Atropisomerism of 2,2′-binaphthalenes

Article abstract of DOI:10.1071/CH00122

The synthesis of diastereo-enriched substituted (4S)-4-isopropyl-2-(2,2′-binaphthalen-1-yl)-4,5-dihydrooxazoles from substituted 2-naphthalenylmagnesium bromides and (4S)-4-isopropyl-2-(2-methoxynaphthalen-1-yl)-4,5-dihydrooxazole (4) and (4S)-4-isopropyl-2-(2,3-dimethoxynaphthalen-1-yl)-4,5-dihydrooxazole (5) is described. The product oxazolines were converted into a number of derivatives and the free energy barriers to internal rotation of several of these derivatives were determined. The determination of the X-ray crystal structures and the c.d. spectra of (S,1S)-N-[2-hydroxy-1-(isopropyl)ethyl]-3-methoxy-1′,N-dimethyl-2,2′ -binaphthalene-1-carboxamide (22) and (R,4S)-4-isopropyl-3-methyl-2-(1′,2′,4′-trimethyl-2,2′-b inaphthalen-1-yl)-4,5-dihydrooxazolium iodide (38) allowed the assignment of the absolute configurations of all the synthetic 2,2′-binaphthalenes by comparison of their c.d. spectra with those of compounds (22) and (38).

Full text of DOI:10.1071/CH00122

C S I R O P U B L I S H I N G
Australian Journal
of Chemistry
Volume 53, 2000
©
CSIRO 2000
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Aust. J. Chem., 2000, 53, 925–938
Atropisomerism of 2,2´-Binaphthalenes
A
B
B,C
B
B
Robert W. Baker, Zinka Brkic, Melvyn V. Sargent, Brian W. Skelton and Allan H. White
A
School of Chemistry, University of Sydney, Sydney, N.S.W. 2006.
Department of Chemistry, The University of Western Australia, Crawley, W.A. 6009.
Author to whom correspondence should be addressed (e-mail: msargent@admin.uwa.edu.au).
B
C
Dedicated to Dr John Zdysiewicz on the occasion of his retirement
The synthesis of diastereo-enriched substituted (4S)-4-isopropyl-2-(2,2´-binaphthalen-1-yl)-4,5-dihydrooxazoles
from substituted 2-naphthalenylmagnesium bromides and (4S)-4-isopropyl-2-(2-methoxynaphthalen-1-yl)-4,5-
dihydrooxazole (4) and (4S)-4-isopropyl-2-(2,3-dimethoxynaphthalen-1-yl)-4,5-dihydrooxazole (5) is described.
The product oxazolines were converted into a number of derivatives and the free energy barriers to internal rotation
of several of these derivatives were determined. The determination of the X-ray crystal structures and the c.d.
spectra of (S,1S)-N-[2-hydroxy-1-(isopropyl)ethyl]-3-methoxy-1´,N-dimethyl-2,2´-binaphthalene-1-carboxamide
(
(
22) and (R,4S)-4-isopropyl-3-methyl-2-(1´,2´,4´-trimethyl-2,2´-binaphthalen-1-yl)-4,5-dihydrooxazolium iodide
38) allowed the assignment of the absolute configurations of all the synthetic 2,2´-binaphthalenes by comparison
of their c.d. spectra with those of compounds (22) and (38).
Keywords: Asymmetric synthesis; atropomers; 2,2´-binaphthalenes; circular dichroic spectra; rotational barriers.
C
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A number of enantiopure atropomers of various
derivatives of 1,1´-binaphthalene have achieved wide use in
asymmetric synthesis and in the separation of racemic
1
mixtures. The free energy barriers to rotation in many such
2
compounds have also been measured. The atropisomerism
of 2,2´-binaphthalenes has, on the other hand, been little
explored.
A number of natural products are known which are based
on the 2,2´-binaphthalene system and occur as atropomers.
3
The first to be recorded was gossypol, which occurs in
cotton seeds in racemic form. The structure of gossypol was
4
elucidated by Adams and his coworkers in 1938. The (+)-
5
binaphthalene17 is estimated to be 29–38 kJ mol–1 so that
this benzannelation, although remote from the biaryl
linkage, has a substantial effect. The free energy barrier in
1,1´-binaphthalene is at the lower limit for the isolation of
(S)-atropomer (1) occurs in Thespesia populnea and since
the (–)-atropomer has the ability to inhibit maturation of
human sperm there has been renewed interest in its
chemistry.6 (+)-(S)-Gossypol (1) has recently been
7
8
15
synthesized. The free energy barrier to rotation in gossypol
atropomers at room temperature.
–
1
has been estimated to be above 210 kJ mol and the absolute
In view of the dearth of data on atropisomerism in the
2,2´-binaphthalene series, we decided to synthesize a
number of these compounds and to investigate their free
energy barriers to racemization. At the outset it appeared
likely that at least two substituents at the positions ortho to
the biaryl linkage would be required to obtain atropomers
that would be thermally stable to racemization at room
temperature. For the synthesis of the naturally occurring
1,2´-binaphthoquinones isodiospyrin and 8´-hydroxyiso-
9
configuration has been determined by the exciton chirality
method.10 Other natural products which are also not easily
1
1
12
thermally racemized are sporandol (2), the flavomannins
and the cardinalins,13 which have also had their absolute
configurations determined by the exciton chirality method.
The synthetic 2,2´-binaphthol (3)14 has been resolved and
the free energy barrier to rotation has been estimated to be
–
1
1
68 kJ mol .
The rotational barrier in 1,1´-biphenyl is c. 8 kJ mol–1
15
18
diospyrin in enantiopure form we adopted the Meyers
–1
19
and this rises to 90.5 kJ mol on benzannelation to give 1,1´-
binaphthalene.16 The free energy barrier to rotation in 2,2´-
oxazoline method and this appeared to be suitable for
adaptation to the present work.
Manuscript received 15 September 2000
© CSIRO 2000
10.1071/CH00122
0004-9425/00/110925

9
26
R. W. Baker et al.
Table 1. Products of coupling reactions between Grignard
reagents and oxazolines
Bromo compound
-Bromonaphthalene
6)
6)
7)
9)
8)
8)
Oxazoline Product Yield (%) D.e. (%)
2
(
(5)
(4)
(5)
(5)
(5)
(4)
(5)
(4)
(5)
(11)
(12)
(13)
(17)
(24)
(28)
(33)
(37)
(44)
95
91
91
92
96
76
82
82
23
0
0
A
A
A
B
A
B
A
(
(
(
(
(
(
(
56.8
73.3
56.6
39.9
37.0
30.8
20.8
10)
10)
A
B
In favour of axial (S)-diastereomer
In favour of axial (R)-diastereomer
For this purpose we required oxazolines in enantiopure
form and we chose compounds (4) and (5) for investigation.
Compound (4) was easily prepared from the known
2
0
2
-methoxynaphthalene-1-carboxylic acid
and (+)-(S)-
21
22
valinol by a standard method. For the synthesis of the
oxazoline (5) the starting material was 2,3-dimeth-
oxynaphthalene which, on bromination by the method of
Mitchell and his coworkers,23 supplied 1-bromo-2,3-
dimethoxynaphthalene. Carboxylation of the Grignard
reagent derived from this bromo compound afforded 2,3-
dimethoxynaphthalene-1-carboxylic acid,24 which was
converted into the required oxazoline (5). A number of
bromo compounds were required as precursors to Grignard
reagents for the synthesis of 2,2´-binaphthalenes by
nucleophilic displacement of the methoxy group at the
2
-positions of the oxazolines (4) and (5). 2-Bromo-1-
25
methoxynaphthalene (6) was prepared by methylation of
2
1
-bromo-1-naphthalenol available by bromination of
-naphthalenol.2 2-Bromo-1-methylnaphthalene (7) was
6
2
7
obtained from the amine by a Sandmeyer reaction.
28
2-Bromo-1,3-dimethylnaphthalene (8) was prepared from
29
2,3-dimethylindene. Bromination of 1,4-dimethylnaphtha-
3
0
lene and 1,2,3-trimethylnaphthalene, each of which was
prepared from 1-methylnaphthalene, provided the bromo
compounds (9)31 and (10).
32
The results of coupling between the oxazolines (4) and (5)
and Grignard reagents derived from 2-bromonaphthalene
and compounds (6)–(10) are summarized in Table 1. An

Atropisomerism of 2,2´-Binaphthalenes
927
Fig. 1. (a) Molecule 1 of (22) projected normal to the
central naphthyl plane. (b) A single molecule of (38) (.2S)
projected normal to the central naphthyl plane; 20%
thermal ellipsoids are shown for the non-hydrogen atoms,
hydrogen atoms have arbitrary radii of 0.1 Å. (The
molecule of the unsolvated form is similar in aspect.) (c)
Unit cell contents of the unsolvated form of (38) projected
down c; hydrogen atoms are omitted.
excess of the Grignard reagent generated in tetrahydrofuran
the oxazolines (4) and (5) was chosen for X-ray crystal
structure determination. Thus, the diasteriomeric mixture of
oxazolines resulting from the coupling of the Grignard
reagent derived from the bromo compound (7) and the
oxazoline (5) was converted by treatment with an excess of
iodomethane in nitromethane at 50° into the derived
methiodides. Hydrolysis of these compounds was achieved
by treatment with aqueous potassium hydroxide with
methanol and thf as cosolvents at 60°. Radial
chromatography of the resultant mixture of amides allowed
the major diastereomer to be isolated in a pure state. An
X-ray crystal structure determination on this compound
revealed that its axial configuration was S as shown in
Fig. 1a and structure (22). The c.d. spectrum of this
compound (Fig. 2) reveals the presence of a bisignate couplet
(
thf) was allowed to react with the oxazoline in thf at room
temperature. This generally resulted in a high yield of the
coupled product except for the cases of the binaphthalenes
(
28), (33), (37) and (44) when it was necessary to boil the
reaction mixtures in order to achieve efficient coupling. In
the case of the highly hindered compound (44) the yield was
poor even under these conditions. In all cases except
compounds (11) and (12) a moderate to good diastereomeric
excess (d.e.) resulted and the magnitude of this excess was
1
easily determined by integration of the H n.m.r. spectra of
the products.
