New chiral Schiff bases derived from (+)- and (-)-α-pinenes in the metal complex catalyzed asymmetric oxidation of sulfides

Article abstract of DOI:10.1007/s11172-008-0017-8

New chiral Schiff bases were derived from (+)- and (-)-α-pinenes for the first time. Coordinated to vanadium ions, they can be used as ligands in catalytic oxidation of sulfides into chiral sulfoxides. Conditions for the asymmetric oxidation of thioanisole to methyl phenyl sulfoxide in optical purity up to 32% were found. Variation of substituents in the ligand has a significant effect not only on enantioselectivity of the reaction, but also on absolute configuration of the sulfoxide formed.

Full text of DOI:10.1007/s11172-008-0017-8

Russian Chemical Bulletin, International Edition, Vol. 57, No. 1, pp. 108—117, January, 2008
108
New chiral Schiff bases derived from
(+)ꢀ and (–)ꢀαꢀpinenes in the metal complex catalyzed asymmetric
oxidation of sulfides*
b
b
b
E. A. Koneva,a K. P. Volcho,b D. V. Korchagina, N. I. Komarova, A. I. Kochnev,

N. F. Salakhutdinov,b and A. G. Tolstikovc
аNovosibirsk State University,
2 ul. Pirogova, 630090 Novosibirsk, Russian Federation
bN. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry,
Siberian Branch of the Russian Academy of Sciences,
9 prosp. Akad. Lavrent´eva, 630090 Novosibirsk, Russian Federation.
Fax: +7 (383) 330 9752. Eꢀmail: volcho@nioch.nsc.ru
cG. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
5 prosp. Akad. Lavrent´eva, 630090 Novosibirsk, Russian Federation
New chiral Schiff bases were derived from (+)ꢀ and (–)ꢀαꢀpinenes for the first time. Coordiꢀ
nated to vanadium ions, they can be used as ligands in catalytic oxidation of sulfides into chiral
sulfoxides. Conditions for the asymmetric oxidation of thioanisole to methyl phenyl sulfoxide in
optical purity up to 32% were found. Variation of substituents in the ligand has a significant effect not
only on enantioselectivity of the reaction, but also on absolute configuration of the sulfoxide formed.
Key words: αꢀpinene, chiral Schiff bases, salicylaldimines, metal complex catalysis, asymmetꢀ
ric oxidation, sulfides, chiral sulfoxides.
Chiral sulfoxides belong to important class of organic
(usually ее was 50—70%). It is necessary to note the
compounds, widely used in asymmetric synthesis.1—3 In
addition, compounds, containing asymmetric sulfoxide
group, were isolated from a number of natural sourses, as
well as biologically active sulfoxides of a certain configuꢀ
ration were found.4—7 All the enumerated facts stimulate
elaboration of efficient methods for the synthesis of chiral
sulfoxides, among which an asymmetric oxidation of
prochiral sulfides, in particular, in the presence of vanaꢀ
diumꢀcontaining metal complex systems,8 seems to be the
most reasonable.
simplicity in conducting the experiment with participation
of these systems as compared with the trials carried out in
the presence of homogeneous catalytic complexes on the
Vanadium complexes with chiral Schiff bases, obtained
from cyclohexaneꢀ1,2ꢀdiamine, were first used for asymꢀ
metric oxidation of aryl methyl sulfides with cumene hyꢀ
droperoxide.9 The yields of sulfoxides were good, and
their enantiomeric excess (ее) reached 40%. Later,10 it
was found that application of vanadium complexes with
ligands 1a,b, synthesized from the corresponding salicylꢀ
aldehydes and optically active βꢀaminoalcohol, in combiꢀ
nation with aqueous hydrogen peroxide as the oxidant
allows one to obtain sulfoxides from alkyl aryl sulfides in
good yields (up to 94%) and acceptable enantioselectivity
Comꢀ
pound
a
R1
R2
R3
X
But
But
But
But
H
H
NO2
But
b
c
But
H
Me
* Dedicated to Academician G. A. Tolstikov in honor of his 75th
anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 105—113, January, 2008.
1066ꢀ5285/08/5701ꢀ0108 © 2008 Springer Science+Business Media, Inc.

New chiral ligands from αꢀpinene
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
109
basis of titanium:8 the reaction proceeds at 0—20 °C, it
does not require anhydrous solvents and an inert atmoꢀ
sphere, the chiral complexes are used in catalytic amounts
(0.01—1 mol.%).
Earlier,16 a procedure for the stereospecific synthesis
of γꢀaminoalcohols from (+)ꢀ and (–)ꢀαꢀpinenes (3) was
proposed (Scheme 1). The key step of this procedure16
included the reaction of pinenes with chlorosulfonyl isoꢀ
cyanate, leading to lactam 4, the optical purity of which
after recrystallization was no less than 99.5%. Further
ethanolysis of compound 4 and subsequent reduction of
ester 5 afforded amino alcohol 6. Methylation of comꢀ
pound 6 at the amino group allowed one to create a
reasonably efficient ligand for the asymmetric addition of
diethylzinc to aldehydes.17
In the following years, a number of new chiral Schiff
bases were synthesized, differing from compounds 1a,b in
their structure and stereochemistry of substituents Х and
R1—R3 (see Ref. 11—13). These ligands were used in the
vanadium ions catalyzed asymmetric oxidation of thioꢀ
anisole to obtain the corresponding sulfoxide in optical
purity from 3 to 70% (the typical ее values were 30—50%)
in 50—90% yield. Salicylaldimine 1b is the only commerꢀ
cially available compound of this type. The use of these
ligands in the metal complex oxidation has a serious limiꢀ
tation consisting in the fact that all of them belong to the
same type of compounds, which decreases the possibiliꢀ
ties in the development of procedures for the asymmetric
oxidation of complex polyfunctional sulfides.
Scheme 1
One of the possible ways for the search for new ligands
consists in the substitution of amino acids, used as the
source of chirality in compounds of the type 1, for terpeꢀ
noids. It should be noted that we found only one exꢀ
ample14 of application of terpene in the synthesis of ligands
for the vanadium ions catalyzed asymmetric oxidation of
sulfides. In this communication, compound 1c with
isobornane substituent was synthesized, and the initially
formed mixture of diаstereomers was separated by preꢀ
parative HPLC. However, even in this case, an optically
active amino acid served as the origin of chirality.
Recently,15 on the basis of available optically active
terpenoids, viz., myrtenal and cariophillene, three new
chiral Schiff bases were synthesized, suitable for the use as
the ligands in the vanadium ions catalyzed oxidation of
sulfides to chiral sulfoxides. In contrast to the ligands
usually used in this reaction, which were obtained by the
reaction of optically active amines with substituted
salicylaldehydes, the new ligands were prepared by us by
the reaction of optically active terpenoid aldehydes with
2,4ꢀdi(tertꢀbutyl)ꢀ6ꢀaminophenol.
It should be noted that the use of compound 2 for the
synthesis of polyfunctional sulfoxide, resembling the antiꢀ
ulcer medicine esomeprasol, turned out to be the more
efficient15 than that of compound 1b. At the same time,
the use of compound 2 as the ligand for the asymmetric
oxidation of thioanisole afforded almost racemic sulfoxꢀ
ide. These results confirm the fact that there are no uniꢀ
versal ligands suitable for oxidation of any sulfides, and it
is highly desirable to have a wide set of ligands differing in
structure for the creation of efficient procedures for asymꢀ
metric oxidation of complex sulfides.
We decided to synthesize new chiral Schiff bases on
the basis of amino alcohols (+)ꢀ and (–)ꢀ6. These aminoꢀ
alcohols were obtained according to the elaborated proꢀ
cedure.16
Contrary to the data in Ref. 16, the reaction of (+)ꢀαꢀ
pinene 3 with chlorosulfonyl isocyanate at room temꢀ
perature gave a complex mixture of products, which virꢀ
tually did not contain the desired compound 4. This
result agrees with the data published earlier,18—20 which
point out the low stability of the intermediate compound
7 at room temperature. In these works, compounds 7 and
4 were obtained at –70 °C in 40—60% yield.
The present work is aimed at the synthesis of a number
of new chiral Schiff bases from available monoterpenes,
which can be used as the ligands in the vanadium ions
catalyzed asymmetric oxidation of sulfides.

110
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
Koneva et al.
We show that the reactions of (–)ꢀ and (+)ꢀαꢀpinenes
3 with chlorosulfonyl isocyanate at 0 °C, after treatment
with Na2SO3, smoothly lead to the corresponding enantiꢀ
omers of compound 4 in 82—86% yield. A decrease in the
reaction time of the ethanolysis of azetidinone 4 into
compound 5 from 12 h, as it was proposed in Ref. 16, to 6
h allowed us to raise the yield in this step from 60 to 92%.
