Highly enantioselective preparation of tricyclo[4.4.0.05,7]decene derivatives via catalytic asymmetric intramolecular cyclopropanation reactions of α-diazo-β-keto esters

Article abstract of DOI:10.1016/j.tetlet.2007.05.046

The enantioselective preparation of the tricyclo[4.4.0.0^5,7]dec-2-ene derivatives via the catalytic asymmetric intramolecular cyclopropanation (CAIMCP) reactions of α-diazo-β-keto esters with excellent ee (95-98% ee) is described. The chiral building blocks reported herein would be versatile intermediates for enantioselective natural products synthesis.

Full text of DOI:10.1016/j.tetlet.2007.05.046

Tetrahedron Letters 48 (2007) 4855–4859
Highly enantioselective preparation of tricyclo[4.4.0.05,7]decene
derivatives via catalytic asymmetric intramolecular
cyclopropanation reactions of a-diazo-b-keto esters
Ryoji Ida and Masahisa Nakada*
Department of Chemistry and Biochemistry, Faculty of Advanced Science and Engineering, Waseda University,
3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan
Received 12 April 2007; revised 2 May 2007; accepted 10 May 2007
Available online 16 May 2007
Abstract—The enantioselective preparation of the tricyclo[4.4.0.05,7]dec-2-ene derivatives via the catalytic asymmetric intramole-
cular cyclopropanation (CAIMCP) reactions of a-diazo-b-keto esters with excellent ee (95–98% ee) is described. The chiral building
blocks reported herein would be versatile intermediates for enantioselective natural products synthesis.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Convergent total synthesis of bioactive natural products
would be facilitated by having suitable chiral precursors
and, hence, preparation of new chiral building blocks is
important in synthetic organic chemistry. Since the
number of commercially available chiral compounds is
limited, chiral building blocks prepared via asymmetric
synthesis are important, and catalytic asymmetric syn-
thesis would be ideal for this purpose because of its effi-
ciency. We have prepared new chiral building blocks via
biocatalysts1 as well as artificial catalysts,2,3 and have
disclosed their applications to the enantioselective total
synthesis of bioactive natural products.3d,f,4 We herein
report the highly enantioselective preparation of tricy-
clo[4.4.0.05,7]decene derivatives via the catalytic asym-
metric intramolecular cyclopropanation (CAIMCP)
reactions of a-diazo-b-keto esters.
exemplified by (+)-busidarasin C5 and acetoxytubipo-
furan6 (Scheme 1), possess a cis-dehydrodecalin core
including substituents at C9 of (+)-busidarasin C and
at C4 of acetoxytubipofuran, prompting us to prepare
new chiral tricyclo[4.4.0.05,7]decene derivatives 1 includ-
ing an ester group as the one-carbon unit.7 Compound 1
would not only be a potential synthetic intermediate for
the natural products in Scheme 1, but would also be for
other natural products because the functional groups
incorporated in 1, alkene, cyclopropane, and b-keto
ester would allow further transformations.
H
CO2R1
H
H
O
O
O
Many polycyclic natural products incorporate a cis-
dehydrodecalin skeleton and, thus, preparation of a chi-
ral cis-dehydrodecalin derivative or its precursor would
accelerate their enantioselective total syntheses. Indeed,
we have reported the highly enantioselective CAIMCP
reactions of a-diazo-b-keto sulfones3a,b providing tri-
cyclo[4.4.0.05,7]decene derivatives, one of which was
successfully converted to a cis-dehydrodecalin deriva-
tive, leading to the enantioselective total synthesis of
(+)-digitoxigenin.4c However, other natural products,
9
O
R2
OAc
AcO
1
Catalytic
Asymmetric
Intramolecular
(+)-busidarasin C
Cyclopropanation
(CAIMCP)
OAc
R1O2C
N2
R2
H
O
4
O
acetoxytubipofuran
2
*
Corresponding author. Tel./fax: +81 3 5286 3240; e-mail: mnakada@
waseda.jp
Scheme 1.
0040-4039/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2007.05.046

4856
R. Ida, M. Nakada / Tetrahedron Letters 48 (2007) 4855–4859
As reported earlier by us3a and others,8 the enantioselec-
tivity in the CAIMCP reactions of a-diazo-b-keto esters
which generate carbocycle-fused cyclopropanes has been
unsatisfactory (up to 56% ee3a) for synthetic purposes.