In order to determine the absolute configuration of the
major products of these coupling reactions one pure
diastereomer secured from each series of reactions based on

9
28
R. W. Baker et al.
Fig. 2. C.d. spectrum of compound (22).
Fig. 3. C.d. spectra of the diastereomeric methiodides (38) and (39).
centred at 230 nm with Σ∆ε 68. The X-ray crystal structure
of the amide shows that the dihedral angles between the
naphthalene planes of the two independent molecules of the
asymmetric unit are 85.06(8) and 77.39(8)° (torsion angles
C(1´)–C(2´)–C(2´´)–C(3´´) 81.8(4) and 78.0(4)°) so that
even in solution there is likely to be little electron
delocalization between the two naphthalene chromophores.
methiodide shows that the dihedral angles between the
naphthalene planes are 68.5(2) (unsolvated form) and
88.5(5)° (solvated form) (torsion angles C(1´)–C(2´)–
C(2´´)–C(3´´) 108.2(6) and 88(2)°, respectively), so that the
conditions for exciton chirality are again met. The longer
wavelength extremum of the couplet for compound (38) is
negative and that at shorter wavelength is positive,
constituting negative exciton chirality in keeping with the
R-axial configuration, the Cahn–Ingold–Prelog priorities of
the fiducial atoms having changed from compound (22) to
compound (38) on account of the 3-methoxy group in
compound (22).
The centre of the bisignate couplet is near the wavelength of
1
the naphthalene B transition band for which the direction
b
of the electron transition dipole moment is along the long
axis of the naphthalene ring10 and, given the magnitude of
Σ∆ε, the requirements for exciton chirality are met. The
longer wavelength extremum of the couplet for compound
Separate reduction of the methiodides (38) and (39) with
sodium borohydride followed by acidic cleavage of the
intermediate oxazolidines33 yielded the enantiomeric
aldehydes (40) and (41). On reduction of these aldehydes
with sodium borohydride the enantiomeric alcohols (42) and
(43) were obtained. The aldehyde (40) did not undergo
racemization during 54 h in boiling tetrachloroethene
(394 K), so that compounds (40)–(43) are presumably
enantiomerically pure. This was shown to be the case since
(
22) is negative and that at shorter wavelength is positive, so
that the electron transition dipole moments exhibit left-
10
handed screwness (negative exciton chirality), in keeping
with the S-axial configuration. Hence, the major
diastereomer (17) resulting from the coupling reaction also
has the S-axial configuration and the c.d. spectrum of the
mixture of oxazolines (73.3% d.e.) resulting from the
coupling reaction also shows negative exciton chirality.
The diastereomeric mixture of oxazolines resulting from
the coupling of the Grignard reagent derived from the bromo
compound (6) and the oxazoline (4) was similarly converted
into the methiodides (38) and (39). Fractional crystallization
of this mixture allowed each diastereomer to be isolated in a
pure state. X-Ray crystal structure determinations on the
major diasteromeric salt (unsolvated and acetone-solvated
forms, independently determined and internally consistent in
their indications of absolute configuration), demonstrated
that its axial configuration was R as shown in Fig. 1b and
structure (38). The c.d. spectra of the R (38) and S (39)
methiodides are shown in Fig. 3. The spectra are mirror
images of each other and each shows a bisignate couplet near
1
the H n.m.r. spectrum of the Mosher ester prepared from the
alcohol (42) showed that its enantiomeric excess (e.e.) was
98.7%. Their c.d. spectra also exhibit exciton chirality and
the spectra of the aldehydes (40) and (41) are shown in Fig. 4.
Determination of the c.d. spectra of the other
diastereomeric mixtures of the 2,2´-binaphthalenes resulting
from the coupling reactions showed that the major
diastereomers produced, (13), (24), (33) and (44), all had the
S-axial configuration except compound (38), which had the
R-axial configuration. The absolute configurations of the
derivatives prepared from these compounds were congruent
with those of their parents. In general, the diastereomeric
mixtures of oxazolines resulting from coupling were
converted into the methiodides and these were reduced to the
230 nm with Σ∆ε c. 160. The X-ray crystal structures of the

Atropisomerism of 2,2´-Binaphthalenes
929
Fig. 4. C.d. spectra of the enantiomeric aldehydes (40) and (41).
oxazolidines with sodium borohydride prior to hydrolysis to
the aldehydes. Thus, for example, the mixture of oxazolines
rich in the diastereomer (17) gave the aldehyde (18) which
was reduced to the alcohol (19). The e.e. of the alcohol was
1
determined to be 57.7% from its H n.m.r. spectrum
determined in the presence of europium(III) tris[3-(hepta-
fluoropropylhydroxymethylene)-(+)-camphorate] (see Ex-
perimental section). Some racemization had thus occurred
during the reduction process since the d.e. of the starting
oxazoline was 73.3%. The alcohol (19) was converted into
its mesylate and this on reduction with lithium aluminium
hydride afforded the methyl compound (20). The aldehyde
(
(
18) was also converted via the derived oxime into the nitrile
21). Hydrolysis of the mixture of methiodides provided the
amide (22) (see above) which was isolated in enantiopure
form by chromatography. Further hydrolysis of this
compound supplied the amide (23).
Scheme 1. Stereochemistry of the coupling reaction.
The methiodides derived from the mixture of oxazolines
enriched in the diastereomer (13) on heating in nitromethane
at 50° underwent an asymmetric transformation of the first
kind (see later) and the predominant diastereomer (14)
present at equilibrium proved to have the R-axial con-
figuration. Fractional crystallization allowed the separation
of this diastereomer in a pure state and thus the preparation
of the aldehyde (15). Reduction of the aldehyde (15)
assumed to be enantiomerically pure since, in the presence of
the anthracenyl shift reagent, the H n.m.r. spectrum of the
(R)-alcohol (31) showed no signals for the enantiomeric
alcohol which were present in a sample prepared from the
diastereomeric mixture of methiodides.
1
Little racemization also occurred during the conversion of
the oxazoline (33) into the alcohol (35). The d.e. of the
starting oxazoline was 37.0% and the e.e. of the alcohol
1
provided the alcohol (16) and integration of the H n.m.r.
spectrum of this compound determined in the presence of
1
obtained was 35.5% as shown by the H n.m.r. spectra of the
(
+)-(S)-1-(anthracen-9-yl)-2,2,2-trifluoroethanol showed the
derived Mosher esters (see Experimental section).
e.e. to be 91.7%, so that little racemization had occurred
during these transformations.
It is pertinent to comment here on the stereochemical
outcome of the coupling reactions. In Scheme 1 is depicted
the course of the reaction between the Grignard reagent
derived from the bromonaphthalene (6) and the oxazoline
(5). It is known that the isopropyl substituents on oxazolines
such as (5) control the direction of attack of the Grignard
reagent18 so that it would attack from the face of the
Fractional crystallization of the mixture of oxazolines
enriched in the diastereomer (28) allowed this isomer to be
obtained in a pure state. It was converted sequentially into
the methiodide (29), the aldehyde (30), the alcohol (31) and
finally the methyl compound (32). All these compounds are

9
30
R. W. Baker et al.
Table 2. Free energy barriers and rates of inversion for compounds (13) and (14)
(s–1
)
k
(s–1
R→S
)
∆G (kJ mol–1)
‡
T (K)
Solvent
Cpd
k
S→R
–
–
6
5
–6
–5
(
(
13)
14)
(4.03 ± 0.25)10
(1.33 ± 0.05)10
(2.46 ± 0.15)10
(1.02 ± 0.04)10
115.3 ± 0.2
108.0 ± 0.1
334
323
CHCl3
MeNO2
oxazoline remote from the isopropyl group as depicted in
Scheme 1 in both paths A and B. The rotamer that leads to
the σ-complex in which the methoxy group of the Grignard
reagent is chelated to the magnesium would be expected to
be preferred, path A rather than path B, and it is seen that this
leads to the product with S-axial configuration as observed
hydrogen on the other side, which of necessity is the pathway
for that for compound (11).
