The formation of the
cluster 41 may be adequate because 41 has been identified as
(25) (a) Snyder, J. P.; Spangler, D. P.; Behling, J. R.; Rossiter, B. E. J.
Org. Chem. 1994, 59, 2665. (b) Snyder, J. P.; Bertz, S. H. J. Org. Chem.
1995, 60, 4312. (c) Bertz, S. H.; Vellekoop, A. S.; Smith, R. A. J.; Snyder,
J. P. Organometallics 1995, 14, 1213. (d) Gerold, A.; Jastrzebski, J. T. B.
H.; Kronenburg, C. M. P.; Krause, N.; van Koten, G. Angew. Chem., Int.
Ed. Engl. 1997, 36, 755. (e) Bertz, S. H.; Chopra, A.; Eriksson, M.; Ogle,
C. A.; Seagle, P. Chem.sEur. J. 1999, 5, 2680. (f) Gschwind, R. M.;
Rajamohanan, P. R.; John, M.; Boche, G. Organometallics 2000, 19, 2868.
(g) Gschwind, R. M.; Xie, X.; Rajamohanan, P. R.; Auel, C.; Boche, G. J.
Am. Chem. Soc. 2001, 123, 7299. (h) Canisius, J.; Mobley, T. A.; Berger,
S.; Krause, K. Chem.sEur. J. 2001, 7, 2671. (i) Mori, S.; Nakamura, E.;
Morokuma, K. Organometallics 2004, 23, 1081. (j) Mori, S.; Uerdingen,
M.; Krause, N.; Morokuma, K. Angew. Chem., Int. Ed. 2005, 44, 4715. (k)
Yoshikai, N.; Yamashita, T.; Nakamura, E. Angew. Chem., Int. Ed. 2005,
44, 4721. (l) Henze, W.; Vyater, A.; Krause, N.; Gschwind, R. M. J. Am.
Chem. Soc. 2005, 127, 17335.
(26) (a) Nakamura, E.; Mori, S.; Nakamura, M.; Morokuma, K. J. Am.
Chem. Soc. 1997, 119, 4887. (b) Nakamura, E.; Mori, S.; Morokuma, K. J.
Am. Chem. Soc. 1997, 119, 4900. (c) Nakamura, E.; Mori, S. Angew. Chem.,
Int. Ed. 2000, 39, 3750. (d) Yamanaka, M.; Nakamura, E. Organometallics
2001, 20, 5675. (e) Nakamura, E.; Yoshikai, N. Bull. Chem. Soc. Jpn. 2004,
77, 1.
(28) (a) Seminario, J. M., Politzer, P., Eds. Modern Density Functional
Theory. A Tool for Chemistry; Elsevier: New York, 1995; Vol. 2
(Theoretical and Computational Chemistry). (b) Koch, W.; Holthausen, M.
C. A Chemist’s Guide to Density Functional Theory; Wiley-VCH: Wein-
heim, Germany, 2000.
(27) Nakamura, E.; Mori, S.; Morokuma, K. J. Am. Chem. Soc. 1998,
120, 8273.
J. Org. Chem, Vol. 71, No. 10, 2006 3947

Niida et al.
SCHEME 6. Organocopper-Mediated anti-SN2′ Reaction of
N-DMB Derivative 47a
phosphate 58 with TBSOCH2(CH2)2CH2Cu(CN)Li‚LiI‚2LiCl
proceeded smoothly in an anti-SN2′ manner34 to afford the
alkylated product 59 as the sole product. After removal of the
TBS group with H2SiF6, the resulting alcohol 60 was subjected
to guanidylation with 1,3-bis(tert-butoxycarbonyl)guanidine
under Mitsunobu conditions35 to afford compound 61. N-Boc
deprotection of 61 followed by guanidylation8d of the resulting
amine and HPLC purification yielded the desired DKP mimetic
62, which showed significant CXCR4 antagonistic activity (IC50
) 15.1 µM). Although the antagonistic activity of mimetic 62
has yet to reach the level for clinical usage, the 3,6-dihydro-
pyridin-2-one could be a potential scaffold for the development
of novel low molecular weight CXCR4 antagonists.
a Reagents and conditions: (i) (PhO)2P(O)Cl, pyridine, CH2Cl2; (ii)
BnCuI‚MgCl‚2LiCl, THF, -78 °C, 20 min; (iii) i-PrCu(CN)‚MgCl‚2LiCl,
THF, -78 °C, 20 min; (iv) BrZnCu(CN)‚CH2CH2CO2Et, THF, 0 °C, 60
min.