However, our recent studies revealed that the enantio-
selectivity of these CAIMCP reactions depends on ester
structure.3h Consequently, we reexamined the CAIMCP
reactions of a-diazo-b-keto esters, starting with the stud-
ies of the CAIMCP reactions of 5 and 6 (Scheme 2)
which were readily prepared from the reported 3.3e
Table 1. The CAIMCP reactions of 5 and 6
R2 R2
CuOTf
O
O
(10 mol %)
N2
ligand
N
N
(15 mol %)
O
O
R3
R3
H
R1O2C
5 (R1=Et)
6 (R1=t-Bu)
R1O2C
H
toluene, rt
7a: R2=Me, R3=H
7b: R2=Me, R3=i-Pr
7c: R2=Bn, R3=i-Pr
8 (R1=Et)
9 (R1=t-Bu)
Entry
R1
Ligand
Time (h)
Yielda (%)
ee (%)
1
2
3
4
Et
Et
t-Bu
t-Bu
7b
7c
7b
7c
8
18.5
4.5
66
60c
69c
95d
98d
34b
78
The carboxylic acid obtained from 3 was reacted with
CDI to form the corresponding acylimidazolide, which
was reacted in a ‘one-pot’ procedure with the magne-
sium salt of mono-ethyl malonate to provide 4 (96%, 3
steps),9 followed by a diazo transfer reaction with p-tol-
uenesulfonylazide to afford 5 (78%). Preparation of 6
was initiated with the hydrolysis of 4, and the resultant
carboxylic acid was condensed with tert-butyl alcohol by
DCC, followed by a diazotransfer reaction to afford 6
(37%, 3 steps).
26.5
64
a Isolated yields.
b Some structurally unidentified products decreased the yield.
c ee determined by HPLC of the p-bromobenzoate corresponding to
90.11 DAICEL CHIRALPAK AS-H (0.46 cm u · 25 cm; hexane/2-
propanol = 29:1; flow rate = 0.4 mL/min); retention time: 17.5 min
for the minor product, 20.6 min for the major product.
d ee determined by HPLC of 90. DAICEL CHIRALPAK AS-H
(0.46 cm u · 25 cm; hexane/2-propanol = 49:1; flow rate = 0.4 mL/
min); retention time: 13.3 min for the minor product, 15.5 min for the
major product.
The CAIMCP reaction of 5 was carried out under the
conditions optimized for the reactions of a-diazo-b-keto
sulfones (Table 1),3a providing 8 in 66% yield with 60%
ee using ligand 7b and in 34% yield with 69% ee using
ligand 7c. Hence, we expected that the enantioselectivity
of the CAIMCP reaction of 6 would be higher because 6
possessed a bulky t-butyl ester group which would
increase the enantioselectivity by the analogy of the
CAIMCP reaction of a-diazo-b-keto sulfones.3a As
predicted, the CAIMCP reaction of 6 with ligand 7b
produced 9 in 78% with 95% ee, although the reaction
with 7c proceeded more slowly, affording 9 in 64% yield
with excellent ee (98% ee).10
We then carried out the diastereoselective IMCP reac-
tion of 10 to further investigate the relationship between
the ester part in the substrate and the diastereoselectivity
(Scheme 3). The a-diazo-b-keto ester 10 was prepared
starting from 4. Thus, DMAP catalyzed transesterifica-
tion of 4 with d-menthol,13 followed by the diazotransfer
reaction to afford the d-menthyl ester 10 (97%, 2 steps).
The IMCP reaction of 10 was carried out under the
same conditions as those listed in Table 1 (Table 2).
The IMCP reaction of 10 with achiral ligand 7a showed
no diastereoselectivity (entry 1). Hence, we next exam-
ined the IMCP reaction of 10 with chiral ligand 7b,
producing 11 in 67% with 60% de (entry 2), but use
of ligand 7c slightly decreased the diastereoselectivity
(entry 3, 35%, 50% de).