It was observed that the mixture of oxazolines enriched
in the diastereomer (13) underwent an asymmetric trans-
formation of the first kind on boiling in chloroform. By
starting with material of d.e. 51.2%, in favour of the
(S)-diastereomer (13), the d.e. at equilibrium was found to be
24.2% in favour of the (R)-diastereomer. The rates of
inversion and the free energy barrier for this reversible first-
order reaction are shown in Table 2 and were determined by
(
56.8% d.e.). When the Grignard reagent derived from the
bromo compound (7) is used in which the chelating methoxy
group of compound (6) is replaced by a non-chelating methyl
group, the d.e. is higher (73.3%) but the stereochemical
outcome is still a preference for the S-axial configuration, so
that path A is preferred. The pathway involves less steric
interaction between the methyl group and the naphthalene
ring of the oxazoline so that steric effects are more important
than chelation. The d.e. falls again with increased methyl
substitution so that with the Grignard reagent derived from
integration of the methyl doublets at δ 0.69 and 0.72 for the
H
(S)-diastereomer and at δH 0.61 and 0.64 for the
1
(R)-diastereomer in their H n.m.r. spectra at 200 MHz.
When this mixture of oxazolines of d.e. 51.2% was
converted into the methiodides by treatment with an excess
of iodomethane at 323 K it was found that the reaction was
complete after c. 3 h and the d.e. of the product had fallen to
40.5% in favour of the (S)-diastereomer. When methiodides
of d.e. 45.6% in favour of the (R)-diastereomer (14) were
heated in nitromethane at 323 K the d.e. at equilibrium was
found to be 13.5% in favour of (14). The rates of inversion
and the free energy barriers are shown in Table 2 and they
were determined in a similar manner to those for the
2-bromo-1,3-dimethylnaphthalene (8) it is 37.0% but still
with a preference for the S-axial configuration. This implies
that the steric demand of a methyl group at the α-position of
a naphthalene is greater than that of a methyl group at the
β-position, probably on account of the steric interaction
between the α-methyl group and the hydrogen at the peri-
position. A similar analysis accounts for the stereoselectivity
in the formation of the oxazoline (28).
oxazolines by integration of the methyl doublets at δ –0.08
H
The free energy barriers to internal rotation in the
oxazolines (11) and (12) were estimated from their variable-
((S)-diastereomer) and 0.08 ((R)-diastereomer).
The rates of racemization and the free energy barriers to
internal rotation for compounds (15), (16), (18), (21), (23),
(25) and (30) are shown in Table 3. These were determined
by polarimetry35 at 394 K in tetrachloroethene except for
1
temperature H n.m.r. spectra by measuring the coalescence
temperature34 of an aromatic signal in the case of compound
(
11) and of a methyl signal in that of compound (12). For
2
compound (11) in ( H )toluene at 276 ± 2 K, the rate constant
was 57 s , which gave ∆G = 58.1 ± 0.6 kJ mol . For
compound(12)in( H )methanolat276±2Ktherateconstant
was 172 s , which gave ∆G = 55.6 ± 0.6 kJ mol . The free
energy barriers are similar, as expected since the internal
rotation leading to the lower energy transition state for
compound (12) would be that where a methoxy passes a
hydrogen on one side and the oxazoline entity passes a
compound (15) where chloroform at 298 K was the solvent.
8
–1
‡
–1
36,37
It is known
that the ability of a group at a position ortho
2
to the biaryl linkage to inhibit racemization depends on its
size, and a good measure of this is the effective van der
Waal’s radius of the group.37 The data in Table 3 are in
keeping with previous results and clearly show that a methyl
group (radius 1.80 ± 0.03 Å) is more effective than a
methoxy group (radius 1.52 ± 0.03 Å) at inhibiting rotation.
Comparison of the free energy for compound (18) with its
4
–1
‡
–1
biphenyl analogue (45)35 (∆G 125.3 kJ mol at 383 K)
shows that the barrier in the binaphthalene is slightly higher.
Compounds (19), (34) and (40) did not racemize at 394 K.
Comparison of (30) and (40) demonstrates the effect of
buttressing of a methyl group remote from the biaryl linkage.
‡
–1
Table 3. Free energy barriers and rates of racemization for
2
,2´-binaphthalenesdeterminedintetrachloroetheneat394K
‡
Cpd
k (s–1
)
∆G (kJ mol–1)
–5
(
(
(
(
(
(
(
15)A
16)
18)
21)
23)
25)
30)
(1.15 ± 0.04)10
(5.33 ± 0.18)10
(1.61 ± 0.05)10
(4.04 ± 0.21)10
(1.45 ± 0.05)10
(1.28 ± 0.12)10
(9.32 ± 0.70)10
101.2 ± 0.1
129.6 ± 0.1
133.6 ± 0.1
130.6 ± 0.2
133.9 ± 0.1
134.3 ± 0.3
142.9 ± 0.2
–
–
–
–
–
–
5
5
5
5
5
7
Experimental
Unless stated otherwise reactions were worked up by dilution with
water and extracted with ethyl acetate, followed by washing with water
and with saturated brine and then drying over anhydrous sodium or
magnesium sulfate. Flash chromatography was performed on BDH
silica gel (40–63 µm) and radial chromatography was performed on a
Harrison Research Chromatotron by using plates coated with Merck
Kieselgel 60 PF254. Melting points were recorded on a Kofler hot-stage
A
Determined in CHCl at 298 K.
3

Atropisomerism of 2,2´-Binaphthalenes
931
apparatus. Optical rotations were measured for solutions in chloroform
on a Perkin–Elmer 141 polarimeter with a 10 cm micro cell. Electronic
spectra were determined for solutions in methanol by using a GBC 918
u.v./visible spectrophotometer. C.d. spectra were recorded for solutions
(13), 172 (31), 157 (10), 144 (14), 127 (17), 126 (13), 115 (11), 113
(12), 101 (23).
2,3-Dimethoxynaphthalene-1-carboxylic Acid
1
19
13
in acetonitrile with a JASCO J-710 spectropolarimeter. H, F and
n.m.r. spectra were recorded for solutions in deuteriochloroform, unless
stated otherwise, on Bruker ARX-500 instrument. Variable-
C
The Grignard reagent was prepared from the foregoing bromo
compound (15.9 g, 59.6 mmol), anhydrous thf (120 ml) and magnesium
a
(1.5 g, 62 matom) in the usual way. The cooled solution was poured
1
temperature H n.m.r. spectra were recorded on a Bruker ARX-500
instrument and the data in Table 2 were obtained by using a Gemini 200
instrument. Mass spectra were recorded with a VG Autospec
spectrometer at 70 eV. The data recorded in Table 3 were determined by
cautiously on to solid carbon dioxide (500 g) and the whole was stirred
for 12 h. An excess of dilute hydrochloric acid was added and the crude
product was isolated by extraction with ether. Further purification was
effected by extraction into dilute aqueous sodium hydroxide in the usual
3
5
the method of Meyers and Himmelsbach. The errors represent the
0% confidence limit from the least-squares analysis.
way. The crude product crystallized from ethyl acetate as prisms
9
24
(
12.0 g, 87%), m.p. 150–152° (lit. 153–155º).
(
–)-(4S)-4-Isopropyl-2-(2-methoxynaphthalen-1-yl)-4,5-dihydrooxa-
(
–)-(4S)-4-Isopropyl-2-(2,3-dimethoxynaphthalen-1-yl)-4,5-dihydroxa-
zole (4)
zole (5)
A mixture of 2-methoxy-1-naphthoic acid (8.5 g, 48 mmol), oxalyl
chloride (8.0 ml, 95 mmol) and 3 drops of dimethylformamide were
stirred in anhydrous dichloromethane for 18 h under argon. The solvent
and excess oxalyl chloride were removed under reduced pressure and
the residue was dissolved in dichloromethane (40 ml) and added
dropwise to a stirred solution of triethylamine (7.6 ml, 55 mmol) and
This was prepared from the foregoing carboxylic acid in a manner
similar to that described for compound (4). It was obtained as a viscous
+•
12
1
14 16
+•
oil (86%) (Found: M , 299.1520. C18 H21
2
N
O3 requires M
99.1521). [α]D –33.4° (c, 2.5). δH 1.04 and 1.10, each d, J 6.8 Hz,
CH(CH ) ; 1.96, m, HCMe ; 3.89 and 3.96, each s, OMe; 4.22, dd, J
25
3
2
2
8
9
.0, 9.0 Hz; CHH5; 4.27, ddd, J 6.8, 8.0, 9.4 Hz, CH4; 4.49, dd, J 8.0,
.4 Hz, CHH5; 7.18, s, H4; 7.35, m, 2 × ArH; 7.36, m, 2 × ArH; 7.66,
(S)-valinol (4.76 g, 47 mmol) in dichloromethane (110 ml) at 0º under
argon. The solution was stirred at room temperature for 18 h. The
solution was cooled to 0º and water was added. Work-up of the organic
layer in the usual way gave the crude hydroxy amide which was
dissolved in dichloromethane (100 ml) and benzene (80 ml). The
solution was stirred and cooled to 0º and thionyl chloride (13.0 ml, 182
mmol) was added dropwise and the solution was next stirred under
argon at room temperature for 18 h. The solvents and excess thionyl
chloride were removed under reduced pressure and ether and 5%
aqueous sodium hydroxide were added. The usual work-up gave a crude
product to which was added acetonitrile (100 ml), water (10 ml) and
potassium carbonate (15 g) and the whole was heated under reflux for
m, ArH; 7.85, m, ArH. δC 18.20 and 18.55, each Me; 32.48, HCMe2;
5
1
5.41, 3-OMe; 61.57, 2-OMe; 69.63, C5; 72.88, C4; 108.89, CHAr;
19.62, CAr; 124.21, 124.48, 125.26 and 126.36, each CHAr; 126.83
and 130.78, each CAr; 141.81 and 151.42, C2,3; 160.70, C2. m/z 299
+
(
M , 76%), 298 (12), 270 (18), 257 (35), 256 (100), 228 (14), 215 (28),
14 (16), 213 (47), 212 (33), 201 (52), 199 (18), 198 (27), 171 (10), 170
15), 127 (19), 115 (13).