Conclusion
In conclusion, regio- and stereoselective alkylations of
γ-phosphoryloxy-R,â-unsaturated-δ-lactams with organocopper
reagents were carefully examined for the synthesis of highly
functionalized DKP mimetics. Organocopper reagents, which
were prepared from equimolar amounts of an organometallic
(Li, Mg or Zn) reagent and a copper salt in the presence of
LiCl, proved to be suitable for these transformations. This
reaction system features several advantages for the diversity-
oriented synthesis of DKP mimetics in terms of available
organocopper reagents, stereoselectivity, and tolerance of
functional groups. Dramatic improvement of regioselectivity
induced by LiCl in the reaction of MeCuI‚MgCl can be
rationalized by a “trap and bite” mechanism in which organo-
copper cluster structures containing LiCl are responsible for
determining regioselectivity. Such a hypothesis was supported
by a DFT calculation. Finally, compound 62, a potential lead
for the development of low molecule CXCR4 antagonists was
synthesized by a reaction sequence utilizing an organocopper-
mediated anti-SN2′ reaction of phosphate 58. Details of the
reaction mechanisms involving organocopper cluster formation
are currently being investigated.
synthesis of a biologically relevant DKP mimetic designed as
a CXCR4-chemokine receptor antagonist (Scheme 7). CXCR4
is a seven-transmembrane G-protein-coupled receptor, which
is involved in HIV infection, cancer metastasis, and other disease
processes.30 Thus, CXCR4 is thought to be an attractive
therapeutic target for these problematic diseases.31 Recently, we
identified a cyclic pentapeptide, cyclo-(-Nal-Gly-D-Tyr-Arg-Arg-
), possessing strong CXCR4 antagonistic activity.32 In this
peptide, guanidyl and naphthyl side chains proved to be
especially important pharmacophores for the antagonistic activ-
ity. We hypothesized that DKP mimetics having guanidine and
naphthalene moieties such as 62 could exhibit CXCR4 antago-
nistic activity. The synthesis of 62 started from L-2-naphthy-
lalanine 51, which was converted to N-Boc-protected methyl
ester 52 (esterification with SOCl2 and MeOH, followed by
N-protection). After reduction of the ester 52, the resulting
aldehyde was treated with vinyl Grignard reagent in the presence
of zinc and lithium salts to yield the syn-allylic alcohol 53 along
with a small amount of the anti isomer. Following Boc
deprotection of 53, O-TBS protected Ns-amide 54 was synthe-
sized by a procedure identical to that used to prepare 12.
N-Alkylation of 54 with BocNHCH2(CH2)2CH2I33 yielded amide
55, which was converted to phosphate 58 by a sequence of
reactions, including ring-closing metathesis. The reaction of
Experimental Section
(3S,4S)-3-[(tert-Butyl)dimethylsiloxy]-4-[N-methyl-N-(2-ni-
trobenzenesulfonyl)amino]-5-phenylpent-1-en (12a). To a stirred
solution of sulfonamide syn-11 (500 mg, 1.05 mmol) in DMF (5
SCHEME 7. Synthesis of a Biologically Relevant DKP Mimetic 62 Designed as a CXCR4-Chemokine Receptor Antagonista
a Reagents and conditions: (i) SOCl2, MeOH; (ii) Boc2O, (i-Pr)2NEt, CHCl3; (iii) DIBAL-H, CH2Cl2-toluene then CH2dCHMgCl, ZnCl2, LiCl, THF;
(iv) 4 M HCl-dioxane; (v) Ns-Cl, 2,4,6-collidine, CHCl3; (vi) TBSOTf, 2,6-lutidine, CH2Cl2; (vii) BocNHCH2(CH2)2CH2I, K2CO3, DMF; (viii) HSCH2CO2H,
LiOH‚H2O, DMF; (ix) CH2dCHCOCl, Et3N, CH2Cl2; (x) TBAF, THF; (xi) Grubbs’ cat. second generation, CH2Cl2; (xii) (PhO)2P(O)Cl, pyridine, CH2Cl2;
(xiii) TBSOCH2(CH2)2CH2Cu(CN)Li‚LiI‚2LiCl, n-pentane-THF; (xiv) H2SiF6, CH3CN; (xv) 1,3-bis(tert-butoxycarbonyl)guanidine, PPh3, diisopropyl
azodicarboxylate, THF; (xvi) 95% aq CF3CO2H; (xvii) 1H-pyrazole-1-carboxamidine hydrochloride, (i-Pr)2NEt, DMF; (xviii) RP-HPLC purification.
Abbreviation: TFA, trifluoroacetic acid.
3948 J. Org. Chem., Vol. 71, No. 10, 2006

Synthesis of 3,6-Disubstituted-3,6-dihydropyridin-2-ones
mL) were added K2CO3 (724 mg, 5.24 mmol) and MeI at 0 °C.
