An approach to a chiral cycloalkanone-mediated asymmetric epoxidation of stilbene with oxone

Article abstract of DOI:10.1248/cpb.49.1653

Chiral and C2-symmetric seven-membered cycloalkanones 2 - 6 bearing 1,2-diphenylethane-1,2-diamine and cyclohexane-1,2-diamine backbones were synthesized and evaluated their asymmetry inductive behaviours in an asymmetric epoxidation of stilbene with oxon

Full text of DOI:10.1248/cpb.49.1653

December 2001
Notes
Chem. Pharm. Bull. 49(12) 1653—1657 (2001)
1653
An Approach to a Chiral Cycloalkanone-Mediated Asymmetric
Epoxidation of Stilbene with Oxone®
Koichiro MATSUMOTO and Kiyoshi TOMIOKA*
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8501, Japan.
Received July 30, 2001; accepted September 27, 2001
Chiral and C2-symmetric seven-membered cycloalkanones 2—6 bearing 1,2-diphenylethane-1,2-diamine
and cyclohexane-1,2-diamine backbones were synthesized and evaluated their asymmetry inductive behaviours
in an asymmetric epoxidation of stilbene with oxone®. Although the reaction of the ketones 2 and 3 of a 1,2-
diphenylethane-1,2-diamine backbone gave stilbene oxide in trace to 31% yield, those of the ketones 4—6 of a cy-
clohexane-1,2-diamine backbone gave the epoxide in satisfactorily high yield up to 98%. It is noteworthy that
both reactions with use of stoichiometric and substoichiometric amounts of a ketone 4 gave the epoxide in the es-
sentially same enantioselectivity, 17 and 18%. Eleven-membered cyclic ketones 7 and 8 bearing a binaphthalene
backbone were also synthesized and examined their behaviours, while the enantioselectivity turned out to be
marginal.
Key words epoxidation; olefin; oxone®; ketone; asymmetric synthesis; stilbene
(R,R)-diamine 129) (Chart 2). The phosphonamide 6 was de-
signed expecting more bulkiness than 4 and 5 around the ni-
trogen.
Synthesis of the 11-Membered Chiral Cycloalkanones
7 and 8 The ketone 7 was readily prepared from a binaph-
In these years we have been involved in the development
of external chiral ligands effective for a variety type of cat-
alytic asymmetric reactions.1,2) As an approach toward asym-
metric epoxidation of an olefin with oxone®,3) we designed a
chiral ketone 1 for a precursor to a dioxilane (Fig. 1).4) The
chiral ketone 1 is characteristic by a 1,2-diphenylethane-1,2-
diamine backbone5) and benzenesulfonamide moiety as an
electron-withdrawing group for electrophilic activation of a
ketone carbonyl group as well as prevention of Baeyer–
Villiger oxidative rearrangement of a dioxilane.6) However,
enantioselectivity was relatively low, 30% ee for epoxidation
of stilbene, even though the sense of enantiofacial differenti-
ation was exactly the same as we predicted.7) The corre-
sponding dioxilane A, generated from 1 and oxone®, is antic-
ipated to take a rigid conformation B due to steric reason, of
which chiral environment is expected to be good for enantio-
facial selection (Fig. 2). Since modification of the benzene
ring of arylsulfonamide is one possibility to tune up the
structure 1, new chiral ketones 2 and 3 bearing bulky 2,4,6-
trimethyl and 2,4,6-triisopropylbenzenesulfonamides were
synthesized and examined their efficiency. Three cyclohexyl
versions 4—6 were also prepared and evaluated in an epoxi-
dation of stilbene. Other than seven-membered cycloalka-
nones, the 11-memberd cycloalkanones 7 and 8 bearing a bi-
naphthyl backbone were prepared and also examined their at-
titudes toward an asymmetric epoxidation of stilbene. It is
noteworthy that epoxidation of stilbene with 4 gave stilbene
oxide in reasonably high yield and almost the same enantio-
selectivity, regardless of whether stoichiometric (1.0 eq) or
substoichiometric (0.3 eq) amount of 4 was used.
Fig. 1. Chiral Ketones for Asymmetric Epoxidation
Fig. 2. Anticipated Structures of Dioxilane A and B of 1—3
Synthesis of the 7-Membered Chiral and C2 Symmet-
ric Cycloalkanones 2—6 The ketones 2 and 3 were readily
prepared in three steps starting from commercially available
(S,S)-diamine 9 (Chart 1). According to the reported proce-
dure, 9 was arylsulfonated with the corresponding chlorides
in methylene chloride giving 10a, b.8) Cyclization of 10 was
carried out with 3-iodo-2-iodomethylpropene in N,N-di-
methylformamide (DMF) to afford olefins 11a, b, which
were then ozonolyzed to the ketones 2 and 3 (Chart 1).
The chiral ketones 4—6 bearing a cyclohexanediamine
backbone were prepared by the same reaction sequence from Chart 1. Synthesis of 2 and 3 from a Diamine 9
To whom correspondence should be addressed. e-mail: tomioka@pharm.kyoto-u.ac.jp
© 2001 Pharmaceutical Society of Japan

1654
Vol. 49, No. 12
thalenedicarboxylic acid 1510) under the standard conditions
(Chart 3). The diacid was converted to a diamine 16b in 69%
yield, which was then subjected to the standard three-step
procedure for the preparation of cycloalkanone. The target
ketone 7 was obtained in satisfactorily high yield.
verted to an alkanone 8 in 99% yield.
Asymmetric Epoxidation of Stilbene with Oxone®
Using Chiral Cycloalkanones 2—8 The cycloalkanones 2
and 3 were evaluated as the precursors of the dioxilane A in
the asymmetric epoxidation reaction of trans-stilbene. Ac-
cording to the previously reported reaction of 1,7) we first ex-
amined the reaction using one equivalent of 2 in 1,4-dioxane
and acetonitrile as a solvent (Table 1, entries 1—3). The
chemical yield of stilbene oxide was not improved and more
surprisingly the enantioselectivity was quite marginal. The
ketone 3 bearing more bulky triisopropylbenzenesulfonyl
group did not mediated the epoxidation and gave only a trace
amount of the epoxide (entry 4). On the other hand, the ke-
tones 4—6 bearing a cyclohexyl backbone behaved more
favourably (entries 5—10). Trifluoromethanesulfonylamide 4
promoted the reaction and gave the epoxide in 49 and 98%
yields in dioxane and acetonitrile, respectively (entries 5, 6).