2
(
General Method for Coupling of Grignard Reagents with Oxazolines
The Grignard reagent was generated from the bromo compound
(25.4 mmol) and magnesium (25.5 matom) in anhydrous thf (40 ml)
2
4 h. The cooled mixture was filtered and the acetonitrile was removed
under argon. The reaction was completed by heating the solution under
reflux for 3 h. The cooled Grignard reagent was then added dropwise at
room temperature to a stirred solution of the oxazoline (15 mmol) in thf
under reduced pressure. The crude product was isolated by extraction
with ether and was purified by flash chromatography with 10–30%
ethyl acetate/light petroleum as eluent. The oxazoline (4) (7.7 g, 60%)
(40 ml) under argon and the solution was stirred for 18 h and then
+
•
was obtained as a viscous oil (Found: C, 75.3, H, 6.9; N, 5.0%; M ,
poured into saturated aqueous ammonium chloride. The crude product
was isolated by extraction with ethyl acetate and purified by flash
chromatography with ethyl acetate/light petroleum as eluent.
2
69.1407. C1 H19NO2 requires C, 75.8; H, 7.1; N, 5.2%.
7
1
2
1
14 16
+•
23
C17 H19
N
O requires M , 269.1416). [α]
–40.0º (c, 3.4). δH
2
D
1.05 and 1.11, each d, J 6.8 Hz, CH(CH ) ; 1.98, m, HCMe ; 3.88, s,
3
2
2
OMe; 4.21, dd, J5,5 = J5,4 = 8.1 Hz, CHH5; 4.29, ddd, J 6.8, J4,5 8.1,
J4,5 9.6 Hz, H4; 4.49, dd, J5,5 8.1, J5,4 9.6 Hz, CHH5; 7.20, d, J3,4 9.1
Hz, H3; 7.33, m, H6 or 7; 7.48, m, H7 or 6; 7.74, d, J 8.2 Hz, H5 or 8;
General Method for Methylation of Oxazolines
Iodomethane (1.6 ml, 25 mmol), the oxazoline (10 mmol) and
nitromethane (40 ml) were stirred together at 50° (bath) for 24 h,
whereupon the solvents were removed under reduced pressure. The
residue was dissolved in dichloromethane and washed with aqueous
sodium thiosulfate solution. The usual work-up gave the crude
oxazoline.
7
1
1
1
.83, d, J4,3 9.1 Hz, H4; 7.89, dd, J 0.7, J 8.5 Hz, H8 or 5. δC 18.13 and
8.59, each Me; 32.44, HCMe ; 56.33, OMe; 69.71, C5; 72.77, C4;
2
12.28, CAr; 112.69, 123.59, 123.79, 127.05 and 127.67, each CHAr;
28.23, CAr; 131.39, CHAr; 132.29, CAr; 155.43, ArC2; 161.05, C2.
+
m/z 269 (M , 59%), 227 (58), 226 (100), 198 (30), 185 (22), 184 (12),
1
83 (32), 182 (22), 171 (48), 169 (14), 141 (11), 140 (20), 127 (12), 114
General Method for Conversion of N-Methyloxazolinium Iodides into
(15).
2
,2´-Binaphthalene-1-carbaldehydes
The methiodide (5 mmol) was dissolved in thf/methanol (4 : 1 v/v,
5 ml) and stirred under argon and cooled to 0°. A solution of sodium
1
-Bromo-2,3-dimethoxynaphthalene
2
A solution of N-bromosuccinimide (15.0 g, 84 mmol) in anhydrous
dimethylformamide (100 ml) was added dropwise to a stirred solution
of 2,3-dimethoxynaphthalene (16.0 g, 85 mmol) in anhydrous
dimethylformamide (100 ml) at room temperature, and the solution was
stirred for a further 24 h. The mixture was poured into saturated brine
borohydride (12.5 mmol) in thf/methanol (4 : 1 v/v, 15 ml) was added
dropwise and stirring was continued at 0° for 2 h. Saturated aqueous
ammonium chloride and ether were added and the mixture was worked
up in the usual way. A solution of the crude product in thf/water (4 : 1
v/v, 15 ml) was stirred and treated with oxalic acid dihydrate (6.5 mmol)
during 3 h. The usual work-up gave the crude product, which was
purified by flash chromatography over silica gel with ethyl acetate/light
petroleum as eluent.
(500 ml) and extracted with dichloromethane. The crude product was
chromatographed over a short column of silica gel with 5% ethyl
acetate/light petroleum as eluent. The bromo compound crystallized
from light petroleum as prisms (17.3 g, 77%), m.p. 46–48° (Found:
M , 265.9931. C12 H11 Br O requires M , 265.9942). δ 3.98,
s, 2 × OMe; 7.14, s, H4; 7.42–7.47, m, H6,7; 7.68–7.77, m, H5; 8.15–
8
1
1
+
•
12
1
79 16
+•
2
H
General Method for Conversion of 2,2´-Binaphthalene-1-carbal-
dehydes into 2,2´-Binaphthalene-1-methanols
.17, m, H8. δ 55.76, 3-OMe; 60.61, 2-OMe; 106.77, C4; 116.23, C1;
C
A solution of sodium borohydride (3 mmol) in aqueous sodium
hydroxide (5%, 10 ml) was added at 0° to a stirred solution of the
aldehyde (2 mmol) in thf (10 ml). The solution was stirred at room
25.01, 125.91, 126.52, 126.64, C5,6,7,8; 127.68 and 131.41, C4a,8a;
+
+
47.02, 152.28, C2,3. m/z 268 (M , 97%), 267 (13), 266 (M , 100), 253
(11), 251 (11), 225 (25), 223 (28), 210 (11), 208 (12), 182 (13), 180

9
32
R. W. Baker et al.
temperature for 2 h and then diluted with water and extracted with ether.
The crude product was purified by radial chromatography with ethyl
acetate/light petroleum as eluent.
light petroleum as needles of the oxazoline, m.p. 113–115° (Found: C,
+
•
79.3; H, 6.4; N, 3.1%. M , 425.1985. C28H27NO requires C, 79.0;
3
H, 6.4; N, 3.3%. 12C28 H27
–
1
14 16
N O requires M , 425.1991). [α]
+•
29
3
D
93.5° (c, 2.5). λmax 234.5, 322, 333.5 nm (log ε 5.09, 3.91, 3.94). C.d.
General Method for Conversion of 2,2´-Binaphthalene-1-methanols
into 1-Methyl-2,2´-binaphthalenes
λ
(
nm/∆ε 205.5 (+6), 223 (+15), 240 (–23), 280 (+5), 302 (–9), 336.5
max
+
+3). λmin nm/∆ε 214.5 (+4.5). m/z 395 (M , 30%), 394 (100), 326 (20),
2
93 (10), 149 (38).
A solution of methanesulfonyl chloride (3.5 mmol) in anhydrous
dichloromethane (4 ml) was added dropwise under argon to a stirred
solution of the alcohol (0.5 mmol) and triethylamine (5 drops) in
dichloromethane (4 ml). The solution was diluted with dichloro-
methane and washed in turn with dilute sodium hydroxide, dilute
hydrochloric acid, water and saturated brine. The crude product was
dissolved in anhydrous thf (4 ml) and added to lithium aluminium
hydride (1.3 mmol) in thf (4 ml) at 0°. The solution was stirred at room
temperature for 18 h and then diluted with ethyl acetate and treated with
dilute hydrochloric acid. The usual work-up gave the crude product,
which was purified by radial chromatography with ethyl acetate/light
petroleum as eluent.
The major (S)-diastereometer (13) had δH 0.74 and 0.78, each d, J
6
.7 Hz, CH(CH ) ; 1.46, m, CHMe ; 3.72, dd, J 8.3, 8.3 Hz, CHH5,
3 2 2
3.73 and 3.87 each, s, OMe; 3.92, ddd, J 6.7, 8.3, 9.7 Hz, H4; 4.21, dd,
J 8.3, 9.7, CHH5; 7.38, s, H4; 7.46–7.49, ArH; 7.49, d, J3´,4´ 8.4 Hz,
H3´; 7.52–7.57, m, 3 × ArH; 7.68, d, J4´,3´ 8.4 Hz, H4´; 7.86, dd, J 0.7,
8
.1 Hz, H5 or 8; 7.92, m, H5´ or 8´; 8.07, br d, J 8.1 Hz, H8 or 5; 8.29,
m, H8´ or 5´. δC 18.49 and 18.89, each Me; 32.49, CHMe ; 55.74,
2
3
-OMe; 61.20, 1´-OMe; 70.24, C5; 73.20, C4; 107.28, ArC4; 122.33
and 122.53, each CHAr; 124.37, CAr; 124.49, 125.40, 125.44, 125.90,
26.56 and 126.66, each CHAr; 126.84, CAr; 127.70, CHAr; 127.83
1
and 128.54, each CAr; 129.61, CHAr; 130.24, 134.09 and 134.59, each
CAr; 153.91 and 155.07, each COMe; 161.92, C2.