After stirring the mixture for 1 h at room temperature, the whole
was extracted with EtOAc. The extract was washed with brine and
dried over MgSO4. Concentration under reduced pressure followed
by flash chromatography over silica gel with n-hexanes-EtOAc
dissolved in CH2Cl2 (5 mL). Et3N (720 µL, 5.17 mmol) and acryloyl
chloride (336 µL, 1.01 mmol) were added dropwise to the above
solution at -20 °C, and the mixture was stirred for 1.5 h at 0 °C
under argon. Saturated NaHCO3 (2 mL) was added to the above
mixture at 0 °C, and the whole was extracted with EtOAc. The
extract was washed successively with saturated citric acid, brine,
saturated NaHCO3, and brine and dried over MgSO4. Concentration
under reduced pressure followed by flash chromatography over
silica gel with n-hexanes-EtOAc (6:1) gave the title compound
13a (316 mg, 83.8% yield) as a colorless oil (rotamer mixture):
[R]33D -51.3 (c 0.94, CHCl3); 1H NMR (600 MHz at 323 K, CDCl3)
δ 0.04 (s, 6H), 0.06 (s, 3H), 0.07 (s, 3H), 0.88 (s, 9H), 0.92 (9H),
2.81 (dd, J ) 14.3, 10.6 Hz, 1H), 2.84-2.90 (m, 1H), 2.87 (s,
3H), 2.91-2.97 (m, 1H), 2.94 (s, 3H), 3.02-3.08 (m, 1H), 4.02
(ddd, J ) 10.4, 6.2, 4.1 Hz, 1H), 4.20 (t, J ) 6.8 Hz, 1H), 4.40-
4.50 (m, 1H), 4.65-4.80 (m, 1H), 5.15 (d, J ) 10.4 Hz, 1H), 5.24-
5.30 (m, 3H), 5.33 (dd, J ) 10.8, 1.8 Hz, 1H), 5.52 (dd, J ) 10.5,
2.0 Hz, 1H), 5.75-5.90 (m, 3H), 6.10 (dd, J ) 16.8, 2.0 Hz, 1H),
6.18 (dd, J ) 17.0, 10.8 Hz, 1H), 6.36 (dd, J ) 16.8, 10.5 Hz,
1H), 7.05-7.26 (m, 10H); 13C NMR (100 MHz, CDCl3) δ -5.0,
-4.9, -4.1, -3.9, 17.9, 18.0, 25.5, 25.6, 25.8, 28.3, 34.1, 34.8,
63.5, 73.6, 75.0, 75.4, 115.6, 117.4, 125.2, 125.8, 126.1, 126.2,
126.7, 127.9, 128.2, 128.4, 128.6, 129.0, 137.4, 138.0, 138.2, 138.4,
166.6, 168.2; HRMS (FAB) m/z calcd for C21H34NO2Si (MH+),
360.2359; found, 360.2352.
(6:1) gave the title compound 12a (507 mg, 98.6%) as colorless
1
crystals: mp 74-75 °C; [R]33 -49.8 (c 1.02, CHCl3); H NMR
D
(270 MHz, CDCl3) δ 0.03 (s, 3H), 0.08 (s, 3H), 0.95 (s, 9H), 2.80
(dd, J ) 14.1, 8.7 Hz, 1H), 3.08 (s, 3H), 3.11 (dd, J ) 13.8, 6.2
Hz, 1H), 4.12-4.24 (m, 1H), 4.32-4.24 (m, 1H), 5.08 (d, J )
10.5 Hz, 1H), 5.19 (dt, J ) 17.1, 1.3 Hz, 1H), 5.90 (ddd, J ) 17.1,
10.2, 6.9 Hz, 1H), 7.07-7.18 (m, 5H), 7.25-7.55 (m, 4H); 13C
NMR (100 MHz, CDCl3) δ -4.8, -3.7, 18.3, 26.1, 31.6, 33.9,
64.1, 75.9, 117.1, 123.6, 126.4, 128.3, 128.9, 130.3, 131.1, 132.5,
133.0, 137.9, 147.8. Anal. Calcd for C24H34N2O5SSi: C, 58.75; H,
6.98; N, 5.71. Found: C, 58.71; H, 7.05; N, 5.69.
(3S,4S)-4-(N-Acryloyl-N-methylamino)-3-[(tert-butyl)dimeth-
ylsiloxy]-5-phenylpent-1-en (13a). To a stirred solution of the
N-Me-sulfonamide 12a (507 mg, 1.03 mmol) in DMF (3.6 mL)
were added LiOH‚H2O (260 mg, 6.20 mmol) and HSCH2CO2H
(216 µL, 1.26 mmol) at 0 °C, and the mixture was stirred for 2 h
at room temperature. The mixture was extracted with EtOAc. The
extract was washed with saturated NaHCO3 and dried over MgSO4.
Concentration under reduced pressure gave oily residues that were
(3S,4S)-4-(N-Acryloyl-N-methylamino)-5-phenylpent-1-en-3-
ol (16a). The acrylamide 13a (116 mg, 0.322 mmol) was dissolved
in 1.0 M TBAF in THF (1 mL) at 0 °C, and the mixture was stirred
for 3 h at room temperature. The mixture was extracted with EtOAc.
The extract was washed with brine and dried over MgSO4.