The enantioselectivities were 14 and 17%. More interest-
ingly, substoichiometric (0.3 eq) amount of 4 gave stilbene
oxide in 78% yield and 18% ee (entry 7). Benezenesulfon-
amide 5 gave the product in 53% chemical yield and 7% ee
(entry 8). Phosphonylamide 6 expecting more bulkiness gave
the product in 71% chemical yield and 20% ee.
On the other hand, the reaction of a diol 1911) with diiodide
did not proceed to cyclize. However, reaction with dichloride
gave mono-alkylation product 20 in 92% yield (Chart 4).
Treatment of 20 with sodium hydride in DMF gave the de-
sired cyclized-olefin 21 in 15% yield, which was then con-
Chart 2. Three Step Synthesis of the Chiral Ketones 4—6
The ketones 7 and 8 bearing a binaphthyl and 11-mem-
bered backbone mediated the epoxidation reaction and gave
the epoxide in relatively high chemical yields (entries 11,
12). However, the enantioselectivity was far away from our
satisfaction. It is also very disappointing to find that Baeyer–
Chart 4. Synthesis of Chiral Ketone 8 from a Diol 19
Chart 3. Synthesis of Chiral Ketone 7 from a Carboxylic Acid 15
Table 1. Asymmetric Epoxidation of Stilbene with Oxone®–Ketone 2—8a)
Entry
Ketone
eq
Oxone/eq
Solvent
Base
eq
Yield/%
ee/%
1
2
3
4
5
6
7
8
9
1
2
2
3
4
4
4
5
6
6
7
8
1.0
1.0
1.0
1.0
1.0
1.0
0.3
1.0
1.0
1.0
1.0
1.0
1.4
5.0
1.4
1.4
5.0
5.0
5.0
5.0
5.0
1.4
1.4
1.4
Dioxane
Dioxane
MeCN
Dioxane
Dioxane
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
K2CO3
NaHCO3
K2CO3
6
16
6
27
16
31
Trace
49
98
78
53
Trace
71
46
30
0
0
K2CO3
6
nd
14
17
18
7
nd
20
2
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
K2CO3
16
16
16
16
16
6
10
11
12
K2CO3
K2CO3
6
6
73
0
a) The data in entry 1 is quoted from ref. 7 for comparison purpose. Oxone® was added over a period of 1 h using a syringe drive, excepting 3 h for entry 10. The mixture was
then stirred at room temperature for another 1 h, excepting 9 h for entry 1. In entry 4, acetonitrile could not be used because of insolubility of 4. nd: not determined.

December 2001
1655
enylphosphine (2.6 g, 9.7 mmol) was added portionwise to the reaction mix-
ture. The whole was stirred at room temperature for 1 h. Concentration and
column chromatography (AcOEt/hexaneϭ1/1) gave 2 (3.0 g, 92%) as
colourless needles of mp 179.5—180.5 °C (tert-butyl methyl ether (TBME))
1
and [a]D25 Ϫ5.9° (cϭ1.52, CHCl3). H-NMR: 2.28 (6H, s, CH3), 2.31 (12H,
s, CH3), 3.83 (2H, d, Jϭ17.6 Hz, CH2), 4.69 (2H, d, Jϭ17.6 Hz, CH2), 6.05
(2H, s, CH2), 6.87 (4H, s, CH2), 7.16—7.17 (4H, m, ArH). 7.23—7.31 (6H,
m, ArH). 13C-NMR: 20.9, 23.1, 51.9, 64.1, 127.5, 127.9, 128.6, 131.7,
132.3, 138.0, 140.5, 143.1, 206.4. IR (Nujol): 1740, 1430 cmϪ1. MS (FAB)
m/z: 632 (MϩϩH). HR-MS m/z: Calcd for C35H39N2O5S2: 631.2300. Found:
631.2288.
Fig. 3. Baeyer–Villiger Product 22
Villiger rearrangement occurred quite easily from the ketone
8 and gave a lactone 22 in 55% chemical yield (entry 12).
Discussions on Catalytic Behaviour of the Cycloalka-
nones The asymmetric epoxidation with cycloalkanones 2
and 3 did not proceed smoothly, probably because of Baeyer–
(2S,3S)-6-Methylene-2,3-diphenyl-1,4-bis(2,4,6-triisopropylbenzene-
sulfonyl)[1,4]diazepane (11b) Prepared from 10b8) and 3-iodo-2-
iodomethylpropene, according to the procedure for 11a. Column chromatog-
raphy (AcOEt/hexaneϭ1/10) gave 11b in 66% yield as a white amorphous
1
of [a]D25 Ϫ50.4° (cϭ1.10, CHCl3). H-NMR: 1.11 (24H, d, Jϭ5.2 Hz, CH3
Villiger type degradation of the ketone. This indicates that 2.82 (2H, seqt, Jϭ6.9 Hz, CH), 3.75 (4H, seqt, Jϭ6.9 Hz, CH), 4.28 (2H, d,
Jϭ16.7 Hz, CH2), 4.70 (2H, d, Jϭ16.7 Hz, CH2), 5.02 (2H, s, CH2), 5.62
bulky arylsulfonylamide group is not effective for activation
of dioxilane and prevention of Bayer–Villiger oxidative re-
(2H, s, CH2), 7.00—7.10 (14H, m, ArH). 13C-NMR: 23.50, 23.53, 24.75,
24.8, 29.5, 34.1, 48.2, 64.5, 123.8, 127.4, 127.9, 128.2, 131.8, 139.9, 145.6,
arrangement. The situation is also same in the reactions
using 7 and 8 though the relative epoxidation rate seemed to
be faster than rearrangement. Hence, it is quite important to
know that the ketones 4—6, especially trifluoromethanesul-
fonamide 4 in 0.3 eq, catalyzed the reaction giving the epox-
ide in the same enantioseletivity and 78% yield. Since the tri-
fluoromethanesulfonyl group is highly electron-withdrawing
in nature, the electrophilic reactivity of the ketone is signifi-
cantly high in converting to a dioxilane, and the electron-
withdrawing character of the amide retards Baeyer–Villiger
oxidative rearrangement. These strongly indicated that elec-
trophilic activation of ketone is possible by attaching elec-
tron-withdrawing sulfonylamide groups on both a-methylene
carbons of the ketone, but not by bulky sulfonylamide (2, 3,
7) and ether group (8).