The absolute configuration of 9 was determined as
shown in Table 1 by X-ray crystallographic analysis of
its derivative,11 and the chemical correlation between 8
and 912 elucidated the absolute configuration of 8 as
shown in Table 1. Compound 9 would be a potential
intermediate for the synthesis of acetoxytubipofuran.
Entries 1–3 in Table 2 clearly indicate that the IMCP
reactions of 10 with ligand 7b or ligand 7c were the chi-
ral ligand-controlled reactions. Consequently, the IMCP
reactions of 10 with ligands ent-7b or ent-7c were also
carried out, resulting in formation of ent-11 as the major
product in either 74% yield (ꢀ89% de) or 34% yield
(ꢀ85% de), respectively. As expected, the diastereoselec-
tivities of the IMCP reactions using ligand ent-7b or
ligand ent-7c (entries 4 and 5) were reversed. Interest-
ingly, either ligand ent-7b or ent-7c was more effective
1) KOH, MeOH, H2O, reflux, 1.5 h
2) CDI, THF, rt, 4 h;
EtO2C
then, (EtO2CCH2CO2)2Mg, THF
rt, 6 h
3
96% (2 steps)
TsN3, TEA
N2
CH3CN, rt, 3.5 h
O
O
1) d-menthol
DMAP
toluene
EtO2C
EtO2C
4
78%
5
6
1) 1M KOH, MeOH, 0 oC to rt, 12 h
2) DCC, t-BuOH, CH2Cl2
0 oC to rt, 2.5 h
reflux, 12 h
N2
d-ment-O2C
N2
O
O
2) TsN3
TEA
CH3CN
rt, 4.5 h
O
EtO2C
3) TsN3, TEA, CH3CN
rt, 12 h
t-BuO2C
4
10
37% (3 steps)
97% (2 steps)
Scheme 2.
Scheme 3.

R. Ida, M. Nakada / Tetrahedron Letters 48 (2007) 4855–4859
Table 2. The intramolecular cyclopropanation of 10
4857
R
O
O
CuOTf
(10 mol %)
ligand
O
O
N
NCu
N2
d-ment-O2C
(15 mol %)
O
O
H
d-ment-O2C
H
O
toluene, rt
conditions
10
11
re-face attack
Entry Ligand Temperature Time
Yielda
(%)
deb
(%)
(ꢁC)
(h)
Figure 2.
1
2
3
4
5
7a
7b
rt, 50
rt
rt
rt
rt
2, 10c 74 (91% conv)
15.5
25
33
10.5
0
60
50
67
35
74
34
7c
ent-7b
ent-7c
block for (+)-busidarasin C. Preparation of 16 started
from 12 (Scheme 4). That is, Swern oxidation of 12,
Horner–Wadsworth–Emmons reaction with triethyl-
phosphonoacetate (97%, 2 steps), and reduction of
the resultant unsaturated ester with magnesium in
methanol afforded methyl ester 14 (88%). Conversion
of 14 to 15 was successfully carried out using the modi-
fied Masamune’s method (98%, 2 steps),16 followed by a
diazotransfer reaction of 15 to produce 16 in quantita-
tive yield.
ꢀ89
ꢀ85
a Isolated yields.
b de determined by 600 MHz 1H NMR.
c Time at the corresponding reaction temperature.
than ligand 7b or 7c. Although the quantitative analysis
of the difference between these results requires theoreti-
cal calculations, the results in entries 2-5 could be
explained by the diastereomeric matching or mis-
matching between the chiral auxiliary in 10 and the
chiral ligand in the transition state.14
An oxygen atom is known to react with a carbene–metal
complex to form an ylide, thereby resulting in the
decreased yield of cyclopropanes.17 However, the
CAIMCP reaction of 16 fortunately afforded 17 with
high yield and excellent ee (84%, 95% ee), proving that
this reaction was applicable to a substrate possessing a
TBDPS-protected hydroxyl group in 16. The structure
The structure of ent-11 obtained in entry 4 was eluci-
dated by X-ray crystallographic analysis (Fig. 1).15 This
result indicated that the outcome of the enantioselectiv-
ity in the reactions of 5, 6, and 10 would be well
explained by the model shown in Figure 2. The model
was almost similar to that reported previously.3a The
cyclopropanation reactions of 5, 6, and 10 are thought
to occur preferentially at the re-face (defined by the
Cu@C–C arrangement) of the chiral catalyst–carbene
complexes, because steric hindrance will be encountered
during cyclopropanation reactions at the si-face. That is,
when the alkene approaches from the si-face, the resul-
tant pyramidal conformation of the carbene C atom in
the transition state means that the ester group will inter-
act unfavorably with the isopropyl group. By contrast,
the reaction at the re-face would be preferred because
the unfavorable interaction of the isopropyl group with
the ester group would be negligible in the transition state
model depicted in Figure 2. For the reason described
above, the excellent enantioselectivity would be ob-
served in the reaction of the bulky tert-butyl ester 6.