Concentration under reduced pressure followed by flash chroma-
tography over silica gel with n-hexanes-EtOAc (3:1) gave the title
compound 16a (78.2 mg, 98.9% yield) as a colorless oil (rotamer
(29) Relative configurations of 48 and 49 were assigned as 3,6-trans
derivatives based on the published data (ref 5). The observed chemical shifts
of the R-protons of 48 and 49 (2.45 and 2.16 ppm, respectively) were nearly
identical to those of the corresponding N-methyl derivatives 27 and 28 (2.41
and 2.14 ppm, respectively). We also confirmed that the R-proton of the
corresponding 3,6-cis diastereomer of 48 appeared downfield (3.16 ppm)
in comparison with 48, as in the cases of N-methyl derivatives. The R-proton
chemical shift of 50 was 2.29 ppm, which is similar to that of the
corresponding N-methyl-3,6-trans derivative 30 (2.21 ppm). Based on these
data, compound 50 was assigned as 3,6-trans.
mixture): [R]29 -92.2 (c 1.58, CHCl3); 1H NMR (600 MHz,
D
CDCl3) δ 2.75 (s, 3H), 2.78 (dd, J ) 14.4, 10.5 Hz, 0.3H), 2.94
(dd, J ) 14.2, 4.1 Hz, 0.3H), 2.97 (s, 0.9H), 3.06 (dd, J ) 14.0,
5.5 Hz, 1H), 3.10-3.30 (m, 1H), 4.01 (ddd, J ) 10.9, 7.4, 4.2 Hz,
0.3H), 4.22 (t, J ) 7.2 Hz, 0.3H), 4.26 (m, 1H), 5.16 (d, J ) 10.5
Hz, 1H), 5.31 (d, J ) 10.3 Hz, 0.3H), 5.37 (dt, J ) 17.1, 1.4 Hz,
1H), 5.35-5.45 (m, 0.6H), 5.66 (dd, J ) 10.4, 1.7 Hz, 1H), 5.80-
5.90 (m, 1.6H), 6.16 (dd, J ) 16.9, 10.8 Hz, 0.3H), 6.24 (dd, J )
16.7, 1.3 Hz, 1H), 6.38 (dd, J ) 16.8, 10.4 Hz, 1H), 7.00-7.30
(m, 6.5H); 13C NMR (100 MHz, CDCl3) δ 28.1, 34.4, 34.9, 63.5,
73.5, 73.8, 115.6, 118.4, 126.0, 126.2, 126.5, 128.1, 128.2, 128.3,
128.4, 128.6, 128.7, 128.8, 137.3, 138.4, 168.0, 168.6; HRMS
(FAB) m/z calcd for C15H20NO2 (MH+), 246.1494; found, 246.1490.
(5S,6S)-6-Benzyl-5,6-dihydro-5-hydroxy-1-methylpyridin-2-
one (17a). To a solution of the acrylamide 16a (750 mg, 3.05 mmol)
in CH2Cl2 (20 mL) was added Grubbs’ catalyst second generation
(129 mg, 0.152 mmol), and the mixture was stirred for 6 h at room
temperature under argon. Concentration under reduced pressure
followed by flash chromatography over silica gel with n-hexanes-
EtOAc (1:1) gave the title compound 17a (558 mg, 84.2% yield)
as colorless crystals: mp 96-97 °C; [R]28D -137.1 (c 1.06, CHCl3);
1H NMR (270 MHz, CDCl3) δ 2.56 (s, 3H), 2.97 (dd, J ) 13.5,
9.2 Hz, 1H), 3.19 (dd, J ) 13.5, 4.6 Hz, 1H), 3.60-3.85 (m, 2H),
4.87 (m, 1H), 5.85 (d, J ) 9.8 Hz, 1H), 6.42 (d, J ) 9.8 Hz, 1H),
7.14-7.35 (m, 5H); 13C NMR (100 MHz, CDCl3) δ 33.1, 35.1,
65.6, 66.7, 122.8, 126.2, 128.3, 129.2, 138.3, 143.7, 163.6. Anal.
Calcd for C13H15NO2: C, 71.87; H, 6.96; N, 6.45. Found: C, 71.69;
H, 7.01; N, 6.37.
(30) (a) Feng, Y.; Broder, C. C.; Kennedy, P. E.; Berger, E. A. Science
1996, 272, 872. (b) Koshiba, T.; Hosotani, R.; Miyamoto, Y.; Ida, J.; Tsuji,
S.; Nakajima, S.; Kawaguchi, M.; Kobayashi, H.; Doi, R.; Hori, T.; Fujii,
N.; Imamura, M. Clin. Cancer Res. 2000, 6, 3530. (c) Nanki, T.; Hayashida,
K.; EI-Gabalawy, H. S.; Suson, S.; Shi, K.; Girshick, H. J.; Yavuz, S.;
Lipsky, P. E. J. Immunol. 2000, 165, 6590. (d) Mu¨ller, A.; Homey, B.;
Soto, H.; Ge, N.; Catron, D.; Buchanan, M. E.; McClanahan, T.; Murphy,
E.; Yuan, W.; Wagner, S. N.; Barrera, J. L.; Mohar, A.; Verastegui, E.;
Zlotnik, A. Nature 2001, 410, 50. (e) Tamamura, H.; Hori, A.; Kanzaki,
N.; Hiramatsu, K.; Mizumoto, M.; Nakashima, H.; Yamamoto, N.; Otaka,
A.; Fujii, N. FEBS Lett. 2003, 550, 79. (f) Tamamura, H.; Fujisawa, M.;
Hiramatsu, K.; Mizumoto, M.; Nakashima, H.; Yamamoto, N.; Otaka, A.;
Fujii, N. FEBS Lett. 2004, 569, 99.