151.4, 153.1. IR (Nujol): 1600, 1460 cmϪ1. MS (FAB) m/z: 797 (MϩϩH).
HR-MS m/z: Calcd for C48H65N2O4S2: 797.4386. Found: 797.4393.
(2S,3S)-2,3-Diphenyl-1,4-bis(2,4,6-triisopropylbenzenesulfonyl)[1,4]-
diazepan-6-one (3) Prepared from 11b, according to the procedure for 2.
Column chromatography (TBME/hexaneϭ1/10) gave 3 in 80% yield as a
white powder of mp 198.5—200.5 °C and [a]D25 ϩ18.9° (cϭ0.54, CHCl3).
1H-NMR: 0.96 (12H, d, Jϭ6.7 Hz, CH3), 1.06 (12H, d, Jϭ6.7 Hz, CH3), 1.24
(12H, d, Jϭ7.0 Hz, CH3), 2.88 (2H, seqt, Jϭ6.7 Hz, CH), 3.62 (4H, seqt,
Jϭ6.7 Hz, CH), 3.88 (2H, d, Jϭ17.7 Hz, CH2), 4.81 (2H, d, Jϭ17.7 Hz,
CH2), 6.09 (2H, s, CH2), 7.11 (4H, s, ArH), 7.26—7.35 (10H, m, ArH). 13C-
NMR: 23.50, 23.53, 24.75, 24.78, 29.7, 34.1, 51.4, 63.4, 124.3, 127.8,
127.9, 128.9, 130.3, 138.9, 151.9, 153.7, 206.4. IR (Nujol): 1740 cmϪ1. MS
(FAB) m/z: 799 (MϩϩH). HR-MS m/z: Calcd for C47H63N2O5S2: 799.4178.
Found: 799.4189.
(6R,7R)-3-Methylene-1,5-bistrifluoromethanesulfonyldecahydrobenzo-
[b][1,4]diazepine (14: R؍CF3SO2) Prepared from 13 (RϭCF3SO2)13)
and 3-iodo-2-iodomethylpropene, according to the procedure for 11. Col-
umn chromatography (AcOEt/hexaneϭ1/5) and recrystallization gave 14
(CF3SO2) in 61% yield as a white powder of mp 145—146 °C (diethyl ether)
and [a]D25 Ϫ12.3° (cϭ1.30, CHCl3). 1H-NMR: 1.33—1.42 (2H, m, CH2),
1.80—2.11 (6H, m, CH2), 3.83 (2H, br s, CH), 4.17—4.28 (4H, m, CH2),
5.15 (2H, s, CH2). 13C-NMR: 25.0, 31.1, 65.9, 66.1, 119.3 (q, Jϭ321 Hz),
119.8, 137.4. IR (Nujol): 3400, 1180 cmϪ1. MS (FAB) m/z: 431 (MϩϩH).
Anal. Calcd for C12H16F6N2O4S2: C, 33.49; H, 3.75; N, 6.51. Found: C,
33.37; H, 3.71; N, 6.53.
Conclusion
The chiral and C2 symmetric seven- and eleven-membered
cycloalkanones 2—8 bearing a 1,2-diphenylethane-1,2-di-
amine, cyclohexane-1,2-diamine, and binaphthalene back-
bones were prepared from the corresponding diamines 9, 12,
16, and diol 19. Asymmetric epoxidation of stilbene with
oxone® was examined using these new cycloalkanones and
was effectively catalyzed especially by the ketone 4 bearing
trifluoromethanesulfonylamide group giving stilbene oxide in
reasonably high 78—98% chemical yield and 18% ee.
(6R,7R)-1,5-Bistrifluoromethanesulfonyldecahydrobenzo[b][1,4]di-
azepin-3-one (4) Prepared from 14 (RϭCF3SO2), according to the proce-
dure for 2. Column chromatography (AcOEt/hexaneϭ1/1) and recrystalliza-
tion gave 4 in 76% yield as colourless granules of mp 126.5 °C (dec.)
1
(CHCl3–hexane) and [a]D25 Ϫ23.9° (cϭ1.76, MeOH). H-NMR: 1.39—2.14
(8H, m, CH2), 3.78 (2H, m, CH), 4.21 (2H, d, Jϭ18.5 Hz, CH2), 4.44 (2H, d,
Jϭ18.5 Hz, CH2). 13C-NMR: 24.7, 29.5, 59.4, 65.4, 119.3 (q, Jϭ323 Hz),
199.3. IR (Nujol): 1725 cmϪ1. MS (FAB) m/z: 433 (MϩϩH). Anal. Calcd for
C11H14F6N2O5S2: C, 30.56; H, 3.26 Found: C, 30.48; H, 3.27.
Experimental12)
(2S,3S)-6-Methylene-2,3-diphenyl-1,4-bis(2,4,6-trimethylbenzenesul-
fonyl)[1,4]diazepane (11a) A solution of 10a8) (8.1 g, 14 mmol) in DMF
(6R,7R)-1,5-Bisbenzenesulfonyl-3-methylenedecahydrobenzo[b][1,4]-
(24 ml) was added to a suspension of sodium hydride (60%, 1.1 g, 28 mmol) diazepine (14: R؍PhSO2) Prepared from 13 (RϭPhSO2) and 3-iodo-2-
in DMF (4.0 ml) at 0 °C. The mixture was stirred at 80 °C for 1 h. To the iodomethylpropene, according to the procedure for 11a. Column chromatog-
mixture was added 3-iodo-2-iodomethylpropene (5.2 g, 17 mmol) at 0 °C. raphy (AcOEt/hexaneϭ1/2) and recrystallization gave 14 (RϭPhSO2) in
The whole was stirred at 80 °C for 1.5 h and was quenched with saturated 84% yield as colorless cubes of mp 165—166 °C (benzene) and [a]D25
(satd) NH4Cl. The mixture was extracted with benzene (100 ml). The com- ϩ18.7° (cϭ1.68, CHCl3). 1H-NMR: 1.25 (2H, m, CH2), 1.73 (4H, m, CH2),
bined organic layers were washed with 10% HCl, satd NaHCO3, and brine. 1.93 (2H, m, CH2), 3.57 (2H, m, CH), 3.99 (2H, d, Jϭ15.6 Hz, CH2), 4.07
Concentration and column chromatography (AcOEt/hexaneϭ1/5) gave 11a
(2H, d, Jϭ15.6 Hz, CH2), 4.90 (2H, s, CH2), 7.44—7.52 (6H, m, ArH),
1
(5.0 g, 58%) as a white amorphous of [a]D25 Ϫ162.1° (cϭ1.51, CHCl3). H- 7.83—7.86 (4H, m, ArH). 13C-NMR: 25.4, 31.3, 52.0, 64.1, 116.5, 127.1,
NMR: 1.93 (6H, s, CH3), 2.36 (12H, s, CH3), 4.65 (2H, d, Jϭ16.8 Hz, CH2), 128.8, 132.1, 139.8, 142.3. IR (Nujol): 1650, 1320 cmϪ1. MS (FAB) m/z:
4.71 (2H, d, Jϭ16.8 Hz, CH2), 5.15 (2H, s, CH2), 5.19 (2H, s, CH2), 6.50 447 (MϩϩH). Anal. Calcd for C22H26N2O4S2: C, 59.17; H, 5.87; N, 6.27.