Thus, the target aminoalcohols (+)ꢀ and (–)ꢀ6 were obꢀ
tained, which were further used for the synthesis of
salicylaldimines.
The reaction of amino alcohol (+)ꢀ6 with 3,5ꢀdi(tertꢀ
butyl)salicylaldehyde 8а afforded new chiral Schiff base 9
(Scheme 2) in 88% yield.
We chose thioanisole 10 as the substrate for the testing
of compound 9 as the possible ligand in the vanadium
acetylacetonate catalyzed asymmetric oxidation of sulꢀ
fides (Scheme 3). Vanadium acetylacetonate was used in
amount of ~1 mol.% relatively to thioanisole 10, the ligand,
in ~1.5 mol.%, these ratios were chosen on the basis of the
literature data.10 The obtained results of the search for the
proper oxidation conditions are given in Table 1.
Scheme 2
Scheme 3
The use of anhydrous organic peroxides (5.5 М soluꢀ
tion of tertꢀbutyl hydroperoxide (TBHP) in hexane or
80% solution of cumene hydroperoxide (СНР) in
cumene) as the oxidants turned out to be inefficient:
optical purity of the product was less than 10% (see Table
1, entries 1 and 2). The application of 70% aq. hydrogen
peroxide allowed us to obtain compound 11 in moderate
enantiomeric excess (ее) of 29% (entry 4). When 30% aq.
hydrogen peroxide was used for the oxidation, ее of sulfꢀ
oxide 11 dropped to 15%.
Table 1. Selection of conditions for the asymmetric oxidation of thioanisole 10
Entryа
Oxidant
τ/h
T/°C
Solvent
Conversion
(%)
Yield (%)b
ее in 11
(%)c
11
12
1
2
3
4
5
6
7
8
TBHP
CHP
4
3
3
3
24
3
2.5
1.5
0.5
1
0
0
0
СH2Cl2
СH2Cl2
СH2Cl2
СH2Cl2
СH2Cl2
СH2Cl2
СH2Cl2
AcOEt
78
85
100
100
97
100
44
88
95
91
56
71
96
83
98
33
17
83
91
5
9
44
29
4
17
2
67
83
17
9
3 (S)
7 (S)
30% H2O2
70% H2O2
70% H2O2
70% H2O2
70% H2O2
70% H2O2
70% H2O2
70% H2O2
15 (S)
29 (S)
14 (S)
11 (S)
32 (S)
21 (S)
4 (S)
0
–23
28
20
20
20
20
20
9
10
11
C6H6
CHCl3
СH2Cl2
75
92
98
24 (S)
24 (S)
d
70% H2O2
0.5
a Molar ratio VO(acac)2/9/10/[O] was 0.01/0.015/1/1.25.
b Calculated from the consumed sulfide 10, the ratio was determined from the 1Н NMR spectroscopy data.
1
c Optical purity of compound 11 was determined from the Н NMR spectroscopy data with (R)ꢀ(–)ꢀ3,5ꢀdinitroꢀNꢀ(1ꢀ
phenylethyl)benzamide being a chiral shifting reagent. The absolute configuration was established by comparison of the sign of
optical rotation of the sulfoxide with the literature data.
d A dissolved in СH2Cl2 (1 mL) oxidant was added to the reaction mixture in the 50 µL portions every 2 min for 40 min.

New chiral ligands from αꢀpinene
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
111
The study of the temperature effect on the reaction
showed (entries 4—7) that the best results in oxidation are
achieved at 0—20 °C, and at 20 °C optical purity of the
product was 32%. Both the lowering the temperature to
–23 °C and its raising to 28 °C led to a sharp drop in ее
values.
Variations in the solvent nature (entries 7—10) showed
that the best results are achieved when dichloromethane is
used, the use of chloroform and ethyl acetate leads to a
decrease in the ее value of the product to 21—24%, and in
case of benzene, the formed sulfoxide 11 was almost
racemic. When the reaction was carried out in ethyl aceꢀ
tate or benzene, sulfone 12 became the main reaction
product, the formation of which in considerable amount,
according to the GLC data, was observed virtually from
the very beginning of the reaction.
It is known21 that in a number of cases, a prolonged
portionwise addition of hydrogen peroxide in the asymꢀ
metric oxidation of alkyl aryl sulfides in the presence of
vanadium complexes leads to significant increase in
enantioselectivity of the reaction as compared with the
addition of hydrogen peroxide in one portion. In our
case, addition of the oxidant in small portions for 40 min
led to a decrease of the ее value of the product to 24%
(entry 11).
Thus, the best results in the asymmetric oxidation of
thioanisole with VO(acac) complex with chiral ligand 9
were achieved when the reaction was carried out in
dichloromethane at room temperature with the use of
70% aq. hydrogen peroxide as the oxidant.
Scheme 4
In order to study the effect the type and size of subꢀ
stituents in the aromatic ring of the ligand on the course
of oxidation, we carried out the reaction of amino alcohol
(–)ꢀ6 with salicylaldehyde 8b, its derivatives 8a,c—j, and
2ꢀhydroxyꢀ1ꢀnaphthaldehyde 13 to synthesize a number
of new chiral Schiff bases 14a—j and 15 (Scheme 4).
These compounds, as a rule, were formed in good
yields; if necessary, a purification was performed by reꢀ
crystallization or by column chromatography. Monitorꢀ
ing of the reaction course was carried out by TLC and
HPLC or GLC. Compound 8c, containing the isobornane
substituent in αꢀposition to the phenol hydroxy group,
was racemic and, correspondingly, salicylaldimine 14c
was obtained from it as a mixture of two diаstereomers in
ratio 1 : 1. We further used compound 14c as the ligand
without separation of isomers.
In contrast to all the other Schiff bases obtained by us,
the reaction of amino alcohol (–)ꢀ6 with 2ꢀhydroxyꢀ3,5ꢀ
dinitrobenzaldehyde 8f led to a tricyclic compound 16 as
the main product (Scheme 5). The ratio of compounds 16
and 14f at 28 °C was 1 : 0.6.
Scheme 5
Comꢀ
pound
a
R1
R2
R3
Yield
(%)
84
But
H
H
H
But
H
b
100
28
27
21
29
26
22
c
H
Me
86
23
20
24
25
d
e
f
g
h
i
Me2C(Ph)
H
H
H
H
H
Me2C(Ph)
NO2
NO2
OMe
H
H
NO2
93
91
79
90
75
90
94
H
NO2
H
OMe
H
NEt2
H
j
Br

112
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
Koneva et al.
Table 2. Asymmetric oxidation of thioanisole 10 with the use of
ligands 9, 14b—j, and 15
instead of Sꢀisomer, formed in small excess when the
catalytic complex with compound 14b was used, we obꢀ
tained excess Rꢀisomer in case of ligand 14g. In cases,
when the methoxy group was in orthoꢀposition to the
phenol hydroxy group, as well as when the complex with
ligand 14i (having an electronꢀdonating substituent (NEt2)
in metaꢀposition to the phenol group) was used, the
formed sulfoxide 11 was almost racemic.
When two nitro groups were presented in the ligand (a
mixture of compounds 14f and 16), methyl phenyl sulꢀ
foxide 11 was obtained in 19% optical purity. It should be
noted that in this case it is impossible to separate contriꢀ
butions of the electronic and steric effects of the substituꢀ
ents. The use of compound 14j with bromine atom inꢀ
stead of the orthoꢀnitro group led to virtually racemic
product.
Entryа Ligand
τ/h Conversion
Yield (%)b
ее in 11
(%)c
(%)
11
12
1
2
3
4
5
6
7
8
9
2.5
44
84
100
92
98
96
57
100
60
100
100
98
98
83
93
91
96
96
71
97
90
77
2
2
17
7
9
4
4
29
3
10
23
32 (S)
4 (S)
2 (S)
5 (R)
1 (S)
19 (S)
8 (R)
1 (R)
2 (R)
1 (S)
2 (R)
14b
14c
14d
14e
2
1
2
3
14f, 16 3.5
14g
14h
14i
14j
15
5
5.5
3
6
3
9
10
11
Compounds 9, 14a—g, and 15 are the new ones, their
a Molar ratio VO(acac)2/ligand/10/Н2О2 was 0.01/0.015/1/1.25,
temperature: 20 °C, solvent: CH2Cl2 (5 mL).
1
structures were established by Н and 13С spectroscopy
b Calculated from the consumed sulfide 10, the ratio was deterꢀ
mined from the 1Н NMR spectroscopy data.
and highꢀresolution mass spectrometry.