of 17 was fully characterized by H NMR, 13C NMR,
IR, and HRMS spectra, and its absolute configuration
was confirmed by converting it to the identical com-
pound which had been derived from 9.12
1
TBDPSO
HO
1) DMSO, (COCl)2, TEA, CH2Cl2
-78 oC to rt, 1 h
2) (EtO)2P(O)CH2CO2Et, t-BuOK, THF
-78 oC to 0 oC, 1 h, then rt, 1 h
12
97% (2 steps)
TBDPSO
EtO2C
TBDPSO
Mg, MeOH
0 oC to rt , 3 h
88%
MeO2C
13
14
We finally examined the CAIMCP reaction of 16 to
prepare 17, which would be a potential chiral building
1) KOH, MeOH, THF
H2O, 50 oC, 8 h
TBDPSO
TsN3, TEA
CH3CN, rt, 8 h
100%
2) CDI, THF, rt, 2 h
then, n-Bu2Mg
O
t-BuO2C
15
t-BuO2CCH2CO2H
THF, rt, 28 h
98% (2 steps)
CuOTf
TBDPSO
(10 mol %)
ligand 7b
(15 mol %)
TBDPSO
N2
O
toluene
rt, 4 h
O
H
t-BuO2C
H
t-BuO2C
84%, 95% ee
16
17
Figure 1.
Scheme 4.

4858
R. Ida, M. Nakada / Tetrahedron Letters 48 (2007) 4855–4859
In conclusion, the tricyclo[4.4.0.05,7]dec-2-ene deriva-
tives 9 and 17 have been synthesized with excellent ee
(95–98% ee). To the best of our knowledge, this is the
first example of preparing the tricyclo[4.4.0.05,7]dec-2-
ene system via the CAIMCP reaction of the a-diazo-b-
keto ester. The chiral cyclopropanes 9 and 17 would
be versatile intermediates for the enantioselective
natural product syntheses, including preparation of
(+)-busidarasin C and acetoxytubipofuran.
Nakamura, M.; Suzuki, A.; Fuchikami, T.; Inoue, M.;
Katoh, T. ARKIVOC 2003, 8, 45–57; (e) Ly, T. W.; Liao,
J.-H.; Shia, K.-S.; Liu, H.-J. Synthesis 2004, 271–275.
8. (a) Dauben, W. G.; Hendricks, R. T.; Luzzio, M. J.; Ng,
H. P. Tetrahedron Lett. 1990, 31, 6969–6972; (b) He, M.;
Tanimori, S.; Ohira, S.; Nakayama, M. Tetrahedron 1997,
´
53, 13307–13314; (c) Muhler, P.; Bolea, C. Helv. Chim.
¨
Acta 2001, 84, 1093–1111.
9. Brooks, D. W.; Lu, L. D. L.; Masamune, S. Angew.
Chem., Int. Ed. Engl. 1979, 18, 72–74, and references cited
therein.
10. The experimental procedure for the IMCP reaction of 6:
A
toluene azeotroped [CuOTf]2ÆC6H5CH3 (24.1 mg;
Acknowledgments
0.0465 mmol, 10 mol % as CuOTf) was placed in a dried
flask (20 mL) and to this flask was added a solution of
toluene azeotroped ligand 7b (37.2 mg, 0.140 mmol,
15 mol %) in toluene (7.7 mL) via a cannula. The mixture
was stirred at room temperature for 0.5 h and then to the
light blue solution was added a solution of toluene
azeotroped 6 (0.273 g, 0.930 mmol) in toluene (10.8 mL)
via a cannula. The reaction mixture was stirred at room
temperature for 4.5 h, quenched with aqueous NH4OH
solution (5.0 mL) and saturated aqueous NH4Cl solution
(2.5 mL), and extracted with ether (15 mL · 3). The
combined organic layer was washed with brine (10 mL),
dried over Na2SO4, and evaporated. The residue was
purified by flash chromatography (hexane/AcOEt = 100:1)
to afford 9 (0.192 g, 78%, 95% ee) as a white solid:
This work was financially supported in part by a Wase-
da University Grant for Special Research Projects and a
Grant-in-Aid for Scientific Research on Priority Areas
(Creation of Biologically Functional Molecules (No.