(
4S)-4-Isopropyl-2-(3-methoxy-2,2´-binaphthalen-1-yl)-4,5-
The n.m.r. spectrum of minor (R)-diastereomer included δH 0.67
dihydrooxazole (11)
and 0.69, each d, J 6.7 Hz, CH(CH ) ; 1.40, m, CHMe ; 3.79, s, OMe;
3 2 2
3
7
.82, dd, J 8.3, 8.3 Hz; CHH5; 3.87, s, OMe; 4.15, dd, J 8.3, 9.7, CHH5;
.37, s, H4, 7.44, d, J3´,4´ 8.4, H3´; 7.67, d, J4´,3´ 8.4 Hz; 8.02, br d, J 8.3
This was prepared from 2-bromonaphthalene and the oxazoline (5).
Flash chromatography of the crude product over silica gel with 5–25%
ethyl acetate/light petroleum as eluent gave the binaphthalene (11)
Hz, ArH. δ 18.26 and 18.47, each Me, 32.31, CHMe ; 55.77, 3-OMe;
6
122.57, each CHAr; 124.38, CAr; 124.49, 125.24, 125.47, 125.90,
126.56 and 126.66; each CHAr; 126.84. CAr; 127.64, CHAr; 127.83
and 128.63, each CAr; 129.00 CHAr; 130.40, 134.09 and 134.61, each
CAr; 154.09 and 155.13, each COMe; 161.89, C2.
C
2
1.11, 1´-OMe; 69.97, C5; 73.00, C4; 107.13, ArC4; 122.44 and
(
95%) as 1 : 1 mixture of diastereomers, which crystallized from ethyl
+
•
acetate/light petroleum as prisms, m.p. 143–145º (Found: M ,
3
1
2
1
14 16
+•
32
95.1881. C27
H
N
O requires M , 395.1885). [α]
–20.9°
25
2
D
+
(c, 5.6). m/z 395 (M , 78%), 394 (100), 352 (33), 295 (19), 252 (12). δ
(
H
2
( H )toluene, 233 K) 0.49, 0.54, 0.72 and 0.89, each d, J 6.7 Hz,
8
CH(CH ) ; 1.25 and 1.35, each m, CHMe ; 3.15, br m, oxazoline H;
3
2
2
(
4
4S)-4-Isopropyl-2-(1´,3-dimethoxy-2,2´-binaphthalen-1-yl)-3-methyl-
,5-dihydrooxazolium Iodide
3.17 and 3.18, each s, OMe; 3.38, m, oxazoline H; 3.51–3.63, m,
4 × oxazoline H; 6.927 and 6.933, each s, ArH; 7.24–7.28, m, 4 × ArH;
7.36–7.40, m, 4 × ArH; 7.60–7.69, m, 8 × ArH; 7.73–7.77, m, 2 × ArH;
7.97 and 8.02, each s, ArH; 8.39–8.41, m, ArH; 8.47, br d, J 7.6 Hz,
The foregoing mixture of oxazolines was methylated at 50º for 28 h,
which gave the crude methiode as a solid (95%). Fractional
crystallization of the mixture from acetone/dichloromethane gave the
major (R)-diastereomer (14) as clusters of needles, m.p. 172–174°
ArH. δ (300 K) 18.52, 2 × Me; 32.39, CHMe ; 55.73, OMe; 70.26, C5;
C
2
7
3.14, C4; 107.37, 124.67, 125.31, 125.76, 125.82, 126.63 and 126.72,
+
•
12
1
127 14 16
+•
(Found: M , 567.1289.
C29 H30
I N O3 requires M ,
each CHAr; 126.73, 2 × CAr; 126.87, CAr; 127.57, 128.02, 128.50 and
5
3
67.1270). [α]D26 +85.2° (c, 2.2). λmax 227, 338.5 nm (log ε 4.98,
.85). C.d. λmax nm/∆ε 215.5 (–67), 229 (+55). m/z 567 (M , 57%), 441
1
1
28.74, each CHAr, 132.60, 132.84, 133.97, and 134.08, each CAr;
54.80, C3; 162.20, C2. One CHAr was not located.
+
(
(
17), 440 (52), 342 (25), 341 (100), 340 (46), 327 (13), 326 (52), 311
18), 310 (28), 255 (12), 239 (11), 226 (12), 128 (23), 127 (24). δH 0.04
(4S)-Isopropyl-2-(1´-methoxy-2,2´-binaphthalen-1-yl)-4,5-dihydro-
and 0.66, each d, J 6.6 Hz, CH(CH ) ; 2.11, m, CHMe ; 3.32, s, Me;
3
oxazole (12)
3 2
2
.63 and 3.88, each s, OMe; 4.01, br m, H4; 5.33 and 5.85, each br m,
This was prepared as a 1 : 1 mixture of diastereomers from 2-bromo-1-
methoxynaphthalene (6) and the oxazoline (4). Flash chromatography
of the crude product over silica gel with 5–20% ethyl acetate/light
petroleum as eluent gave the binaphthalene (12) (91%) as a gum which
H C5; 7.21, br d, J 8.4 Hz, ArH; 7.26–760, m, 4 × ArH; 7.66–7.69, m,
2
2
× ArH; 7.87–7.93, m, 2 × ArH; 8.00–8.01, br m, ArH, 8.27, br m,
ArH. δ 13.23 and 17.67, each Me; 25.81, CHMe ; 34.21, 3-Me; 56.01,
C
2
3
-OMe; 61.69, 1´-OMe; 68.37, C4; 72.84, C5, 111.07, CHAr, 119.20,
+•
slowly decomposed on standing (Found: M +1, 396.1949.
CAr; 122.08, CHAr; 122.59 and 123.50, CAr; 124.06, 124.82, 126.55,
127.11 and 127.36, CHAr; 127.64, CAr; 127.75, 127.98, 128.09 and
128.29, CHAr; 130.73, 133.78 and 134.98, each CAr, 153.35 and
154.23, COMe; 173.12, C2.
1
2
C271H26
14 16
+•
20
N
O requires M +1, 396.1964). [α]
–38.3º (c, 0.76).
2
D
2
δH (( H )methanol, 223 K) 0.51, 0.67, 0.717 and 0.722, each d, J 6.5
4
Hz, CH(CH ) ; 1.43 and 1.51, each m, HCMe ; 3.43 and 3.51, each s,
3
2
2
OMe; 3.80–3.95, 4.02, 4.22 and 4.39, each m, oxazoline H; 7.43, d, J
.4 Hz, ArH; 7.50, d, J 8.4 Hz, ArH; 7.52–7.63, m, 10 × ArH; 7.65, d,
The n.m.r. spectrum of the minor (S)-diastereomer included δH
8
–
0.10 and 0.45, each d, J 6.9 Hz, CH(CH ) ; 1.84, m, CHMe ; 3.01, s,
3 2 2
J 8.5 Hz, ArH; 6.90, d, J 5.0 Hz, ArH; 7.88–7.91, m, 2 × ArH; 7.96, d,
J 7.8 Hz, 2 × ArH; 7.99, d, J 8.5 Hz, ArH; 8.02, d, J 8.5 Hz, ArH; 8.09,
d, J 8.2 Hz, ArH; 8.12, d, J 8.3 Hz, ArH; 8.15–8.17, m, ArH; 8.18–8.21,
Me, 3.48 and 3.93, each s, OMe; 4.59, m, H4; 5.51, m, HHC5; 5.67, dd,
J 9.5, 10.8 Hz, HHC5.
m, ArH. δC (300 K) 18.68 and 19.06, each Me; 32.67, HCMe ; 61.33,
(+)-(R)-1´,3-Dimethoxy-2,2´-binaphthalene-1-carbaldehyde (15)
2
OMe; 70.32, C5; 73.36, C4; 122.50, 122.83, 125.51 and 125.90, each
ArH; 126.03, CAr; 126.22, 2 × CHAr; 127.00, 127.70 and 128.01, each
CHAr; 128.33, CAr; 128.58 and 128.86, each CHAr; 129.16, CAr;
Reduction of the (R)-diastereomer (14) at 0° and work-up at 5º gave a
crude product which was rapidly purified by radial chromatography
over silica gel with 1–10% ethyl acetate/light petroleum as eluent. The
aldehyde (15) was obtained as a solid (50%), a portion of which
crystallized from acetone as prisms, m.p. 154–156° (Found: C, 80.8; H,
1
29.41, CHAr; 131.66, 132.48, 134.45 and 137.13, each CAr; 153.29,
C1´; 162.63, C2.
+
•
5
.1%. M , 342.1253.
C
23H18O3 requires C, 80.7; H, 5.3%.