In conclusion, on the basis of available (+)ꢀ and
(–)ꢀαꢀpinenes, a number of new chiral Schiff bases have
been synthesized for the first time, which can be used as
the ligands in the vanadium ions catalyzed oxidation of
sulfides into chiral sulfoxides. The conditions for the
asymmetric oxidation of thioanisole were optimized, the
optical purity of methyl phenyl sulfoxide obtained was
32%. The effect of various substituents in the aromatic
ring of the ligands on enantioselectivity of the oxidation
has been studied. It turned out that the variations in subꢀ
stituents of the ligand significantly affect not only enantioꢀ
selectivity of the reaction, but also the absolute configuraꢀ
tion of the sulfoxide formed.
c Optical purity of compound 11 was determined from the 1Н NMR
spectroscopy data with (R)ꢀ(–)ꢀ3,5ꢀdinitroꢀNꢀ(1ꢀphenylꢀ
ethyl)benzamide being a chiral shifting reagent. The absolute
configuration was established by comparison of the sign of optical
rotation of the sulfoxide with the literature data.
Earlier, a formation of similar mixture of the Schiff
base and the corresponding cyclic perhydrobenzoxazine
was observed in the reaction of cisꢀ2ꢀaminomethylꢀ
cyclohexanꢀ1ꢀol with 4ꢀnitrobenzaldehyde.22 As in our
case, the equilibrium at 27 °C was shifted in favor of the
cyclic form.
Result of the oxidation of thioanisole 10 in the presꢀ
ence of new chiral Schiff bases 9, 14b—j, and 15 under
the earlier selected conditions (see Table 1, entry 7) are
summarized in Table 2.
The ligands obtained considerably differ in the steric
hindrance, created by them directly near the active cenꢀ
ter, and in the electronic factors, which makes it prospecꢀ
tive to use them in the search for conditions for the
oxidation of complex polyfunctional sulfides.
Both the increase in the hindrance of αꢀposition of the
phenol group, going from the tertꢀbutyl substituent (comꢀ
pound 9) to the cumyl or isobornyl ones (compounds
14d and 14c), and its decrease (compounds 14b and 15)
lead to a sharp drop in optical purity of sulfoxide 11. It
should be noted that the enantiomeric excess values of
1—2% are within the limits of applicability of the method
for their determination.
Optical purity of sulfoxide 11 in the absence of a
substituent in αꢀposition to the phenol hydroxy group of
the ligand (compounds 14b, 14e, 14g, and 14i) depended
on the nature of substituents R2 and R3 and did not
exceed 8%. Introduction of the electronꢀwithdrawing subꢀ
stituent (nitro group) into the paraꢀposition of the phenol
moiety of the ligand led to the formation of virtually
racemic product. Introduction of the methoxy group into
this position allowed us to obtain sulfoxide 11 in ее of 8%.
In this case, an inversion of configuration was observed:
Experimental
1Н and 13С NMR spectra were recorded on a Bruker АМꢀ400
and Bruker AVꢀ300 spectrometers (400.13 and 300.13 МHz for 1Н,
100.61 and 75.47 МHz for 13С, respectively) for the solutions of
substances in CDCl3 or in CDCl3—CCl4 (~1 : 1, v/v). Signals of
chloroform (δH 7.24, δ 76.90) were used as the internal standard.
Structures of the comСpounds obtained were established by the
analysis of their Н NMR spectra with the help of the Н—1Н
decoupling experiments, as well as by the analysis of their 13С NMR
spectra with the use of the spectra with nonresonance irradiation of
protons, the twoꢀdimensional 13С—1H NMR spectra (C—H COSY,
1JC,H = 135 Hz) and the singleꢀdimensional 13С—1H NMR spectra
(LRJMD, nJС,H = 10 Hz, n = 2, 3). Highꢀresolution mass spectra
were recorded on a Finnigan MAT 8200 instrument, the specific
rotation values [α]580 (deg mL g–1 dm–1) were determined on a
Polamat A spectrometer, the concentration of solution was c (g
(100 mL)–1).
1
1

New chiral ligands from αꢀpinene
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
113
Monitoring of the purity of the starting substances and analysis
of the reaction products were performed by GLC on a Model 3700
instrument (30000×0.25 mm quartz capillary column; ZBꢀ5 as the
stationary phase; flameꢀionization detector; helium as the carrier
gas; at 1 atm) and by HPLC on a Milikhrom A02 instrument
(stationary phase: ProntoSilꢀ120ꢀ5ꢀC18 AQ; eluent: 90% aq.
MeOH with 0.1% aq. trifluoroacetic acid).
(1R,2R,3S,5R)ꢀ2ꢀAminoꢀ3ꢀhydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptane ((+)ꢀ6) (0.92 g, 99%) was obtained similarly
from compound (–)ꢀ5 (1.1 g, 0.0051 mol).
2,4ꢀDi(tertꢀbutyl)ꢀ6ꢀ{[(1R,2R,3S,5R)ꢀ3ꢀhydroxymethylꢀ
2,6,6ꢀtrimethylbicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}phenol (9).
A preꢀfiltered solution of 3,5ꢀdi(tertꢀbutyl)ꢀ2ꢀhydroxybenzaldehyde
(8а) (0.16 g, 0.68 mmol) in methanol (5 mL) was added dropwise to
a stirred solution of compound (+)ꢀ6 (0.11 g, 0.61 mmol) in
anhydrous methanol (8 mL). Monitoring of the reaction course
was performed by HPLC. The reaction mixture was stirred at ~20
°C for 3 h, then preꢀcalcined Na2SO4 was added, and the stirring
was continued for another 20 h. Then the reaction mixture was
refluxed for 24 h. Sodium sulfate was filtered off. Separation of the
reaction products was performed by column chromatography on
silica gel (8 g), eluent: 1% triethylamine in hexane with gradient of
chloroform from 0 to 100%. Compound 9 was obtained (0.21 g,
88%), m.p. 121—131 °C, [α]22580 +9.9 (c 4.1, CHCl ). 1H NMR, δ:
1.17 (s, 3 H, С(9)Ме); 1.29 (s, 3 H, С(10)Ме); 1.30,31.44 (both s, 18
Separation of the reaction products were performed by column
chromatography on silica gel (70—230 µ, Merck).
(1S,2S,3R,5S)ꢀ2ꢀAminoꢀ3ꢀhydroxymethylꢀ2,6,6ꢀtriꢀ
methylbicyclo[3.1.1]heptane ((–)ꢀ6). A solution of chlorosulfoꢀ
nyl isocyanate (5.2 g, 3.2 mL, 0.037 mol) in anhydrous diethyl
ether (5 mL) was added to a solution of (+)ꢀαꢀpinene (Aldrich,
99.8%, ее 97.4%, [α]D +50.5 (c 5, CHCl3)) (+)ꢀ3 (5.0 g, 0.037 mol)
in anhydrous diethyl ether (50 mL) at 0 °C, then another portion of
anhydrous diethyl ether (50 mL) was added. The reaction mixture
obtained was stirred with magnetic stirrer under ice cooling for
1.5 h. A solution of Na2SO3 (15 g) in water (103 mL) was added
dropwise to the mixture under stirring and cooling, while keeping
pН 7—8 by the gradual addition of the necessary amount of 20% aq.