17035082)) from the Ministry of Education, Culture,
Sports, Science and Technology (MEXT), Japan. We
are also indebted to 21COE ‘Practical Nano-Chemistry’.
References and notes
1. (a) Iwamoto, M.; Kawada, H.; Tanaka, T.; Nakada, M.
Tetrahedron Lett. 2003, 44, 7239–7243; (b) Watanabe, H.;
Iwamoto, M.; Nakada, M. J. Org. Chem. 2005, 70, 4652–
4658; (c) Noguchi, N.; Nakada, M. Org. Lett. 2006, 8,
2039–2042.
2. (a) Inoue, M.; Suzuki, T.; Nakada, M. J. Am. Chem. Soc.
2003, 125, 1140–1141; (b) Suzuki, T.; Kinoshita, A.;
Kawada, H.; Nakada, M. Synlett 2003, 570–572; (c)
Inoue, M.; Nakada, M. Org. Lett. 2004, 6, 2977–2980; (d)
Inoue, M.; Nakada, M. Angew. Chem., Int. Ed. 2006, 45,
252–255.
3. (a) Honma, M.; Sawada, T.; Fujisawa, Y.; Utsugi, M.;
Watanabe, H.; Umino, A.; Matsumura, T.; Hagihara, T.;
Takano, M.; Nakada, M. J. Am. Chem. Soc. 2003, 125,
2860–2861; (b) Honma, M.; Nakada, M. Tetrahedron Lett.
2003, 44, 9007–9011; (c) Sawada, T.; Nakada, M. Adv.
Synth. Catal. 2005, 347, 1527–1532; (d) Miyamoto, H.;
Iwamoto, M.; Nakada, M. Heterocycles 2005, 66, 61–68;
(e) Abe, M.; Nakada, M. Tetrahedron Lett. 2006, 47,
6347–6351; (f) Takeda, H.; Watanabe, H.; Nakada, M.
Tetrahedron 2006, 62, 8054–8063; (g) Takeda, H.; Nakada,
M. Tetrahedron: Asymmetry 2006, 17, 2896–2906; (h)
Takeda, H.; Honma, M.; Ida, R.; Sawada, T.; Nakada, M.
Synlett 2007, 579–582.
4. (a) Takano, M.; Umino, A.; Nakada, M. Org. Lett. 2004,
6, 4897–4900; (b) Watanabe, H.; Takano, M.; Umino, A.;
Ito, T.; Ishikawa, H.; Nakada, M. Org. Lett. 2007, 9, 359–
362; (c) Honma, M.; Nakada, M. Tetrahedron Lett. 2007,
48, 1541–1544; (d) Inoue, M.; Nakada, M. J. Am. Chem.
Soc. 2007, 129, 4164–4165.
24
mp = 74 ꢁC (hexane); ½aꢁD +181.7 (c 0.98, CHCl3); IR
(KBr): 2926, 1717, 1693, 1338, 1172 cmꢀ1 1H NMR
;
(400 MHz, CDCl3): d = 5.54 (dddd, J = 10.5, 3.5, 3.5,
0.7 Hz, 1H), 5.18 (dddd, J = 10.5, 1.2, 1.2, 1.2 Hz, 1H),
2.42 (ddd, J = 19.8, 2.9, 2.9 Hz, 1H), 2.35 (ddd, J = 15.1,
7.0, 1.2 Hz, 1H), 2.23–2.02 (m, 4H), 1.80 (dd, J = 9.3,
1.2 Hz, 1H), 1.62 (dd, J = 12.1, 6.6 Hz, 1H), 1.43 (s, 9H),
1.30 (s, 3H); 13C NMR (100 MHz, CDCl3): d = 205.2,
169.6, 131.7, 124.6, 81.6, 37.3, 36.3, 33.8, 33.2, 29.2, 29.1,
28.0, 22.8, 20.0; HRMS(FAB): m/z calcd for C16H22NaO3
[M+Na]+: 285.1467. Found: 285.1462.