(4H, s, ArH), 6.58 (4H, d, Jϭ7.3 Hz, ArH), 6.72 (4H, dd, Jϭ7.3, 7.3 Hz, Found: C, 59.07; H, 5.86; N, 6.11.
ArH). 6.81 (2H, d, Jϭ7.3 Hz, ArH). 13C-NMR: 20.5, 22.8, 26.9, 49.6, 65.1,
(6R,7R)1,5-Bisbenzenesulfonyldecahydrobenzo[b][1,4]diazepin-3-one
(5) Prepared from 14 (RϭPhSO2) according to the procedure for 2. Col-
111.7, 126.8, 127.0, 127.2, 131.5, 133.3, 138.6, 139.5, 142.2, 144.6. IR
(Nujol): 1605, 1470 cmϪ1. MS (FAB) m/z: 629 (MϩϩH). High resolution umn chromatography (AcOEt/hexaneϭ1/2) and recrystallization gave 5 in
(HR)-MS m/z: Calcd for C36H41N2O4S2: 629.2508. Found: 629.2512.
(2S,3S)-2,3-Diphenyl-1,4-bis(2,4,6-trimethylbenzenesulfonyl)[1,4]di-
azepan-6-one (2) A solution of 11a (4.1 g, 6.5 mmol) in chloroform (65
99% yield as colourless needles of mp 195—196 °C (benzene–hexane) and
[a]D25 Ϫ26.2° (cϭ1.55, CHCl3). 1H-NMR: 1.21—1.30 (2H, m, CH2), 1.74—
1.83 (6H, m, CH2), 3.66—3.68 (2H, m, CH), 4.15 (2H, d, Jϭ18.3 Hz, CH2),
ml) was ozonized at Ϫ60 °C by passing the O3/O2 stream until the solution 4.21 (2H, d, Jϭ18.3 Hz, CH2), 7.49—7.52 (4H, m, ArH), 7.55—7.58 (2H,
was saturated with O3. Excess O3 was removed by O2 stream, and triph- m, ArH), 7.82—7.84 (4H, m, ArH). 13C-NMR: 25.0, 29.9, 56.3, 63.9, 126.7,

1656
Vol. 49, No. 12
129.2, 132.7, 141.6, 204.2. IR (Nujol): 1720 cmϪ1. MS (FAB) m/z: 449
(MϩϩH). Anal. Calcd for C21H24N2O5S2: C, 56.23; H, 5.39. Found: C,
56.04; H, 5.36.
m/z: Calcd for C34H29N2O4S2: 593.1569. Found: 593.1577.
(R)-10-Methylene-8,12-bis(phenylsulfonyl)-8,9,10,11,12,13-hexahydro-
7H-dinaphtho[2,1-g:1,2-i][1,5]diazacycloundecine (18) Prepared from
17 and 3-iodo-2-iodomethylpropenein, according to the procedure for 11a.
Recrystallization gave 18 in 72% yield as colourless needles of mp 203.5—
(1R,2R)-N,N؅-Bis(5,5-dimethyl-2-oxo-2l5-[1,3,2]dioxaphosphinan-2-
yl)cyclohexane-1,2-diamine (13: R؍PO(OCH2C(Me)2CH2O)) A solu-
tion of 2-chloro-5,5-dimethyl[1,3,2]dioxaphosphinane 2-oxide (11 g, 57
mmol) in CH2Cl2 (60 ml) was added to a solution of 12 in CH2Cl2 (24 ml)
containing N,N-diisopropylethylamine (20 ml, 110 mmol) at 0 °C. The mix-
ture was stirred at room temperature for 12 h, and was poured onto 10% HCl
(100 ml), and then extracted with CHCl3 (100 ml). The combined organic
layers were washed with satd NaHCO3, brine. Concentration and recrystal-
lization from AcOEt–CHCl3 afforded 13 (RϭPO(OCH2C(Me)2CH2O)) in
64% yield as a white powder of mp 185—188 °C and [a]D25 ϩ8.3° (cϭ1.44,
205 °C (AcOEt) and [a]D25 ϩ182° (cϭ0.98, CHCl3). H-NMR: 3.38 (2H, d,
1
Jϭ15.9 Hz, CH2), 3.53 (2H, d, Jϭ14.7 Hz, CH2), 3.55 (2H, d, Jϭ15.9 Hz,
CH2), 4.44 (2H, d, Jϭ14.7 Hz, CH2), 4.65 (2H, s, CH2), 7.01 (2H, d, Jϭ8.6
Hz, ArH). 7.25—7.30 (2H, m, ArH), 7.43—7.49 (6H, m, ArH), 7.52—7.55
(2H, m, ArH), 7.68—7.73 (6H, m, ArH) 7.90—7.94 (4H, m, ArH). 13C-
NMR: 49.3, 50.8, 118.5, 125.9, 126.3, 126.7, 127.0, 127.1, 128.2, 129.0,
132.7, 132.9, 133.0, 133.1, 134.2, 136.3, 138.9. IR (Nujol): 1640 cmϪ1. MS
(FAB) m/z: 645 (MϩϩH). HR-MS m/z: Calcd for C38H33N2O4S2: 645.1882.
Found: 645.1901.