(31) For an example of CXCR4 inhibitors, see: (a) Schols, D.; Struyf,
S.; Van Damme, J.; Este, J. A.; Henson, G.; De Clercq, E. J. Exp. Med.
1997, 186, 1383. (b) Murakami, T.; Nakajima, T.; Koyanagi, Y.; Tachibana,
K.; Fujii, N.; Tamamura, H.; Yoshida, N.; Waki, M.; Matsumoto, A.; Yoshie,
O.; Kishimoto, T.; Yamamoto, N.; Nagasawa, T. J. Exp. Med. 1997, 186,
1389. (c) Doranz, B. J.; Grovit-Ferbas, K.; Sharron, M. P.; Mao, S.-H.;
Bidwell Goetz, M.; Daar, E. S.; Doms, R. W.; O’Brien, W. A. J. Exp. Med.
1997, 186, 1395. (d) Donzella, G. A.; Schols, D.; Lin, S. W.; Este, J. A.;
Nagashima, K. A.; Maddon, P. J.; Allaway, G. P.; Sakmar, T. P.; Henson,
G.; De Clercq, E.; Moore, J. P. Nat. Med. 1998, 4, 72. (e) Howard, O. M.
Z.; Oppenheim, J. J.; Hollingshead, M. G.; Covey, J. M.; Bigelow, J.;
McCormack, J. J.; Buckheit, R. W., Jr.; Clanton, D. J.; Turpin, J. A.; Rice,
W. G. J. Med. Chem. 1998, 41, 2184.
(32) Fujii, N.; Oishi, S.; Hiramatsu, K.; Araki, T.; Ueda, S.; Tamamura,
H.; Otaka, A.; Kusano, S.; Terakubo, S.; Nakashima, H.; Broach, J. A.;
Trent, J. O.; Wang, Z.; Peiper, S. C. Angew. Chem., Int. Ed. 2003, 42,
3251.
(33) Lamothe, S.; Zacharie, B.; Attardo, G.; Labrecque, D.; Courchesne,
M.; Falardeau, G.; Rej, R.; Abbott, S. PCT Int. Appl. WO 2000017197 A1
20000330, 2000; p 187.
(5S,6S)-6-Benzyl-5,6-dihydro-5-diphenylphosphoryloxy-1-meth-
ylpyridine-2-one (24). To a solution of the alcohol 17a (450 mg,
2.07 mmol) and pyridine (1.33 mL, 16.5 mmol) in CH2Cl2 (7.5
mL) was added dropwise diphenylphosphoryl chloride (1.72 mL,
8.28 mmol) at 0 °C, and the mixture was stirred at 0 °C for 4 h.
H2O (10 mL) was added to the above mixture, and the whole was
extracted with EtOAc. The extract was washed successively with
saturated citric acid, brine, saturated NaHCO3, and brine and dried
(34) In 1H NMR experiments, the R-proton of compound 59 was detected
at higher field (2.20 ppm) in comparison with that of the corresponding
diastereomer (2.72 ppm). This can be rationalized by the anisotropic effect
of the naphthalene ring, as in the case of phenylalanine-derived compounds.
Based on these data, the relative configuration of 59 was assigned as 3,6-
trans. See the Supporting Information.
(35) (a) Dodd, D. S.; Kozikowski, A. P. Tetrahedron Lett. 1994, 35,
977. (b) Beumer, R.; Reiser, O. Tetrahedron 2001, 57, 6497.
J. Org. Chem, Vol. 71, No. 10, 2006 3949

Niida et al.
over MgSO4. Concentration under reduced pressure followed by
flash chromatography over silica gel with n-hexanes-EtOAc (1:
1) gave the title compound 24 (790 mg, 84.8% yield) as a colorless
oil: [R]26D -25.8 (c 0.28, CHCl3); 1H NMR (400 MHz, CDCl3) δ
2.46 (s, 3H), 2.92 (dd, J ) 13.6, 7.2 Hz, 1H), 3.00 (dd, J ) 13.6,
3.0 Hz, 1H), 3.83 (m, 1H), 5.69 (m, 1H), 5.88 (dd, J ) 10.0, 0.8
Hz, 1H), 6.29 (dt, J ) 10.0, 1.6 Hz, 1H), 7.00-7.07 (m, 2H), 7.17-
7.44 (m, 13H); 13C NMR (100 MHz, CDCl3) δ 33.3, 34.8, 63.2,
63.3, 73.5, 73.6, 119.5, 119.6, 119.7, 125.0, 125.4, 126.3, 128.2,
129.0, 129.5, 136.8, 137.0, 137.1, 149.7, 149.8, 161.9; HRMS
(FAB) m/z calcd for C25H25NO5P (MH+), 450.1470; found,
450.1462.
General Procedure for the Organocopper-Mediated anti-SN2′
Reaction of γ-Phosphoryloxy-r,â-unsaturated-δ-lactams. Syn-
thesis of (3S,6S)-6-Benzyl-3,6-dihydro-1,3-dimethylpyridin-2-one
(25). To a solution of CuI (37.3 mg, 0.196 mmol) and anhydrous
LiCl (16.6 mg) in THF (0.75 mL) was added dropwise a solution
of MeMgCl in THF (3.0 M, 65.3 µL, 0.196 mmol) at -78 °C under
argon, and the mixture was stirred for 10 min at 0 °C. To the above
mixture, was added dropwise a solution of the lactam 24 (44.1 mg,
0.0981 mmol) in THF (0.75 mL) at -78 °C, and the mixture was
stirred for 20 min at -78 °C. The reaction was quenched at -78
°C by the addition of a 1:1 saturated NH4Cl/28% NH4OH solution
(2 mL), with additional stirring at room temperature for 30 min.