КОН. The cooling bath was removed, the mixture was stirred for
another 3 h. The organic phase was separated, the aqueous one was
extracted with diethyl ether (2×75 mL). The combined organic
phase was dried with MgSO4. The solvent was evaporated on a
rotary evaporator, the residue was recrystallized from diethyl ether
H, 2 But); 1.45 (s, 3 H, С(8)Ме); 1.26 (d, 1 H, Hanti(7), J7anti,7syn
10 Hz); 1.58 (ddd, 1 H, Hanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 7.5
=
Hz, J5anti,6 = 2.2 Hz); 1.97 (dd, 1 H, H(2), J2,7syn = 5.5 Hz, J2,6
5.5 Hz); 1.99 (m, 1 H, H(6)); 2.15 (dddd, 1 H, Hsyn(5), J5syn,5anti
=
=
13 Hz, J5syn,4syn = 11.5 Hz, J5syn,6 = 3.5 Hz, J5syn,7syn = 2 Hz); 2.22
(dddd, 1 H, Hsyn(7), J7syn,7anti = 10 Hz, J7syn,2 = 5.5 Hz, J7syn,6
=
5.5 Hz, J7syn,5syn = 2 Hz); 2.41 (m, 1 H, Hsyn(4)); 3.64 (dd, 1 H,
H(11), J11,11´ = 11 Hz, J11,4syn = 6.5 Hz); 3.82 (dd, 1 H, H(11´),
J11´,11 = 11 Hz, J11´,4syn = 7 Hz); 7.08 (d, 1 H, H(18), J18,16 = 2.4
to
obtain
(1S,2S,5R,7S)ꢀ2,8,8ꢀtrimethylꢀ3ꢀazatricycꢀ
lo[5.1.1.02,5]nonanꢀ4ꢀone (+)ꢀ4 (5.7 g, 86%), [α]D25 +97.9 (c 2.1,
MeOH) (cf. Ref. 16: [α]D20 +96.5 (c 0.1, MeOH)). The 1H NMR
spectrum of compound (+)ꢀ3 agreed with the spectrum reported in
the literature.16
Hz); 7.36 (d, 1 H, H(16), J16,18 = 2.4 Hz); 8.31 (s, 1 H, H(12)). 13
C
NMR, δ: 38.73 (s, С(1)); 53.66 (d, С(2)); 64.94 (s, С(3)); 41.92 (d,
С(4)); 31.21 (t, С(5)); 40.08 (d, С(6)); 29.39 (t, С(7)); 28.55 (q,
С(8)); 23.54 (q, С(9)); 28.15 (q, С(10)); 66.42 (t, С(11)); 162.23 (d,
С(12)); 117.95 (s, С(13)); 158.51 (s, С(14)); 136.81 (s, С(15));
126.72 (d, С(16)); 139.54 (s, С(17)); 126.07 (d, С(18)); 34.93, 33.99
(both s, 2 С, С(19), С(20)); 31.38, 29.30 (both q, ButС(19),
ButС(20)). Found: m/z 399.31455 [M]+. С26H41NО2. Calculated:
М = 399.31371.
Similarly, (–)ꢀαꢀpinene (Aldrich, 99.6%, [α]D –48.4) ((–)ꢀ6)
(5.0 g, 0.038 mol) gave rise to (1R,2R,5S,7R)ꢀ2,8,8ꢀtrimethylꢀ3ꢀ
azatricyclo[5.1.1.02,5]nonanꢀ4ꢀone ((–)ꢀ4) (5.4 g, 82%), [α]D
–
26
95.3 (c 1.3, MeOH) (cf. Ref. 16: [α]D20 –96 (c 0.1, MeOH)).
Solution of HCl in ethanol (8%, 50 mL) was added to compound
(+)ꢀ4 (4.4 g, 0.025 mol). The reaction mixture was refluxed under
stirring for 6 h. Ethanol was evaporated, water was added, pH was
raised to 8 by saturated aq. sodium hydrogen carbоnate, the mixture
was extracted with diethyl ether (3×20 mL), the extract was dried
with MgSO4. The solvent was evaporated on a rotary evaporator.
Separation of the reaction products was performed by column
chromatography on silica gel (16 g) with hexane with gradient of
ethyl acetate from 0 to 100% as the eluent to obtain ethyl
(1S,2S,3R,5S)ꢀ2ꢀaminoꢀ2,6,6ꢀtrimethylbicyclo[3.1.1]heptaneꢀ3ꢀ
2,4ꢀDi(tertꢀbutyl)ꢀ6ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀhydroxymethylꢀ
2,6,6ꢀtrimethylbicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}phenol
(14a). A preꢀfiltered solution of 3,5ꢀdi(tertꢀbutyl)ꢀ2ꢀhydroxyꢀ
benzaldehyde (8а) (0.15 g, 0.62 mmol) in methanol (5 mL) was
added dropwise to a stirred solution of compound (–)ꢀ6 (0.10 g,
0.55 mmol) in anhydrous methanol (4 mL) followed by the addition
of preꢀcalcined Na2SO4. The reaction mixture was stirred at
~20 °C for 2 h. Sodium sulfate was filtered off. The solvent was
evaporated, the residue was recrystallized from МеОH to obtain
1
carboxylate ((–)ꢀ5) (5.1 g, 92%) . The H NMR spectrum of
compound (–)ꢀ5 agreed with the spectrum reported in the literaꢀ
compound 14а (0.19 g, 84%), m.p. 135—137 °C, [α]22 –6.7
580
ture.16
(c 2.2, CHCl3).1H NMR spectrum of compound 14а was identical
to the spectrum of compound (9).
Ethyl
(1R,2R,3S,5R)ꢀ2ꢀaminoꢀ2,6,6ꢀtrimethylbicycꢀ
lo[3.1.1]heptaneꢀ3ꢀcarboxylate ((+)ꢀ5) (2.6 g, 82%) was obtained
similarly from compound (–)ꢀ4 (2.5 g, 0.014 mol).
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbicycloꢀ
[3.1.1]heptꢀ2ꢀylimino]methyl}phenol (14b). 2ꢀHydroxybenzaldeꢀ
hyde (8b) (0.033 g, 0.27 mmol) in methanol (5 mL) was added
dropwise to a stirred solution of compound (–)ꢀ6 (0.050 g,
0.27 mmol) in anhydrous methanol (4 mL). The reaction mixture
was stirred at ~20 °C for 6 h. The solvent was evaporated to obtain
compound 14b (0.078 g, 100%), [α]22 +2.8 (c 2.8, CHCl ).
A solution of compound (–)ꢀ5 (1.0 g, 4.4 mmol) in THF (10
mL) was added dropwise to a stirred suspension of LiAlH4 (0.42 g,
0.011 mol) in anhydrous THF (10 mL) at 0 °C. The cooling was
removed, and the reaction mixture was refluxed under stirring for
2 h. Excess reducing agent was decomposed by the careful addition
of water (5.5 mL) under stirring. Inorganic phase was filtered off,
washed with diethyl ether, the filtrate was dried with MgSO4. The
solvent was removed on a rotary evaporator to obtain (1S,2S,3R,5S)ꢀ
2ꢀaminoꢀ3ꢀhydroxymethylꢀ2,6,6ꢀtrimethylbicyclo[3.1.1]heptane
580
3
1H NMR, δ: 1.13 (s, 3 H, С(9)Me); 1.19 (d, 1 H, Hanti(7), J7anti, 7syn
= 10 Hz); 1.27 (s, 3 H, С(10)Me); 1.42 (s, 3 H, С(8)Me); 1.44 (ddd,
1 H, Hanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 8 Hz, J5anti,6 = 2 Hz);
1.92 (dd, 1 Н, Н(2), J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.95 (m, 1 Н,
1
((–)ꢀ6) (0.70 g, 86%). H NMR spectrum of compound (–)ꢀ6
Н(6)); 2.09 (dddd, 1 Н, Нsyn(5), J5syn,5anti = 13 Hz, J5syn,4syn
=
agreed with the spectrum reported in the literature.16
12 Hz, J5syn,6 = 3.5 Hz, J5syn,7syn = 2 Hz); 2.20 (dddd, 1 Н, Нsyn(7),

114
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
Koneva et al.
J7syn,7anti = 10 Hz, J7syn,2 = 5.5 Hz, J7syn,6 = 5.5 Hz, J7syn,5syn
2 Hz); 2.28—2.42 (m, 1 Н, Нsyn(4)); 3.51 (dd, 1 Н, Н(11), J11,11´
=
=
J20endo,25endo = 9 Hz, J20endo,25exo = 8 Hz); 3.62 (dd, 1 Н, Н(11),
J11,11´ = 11 Hz, J11,4syn = 6.5 Hz); 3.78 (dd, 1 Н, Н(11´), J11´,11 = 11
10 Hz, J11,4 = 6.5 Hz); 3.67 (dd, 1 Н, Н(11´), J11´,11 = 10 Hz,
J11´,4 = 8 Hz); 6.72 (ddd, 1 Н, Н(17), J17,18 = 8 Hz, J17,16 = 7 Hz,
J17,15 = 1.2 Hz); 6.82 (dd, 1 Н, Н(15), J15,16 = 8.3 Hz, J15,17 = 1.2
Hz); 7.14 (dd, 1 Н, Н(18), J18,17 = 8 Hz, J18,16 = 1.5 Hz); 7.21 (ddd,
1 Н, Н(16), J16,15 = 8.3 Hz, J16,17 = 7 Hz, J16,18 = 1.5 Hz); 8.20 (s,
1 Н, Н(12)); 14.35 (br.s, 1 Н, С(14)—OH). 13C NMR, δ: 39.77
(s, С(1)); 53.69 (d, С(2)); 64.91 (s, С(3)); 41.53 (d, С(4)); 31.32
(t, С(5)); 40.07 (d, С(6)); 29.47 (t, С(7)); 28.48 (q, С(8)); 23.64 (q,
С(9)); 28.28 (q, С(10)); 66.01 (t, С(11)); 160.93 (d, С(12)); 118.41
(s, С(13)); 163.41 (s, С(14)); 117.92 (d, С(15)); 132.50 (d, С(16));
117.40 (d, С(17)); 131.63 (d, С(18)). Found: m/z 287.18944 [M]+.