1
CHCl3). H-NMR: 1.01, 1.09 (each 6H, s, CH3), 1.26 (4H, m, CH2), 1.69,
(R)-8,12-Bis(phenylsulfonyl)-7,8,9,11,12,13-hexahydro-10H-dinaph-
tho[2,1-g:1,2-i][1,5]diazacycloundecine-10-one (7) To a suspension of
18 (64 mg, 0.1 mmol) and K2OsO4·2H2O (3 mg, 0.01 mmol in THF (1.5 ml)
was added a solution of sodium metaperiodate (63 mg, 0.3 mmol) in water
(0.5 ml). The whole was stirred at room temperature for 2.5 d. After addition
of water (10 ml), the mixture was extracted with AcOEt. The extract was
washed with 10% HCl, satd NaHCO3 and brine. Concentration and column
chromatography (benzene) gave 7 (38 mg, 59%) as a solid of mp 146—
148 °C and [a]D25 ϩ216.6° (cϭ0.27, CHCl3). 1H-NMR: 3.24 (2H, d, Jϭ16.2
Hz, CH2), 3.57 (2H, d, Jϭ13.2 Hz, CH2), 4.05 (2H, d, Jϭ16.2 Hz, CH2),
4.30 (2H, d, Jϭ13.2 Hz, CH2), 7.25 (2H, d, Jϭ8.3 Hz, ArH). 7.36—7.39
(4H, m, ArH), 7.46—7.49 (4H, m, ArH), 7.54—7.59 (8H, m, ArH), 7.99—
7.03 (4H, m, ArH). 13C-NMR d: 52.6, 53.9, 125.3, 126.6, 127.1, 127.9,
128.3, 128.4, 128.6, 129.1, 130.5, 132.6, 133.1, 134.2, 135.2, 136.2, 201.1.
IR (Nujol): 1735 cmϪ1. MS (FAB) m/z: 647 (MϩϩH). HR-MS m/z: Calcd
for C37H31N2O5S2: 647.1674. Found: 647.1668.
(R)-[2Ј-(2-Chloromethylallyloxymethyl)[1,1Ј]binaphthalenyl-2-
yl]methanol (20) A solution of a diol 19 (443 mg, 1.41 mmol) in DMF
(11 ml) was added to a suspension of sodium hydride (60%, 57 mg, 1.43
mmol) in DMF (130 ml) at 0 °C. The mixture was stirred at room tempera-
ture for 1 h. To the mixture was added 3-chloro-2-chloromethylpropene
(4.90 ml, 42.3 mmol) at Ϫ40 °C. The whole was stirred at Ϫ40 °C for 24 h
and was quenched with satd NH4Cl. The mixture was extracted with ben-
zene (30 ml). The combined organic layers were washed with brine. Concen-
tration and column chromatography (AcOEt/hexaneϭ1/6) gave 20 (520 mg,
92%) as a colourless gum of [a]D25 ϩ104.4° (cϭ0.43, CHCl3). 1H-NMR:
2.94 (1H, dd, Jϭ3.7, 9.4 Hz, OH), 3.87 (1H, d, Jϭ11.9 Hz, CH2), 3.89 (1H,
d, Jϭ12.4 Hz, CH2), 3.92 (1H, d, Jϭ11.9 Hz, CH2), 3.96 (1H, d, Jϭ12.4 Hz,
CH2), 4.07 (1H, d, Jϭ10.7 Hz, CH2), 4.16 (1H, dd, Jϭ3.7, 12.2 Hz, CH2),
4.20 (1H, d, Jϭ10.7 Hz, CH2), 4.28 (1H, dd, Jϭ9.4, 12.2 Hz, CH2), 5.06
(1H, s, CH2), 5.19 (1H, s, CH2), 7.04 (1H, d, Jϭ8.5 Hz, ArH), 7.07 (1H, d,
Jϭ8.5 Hz, ArH), 7.24 (2H, m, ArH), 7.47 (2H, m, ArH), 7.69 (1H, d, Jϭ8.5
Hz, ArH), 7.79 (1H, d, Jϭ8.5 Hz, ArH), 7.94 (1H, d, Jϭ8.5 Hz, ArH), 7.94
(1H, d, Jϭ8.5 Hz, ArH), 8.02 (2H, m, ArH). 13C-NMR: 44.9, 63.2, 71.0,
71.1, 117.6, 126.0, 126.1, 126.29, 126.34, 126.5, 126.7, 127.4, 127.6,
128.06, 128.08, 128.5, 128.7, 132.7, 133.0, 133.1, 133.3, 133.5, 133.8,
135.4, 138.1, 141.2. IR (Nujol): 3400, 1595 cmϪ1. MS m/z: 402 (Mϩ). HR-
MS m/z: Calcd for C26H23ClO2: 402.1387. Found: 402.1381.
(R)-10-Methylene7,10,11,13-tetrahydro-9H-dinaphtho[2,1-g:1,2-
i][1,5]dioxacycloundecine (21) A solution of 20 (470 mg, 1.20 mmol) in
DMF (45 ml) was added to a suspension of sodium hydride (60%, 56 mg,
1.40 mmol) in DMF (140 ml) at 0 °C over a period of 5 h. The whole was
stirred at room temperature for 24 h and was quenched with satd NH4Cl. The
mixture was extracted with benzene (30 ml). The combined organic layers
were washed with brine. Concentration and column chromatography (ace-
tone/hexaneϭ1/20) gave 21 (69 mg, 15%) as a white amorphous of [a]D25
ϩ278° (cϭ0.18, CHCl3). 1H-NMR: 3.76 (2H, d, Jϭ11.9 Hz, CH2), 4.08 (2H,
d, Jϭ11.9 Hz, CH2), 4.23 (2H, Jϭ11.8 Hz, CH2), 4.46 (2H, Jϭ11.8 Hz,
CH2), 4.87 (2H, s, CH2), 7.04 (2H, d, Jϭ8.0 Hz, ArH), 7.22 (2H, dd, Jϭ7.3,
7.3 Hz, ArH), 7.44 (2H, dd, Jϭ7.3, 7.3 Hz, ArH), 7.68 (2H, d, Jϭ8.4 Hz,
ArH), 7.92 (2H, d, Jϭ8.0 Hz, ArH), 7.98 (2H, d, Jϭ8.4 Hz, ArH). 13C-NMR:
70.6, 71.2, 113.6, 125.8, 125.9, 126.0, 126.4, 128.0, 128.1, 128.2, 132.8,
133.3, 135.2, 145.0. IR (Nujol): 1640 cmϪ1. MS m/z: 366 (Mϩ). HR-MS
m/z: Calcd for C26H22O2: 366.1620. Found: 366.1626.