The mixture was extracted with Et2O, and the extract was washed
with H2O and dried over MgSO4. Concentration under reduced
pressure followed by flash chromatography over silica gel with
n-hexanes-EtOAc (1:1) gave the title compound 25 (19.6 mg,
92.8% yield) as a colorless oil: [R]23D +231.9 (c 0.21, CHCl3); 1H
NMR (600 MHz, CDCl3) δ 1.16 (d, J ) 7.5 Hz, 3H), 2.11-2.17
(m, 1H), 2.88 (dd, J ) 13.4, 3.7 Hz, 1H), 2.93 (dd, J ) 13.5, 6.6
Hz, 1H), 3.08 (s, 3H), 4.08-4.14 (m, 1H); 5.55 (dd, J ) 10.1, 2.1
Hz, 1H), 5.62 (ddd, J ) 9.9, 4.3, 2.9 Hz, 1H), 7.05-7.32 (m, 5H);
13C NMR (100 MHz, CDCl3) δ 17.7, 33.1, 34.9, 39.3, 61.6, 123.5,
126.3, 127.8, 129.5, 129.9, 135.5, 171.4; HRMS (FAB) m/z calcd
for C14H18NO (MH+), 216.1388; found, 216.1389.
successively with saturated K2CO3 and brine and dried over MgSO4.
Concentration under reduced pressure followed by flash chroma-
tography over silica gel with n-hexanes-EtOAc (1:3) gave the title
compound 60 (69.8 mg, 87.2% yield) as a colorless oil: [R]24
D
1
+142.3 (c 1.14, CHCl3); H NMR (400 MHz, CDCl3) δ 1.12-
1.35 (m, 4H), 1.43 (s, 9H), 1.39-1.56 (m, 4H), 1.58-1.73 (m,
2H), 1.73-1.88 (m, 1H), 2.15-2.25 (m, 1H), 2.95-3.11 (m, 3H),
3.08-3.22 (m, 2H), 3.50-3.65 (m, 2H), 4.10-4.28 (m, 2H), 4.80-
4.94 (m, 1H), 5.57 (dd, J ) 10.0, 2.0 Hz, 1H), 5.63-5.78 (m, 1H),
7.18-7.30 (m, 1H), 7.40-7.60 (m, 3H), 7.70-7.85 (m, 3H); 13C
NMR (100 MHz, CDCl3) δ 21.7, 24.7, 27.5, 28.4, 30.5, 32.2, 39.9,
40.0, 40.1, 44.3, 59.0, 62.2, 79.0, 125.2, 125.6, 126.0, 127.5, 127.6,
127.7, 127.9, 128.5, 128.6, 132.1, 133.2, 133.6, 156.1, 171.0; HRMS
(FAB) m/z calcd for C29H41N2O4 (MH+), 481.3066; found, 481.3060.
(3S,6S)-3-{4-{[N,N-Bis(tert-butoxycarbonyl)guanidino]}butyl}-
1-{4-[(tert-butoxycarbonyl)amino]butyl}-3,6-dihydro-6-[(2-naph-
thyl)methyl]pyridin-2-one (61). To a solution of the alcohol 60
(62.6 mg, 0.183 mmol), PPh3 (144 mg, 0.548 mmol), and 1,3-bis-
(tert-butoxycarbonyl)guanidine (142 mg, 0.548 mmol) in THF (0.98
mL) was added dropwise a solution of diisopropyl azodicarboxylate
in toluene (1.9 M, 288 mL, 0.548 mmol) at 0 °C under argon, and
the mixture was stirred for 12 h at room temperature. Concentration
under reduced pressure followed by flash chromatography over
silica gel with n-hexanes-EtOAc (3:1) gave the title compound
61 (66.8 mg, 50.7% yield) as a colorless oil: [R]24 +103.3 (c
D
0.79, CHCl3); 1H NMR (400 MHz, CDCl3) δ 1.07-1.69 (m, 37H),
2.17-2.25 (m, 1H), 2.94-3.26 (m, 5H), 3.67-3.95 (m, 2H), 4.13
(m, 1H), 4.17-4.27 (m, 1H), 4.74-4.89 (m, 1H), 5.58 (dd, J )
10.0, 1.6 Hz, 1H), 5.66-5.77 (m, 1H), 7.17-7.28 (m, 1H), 7.38-
7.60 (m, 3H), 7.69-7.86 (m, 3H); 13C NMR (100 MHz, CDCl3) δ
22.9, 24.8, 27.6, 28.0, 28.3, 28.4, 28.7, 31.0, 39.9, 40.1, 40.2, 44.3,
44.4, 59.0, 83.5, 125.1, 125.6, 126.0, 127.5, 127.7, 127.9, 128.3,
128.6, 132.1, 133.2, 133.6, 155.1, 156.0, 160.6, 163.8, 170.6; HRMS
(FAB) m/z calcd for C40H60N5O7 (MH+), 722.4493; found, 722.4482.