С18H25NO2. Calculated: М = 287.18852.
Hz, J11´,4syn = 7 Hz); 6.86 (d, 1 Н, Н(18), J18,16 = 2.4 Hz); 7.14 (d,
1 Н, Н(16), J16,18 = 2.4 Hz); 8.26 (s, 1 Н, Н(12)). 13C NMR, δ:
38.80 (s, С(1)); 53.89 (d, С(2)); 64.95 (s, С(3)); 41.99 (d, С(4));
31.13 (t, С(5)); 40.15 (d, С(6)); 29.33 (t, С(7)); 28.36 (q, С(8));
23.57 (q, С(9)); 28.15 (q, С(10)); 66.39 (t, С(11)); 161.60 (d, С(12));
117.66 (s, С(13)); 158.74 (s, С(14)); 125.81 (s, С(15)); 131.66 (d,
С(16)); 131.86 (s, С(17)); 128.94 (d, С(18)); 20.70 (q, С(19)); 44.33
(d, С(20)); 49.81 (s, С(21)); 39.56 (t, С(22)); 27.43 (t, С(23)); 45.69
(d, С(24)); 33.91 (t, С(25)); 47.92 (s, С(26)); 12.22 (q, С(27));
21.37, 20.33 (both q, С(28), С(29)).
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4,6ꢀbis(2ꢀphenylpropꢀ2ꢀ
yl)phenol (14d). 2ꢀHydroxyꢀ3,5ꢀbis(2ꢀphenylpropꢀ2ꢀyl)benzaldeꢀ
hyde (8d) (0.025 g, 0.070 mmol) in methanol (5 mL) was added to a
stirred solution of compound (–)ꢀ6 (0.025 g, 0.14 mmol) in anhydrꢀ
ous methanol (4 mL) followed by the addition of Na2SO4. The
reaction mixture was stirred at ~20 °C for 2 h, then another portion
of compound 8d (0.027 g, 0.075 mmol) was added, and the stirring
was continued for 22 h, after addition of the second portion of
Na2SO4, the stirring was continued for 5 h. Separation of the
reaction products was performed by column chromatography on
silica gel, eluent: 1% triethylamine in hexane with gradient of
chloroform from 0 to 100%. Compound 8d was obtained (0.068 g,
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4ꢀmethylꢀ6ꢀ(1,7,7ꢀtriꢀ
methylbicyclo[2.2.1]heptꢀ2ꢀyl)phenol (14c). Racemic 2ꢀhydroxyꢀ
5ꢀmethylꢀ3ꢀ(1,7,7ꢀtrimethylbicyclo[2.2.1]heptꢀ2ꢀyl)benzaldehyde
(8c) (0.050 g, 0.18 mmol) in methanol (4 mL) was added to a stirred
solution of compound (–)ꢀ6 (0.033 g, 0.18 mmol) in anhydrous
methanol (3 mL) followed by the addition of preꢀcalcined Na2SO4.
The reaction mixture was stirred at ~20 °C for 7 h. Sodium sulfate
was filtered off. Separation of the reaction products was carried out
by column chromatography on silica gel, eluent: 1% triethylamine
in hexane with gradient of chloroform from 0 to 100%. Compound
14с was obtained (0.068 g, 86%), [α]22580 –16.4 (c 0.5, CHCl ).
Found: m/z 437.33126 [M]+. С29H43NO2. Calculated М 3=
437.32936.
1
93%), [α]22 –9.3 (c 1.25, CHCl ). H NMR, δ: 1.12 (s, 3 Н,
580
3
С(9)Me); 1.26 (s, 3 Н, С(10)Me); 1.37 (s, 3 Н, С(8)Me); 1.65, 1.66
(both s, 12 Н, 4 Ме); 1.10 (d, 1 Н, Нanti(7), J7anti,7syn = 10 Hz); 1.50
(ddd, 1 Н, Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 7.5 Hz, J5anti,6 =
1
Compound 14c, the first isomer. H NMR, δ: 0.75 (s, 3 Н,
С(27)Me); 0.82, 0.88 (both s, 6 Н, С(28)Me, С(29)Me); 1.15 (s, 3
Н, С(9)Me); 1.29 (s, 3 Н, С(10)Me); 1.41 (s, 3 Н, С(8)Me); 2.26 (s,
3 Н, С(19)Me); 1.23 (d, 1 Н, Нanti(7), J7anti,7syn = 10 Hz); 1.26—
1.38 (m, 2 Н, Нendo(22), Нendo(23)); 1.52—1.62 (m, 3 Н, Нanti(5),
Нendo(25), Нexo(22)); 1.80 (dd, 1 Н, Н(24), J24,23exo = 4 Hz,
J24,25exo = 4 Hz); 1.77—1.88 (m, 1 Н, Нexo(23)); 1.95 (dd, 1 Н,
Н(2), J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.98 (m, 1 Н, Н(6)); 2.07—
2.17 (m, 2 Н, Нsyn(5), Нexo(25)); 2.17—2.27 (m, 1 Н, Нsyn(7));
2.34—2.44 (m, 1 Н, Нsyn(4)); 3.34 (dd, 1 Н, Нendo(20),
J20endo,25endo = 9 Hz, J20endo,25exo = 8 Hz); 3.61 (dd, 1 Н, Н(11),
2.2 Hz); 1.89 (dd, 1 Н, Н(2), J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.93
(m, 1 Н, Н(6)); 2.05 (dddd, 1 Н, Нsyn(5), J5syn,5anti = 13 Hz,
J5syn,4syn = 11.5 Hz, J5syn,6 = 3.5 Hz, J5syn,7syn = 2 Hz); 2.13 (dddd,
1 Н, Нsyn(7), J7syn,7anti = 10 Hz, J7syn,2 = 5.5 Hz, J7syn,6 = 5.5 Hz,
J7syn,5syn = 2 Hz); 2.30 (m, 1 Н, Нsyn(4)); 3.47 (dd, 1 Н, Н(11),
J
11,11´ = 11 Hz, J11,4syn = 6 Hz); 3.60 (dd, 1 Н, Н(11´), J11´,11 =
11 Hz, J11´,4syn = 7 Hz); 6.95 (d, 1 Н, Н(18), J18,16 = 2.4 Hz); 7.19
(d, 1 Н, Н(16), J16,18 = 2.4 Hz); 7.04—7.30 (m, 10 Нarom); 8.15
(s, 1 Н, Н(12)). 13C NMR, δ: 38.86 (s, С(1)); 53.54 (d, С(2)); 65.03
(s, С(3)); 42.01 (d, С(4)); 31.01 (t, С(5)); 40.12 (d, С(6)); 29.41
(t, С(7)); 28.82 (q, С(8)); 23.72 (q, С(9)); 28.31 (q, С(10)); 66.00
(t, С(11)); 161.70 (d, С(12)); 118.07 (s, С(13)); 158.58 (s, С(14));
136.62 (s, С(15)); 129.30 (d, С(16)); 138.98 (s, С(17)); 127.85
(d, С(18)); 42.40, 42.25 (both s, 2 С, С(19), С(20)); 31.01, 29.27,
29.24 (all q, 4 С, 2 Ме—С(19), 2 Ме—С(20)); carbon atoms of
aromatic rings of cumyl fragments: 124.96 (d); 125.59 (d); 125.86
(d, 2 С); 126.68 (d, 2 С); 127.61 (d, 2 С); 127.98 (d, 2 С); 150.30 (s);
150.68 (s). Found: m/z 523.34784 [M]+. С36Н45NО2. Calculated:
М = 523.34501.
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4ꢀnitrophenol (14e).