2.17 (each 2H, m, CH2), 2.86 (2H, m, CH), 3.51 (2H, m, NH), 3.91 (1H, dd,
Jϭ11.6, 11.6 Hz, CH2), 3.91 (1H, dd, Jϭ10.1, 10.1 Hz, CH2), 3.94 (1H, dd,
Jϭ11.6, 11.6 Hz, CH2), 3.94 (1H, dd, Jϭ10.1, 10.1 Hz, CH2), 4.13 (2H, dd,
Jϭ10.1, 10.1 Hz, CH2), 4.14 (2H, dd, Jϭ10.1, 10.1 Hz, CH2). 13C-NMR
(CDCl3): 21.1, 21.5, 24.7, 32.0 (d, Jϭ5.2 Hz), 34.7, 56.4 (Jϭ7.2 Hz), 76.3
(d, Jϭ6.2 Hz), 76.5 (d, Jϭ6.2 Hz). IR (Nujol): 3200, 1275 cmϪ1. MS m/z:
410 (Mϩ). HR-MS m/z: Calcd for C16H32N2O6P2: 410.1736. Found:
410.1733.
(6R,7R)-1,5-Bis(5,5-dimethyl-2-oxo-l5-[1,3,2]dioxaphosphin-2-yl)-
decahydrobenzo[b][1,4]diazepin-3-one (6) Prepared from 13 (RϭPO-
(OCH2C(Me)2CH2O)), according to the procedure for 11a and 2. Column
chromatography (EtOH/AcOEtϭ1/20) and recrystallization gave 6 in 48%
two-step yield as pale yellow granules of mp 155—156 °C (AcOEt) and
[a]D25 ϩ17.2° (cϭ1.33, CHCl3). 1H-NMR: 0.93, 1.18 (each 6H, s, CH3),
1.34, 1.78 (each 2H, m, CH2), 1.88 (2H, m, CH2), 2.00 (2H, m, CH2), 3.43
(2H, m, CH), 3.81 (2H, dd, Jϭ7.7, 18.0 Hz, CH2), 3.96 (2H, dd, Jϭ18.3,
18.3 Hz, CH2), 3.98 (2H, dd, Jϭ18.3, 18.3 Hz, CH2), 4.03 (2H, dd, Jϭ10.7,
18.0 Hz, CH2), 4.19 (2H, dd, Jϭ11.0, 11.0 Hz, CH2), 4.20 (2H, dd, Jϭ11.0,
11.0 Hz, CH2). 13C-NMR: 21.0, 21.9, 25.3, 30.6, 31.8 (d, Jϭ5.2 Hz), 55.6,
62.5, 76.3 (d, Jϭ6.3 Hz), 76.4 (d, Jϭ6.3 Hz), 206.4. IR (Nujol): 1715 cmϪ1
.
MS m/z: 464 (Mϩ). HR-MS (FAB) m/z: Calcd for C19H35N2O7P2: 465.1919.
Found: 465.1910.
(R)-[1,1؅]Binaphthalenyl-2,2؅-dicarboxylic Acid Diamide (16a) A so-
lution of (R)-15 (1.69 g, 4.94 mmol) in thionyl chloride (5.0 ml) was refluxed
with stirring for 1 h. After the whole was concentrated, benzene (5.0 ml) and
aqueous NH3 (28%, 5.0 ml) were added. The mixture was stirred at room
temperature for 0.5 h, and then poured onto 10% HCl, and was extracted
with AcOEt (100 ml). The organic layer was washed with brine. Concentra-
tion, column chromatography (hexane/AcOEtϭ9/1, then AcOEt), and re-
crystallization gave 16a (1.53 g, 91%) as colourless cubes of mp 222.5—
224.0 °C (benzene) and [a]D25 ϩ237.5° (cϭ0.80, CHCl3). 1H-NMR: 5.44
(2H, br s, NH2), 7.04 (2H, br s, NH2), 7.11 (2H, d, Jϭ8.6 Hz, ArH), 7.25—
7.28 (2H, m, ArH), 7.47—7.50 (2H, m, ArH), 7.73 (2H, d, Jϭ8.6 Hz, ArH),
7.92 (2H, d, Jϭ8.3 Hz, ArH), 8.01 (2H, d, Jϭ8.3 Hz, ArH). 13C-NMR:
123.7, 126.4, 127.2, 127.3, 128.2, 128.3, 129.0, 132.3, 133.1, 134.2, 172.4.
IR (Nujol): 3300, 3150, 1660 cmϪ1. MS m/z: 340 (Mϩ). HR-MS m/z: Calcd
for C22H16N2O2: 340.1212. Found: 340.1217.
(R)-N,N؅-Bisbenzenesulfonyl-1,1؅-binaphthyl-2,2؅-bis(methylamine)
(17) A solution of 16a (525 mg, 1.54 mmol) in tetrahydrofuran (THF)
(2.5 ml) was added to BH3·Me2S in THF (2.5 ml, 10 M) and refluxed for 2 d
with stirring. To the mixture were added MeOH (8.0 ml) and aqueous HCl
(35%, 1.0 ml) at 0 °C and then the mixture was concentrated. The residue
was poured onto 15% NaOH (15 ml) and extracted with TBME (30 ml).
Combined organic layers were washed with satd NaHCO3 (15 ml) and brine.
Concentration gave (R)-16b (360 mg, 75%) as a pale yellow oil, which was
used in the next step without any purification.