11. Preparation of 90 (below) from 9: (a) NaBH4, CeCl3Æ7H2O,
MeOH, rt, 12 h, 90%. (b) 4-BrBzCl, DMAP, CH2Cl2, rt, 2
h, 95%. Crystallographic data (excluding structure factors)
for compound 90 have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publica-
tion number CCDC 643687. Copies of the data can be
obtained free of charge, on application to CCDC, 12
Union Road, Cambridge CB2 1EZ, UK [fax: +44 (0) 1223
336033 or e-mail: deposit@ccdc.cam.ac.uk].
p
-BrBzO
H
t
-BuO2C
H
9'
5. Hayashi, K.-I.; Nakanishi, Y.; Bastow, K. F.; Cragg, G.;
Nozaki, H.; Lee, K.-H. Bioorg. Med. Chem. Lett. 2002, 12,
345–348.
6. Iguchi, K.; Mori, K.; Suzuki, M.; Takahashi, H.; Yamada,
Y. Chem. Lett. 1986, 1789–1790.
7. Total synthesis of cis-clerodane diterpenoides, see: (a)
Tokoroyama, T. Synthesis 2000, 611–633, and references
cited therein; (b) Kato, M.; Kosugi, H.; Ichiyanagi, T.;
Hagiwara, H.; Kodaira, A.; Kusakari, T.; Suzuki, T.;
Ando, M.; Lee, J.; Drechsel, P.; Vogler, B. Tetrahedron
2001, 57, 8243–8256; (c) Liu, H.-J.; Ho, Y.-L.; Wu, J.-D.;
Shia, K.-S. Synlett 2001, 1805–1807; (d) Nakatani, M.;
ORTEP of 9'

R. Ida, M. Nakada / Tetrahedron Letters 48 (2007) 4855–4859
4859
12. Compounds 8, 9, and 17 were converted to the same diol
by LiAlH4 reduction. The spectra of these compounds
were identical in all respects.
obtained free of charge, on application to CCDC, 12
Union Road, Cambridge CB2 1EZ, UK [fax: +44 (0) 1223
336033 or e-mail: deposit@ccdc.cam.ac.uk].
13. Although l-menthol was less expensive, a readily available
bottle of d-menthol in our laboratory was used.
16. Ghosh, M.; Miller, M. J. Tetrahedron 1996, 52, 4225–
4238.
14. (a) Heathcock, C. H.; White, C. T. J. Am. Chem. Soc.
1979, 101, 7076–7077; (b) Heathcock, C. H.; Pirrung, M.
C.; Buse, C. T.; Hagen, J. P.; Young, S. D.; Sohn, J. E. J.
Am. Chem. Soc. 1979, 101, 7077–7079; (c) Masamune, S.;
Choy, W.; Petersen, J. S.; Sita, L. R. Angew. Chem., Int.
Ed. 1985, 24, 1–30.
15. The diastereomer of 11, ent-11, is shown in Figure 1.
Crystallographic data (excluding structure factors) for
compound ent-11 have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publica-
tion number CCDC 643686. Copies of the data can be
17. Reviews for the preparation and use of cyclopropanes: (a)
Wong, H. N. C.; Hon, M.-Y.; Tse, C.-W.; Yip, Y.-C.;
Tanko, J.; Hudlicky, T. Chem. Rev. 1989, 89, 165–198; (b)
Davies, H. M. L. In Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford, 1991;
Vol. 1, pp 1031–1067, Chapter 4.8; (c) Ye, T.; McKervey,
M. A. Chem. Rev. 1994, 94, 1091–1160; (d) Doyle, M. P.;
Protopopova, M. N. Tetrahedron 1998, 54, 7919–7946; (e)
Doyle, M. P. In Catalytic Asymmetric Synthesis, 2nd ed.;
Ojima, I., Ed.; YHC Publishers: New York, 2000; pp 191–
228, Chapter 5, and references cited therein.