2ꢀHydroxyꢀ5ꢀnitrobenzaldehyde (8e) (0.061 g, 0.37 mmol) in
methanol (5 mL) was added dropwise to a stirred solution of
compound (–)ꢀ6 (0.067 g, 0.37 mmol) in anhydrous methanol
(4 mL). The reaction mixture was stirred at ~20 °C for 4 h. The
solvent was evaporated, the residue was recrystallized from diethyl
ether to obtain compound 14e (0.11 g, 91%), m.p. 144—147 °C,
[α]22580 +24.1 (c 2.6, CHCl3). 1H NMR, δ: 1.15 (d, 1 Н, Нanti(7),
J7anti,7syn = 10 Hz); 1.17 (s, 3 Н, С(9)Me); 1.34 (s, 3 Н, С(10)Me);
1.35 (dddd, 1 Н, Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 8 Hz,
J5anti,6 = 2.2 Hz); 1.62 (s, 3 Н, С(8)Me); 2.03 (m, 1 Н, Н(6)); 2.08
J
11,11´ = 11 Hz, J11,4syn = 6.5 Hz); 3.76 (dd, 1 Н, Н(11´), J11´,11 =
11 Hz, J11´,4syn = 7 Hz); 6.86 (d, 1 Н, Н(18), J18,16 = 2.4 Hz); 7.14
(d, 1 Н, Н(16), J16,18 = 2.4 Hz); 8.23 (s, 1 Н, Н(12)). 13C NMR, δ:
38.80 (s, С(1)); 53.60 (d, С(2)); 60.48 (s, С(3)); 41.99 (d, С(4));
31.13 (t, С(5)); 40.15 (d, С(6)); 29.33 (t, С(7)); 28.57 (q, С(8));
23.57 (q, С(9)); 28.18 (q, С(10)); 66.32 (t, С(11)); 161.44 (d, С(12));
117.66 (s, С(13)); 158.87 (s, С(14)); 125.73 (s, С(15)); 131.66 (d,
С(16)); 131.86 (s, С(17)); 128.94 (d, С(18)); 20.70 (q, С(19)); 44.33
(d, С(20)); 49.81 (s, С(21)); 39.56 (t, С(22)); 27.43 (t, С(23)); 45.69
(d, С(24)); 33.91 (t, С(25)); 47.92 (s, С(26)); 12.22 (q, С(27));
21.37, 20.33 (both q, С(28), С(29)).
Compound 14c, the second isomer. 1H NMR, δ: 0.76 (s, 3 Н,
С(27)Me); 0.82, 0.88 (both s, 6 Н, С(28)Me, С(29)Me); 1.15 (s, 3
Н, С(9)Me); 1.28 (s, 3 Н, С(10)Me); 1.43 (s, 3 Н, С(8)Me); 2.26 (s,
3 H, С(19)Me); 1.23 (d, 1 Н, Нanti(7), J7anti,7syn = 10 Hz); 1.26—
1.38 (m, 2 Н, Нendo(22) Нendo(23)); 1.52—1.62 (m, 3 Н, Нanti(5),
Нexo(22), Нendo(25)); 1.80 (dd, 1 Н, Н(24), J24,23exo = 4 Hz,
J24,25exo = 4 Hz); 1.77—1.88 (m, 1 Н, Нexo(23)); 1.92 (dd, 1 Н,
Н(2), J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.98 (m, 1 Н, Н(6)); 2.07—
2.17 (m, 2 Н, Нexo(25), Нsyn(5)); 2.17—2.27 (m, 1 Н, Нsyn(7));
2.34—2.44 (m, 1 Н, Нsyn(4)); 3.34 (dd, 1 Н, Нendo(20),

New chiral ligands from αꢀpinene
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
115
(m, 1 Н, Нsyn(5)); 2.12 (dd, 1 Н, Н(2), J2,6 = 5.5 Hz, J2,7syn
5.5 Hz); 2.41 (dddd, 1 Н, Нsyn(7), J7syn,7anti = 10 Hz, J7syn,2
=
=
[α]22580 +1.2 (c 1.6, CHCl3). 1H NMR, δ: 1.14 (s, 3 Н, С(9)Me);
1.20 (d, 1 Н, Нanti(7), J7anti,7syn = 10 Hz); 1.27 (s, 3 Н, С(10)Me);
1.41 (s,3 Н, С(8)Me); 1.47 (ddd, 1 Н, Нanti(5), J5anti,5syn = 13 Hz,
J5anti,4syn = 7.5 Hz, J5anti,6 = 2 Hz); 1.91 (dd, 1 Н, Н(2),
J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.96 (m, 1 Н, Н(6)); 2.10 (dddd,
1 Н, Нsyn(5), J5syn,5anti = 13 Hz, J5syn,4syn = 10 Hz, J5syn,6 = 3.5 Hz,
J5syn,7syn = 2.2 Hz); 2.20 (dddd, 1 Н, Нsyn(7), J7syn,7anti = 10 Hz,
J7syn,2 = 5.5 Hz, J7syn,6 = 5.5 Hz, J7syn,5syn = 2.2 Hz); 2.28—2.42
5.5 Hz, J7syn,6 = 5.5 Hz, J7syn,5syn = 2.2 Hz); 2.37—2.55 (m, 1 Н,
Нsyn(4)); 3.56 (dd, 1 Н, Н(11), J11,11´ = 10 Hz, J11,4syn = 10 Hz);
3.66 (dd, 1 Н, Н(11´), J11´,11 = 10 Hz, J11´,4syn = 5 Hz); 6.58 (d, 1 Н,
Н(15), J15,16 = 9.5 Hz); 7.97 (dd, 1 Н, Н(16), J16,15 = 9.5 Hz,
J16,18 = 3 Hz); 8.14 (br.d, 1 Н, Н(12), J = 8 Hz); 8.16 (d, 1 Н,
Н(18), J18,16 = 3 Hz); 15.33 (br.s, 1 Н, С(14)—ОН). 13C NMR,
δ: 38.75 (s, С(1)); 52.61 (d, С(2)); 65.81 (s, С(3)); 40.24 (d, С(4));
30.22 (t, С(5)); 39.65 (d, С(6)); 29.19 (t, С(7)); 28.89 (q, С(8));
23.55 (q, С(9)); 28.08 (q, С(10)); 65.13 (t, С(11)); 162.18 (d, С(12));
113.43 (s, С(13)); 178.00 (s, С(14)); 122.80 (d, С(15)); 131.84 (d,
С(16)); 135.15 (s, С(17)); 129.79 (d, С(18)). Found: m/z 332.17279
[M]+. С18H24N2O4. Calculated: М = 332.17359.
(m, 1 Н, Нsyn(4)); 3.51 (dd, 1 Н, Н(11), J11,11´ = 10 Hz, J11,4syn
=
6.5 Hz); 3.67 (dd, 1 Н, Н(11´), J11´,11 = 10 Hz, J11´,4syn = 8 Hz);
3.71 (s, 3 Н, ОМе); 6.66 (d, 1 Н, Н(18), J18,16 = 3 Hz); 6.76 (d, 1 Н,
Н(15), J15,16 = 9 Hz); 6.82 (dd, 1 Н, Н(16), J16,15 = 9 Hz,
J16,18 = 3 Hz); 8.19 (s, 1 Н, Н(12)); 13.65 (br.s, 1 Н, С(14)—ОН).
13C NMR, δ: 38.81 (s, С(1)); 53.81 (d, С(2)); 65.03 (s, С(3)); 41.70
(d, С(4)); 31.36 (t, С(5)); 40.13 (d, С(6)); 29.48 (t, С(7)); 28.47 (q,
С(8)); 23.65 (q, С(9)); 28.30 (q, С(10)); 66.05 (t, С(11)); 160.54 (d,
С(12)); 118.15 (s, С(13)); 156.50 (s, С(14)); 118.12 (d, С(15));
119.73 (d, С(16)); 151.49 (s, С(17)); 114.58 (d, С(18)); 55.58 (q,
С(19)). Found: m/z 317.19860 [M]+. С19H27NO3. Calculated:
М = 317.19908.
6ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ2ꢀmethoxyphenol (14h).
2ꢀHydroxyꢀ3ꢀmethoxybenzaldehyde (8h) (0.037 g, 0.24 mmol) in
methanol (5 mL) was added dropwise to a stirred solution of
compound (–)ꢀ6 (0.080 g, 0.44 mmol) in anhydrous methanol
(4 mL). The reaction mixture was stirred at ~20 °C for 5.5 h. The
solvent was evaporated, the residue was recrystallized from diethyl
ether with addition of hexane to obtain product 14h (0.090 g, 75%),
[α]22580 +10.7 (c 0.9, CHCl3). 1H NMR, δ: 1.15 (s, 3 Н, С(9)Me);
1.23 (d, 1 Н, Нanti(7), J7anti,7syn = 10 Hz); 1.29 (s, 3 Н, С(10)Me);
1.42 (dd, 1 Н, Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 7.5 Hz); 1.48
(s, 3 Н, С(8)Me); 1.97 (d, 2 Н, Н(2), Н(6), J2,7syn = J6,7syn = 6 Hz);
2.08 (br.dd, 1 Н, Нsyn(5), J5syn,5anti = 13 Hz, J5syn,4syn = 10 Hz);
2.24 (dddd, 1 Н, Нsyn(7), J7syn,7anti = 10 Hz, J7syn,2 = 6 Hz, J7syn,6
= 6 Hz, J7syn,5syn = 2.2 Hz); 2.35—2.45 (m, 1 Н, Нsyn(4)); 3.58 (dd,
1 Н, Н(11), J11,11´ = 10 Hz, J11,4syn = 6 Hz); 3.72 (dd, 1 Н, Н(11´),
J11´,11 = 10 Hz, J11´,4syn = 10 Hz); 3.84 (s, 3 Н, ОМе); 6.56 (t, 1 Н,
Н(17), J = 8 Hz); 6.73, 6.76 (both d, 2 Н, Н(16), Н(18), J = 8 Hz);
8.11 (s, 1 Н, Н(12)). 13C NMR, δ: 38.74 (s, С(1)); 53.50 (d, С(2));
64.69 (s, С(3)); 41.12 (d, С(4)); 30.96 (t, С(5)); 39.98 (d, С(6));
29.41 (t, С(7)); 28.70 (q, С(8)); 23.62 (q, С(9)); 28.24 (q, С(10));
65.91 (t, С(11)); 160.71 (d, С(12)); 116.98 (s, С(13)); 149.89
(s, С(14)); 158.25 (s, С(15)); 113.21 (d, С(16)); 115.42 (d, С(17));
123.37 (d, С(18)); 55.63 (q, ОМе). Found: m/z 317.19924 [M]+.