To a solution of 16b (100 mg, 0.29 mmol) in CH2Cl2 (3.0 ml) containing
triethylamine (TEA, 0.12 ml, 0.87 mmol) was added benzenesulfonyl chlo-
ride (0.09 ml, 0.73 mmol) at 0 °C. The whole was stirred for 1 h at room tem-
perature. After addition of water (10 ml), the mixture was extracted with
benzene (30 ml). The extract was washed with 10% HCl, satd NaHCO3 and
brine. Concentration and column chromatography (AcOEt/hexaneϭ1/2)
gave 17 (150 mg, 89%) as a white amorphous of mp 85—89 °C and [a]D25
ϩ86.9° (cϭ0.72, CHCl3). 1H-NMR: 3.68, 3.73 (each 2H, dd, Jϭ6.0,
14.4 Hz, CH2), 4.69 (2H, dd, Jϭ6.0, 6.0 Hz, NH), 6.92 (2H, d, Jϭ8.6 Hz,
ArH), 7.24—7.26 (2H, m, ArH), 7.32—7.36 (6H, m, ArH), 7.46—7.49 (4H,
m, ArH), 7.52 (2H, d, Jϭ8.0 Hz, ArH), 7.64 (2H, d, Jϭ8.6 Hz, ArH), 7.92
(4H, dd, Jϭ8.6, 8.6 Hz, ArH). 13C-NMR (CDCl3): 45.1, 125.5, 126.4, 126.5,
126.7, 127.1, 128.31, 128.33, 129.0, 132.51, 132.53, 133.0, 133.1, 133.6,
139.3. IR (Nujol): 3250, 1325 cmϪ1. MS (FAB) m/z: 593 (MϩϩH). HR-MS
(R)-7,13-Dihydro-9H-dinaphtho[2,1-g:1,2-i][1,5]dioxacycloundecine-
10(11H)-one (8) To a suspension of 21 (42 mg, 0.1 mmol) and K2OsO4·
2H2O (4 mg, 0.01 mmol) in THF (2.4 ml) was added a solution of sodium
metaperiodate (99 mg, 0.5 mmol) in water (0.8 ml). The whole was stirred at
room temperature for 1 d. After addition of water (10 ml), the mixture was
extracted with TBME (10 ml). The extract was washed with brine. Concen-

December 2001
1657
Crudden C. M., Matsuhashi H., ibid., 62, 8288—8289 (1997); Wang
Z. X., Tu Y., Frohn M., Zhang J. R., Shi Y., J. Am. Chem. Soc., 119,
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8623 (1997); Zhao C. G., Adam W., Tetrahedron: Asymmetry, 8,
3995—3998 (1997); Adam W., Fell R. T., Saha-Moller C. R., Zhao C.-
G., ibid., 9, 397—401 (1998); Song C. E., Kim Y. H., Lee K. C., Lee
S. G., Jin B. W., ibid., 8, 2921—2926 (1997); Armstrong A., Hayter B.
R., Chem. Commun., 1998, 621—622; Frohn M., Dalkiewicz M., Tu
Y., Wang Z.-X., Shi Y., J. Org. Chem., 63, 2948—2953 (1998); Wang
Z.-X., Shi Y., ibid., 63, 3099—3104 (1998); Cao G.-A., Wang Z.-X.,
Tu Y., Shi Y., Tetrahedron Lett., 39, 4425—4428 (1998); Yang D.,
Wong M.-K., Yip Y.-C., Wang X.-C., Tang M.-W., Zheng J.-H., Che-
ung K.-K., J. Am. Chem. Soc., 120, 5943—5952 (1998); Zhu Y., Tu Y.,
Yu H., Shi Y., Tetrahedron Lett., 39, 7819—7822 (1998); Tu Y., Wang
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8475—8485 (1998); Yang D., Yip Y.-C., Chen J., Cheung K.-K., J.
Am. Chem. Soc., 120, 7659—7660 (1998); Adam W., Saha-Moller C.
R., Zhao C.-G., Tetrahedron: Asymmetry, 10, 2749—2755 (1999);
Wang Z.-X., Miller S. M., Anderson O. P., Shi Y., J. Org. Chem., 64,
6443—6458 (1999); Carnell A. J., Johnstone R. A. W., Parsy C. C.,
Sanderson W. R., Tetrahedron Lett., 40, 8029—8032 (1999); Arm-
strong A., Hayter B. R., Tetrahedron, 55, 11119—11126 (1999);
Wang Z.-X., Cao G.-A., Shi Y., J. Org. Chem., 64, 7646—7650
(1999); Warren J. D., Shi Y., ibid., 64, 7675—7677 (1999); Frohn M.,
Zhou X., Zhang J.-R., Tang Y., Shi Y., J. Am. Chem. Soc., 121,
7718—7719 (1999); Shu L., Shi Y., Tetrahedron Lett., 40, 8721—
8724 (1999); Armstrong A., Hayter B. R., Moss W. O., Reeves J. R.,
Wailes J. S., Tetrahedron: Asymmetry, 11, 2057—2061 (2000); Sol-
ladie-Cavallo A., Bouerat L., Organic Lett., 2, 3531—3534 (2000);
Tian H., She X., Xu J., Shi Y., ibid., 3, 1929—1931 (2001).
tration and column chromatography (AcOEt/hexane/TEAϭ2/20/1) gave 8
(42 mg, 99%) as a solid of mp 171.0—172.5 °C and [a]D25 ϩ257° (cϭ0.32,
1
CHCl3). H-NMR: 3.86 (2H, d, Jϭ14.1 Hz, CH2), 4.07 (2H, d, Jϭ14.1 Hz,
CH2), 4.30 (2H, d, Jϭ10.5 Hz, CH2), 4.55 (2H, d, Jϭ10.5 Hz, CH2), 7.02
(2H, d, Jϭ8.6 Hz, ArH), 7.23 (2H, ddd, Jϭ1.1, 8.6, 8.6 Hz, ArH), 7.47 (2H,
ddd, Jϭ1.1, 8.3, 8.3 Hz, ArH), 7.68 (2H, d, Jϭ8.6 Hz, ArH), 7.94 (2H, d,
Jϭ8.3 Hz, ArH), 8.01 (2H, d, Jϭ8.6 Hz, ArH). 13C-NMR: 73.0, 73.4, 126.2,
126.3, 126.6, 128.0, 128.2, 128.4, 132.9, 133.4, 134.0, 135.4, 208.6. IR
(Nujol): 1725 cmϪ1. MS m/z: 368 (Mϩ). HR-MS m/z: Calcd for C25H20O3:
368.1412. Found: 368.1402.
Asymmetric Epoxidation of Stilbene Catalyzed by 4 (Table 1, Entry 7)
To an acetonitrile solution (7.5 ml) of trans-stilbene (90 mg, 0.50 mmol), 4
(65 mg, 0.15 mmol), and an aqueous Na2EDTA solution (3 ml, 4ϫ10Ϫ4 M)
was added a mixture of oxone® (922 mg, 1.5 mmol) and sodium bicarbonate
(391 mg, 4.7 mmol) in portions over a period of 1 h at room temperature
(r.t.). After stirring for 1 h, the mixture was poured onto water (20 ml), and
extracted with CHCl3 (60 ml). The combined organic layers were washed
with brine. Concentration and column chromatography (hexane, then
hexane/AcOEtϭ9/1) gave trans-stilbene epoxide (74 mg, 78%) of [a]D25
1
Ϫ47.6° (cϭ1.19, CHCl3) in 18 % ee. H-NMR, IR, and MS were identical
with those reported.14) The ee was determined by HPLC analysis using a chi-
ral stationary phase column (Daicel Chiralcel OD-H, hexane/iso-PrOHϭ
9 : 1, 0.5 ml/min, 15.0 min (major enantiomer), 26.9 min (miner enantiomer).