(4S)-4-Isopropyl-2-(1´,3-dimethoxy-2,2´-binaphthalen-1-yl)-4,5-
12
C231H
+
16
+•
25
O requires M , 342.1256). [α]
+182.7° (c, 2.0). m/z
18
3
D
dihydrooxazole
3
42 (M , 35%), 312 (27), 311 (100), 296 (11), 268 (22), 239 (12), 113
This was prepared as a diastereomeric mixture from the oxazoline (5)
and 2-bromo-1-methoxynaphthalene (6) and it was obtained by flash
chromatography with 5–10% ethyl acetate/light petroleum as eluent as
a solid (91%, 56.8% d.e.) which crystallized from dichloromethane/
(10). δH 3.57 and 3.91, each s, OMe; 7.37, d, J3´,4´ 8.4 Hz, H3´; 7.53, s,
H4, 7.56–7.60, m, H6,6´,7,7´; 7.72, d, J4´,3´ 8.4 Hz, H4; 7.86–7.88,
7.92–7.94 and 8.22–8.24, each 1 × ArH; 9.19–9.21, m, H8; 10.11, s,
CHO. δC 55.92, 3-OMe; 61.09, 1´-OMe; 111.72, CHAr; 122.13, CAr;

Atropisomerism of 2,2´-Binaphthalenes
933
1
1
1
1
22.60 and 123.24, each CHAr; 125.72, CAr; 125.80, 126.32, 126.58,
26.77, 126.89 and 127.19, each CHAr; 127.81, CAr; 127.96 and
29.15, each CHAr, 130.24, 134.41, 134.94 and 137.05, each CAr;
54.28 and 154.63, each COMe; 194.50, CHO.
(18) (55%) which was purified by radial chromatography with 1–10%
ethyl acetate/light petroleum as eluent and which crystallized from
+
•
ethyl acetate as prisms, m.p. 190–192° (Found: M , 326.1296.
1
2
1
16
+•
25
C23 H18 O requires M , 326.1307). [α]
–29.5° (c, 2.0). λmax
2
D
2
29.5, 269, 354 nm (log ε 5.19, 4.56, 4.04). C.d. λ nm/∆ε 218
max
(+)-(R)-1,3´-Dimethoxy-2,2´-binaphthalene-1-methanol (16)
+
(
+12.5), 231 (–13.5). m/z 326 (M , 94%), 312 (23), 311 (100), 268 (26),
267 (14), 266 (11), 265 (27), 253 (11), 252 (21), 239 (17), 154 (14), 149
18), 134 (13), 126 (20), 119 (14). δH 2.45, s, Me; 3.87, s, OMe; 7.34,
Reduction of the foregoing aldehyde (15), [α]D28 +170.2° (c, 2.0),
gave, after radial chromatography of the crude product over silica gel
with 2–20% ethyl acetate/light petroleum as eluent, the alcohol (16)
(
d, J 8.4 Hz, H3´; 7.51, s, H4; 7.57–7.64, m, H6,6´,7,7´; 7.82, d, J4´,3´ 8.4
Hz, H4´; 7.85–7.87, m, ArH; 7.94, br d, J 8.0 Hz, ArH; 8.13, br d, J 8.6
Hz, ArH; 9.19–9.21, m, ArH; 10.01, s, CHO. δC 16.26, Me; 55.88,
OMe; 111.70 and 124.33, each CHAr; 125.68, CAr; 125.69, 125.77,
(92%, 91.7% e.e) as a solid, which precipitated from ethyl acetate/light
+
•
petroleum in amorphous form, m.p. 133–135° (Found: M , 344.1407.
1
2
1
16
+•
25
C23 H20 O requires M , 344.1412). [α]
+71.0° (c, 2.1). λmax
34.5, 320.5, 332 nm (log ε 5.03, 3.62, 3.65). C.d. λmax nm/∆ε 205.5
–22), 221 (–57), 237 (+45), 276 (–6), 295.5 (+17). λ nm/∆ε 211
3
D
125.97, 126.46, 126.67, 126.93, 127.13, 128.37 and 128.64, each
2
CHAr; 130.40, 130.58, 132.46, 133.17, 133.40, 134.28 and 141.21,
each CAr; 154.59, COMe; 194.40, CHO.
(
(
(
(
(
(
min
+
–21). m/z 344 (M , 81%), 328 (13), 313 (29), 312 (100), 311 (52), 298
11), 297 (21), 269 (35), 295 (17), 284 (11), 282 (17), 281 (57), 269
20), 268 (31), 255 (14), 253 (22), 252 (31), 241 (10), 240 (11), 239
32), 226 (14), 159 (10), 158 (79), 156 (13), 149 (19), 148 (15), 134
23), 126 (22), 120 (13), 119 (23), 113 (13). δH 3.54 and 3.88, each s,
(–)-(S)-3-Methoxy-1´-methyl-2,2´-binaphthalene-1-methanol (19)
The foregoing aldehyde (18) was reduced to the alcohol (19) (87%,
57.7% e.e) which was purified by radial chromatography with 5–30%
ethyl acetate/light petroleum as eluent and which crystallized from
dichloromethane/light petroleum as prisms, m.p. 163–166° (Found:
OMe, 4.49 and 5.00, each d, J 12.1 Hz, CH OH; 7.31, s, H4; 7.35, d,
2
J3´,4´ 8.4 Hz, H3´; 7.50–7.53, m, H7; 7.54–7.59, m, H6,6´,7´; 7.73, d,
J4´,3´ 8.4 Hz, H4´; 7.86–7.88, m, H5; 7.93–7.95, m, H5´; 8.22–8.24, m,
+
•
12
1
16
+•
20
M , 328.1460. C23 H20 O requires M , 328.1463). [α]
–29.2°
2
D
H8´; 8.33, br d, J 8.2 Hz, H8. δC 55.57, 3-OMe; 60.39, CH ; 61.33,
(c, 2.0). λmax 234.5, 317, 331 nm (log ε 5.39, 3.89, 3.97). C.d. λmax/∆ε
222.5 (+44), 238 (–44.5). m/z 328 (M , 80), 311 (100), 309 (16), 295
2
+
1
1
´-OMe; 106.01, 122.33, 123.61, 124.54 and 124.91, each CHAr;
25.90, CAr; 126.18, 126.45, 126.57 and 127.11, each CHAr; 127.74,
(29), 281 (12), 279 (27), 278 (17), 267 (16), 266 (13), 265 (30), 253
CAr; 127.91, CHAr; 127.96 and 128.07, each CAr; 129.62, CHAr;
(19), 252 (38), 239 (12), 148 (14), 133 (18), 126 (19), 120 (15). δH 2.42,
1
34.50, 134.70 and 136.63, each CAr; 153.30 and 155.09, each COMe.
The e.e. was estimated by H n.m.r. spectroscopy in CDCl3 in
s, Me; 3.83, s, OMe; 4.72 and 4.86, each d, J 11.7 Hz, CH OH; 7.28, s,
2
1
H4; 7.31, d, J3´,4´ 8.3 Hz, H3´; 7.50, m, ArH; 7.54–7.63, m, 3 × ArH;
7.81, d, J4´,3´ 8.3 Hz, H4´; 7.88, br d, J 8.1 Hz, ArH; 7.94, br d, J 8.5 Hz,
presence of 1.24 mol equiv. of (+)-(S)-1-(anthracen-9-yl)-
,2,2-trifluoroethanol. The major enantiomer had δH 3.47 and 3.87,
each s, OMe; 4.43 and 4.94, each d, J 12.2 Hz, CH OH; 7.30, s, H4,
2
ArH; 8.14, br d, J 8.1 Hz, ArH; 8.26, br d, J 8.1 Hz, ArH. δ 15.97, Me;
C
55.60, OMe, 59.52, CH ; 105.88, 124.35, 124.42, 124.56, 125.49,
2
2
7
.32, d, J3´,4´ 8.4 Hz, H3´; 7.40–7.59, m, 4 × ArH; 7.71, d, J4´,3´ 8.4 Hz,
H4´; 7.86, dd, J 8.6, 8.1 Hz, H5; 7.92–7.95, m, H5´; 8.12–8.21, m, H8´;
.24, d, J 8.4 Hz, H8. The n.m.r. spectrum of minor enantiomer included
δH 3.52 and 3.87, each s, OMe.
125.81, 126.07, 126.32, 127.27, 128.12 and 128.57, each CHAr;
127.56, CAr; 132.66, 2 × CAr; 132.97, 133.12, 133.40, 134.56 and
8
135.08, each CAr; 155.21, COMe.
1
The e.e. was estimated by H n.m.r. spectroscopy in CDCl in the
3
presence of 0.36 mol equiv. of europium(III) tris[3-(hepta-
fluoropropylhydroxymethylene)-(+)-camphorate]. The major enan-
tiomer had δH 3.14, s, Me; 4.20, s, OMe; 7.46–7.60, m, 3 × ArH; 7.67–
(
4S)-4-Isopropyl-2-(3-methoxy-1´-methyl-2,2´-binaphthalen-1-yl)-4,5-
dihydrooxazole
7
8
9
.70, m, ArH; 7.85, s, H4; 7.92, d, J 8.2 Hz, ArH; 8.04, d, J 8.4 Hz, ArH;
This was prepared as a mixture of diastereomers from the oxazoline (5)
and 2-bromo-1-methylnaphthalene (7) and it was purified by flash
chromatography over silica gel with 1–20% ethyl acetate/light
petroleum as eluent. The oxazoline was obtained as a solid (92%, 73.3%
d.e.) which precipitated from acetone/light petroleum in amorphous
.23, d, J 7.8 Hz, m, ArH; 8.29, d, J 8.6 Hz, ArH; 8.71, d, J 7.9 Hz, ArH;
.03–9.16, br m, CH OH; 10.68, br s, ArH. The n.m.r. spectrum of the
2
minor enantiomer included δH 4.19, s, OMe; 8.54, d, J 8.0 Hz, ArH;
0.88, br s, ArH.