(3S,6S)-1,3-Bis(4-guanidinobutyl)-3,6-dihydro-6-[(2-naphthyl)-
methyl]pyridin-2-one Trifluoroacetate (62). The lactam 61 (47.8
mg, 0.0662 mmol) was dissolved in 95% aq TFA (1.2 mL), and
the mixture was stirred for 4 h at room temperature. Concentration
under reduced pressure gave an oily residue, which was dissolved
in DMF (0.1 mL). 1H-pyrazole-1-carboxamidine hydrochloride
(29.1 mg, 0.198 mmol) and (i-Pr)2NEt (210 µL, 1.23 mmol) was
added to the above mixture at 0 °C, and the mixture was stirred
overnight at room temperature. Concentration under reduced
pressure and purification by preparative HPLC gave the title
(5R,6S)-6-Benzyl-5,6-dihydro-1,5-dimethylpyridin-2-one (SN2-
25). A colorless oil: [R]24D -212.0 (c 0.49, CHCl3); 1H NMR (400
MHz, CDCl3) δ 1.05 (d, J ) 7.1 Hz, 3H), 2.31 (m, 1H), 2.73 (dd,
J ) 13.4, 9.0 Hz, 1H), 2.91 (s, 3H), 3.00 (dd, J ) 13.4, 5.8 Hz,
1H), 3.31 (m, 1H), 5.93 (d, J ) 9.8 Hz, 1H), 6.45 (ddd, J ) 9.8,
6.1, 1.7 Hz, 1H), 7.07-7.40 (m, 5H); 13C NMR (100 MHz, CDCl3)
δ 18.8, 31.5, 34.5, 38.3, 66.6, 123.6, 126.7, 128.7, 129.2, 137.8,
142.7, 163.2; HRMS (FAB) m/z calcd for C14H18NO (MH+),
216.1388; found, 216.1393.
compound 62 (15.4 mg, 33.6% yield) as a freeze-dried powder:
1
[R]21 +132.5 (c 0.35, CH3OH); H NMR (400 MHz, CD3OD) δ
(3S,6S)-1-{4-[(tert-Butoxycarbonyl)amino]butyl}-3-{4-[(tert-
butyl)dimethylsiloxy]butyl}-3,6-dihydro-6-[(2-naphthyl)methyl]-
pyridin-2-one (59). By use of a procedure identical with that
described for the preparation of 29 from 24, treatment of the
phosphate 58 (196 mg, 0.300 mmol) with TBSOCH2(CH2)2CH2-
Cu(CN)Li‚LiI‚2LiCl (4 equiv) at -78 °C for 1 h gave the title
D
1.04-1.19 (m, 2H), 1.30-1.40 (m, 2H), 1.54-1.74 (m, 5H), 2.96-
3.08 (m, 3H), 3.14-3.30 (m, 4H), 4.02-4.15 (m, 1H), 4.36-4.45
(m, 1H), 5.59 (dd, J ) 9.8, 2.0 Hz, 1H), 5.87-5.96 (m, 1H), 7.21-
7.28 (m, 1H), 7.37-7.49 (m, 2H), 7.56 (s, 1H), 7.70-7.84 (m,
3H); 13C NMR (100 MHz, CD3OD) δ 23.9, 25.7, 27.3, 29.6, 31.6,
39.7, 40.6, 40.9, 42.1, 45.5, 60.5, 126.8, 126.9, 127.1, 128.4, 128.6,
129.2, 129.7, 130.3, 133.7, 134.7, 134.8, 158.5, 158.6, 162.7, 178.6;
HRMS (FAB) m/z calcd for C26H38N7O (MH+), 464.3138; found,
464.3147.
compound 59 (120 mg, 67.2% yield) as a colorless oil: [R]23
D
1
+80.3 (c 1.06, CHCl3); H NMR (400 MHz, CDCl3) δ 0.00 (s,
6H), 0.85 (s, 9H), 1.11-1.23 (m, 2H), 1.43 (s, 9H), 1.38-1.72
(m, 8H), 2.14-2.25 (m, 1H), 2.93-3.23 (m, 5H), 3.45-3.59 (m,
2H), 4.04-4.27 (m, 2H), 4.64-4.76 (m, 1H), 5.58 (dd, J ) 10.0,
2.0 Hz, 1H), 5.64-5.75 (m, 1H), 7.17-7.30 (m, 1H), 7.40-7.60
(m, 3H), 7.70-7.86 (m, 3H); 13C NMR (100 MHz, CDCl3) δ -5.3,
18.3, 22.0, 24.7, 25.9, 27.5, 28.4, 31.1, 32.7, 39.9, 40.0, 40.3, 44.4,
59.0, 62.9, 79.0, 125.1, 125.6, 126.0, 127.5, 127.6, 127.7, 127.9,
128.3, 128.5, 132.1, 133.2, 133.7, 156.0, 170.7; HRMS (FAB) m/z
calcd for C35H55N2O4Si (MH+), 595.3931; found, 595.3939.