С19H27NO3. Calculated: М = 317.19908.
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylꢀ
bicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4,6ꢀdinitrophenol (14f)
and 6ꢀ[(1S,2S,7R,9S)ꢀ2,10,10ꢀtrimethylꢀ5ꢀoxaꢀ3ꢀazaꢀ
tricyclo[7.1.1.02,7]undecꢀ4ꢀyl]ꢀ2,4ꢀdinitrophenol
(16).
3,5ꢀDinitrosalicylaldehide (8f) (0.067 g, 0.32 mmol) in methanol
(5 mL) was added dropwise to a stirred solution of compound (–)ꢀ6
(0.083 g, 0.45 mmol) in anhydrous methanol (4 mL). The reaction
mixture was stirred at ~20 °C for 2 h. The solvent was evaporated to
obtain a mixture of products 14f and 16 (0.094 g, 79%), [α]22
580
+5.6 (c 0.9, CHCl3). Found: m/z 375.14302 [М – Н2]+.
С18H21N3O6. Calculated: [М – Н2]+ 375.14302.
NMR spectra were recorded for a mixture of compounds 14f
and 16 in ratio ~0.4 : 1.
Compound 14f. 1H NMR, δ: 1.03 (d, 1 Н, Нanti(7), J7anti,7syn
=
10 Hz); 1.14 (s, 3 Н, С(9)Ме); 1.35 (s, 3 Н, С(10)Ме); 1.62 (s, 3 Н,
С(8)Ме); 1.98—2.11 (m, 3 Н, Н(2), Н(5), Н(6)); 2.44 (m, 1 Н,
Нsyn(7)); 2.53 (m, 1 Н, Н(4)); 3.53 (dd, 1 Н, Н(11), J11,11´ = 11 Hz,
J11,4 = 8 Hz); 3.80 (dd, 1 Н, Н(11´), J11´,11 = 11 Hz, J11´,4 = 6 Hz);
8.12 (s, 1 Н, Н(12)); 8.39 (d, 1 Н, Н(18), J18,16 = 3 Hz); 8.84 (d,
1 Н, Н(16), J16,18 = 3 Hz). 13C NMR, δ: 38.63 (s, С(1)); 51.13 (d,
С(2)); 60.98 (s, С(3)); 39.36 (d, С(4)); 29.01 (t, С(5)); 39.89 (d,
С(6)); 28.24 (t, С(7)); 29.85 (q, С(8)); 23.34 (q, С(9)); 27.85 (q,
С(10)); 64.47 (t, С(11)); 162.73 (d, С(12)); 118.27 (s, С(13)); 170.36
(s, С(14)); 131.09 (s, С(15)); 128.65 (d, С(16)); 139.61 (s, С(17));
136.96 (d, С(18)).
Compound 16. 1H NMR, δ: 0.99 (s, 3 Н, С(9)Me); 1.10 (d,
1 Н, Нanti(7), J7anti,7syn = 11 Hz); 1.20 (s, 3 Н, С(10)Me); 1.42 (s,
3 Н, С(8)Me); 1.53 (dd, 1 Н, Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn
= 7 Hz); 1.87—1.97 (m, 3 Н, Н(2), Н(6), Нsyn(5)); 2.14—2.26 (m,
2 Н, Нsyn(4), Нsyn(7)); 3.61 (dd, 1 Н, Н(11), J11,11´ = 11 Hz, J11,4syn
= 8 Hz); 3.84 (dd, 1 Н, Н(11´), J11´,11 = 11 Hz, J11´,4syn = 4 Hz);
5.57 (s, 1 Н, Н(12)); 8.21 (d, 1 Н, Н(18), J18,16 = 3 Hz); 8.75 (d,
1 Н, Н(16), J16,18 = 3 Hz). 13C NMR, δ: 38.90 (s, С(1)); 52.91 (d,
С(2)); 60.74 (s, С(3)); 37.95 (d, С(4)); 29.14 (t, С(5)); 39.91 (d,
С(6)); 27.68 (t, С(7)); 29.14 (q, С(8)); 23.42 (q, С(9)); 27.53 (q,
С(10)); 63.57 (t, С(11)); 98.41 (d, С(12)); 130.84 (s, С(13)); 168.03
(s, С(14)); 132.29 (s, С(15)); 124.71 (d, С(16)); 136.41 (s, С(17));
127.17 (d, С(18)).
5ꢀDiethylaminoꢀ2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀhydroxymethylꢀ
2,6,6ꢀtrimethylbicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}phenol
(14i). 4ꢀDiethylaminoꢀ2ꢀhydroxybenzaldehyde (8i) (0.046 g,
0.24 mmol) in methanol (5 mL) was added dropwise to a stirred
solution of compound (–)ꢀ6 (0.049 g, 0.27 mmol) in anhydrous
methanol (4 mL). The reaction mixture was stirred at ~20 °C for
4 h. The solvent was evaporated, the residue was recrystallized from
2ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtrimethylbiꢀ
cyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4ꢀmethoxyphenol (14g).
2ꢀHydroxyꢀ5ꢀmethoxybenzaldehyde (8g) (0.037 g, 0.24 mmol) in
methanol (5 mL) was added dropwise to a stirred solution of
compound (–)ꢀ6 (0.050 g, 0.27 mmol) in anhydrous methanol
(4 mL). The reaction mixture was stirred at ~20 °C for 1 h. The
solvent was evaporated to obtain product 14g (0.069 g, 90%),
diethyl ether—hexane to obtain product 14i (0.077 g, 90%), [α]22
580
+13.1 (c 0.37, CHCl3). 1H NMR, δ: 1.13 (s, 3 Н, С(9)Me); 1.16 (t,
6 Н, N(С(19)Н2С(20)Н3)2, J = 6.5 Hz); 1.18 (d, 1 Н, Нanti(7),
J7anti,7syn = 10.5 Hz); 1.29 (s, 3 Н, С(10)Me); 1.45 (ddd, 1 Н,
Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 7.5 Hz, J5anti,6 = 2 Hz);
1.47 (s, 3 Н, С(8)Me); 1.96 (m, 1 Н, Н(6)); 2.02 (dd, 1 Н, Н(2),
J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 1.98—2.11 (m, 1 Н, Нsyn(5)); 2.25

116
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 1, January, 2008
Koneva et al.
(dddd, 1 Н, Нsyn(7), J7syn,7anti = 10.5 Hz, J7syn,2 = 5.5 Hz, J7syn,6
5.5 Hz, J7syn,5syn = 2.2 Hz); 2.30—2.43 (m, 1 Н, Н(4)); 3.34 (q,
4 Н, N(СН2СН3)2, J = 6.5 Hz); 3.38 (dd, 1 Н, Н(11), J11,11´
=
8 Hz, J18,19 = 7 Hz, J18,20 = 1 Hz); 7.32 (ddd, 1 Н, Н(19), J19,20 =
8.3 Hz, J19,18 = 7 Hz, J19,17 = 1.3 Hz); 7.64 (br.d, 1 Н, Н(17), J17,18
= 8 Hz); 7.51 (d, 1 Н, Н(16), J16,15 = 9.2 Hz); 7.70 (br.d, 1 Н,
Н(20), J20,19 = 8.3 Hz); 8.65 (br.d, 1 Н, Н(12), J = 11 Hz); 14.85
(br.d, 1 Н, С(14)—ОН, J = 11 Hz). 13C NMR, δ: 38.76 (s, С(1));
53.44 (d, С(2)); 63.51 (s, С(3)); 40.73 (d, С(4)); 30.45 (t, С(5));
39.84 (d, С(6)); 29.35 (t, С(7)); 29.15 (q, С(8)); 23.69 (q, С(9));
28.31 (q, С(10)); 65.47 (t, С(11)); 153.38 (d, С(12)); 105.92
(s, С(13)); 178.90 (s, С(14)); 126.25 (d, С(15)); 137.64 (d, С(16));
129.22 (d, С(17)); 122.13 (d, С(18)); 127.77 (d, С(19)); 117.20
(d, С(20)); 134.56 (s, С(21)); 125.78 (s, С(22)). Found:
m/z 337.20715 [M]+. С22H27NO2. Calculated: М = 337.20417.