1
+
•
12
1
14 16
form, m.p. 122–125° (Found: M , 409.2045. C28 H27
N
O2
–44.6° (c, 4.3) λmax 233.5, 319, 332 nm
log ε 5.08, 3.69, 3.78). C.d. λmax/∆ε 205.5 (+4), 222 (+15), 236.5
+
33
(–)-(S)-1,1´-Dimethyl-3-methoxy-2,2´-binaphthalene (20)
requires M , 409.2042). [α]
D
(
(
(
(
This was prepared from the foregoing alcohol and was purified by
radial chromatography with 1–5% ethyl acetate/light petroleum as
eluent. The binaphthalene (20) (85%) was obtained as a solid which
–18), 269.5 (+1), 280.5 (+2), 302 (–5). λ
nm/∆ε 210 (+3), 273
min
+
+0.8). m/z 409 (M , 36%), 395 (11), 394 (37), 297 (24), 296 (100), 265
13), 253 (11), 158 (15), 149 (17), 114 (28).
+•
crystallized from acetone as prisms, m.p. 168–170° (Found: M ,
1
16
+•
28
The major (S)-diastereomer (17) had δH 0.65 and 0.73, each d, J 6.7
312.1504. 12C23 H20 O requires M , 312.1514). [α]D –46.4° (c,
Hz, HC (CH ) ; 1.38, m, CHMe ; 2.43, s, Me; 3.56, dd, J 8.5, 8.5 Hz,
CHH5; 3.83, s, OMe; 3.86, ddd, J 6.7, 8.5, 9.7 Hz, H4; 4.05, dd, J 8.5, 9.7
Hz, CHH5; 7.33, br s, H4; 7.40, d, J3´,4´8.4 Hz, H3´; 7.43, m, ArH; 7.49–
2.7). λmax 236, 281, 317, 331 nm (log ε 5.01, 4.12, 3.34, 3.40). C.d.
λmax nm/∆ε 222 (+58.5), 237 (–42), 296 (–9.5). m/z 312 (M , 100), 297
3
2
2
+
(31), 282 (22), 281 (19), 266 (16), 265 (25), 253 (12), 252 (15), 149
(17), 141 (16), 132 (11), 126 (20). δH 2.36 and 2.41, each s, Me; 3.82,
s, OMe; 7.17, s, H4; 7.29, d, J 8.3 Hz, ArH; 7.44–7.61, m, 4 × ArH;
7.81, d, J 8.3 Hz, ArH; 7.85, d, J 8.0 Hz, ArH; 7.93, d, J 8.0 Hz, ArH;
7
.57,m,3×ArH;7.73,d,J4´,3´8.4Hz,H4´;7.83,brd,J8.2Hz,ArH;7.88,
br d, J 8.0 Hz, ArH, 7.96, br d, J 8.4 Hz, ArH; 8.10, br d, J 8.5 Hz, ArH. δC
6.08, 18.29 and 18.82, each Me; 32.23, CHMe ; 55.63, OMe; 69.98,
1
2
C5; 72.93, C4; 106.99, 124.32, 124.60 and 124.97, each CHAr; 125.21,
× CHAr; 125.56, 126.55 and 126.69, each CHAr; 126.76 and 128.24,
each CAr; 128.37 and 128.59, each CHAr; 132.45, 132.89, 132.98,
8.04, d, J 8.3 Hz, ArH; 8.14, d, J 8.4 Hz, ArH. δ 15.57 and 15.96, each
C
2
Me; 55.48, OMe; 103.52 and 123.66, each CHAr; 124.41, 2 × CHAr;
125.25, 125.67, 125.79, 125.99 and 127.20, each CHAr; 128.36, CAr;
128.50 and 128.54, each CHAr; 132.09, 132.43, 132.80, 132.86,
133.74, 134.04 and 134.86, each CAr; 155.66, COMe.
1
33.24, 133.34 and 133.99, each CAr; 154.92, COMe; 162.12, C2.
The minor (R)-diastereomer had δH 0.56 and 0.57, each d, J 6.7 Hz,
CH(CH ) ; 1.16, m, CHMe ; 2.45, s, Me; 3.64, dd, J 8.5, 8.5 Hz,
3
2
2
1
3
(–)-(S)-3-Methoxy-1´-methyl-2,2´-binaphthalene-1-carbonitrile (21)
CHH5; 3.84, s, OMe. The C n.m.r. spectrum included δ 16.10, 18.22
and 18.45, each Me, 32.30, CHMe ; 55.63, OMe, 70.05, C5; 72.85, C4;
C
2
Hydroxylamine hydrochloride (180 mg, 2.6 mmol) and the aldehyde
107.15, 124.94, 125.59, 128.07 and 128.28, each CHAr; 128.33, 133.00
(18) (600 mg, 1.84 mmol) in pyridine (4.5 ml) and water (0.5 ml) were
and 133.93, each CAr; 154.90, COMe; 162.06, C2.
stirred at room temperature for 1.5 h and then copper(II) sulfate
pentahydrate (150 mg, 0.6 mmol) was added. The mixture was
sequentially treated with solutions of triethylamine (0.6 ml, 4.3 mmol)
in dichloromethane (1 ml) and dicyclohexylcarbodiimide (510 mg,
2.5 mmol) in dichloromethane (3 ml) and the whole was stirred for
(–)-(S)-3-Methoxy-1´-methyl-2,2´-binaphthalene-1-carbaldehyde (18)
The foregoing mixture of diastereomers was converted into the
methiodide (96%) and a portion of this was reduced to the aldehyde

9
1
34
R. W. Baker et al.
7 h. Formic acid (5 drops) was added and the dicyclohexylurea was
125.41, 125.49, 125.71, 125.88, 126.68; 126.74; 127.81 and 128.49,
each CHAr; 129.98, 132.43, 132.55, 132.75, 132.96, 134.17 and
136.34, each CAr; 154.87, COMe; 168.91, CO. One CAr was not
located.
separated by filtration. The filtrate was diluted with dichloromethane
and washed in turn with dilute hydrochloric acid, saturated aqueous
sodium hydrogen carbonate, water and saturated brine. Radial
chromatography of the crude product with 10–50% ethyl acetate/light
petroleum as eluent gave the nitrile (21) as a solid (570 mg, 96%) which
crystallized from acetone as prisms, m.p. 210–212° (Found: C, 85.7; H,
(
4S)-4-Isopropyl-2-(3-methoxy-1´,4´-dimethyl-2,2´-binaphthalen-1-
yl)-4,5-dihydroxazole
+
•
5
4
2
.2; N, 4.1%. M , 323.1299. C 3H NO requires C, 85.4; H, 5.3; N,
2
17
+•
O requires M , 323.1310). [α]D
This diastereomeric mixture of oxazolines was prepared from 2-bromo-
1,4-dimethylnaphthalene (9) and the oxazoline (5) and was obtained by
1
2
1
14 16
20
.3%. C23 H17
N
–67.6° (c,
.0). λmax 228, 251, 346 nm (log ε 4.86, 4.65, 3.94). C.d. λmax/∆ε 202
flash chromatography with 5–30% ethyl acetate/light petroleum as
(+14.5), 216.5 (+27.5), 233 (–19), 246.5 (–14.5), 285.5 (+4). λmin/∆ε
+•
eluent as
a
gum (96%, 56.6% d.e.) (Found: M , 423.2194.
+
2
09 (+10.5), 239 (–11). m/z 323 (M ,100), 322 (39), 307 (11), 293 (20),
12
C291H
14
N16O2 requires M , 423.2198). [α]D –20.6° (c, 2.0).
+•
31
29
292 (10), 291 (11) 290 (13), 280 (10), 146 (13). δH 2.51, s, Me; 3.88, s,
λmax 238.5, 277, 316.5, 322 nm (log ε 5.02, 4.17, 3.75, 3.76). λinfl 226
OMe; 7.38, d, J3´,4´ 8.4 Hz, H3´; 7.49, s, H4; 7.55–7.64, m, H6,6´7,7´;
.86, d, J4´,3´ 8.4 Hz, H4´; 7.91, br d, J 8.3 Hz, ArH; 7.93, br d, J 8.6 Hz,
nm (log ε 4.91). C.d. λmax/∆ε 224.5 (+32), 241 (–26), 282.5 (+4), 302.5
7
+
(–7). λinfl
/∆ε 210 (+11). m/z 423 (M , 24%), 409 (12), 408 (37), 311
ArH; 8.15, d, J 8.4 Hz, ArH; 8.26, br d, J 8.0 Hz, ArH. δC 16.03, Me,
(25), 310 (100), 295 (14), 252 (11), 114 (24).
5
1
5.94, OMe; 110.52, C4; 112.08, C1; 116.39, CN; 124.55, 125.55,
26.01, 126.19, 126.22, 126.25, 127.14, 127.25 and 127.75, each
The (S)-diastereomer (24) had δH 0.65 and 0.74, each d, J 6.8 Hz,
CH(CH ) ; 1.30, m, CHMe ; 2.42 and 2.68, each s, Me; 3.49, dd, J 8.4,
.4 Hz, CHH5; 3.84, s, OMe; 3.91, ddd, J 6.8, 8.4, 9.7 Hz, H4; 4.09,
dd, J 8.4, 9.7 Hz, CHH5; 7.28 and 7.33, each s, ArH; 7.42–7.45 and
3
2
2
CHAr; 127.89, CAr; 128.63, CHAr; 131.40, 132.67, 133.08, 133.50,
33.62 and 139.70, each CAr; 154.83, COMe.