In entry 12, column chromatography gave (R)-7,14-dihydrodinaphtho[2,1-
h:1,2-j][1,3,6]trioxacyclododecin-11(12H)-one 22 as a white gum in 55%
yield: 1H-NMR: 3.85 (1H, d, Jϭ12.5 Hz, CH2), 3.89 (1H, d, Jϭ16.2 Hz,
CH2), 4.23 (1H,d, Jϭ16.2 Hz, CH2), 4.30 (1H, Jϭ12.2 Hz, CH2), 4.67 (1H,
Jϭ12.5 Hz, CH2), 4.77 (1H, Jϭ12.2 Hz, CH2), 4.78 (1H, Jϭ5.8 Hz, CH2),
5.73 (1H, Jϭ5.8 Hz, CH2), 6.95 (1H, d, Jϭ8.6 Hz, ArH), 6.95 (1H, d,
Jϭ8.6 Hz, ArH), 7.23 (2H, m, ArH), 7.45 (1H, d, Jϭ7.3 Hz, ArH), 7.47 (1H,
d, Jϭ7.3 Hz, ArH), 7.75 (1H, d, Jϭ8.6 Hz, ArH), 7.87 (1H, d, Jϭ8.6 Hz,
ArH), 7.92 (1H, d, Jϭ8.6 Hz, ArH), 7.94 (1H, d, Jϭ8.3 Hz, ArH), 8.01 (1H,
d, Jϭ8.5 Hz, ArH), 8.06 (1H, d, Jϭ8.6 Hz, ArH). 13C-NMR: 69.2, 69.4,
71.3, 88.7, 126.4, 126.8, 127.0, 127.1, 127.4, 127.5, 127.76, 127.83, 129.3,
129.4, 129.6, 129.7, 133.3, 134.3, 134.39, 134.42, 134.47, 134.53, 134.6,
135.9, 172.0. IR (CHCl3): 1740 cmϪ1. MS m/z: 384 (Mϩ). HR-MS m/z:
Calcd for C25H20O4: 384.1362. Found: 384.1368.
4) For a recent review on asymmetric epoxidation of electron-deficient
olefins, see: Porter M. J., Skidmore J., Chem. Commun., 2000, 1215—
1225.
5) a) Shindo M., Koga K., Tomioka K., J. Org. Chem., 63, 9351—9357
(1998); b) Mori T., Kosaka K., Nakagawa Y., Nagaoka Y., Tomioka K.,
Tetrahedron: Asymmetry, 9, 3175—3178 (1998); c) Tomioka K., Fu-
jieda H., Hayashi S., Hussein M. A., Kambara T., Nomura Y., Kanai
M., Koga K., Chem. Commun., 715—716 (1999); d) Hussein M. A.,
Iida A., Tomioka K., Tetrahedron, 55, 11219—11228 (1999).
6) a) Murray R. W., Chem. Rev., 89, 1187—1201 (1989); b) Adam W.,
Curci R., Edwards J. O., Acc. Chem. Res., 22, 205—211 (1989); c)
Curci R., Dinoi A., Rubino M. F., Pure Appl. Chem., 67, 811—822
(1995).
Acknowledgments This research was supported by a Grant-in-Aid for
Scientific Research on Priority Areas (A) “Exploitation of Multi-Element
Cyclic Molecules” from the Ministry of Education, Culture, Sports, Science
and Technology, Japan.
7) Matsumoto K., Tomioka K, Heterocycles, 54, 615—617 (2001).
8) Quinkert G., Grosso M. D., Doring A., Doring W., Schenkel R. I.,
Bauch M., Dambacher G. T., Bats J. W., Zimmermann G., Durner G.,
Helv. Chim. Acta, 78, 1345—1389 (1995).
References and Notes
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12055—12056 (2000); b) Nishimura K., Ono M., Nagaoka Y.,
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2) For reviews on chiral ligand-promoted asymmetric reactions, see: a)
Tomioka K., Synthesis, 1990, 541—549; b) Noyori R., “Asymmetric
Catalysis in Organic Synthesis,” John Wiley and Sons, Inc., New York,
1994; c) Seyden-Penne J., “Chiral Auxiliaries and Ligands in Asym-
metric Synthesis,” John Wiley and Sons, Inc., New York 1995.
3) Leading references on an asymmetric epoxidation with chiral ketones.
Curci R., Fiorentino M., Serio M. R., J. Chem. Soc., Chem. Commun.,
1984, 155—156; Curci R., D’Accolti L., Fiorentino M., Rosa A.,
Tetrahedron Lett., 36, 5831—5834 (1995); Denmark S. E., Forbes D.
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1407 (1995); Brown D. S., Marples B. A., Smith P., Walton L., Tetra-
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(1996); Yang D., Wang X.-C., Wong M.-K., Yip Y.-C., Tang M.-W.,
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1616 (1993).
11) Rosini C., Tanturli R., Pertici P., Salvadori P., Tetrahedron: Asymmetry,
7, 2971—2982 (1996).
12) The reaction was monitored by TLC. The extracted organic layers
were dried over Na2SO4 unless otherwise noted. Purification was car-
ried out using silica gel column chromatography unless otherwise
1
noted. H-NMR (500 MHz) and 13C-NMR (126 MHz) were measured
in CDCl3 unless otherwise noted. Chemical shift (d) was presented in
ppm relative to internal tetramethylsilane. Coupling constant value (J)
was presented in Hz. Mass spectra were measured by electron impact
(EI) mode unless otherwise noted.
13) Takahashi H., Kawakita T., Ohno M., Yoshioka M., Kobayashi S.,
Tetrahedron, 48, 5691—5700 (1992).
14) Chang H. T., Sharpless K. B., J. Org. Chem., 61, 6456—6457 (1996).