(3S,6S)-1-{4-[(tert-Butoxycarbonyl)amino]butyl}-3,6-dihydro-
3-(4-hydroxy)butyl-6-[(2-naphthyl)methyl]pyridin-2-one (60). To
a solution of the lactam 59 (102 mg, 0.172 mmol) in CH3CN (1.7
mL) was added a solution of H2SiF6 in H2O (3.23 M, 11.0 µL,
0.0357 mmol) at 0 °C, and the mixture was stirred for 1 h at 0 °C.
Saturated aq K2CO3 (2 mL) was added to the above mixture, and
the whole was extracted with Et2O. The extract was washed
Density Functional Theory (DFT) Calculation. DFT calcula-
tions were carried out on a SGI Origin 3800 system within the
Gaussian 98 package.36 Geometry optimizations were performed
by the B3LYP hybrid functional37 with the basis set denoted as
B3LYP/631A, which consists of the Ahlrichs all-electron SVP basis
set38 for Cu and 6-31G(d)39 for the rest. The geometry of the
transition state (45) was optimized by QST2 transition state search
from the optimized structures 43 and 46. The number of imaginary
frequencies of these optimized structures was confirmed by
frequency analysis (43 and 46, 0; 45, 1).
[
125I]-SDF-1 Binding and Displacement. Stable CHO cell
transfectants expressing CXCR4 variants were prepared as described
previously.40 CHO transfectants were harvested by treatment with
trypsin-EDTA, allowed to recover in complete growth medium
3950 J. Org. Chem., Vol. 71, No. 10, 2006

Synthesis of 3,6-Disubstituted-3,6-dihydropyridin-2-ones
(MEM-R, 100 µg/mL penicillin, 100 µg/mL streptomycin, 0.25 µg/
mL amphotericin B, 10% (v/v)) for 4 to 5 h, and then washed in
cold binding buffer (PBS containing 2 mg/mL BSA). For ligand
binding, the cells were resuspended in binding buffer at 1 × 107
cells/mL, and 100 µL aliquots were incubated with 0.1 nM of [125I]-
SDF-1 (PerkinElmer Life Sciences) for 2 h on ice under constant
agitation. Free and bound radioactivity were separated by centrifu-
gation of the cells through an oil cushion, and bound radioactivity
was measured with a gammma-counter (Cobra, Packard, Downers
Grove, IL). Inhibitory activity of compound 62 was determined
based on the inhibition of [125I]-SDF-1-binding to CXCR4 trans-
fectants (IC50).
Acknowledgment. We thank Dr. Motoo Shiro, Rigaku
International Corporation, Japan, and Dr. Terrence R. Burke,
Jr., NCI, NIH, U.S.A., for X-ray analysis and for proofreading
this manuscript, respectively. Computation time was provided
by the Supercomputer Laboratory, Institute for Chemical
Research, Kyoto University. This research was supported in part
by 21st Century COE Program “Knowledge Information
Infrastructure for Genome Science”, a Grant-in-Aid for Scientific
Research from the Ministry of Education, Culture, Sports,
Science and Technology, Japan, Philip Morris U.S.A., Inc.,
Philip Morris International, and the Japan Health Science
Foundation. A.N. and Y.S. are grateful for research fellowships
of the JSPS for Young Scientists.
(36) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb,
M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A., Jr.;
Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels, A.
D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone, V.; Cossi,
M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.;
Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Malick,
D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Cioslowski, J.;
Ortiz, J. V.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi,
I.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.;
Peng, C. Y.; Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P. M.
W.; Johnson, B. G.; Chen, W.; Wong, M. W.; Andres, J. L.; Head-Gordon,
M.; Replogle, E. S.; Pople, J. A. Gaussian 98, revision A.11; Gaussian,
Inc.: Pittsburgh, PA, 1998.
(37) (a) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (b) Lee, C.; Yang,
W.; Parr, R. G. Phys. ReV. B: Condens. Matter 1988, 37, 785.
(38) Scha¨fer, A.; Horn, H.; Ahlrichs, R. J. Chem. Phys. 1992, 97, 2571.
(39) Hehre, W. J.; Radom, L.; von Rague´ Schleyer, P.; Pople, J. A. Ab
Initio Molecular Orbital Theory; John Wiley: New York, 1986.
(40) Navenot, J. M.; Wang, Z. X.; Trent, J. O.; Murray, J. L.; Hu, Q.
X.; DeLeeuw, L.; Moore, P. S.; Chang, Y.; Peiper, S. C. J. Mol. Biol. 2001,
313, 1181.
Supporting Information Available: Experimental details.
Alternative synthetic route of SN2-25. Determination of the relative
configuration of 53 and 59. ORTEP diagrams and CIF files for
X-ray structures of 28 and 33. Optimized coordinates and energies
of complexes 43, 45, and 46. 1H and 13C NMR spectra of
representative compounds. This material is available free of charge
via the Internet at http://pubs.acs.org.
JO060390T
J. Org. Chem, Vol. 71, No. 10, 2006 3951