Asymmetric oxidation of thioanisole 10 (general procedure).
A mixture of VO(acac)2 (2 mg, 8 µmol) and the corresponding
ligand (12 µmol) in a preꢀdried solvent (2 mL) was stirred until the
complete dissolution of VO(acac)2 crystals (~20 min). Thioanisole
10 (0.105 g, 847 µmol) in the preꢀdried solvent (3 mL) was added to
a stirred solution obtained, if necessary, with cooling, followed by
the addition of the oxidant (1060 µmol). The reaction course was
monitored by GLC. After the reaction was over, deionized water
(10 mL) was added to the reaction mixture, the organic layer was
separated, the aqueous layer was extracted with the solvent used in
the reaction (2×5 mL), the combined organic phase was washed
with water (2×10 mL) and dried with MgSO4. The drying agent was
filtered off, the solvent was evaporated on a rotary evaporator. The
conversion and ratio of the reaction products were determined from
=
10 Hz, J11,4syn = 6 Hz); 3.65 (dd, 1 Н, Н(11´), J11´,11 = 10 Hz,
J11´,4syn = 8 Hz); 5.89 (d, 1 Н, Н(15), J15,17 = 2.2 Hz); 6.00 (dd,
1 Н, Н(17), J17,18 = 9 Hz, J17,15 = 2.2 Hz); 6.83 (d, 1 Н, Н(18),
J18,17 = 9 Hz); 7.65 (br.s, 1 Н, Н(12)); 14.17 (br.s, 1 Н, С(14)—
ОН). 13C NMR, δ: 38.63 (s, С(1)); 53.11 (d, С(2)); 63.25 (s, С(3));
41.11 (d, С(4)); 30.59 (t, С(5)); 39.93 (d, С(6)); 29.32 (t, С(7));
29.37 (q, С(8)); 23.65 (q, С(9)); 28.30 (q, С(10)); 65.42 (t, С(11));
157.38 (d, С(12)); 108.22 (s, С(13)); 173.01 (s, С(14)); 99.64 (d,
С(15)); 153.18 (s, С(16)); 102.83 (d, С(17)); 134.22 (d, С(18));
44.52 (t, 2 С, С(19)); 12.93 (q, 2 С, С(20)). Found: m/z 358.26207
[M]+. С22H34N2O2. Calculated: М = 358.26201.
2ꢀBromoꢀ6ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀhydroxymethylꢀ2,6,6ꢀtriꢀ
methylbicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ4ꢀnitrophenol
(14j). 3ꢀBromoꢀ2ꢀhydroxyꢀ5ꢀnitrobenzaldehyde (8j) (0.064 g,
0.26 mmol) in methanol (5 mL) was added dropwise to a stirred
solution of compound (–)ꢀ6 (0.054 g, 0.29 mmol) in anhydrous
methanol (4 mL). The reaction mixture was stirred at ~20 °C for
6 h. The solvent was evaporated, the residue was recrystallized from
chloroform—hexane to obtain product 14j (0.100 g, 94%), m.p.
202—205 °C, [α]22 +4.0 (c 1.2, CHCl3). 1H NMR, δ: 1.19 (s,
3 Н, С(9)Me); 1.245(8d0, 1 Н, Нanti(7), J7anti,7syn = 11 Hz); 1.35 (ddd,
1 Н, Нanti(5), J5anti,5syn = 13 Hz, J5anti,4syn = 7.5 Hz, J5anti,6
=
2 Hz); 1.36 (s, 3 Н, С(10)Me); 1.67 (s, 3 Н, С(8)Me); 2.03—2.18
(m, 3 Н, Н(6), Нsyn(5), Н(2)); 2.48 (dddd, 1 Н, Нsyn(7), J7syn,7anti
= 11 Hz, J7syn,2 = 6 Hz, J7syn,6 = 6 Hz, J7syn,5syn = 2.2 Hz); 2.50—
2.62 (m, 1 Н, Н(4)); 2.72 (br.s, 1 Н, С(11)—ОН); 3.61 (dd, 1 Н,
Н(11), J11,11´ = 10 Hz, J11,4syn = 10 Hz); 3.72 (dd, 1 Н, Н(11´),
J11´,11 = 10 Hz, J11´,4syn = 5 Hz); 8.08 (d, 1 Н, Н(12), J = 13 Hz);
1
the Н NMR spectra of the obtained mixture by comparison of
intensities of signals of the methyl groups of compounds 10
(2.39 ppm), 11 (2.63 ppm), and 12 (2.95 ppm). Enantiomeric
excess in compound 11 was determined from the 1H NMR spectra
(solvent CCl4—CDCl3), recorded in the presence of the same in
weight amount of (R)ꢀ(–)ꢀ3,5ꢀdinitroꢀNꢀ(1ꢀphenylethyl)benzꢀ
amide, by integration of signals of the methyl groups of the
enantiomers.
8.16 (d, 1 Н, Н(18), J18,16 = 3 Hz); 8.45 (d, 1 Н, Н(16), J16,18
=
3 Hz); 14.95 (br.d, 1 Н, С(14)—ОН, J = 13 Hz). 13C NMR, δ: 38.82
(s, С(1)); 52.49 (d, С(2)); 66.04 (s, С(3)); 40.02 (d, С(4)); 29.90
(t, С(5)); 39.56 (d, С(6)); 29.18 (t, С(7)); 28.87 (q, С(8)); 23.57 (q,
С(9)); 28.04 (q, С(10)); 65.32 (t, С(11)); 162.44 (d, С(12)); 118.93
(s, С(13)); 174.37 (s, С(14)); 111.71 (s, С(15)); 132.26 (d, С(16));
134.32 (s, С(17)); 131.34 (d, С(18)). Found: m/z 410.0844 [M]+.
С18H23N2O4Br. Calculated: М = 410.0842.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 06ꢀ03ꢀ
32052).
1ꢀ{[(1S,2S,3R,5S)ꢀ3ꢀHydroxymethylꢀ2,6,6ꢀtriꢀ
methylbicyclo[3.1.1]heptꢀ2ꢀylimino]methyl}ꢀ2ꢀnaphthol (15).
2ꢀHydroxyꢀ1ꢀnaphthaldehyde (13) (0.032 g, 0.19 mmol) in methaꢀ
nol (5 mL) was added dropwise to a stirred solution of compound
(–)ꢀ6 (0.053 g, 0.29 mmol) in anhydrous methanol (4 mL). The
reaction mixture was stirred at ~20 °C for 7 h. The solvent was
evaporated, the residue was recrystallized from diethyl ether to obtain
product 15 (0.059 g, 92%), m.p. 166—170 °C, [α]22580 –1.8 (c 1.6,
CHCl3). 1H NMR, δ: 1.19 (s, 3 Н, С(9)Me); 1.29 (d, 1 Н, Нanti(7),
J7anti,7syn = 10 Hz); 1.35 (s, 3 Н, С(10)Me); 1.41 (ddd, 1 Н, Нanti(5),
J5anti,5syn = 13 Hz, J5anti,4syn = 7.5 Hz, J5anti,6 = 2 Hz); 1.64 (s, 3 Н,
С(8)Me); 2.02 (m, 1 Н, Н(6)); 2.07 (dddd, 1 Н, Нsyn(5), J5syn,5anti
= 13 Hz, J5syn,4anti = 12 Hz, J5syn,6 = 3.5 Hz, J5syn,7anti = 2.2 Hz);
2.15 (dd, 1 Н, Н(2), J2,6 = 5.5 Hz, J2,7syn = 5.5 Hz); 2.40 (dddd,
1 Н, Нsyn(7), J7syn,7anti = 10 Hz, J7syn,2 = 5.5 Hz, J7syn,6 = 5.5 Hz,
J7syn,5syn = 2.2 Hz); 2.42—2.53 (m, 1 Н, Н(4)); 3.02 (br.s, 1 Н,
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New chiral ligands from αꢀpinene
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