8
1
7
.50–7.53, each m, ArH; 7.56–7.58, m, 2 × ArH; 7.83, dd, J 0.5, 8.2 Hz,
(
–)-(S,1S)-N-[2-Hydroxy-1-(isopropyl)ethyl]-3-methoxy-1´,N-
ArH; 7.97, dd, J 8.3 Hz, ArH; 8.04–8.06 and 8.12–8.14, each m, ArH.
δC 16.03 and 18.39, CH(CH ) ; 18.78 and 19.22, each MeAr; 32.37,
CHMe ; 55.70, OMe; 70.10, C5; 73.04, C4; 107.09, 124.51, 124.59,
dimethyl-2,2´-binaphthalene-1-carboxamide (22)
3 2
The foregoing methiodides (2.0 g, 3.6 mmol) and potassium hydroxide
2
(
2.0 g, 35.6 mmol) were stirred and heated at 60° (bath) in methanol/
124.89 and 125.03, each CHAr; 125.21, 2 × CHAr; 126.52 and 126.69,
each CHAr; 126.84, CAr; 129.28, CHAr; 130.77, 131.09, 132.25,
132.55, 132.59, 133.34 and 133.99, each CAr; 154.97, COMe; 162.12,
C2. One CAr was not located.
thf/water (1 : 4 : 1 v/v, 30 ml). The cooled mixture was acidified with
dilute hydrochloric acid and extracted with ethyl acetate and the crude
product was subjected to radial chromatography with 5–50% ethyl
acetate/light petroleum as eluent. A mixture of diastereomeric amides
The n.m.r. spectra of the (R)-diastereomer included δH 0.56 and
(S : R, 2.1 : 1) (428 mg, 27%) was eluted first and this was followed
0.58, each d, J 6.8 Hz, CH(CH ) ; 1.18, m, CHMe ; 2.44 and 2.70, each
3 2 2
by the (S,1S)-diastereomer (22) (554 mg, 35%) which crystallized from
acetone/chloroform/light petroleum as plates, m.p. 184–186° (Found:
s, Me; 3.66, dd, J 8.4, 8.4 Hz, CHH5; 3.85, s, OMe; 4.06, dd, J 8.4, 9.7
Hz, CHH5. δC 16.08 and 18.26, CH(CH ) ; 18.46 and 19.19, each
3 2
+
•
C, 78.4; H, 7.5; N, 2.9%. M , 441.2316. C29H31NO requires C, 78.9;
MeAr; 55.70, OMe; 70.13, C5; 72.97, C4; 106.97, 124.39, 124.56,
125.17, 125.23 and 128.74, each CHAr.
3
1
2
1
14 16
+•
32
H, 7.1; N, 3.1%. C29 H31
N O requires M , 441.2304). [α]
3
D
–
2
2
79.9° (c, 2.3). λmax 234.5, 319, 333.5 nm (log ε 4.91, 3.52, 3.59). λinfl
21, 247 nm (log ε 4.60, 4.63). C.d. λmax nm/∆ε 203 (+50), 222 (+22),
(
–)-(S)-3-Methoxy-1´,4´-dimethyl-2,2´-binaphthalene-1-carbaldehyde
(25)
38.5 (–46), 275.5 (+12), 298.5 (–24.5), 312 (+6.5). λ
nm/∆ε 217
min
+
(
(
+3). m/z 441 (M , 12%), 356 (14), 325 (100), 324 (23), 310 (18), 265
11), 252 (10), 149 (41). δH –0.29 and 0.71, each d, J 6.6 Hz,
The foregoing diastereomeric mixture of oxazolines was methylated
(98%). Reduction of the methiodide and hydrolysis gave the aldehyde
(25) as a solid (57%) which crystallized from dichloromethane/light
petroleum as needles, m.p. 220–223° (Found: C, 84.8; H, 5.9%. M ,
3
CH(CH ) ; 1.51, m, CHMe ; 2.50, s, Me; 2.53, s, NMe; 3.50, dd, J 9.8,
1
4
d, J3´,4´ 8.4 Hz; H3´; 7.76, d, J 8.4 Hz, ArH; 7.84, m, 2 × ArH; 8.00, d,
J 8.4 Hz, ArH; 8.06, d, J 8.4 Hz, ArH. δC 16.37, 18.00 and 19.72, each
Me; 26.04, CHMe ; 31.69, NMe; 55.60, OMe; 61.63, CH ; 61.94,
CHN; 105.62, 123.94 and 125.01, each CHAr; 125.06, CAr; 125.40,
1
1
3
2
2
1.6 Hz, CHHOH; 3.76, dd, J 3.5, 11.6 Hz, CHHOH; 3.84, s, OMe;
.04, m, CHN; 7.27, s, H4; 7.40, m, ArH; 7.48–7.56, m, 3 × ArH; 7.58,
+•
12
1
16
40.1459. C24H20O2 requires C, 84.7; H, 5.9%. C24 H20 O2
+•
30
requires M , 340.1463). [α]D –7.0° (c, 2.3). λ
232, 269, 355 nm
max
+
(log ε 5.26, 4.69, 4.20). m/z 340 (M , 92%), 326 (26), 325 (100), 311
2
2
(13), 310 (13), 282 (24), 265 (25), 252 (24), 162 (27), 149 (30), 141
(29), 132 (18), 127 (20), 126 (37), 125 (20), 119 (20), 111 (26). δH 2.43
25.47, 125.72, 125.94, 126.70, 126.82 and 128.48, each CHAr;
28.58, CAr; 129.18, CHAr; 131.94, 132.36, 132.65, 133.21, 134.29
and 2.73, each s, Me; 3.88, s, OMe; 7.20, s, H3´; 7.51, s, H4; 7.58–7.64,
m, 4 × ArH; 7.87–7.89, m, ArH, 8.10–8.16, m, 2 × ArH; 9.19–9.21, m,
ArH; 10.02, s, CHO. δC 16.16 and 19.36, each Me; 55.90, OMe;
and 136.45, each CAr; 155.17, COMe; 171.38, CO.
111.64, 124.77, 124.86 and 125.68, each CHAr; 125.69, CAr; 125.76,
126.08, 126.63, 126.91, 127.07, 129.08, each CHAr; 130.18, 130.36,
131.47, 131.80, 132.47, 132.56, 134.23 and 141.44, each CAr; 154.63,
(
–)-(S)-3-Methoxy-1´,N-dimethyl-2,2´-binaphthalene-1-carboxamide
(23)
A solution of the (S)-carboxamide (22) (300 mg, 0.68 mmol) in thf
6 ml) and water (35 µl) was stirred under reflux with potassium
COMe; 194.59, CHO.
(
(–)-(S)-3-Methoxy-1´,4´-dimethyl-2,2´-binaphthalene-1-methanol (26)
t-butoxide (640 mg, 5.7 mmol) for 31 h. The cooled mixture was
acidified with dilute hydrochloric acid and extracted with
dichloromethane. The crude product was purified by radial
chromatography with 5–40% ethyl acetate/light petroleum as eluent,
Reduction of the aldehyde (25) gave, after radial chromatography with
5–20% ethyl acetate/light petroleum as eluent, the alcohol (26) as a solid
(93%, 58.0% e.e) which precipitated from light petroleum/ethyl acetate
+
•
+•
which gave the amide (23) (180 mg, 75%) as a foam (Found: M ,
in amorphous form, m.p. 150–152° (Found: M , 342.1610.
1
2
1
14 16
+•
33
12
1
16
+•
33
3
(
∆
3
55.1571. C24 H21
N
O requires M , 355.1572). [α]
–76.9°
nm/
C24 H22 O2 requires M , 342.1620). [α]D –9.9° (c, 2.0). λmax
238.5, 278, 331 nm (log ε 5.14, 4.23, 3.71). C.d. λ nm/∆ε 232.5 (+47),
2
D
c, 1.9). λmax 234.5, 318, 332 nm (log ε 5.09, 3.68, 3.74). C.d. λ
max
max
+
+
ε 222 (+75.5), 237 (–50.5), 278 (+4), 298 (–10). m/z 355 (M , 72%),
241 (–36), 274.5 (+2.5), 298 (–7). m/z 342 (M , 25%), 326 (21), 325
(30), 311 (16), 310 (33), 309 (100), 295 (11), 294 (18), 293 (11), 281
(24), 279 (13), 278 (20), 277 (11), 276 (11), 266 (25), 265 (35), 263 (11),
252 (18), 154 (13), 147 (11), 139 (10), 133 (15), 132 (18), 131 (10), 126
40 (17), 325 (47), 324 (100), 310 (12), 297 (24), 296 (22), 282 (10),
81 (16), 266 (10), 265 (26), 253 (23), 252 (27), 239 (13), 149 (28), 126
2
(
22). δH 2.46, s, Me; 2.52, d, J 4.9 Hz, NMe; 3.82, s, OMe; 5.46,
br q, J 4.9 Hz, NH; 7.28, s, H4; 7.33, d, J3´,4´ H3´; 7.41–7.44, m, ArH,
.50–7.58, m, 3 × ArH; 7.75, d, J4´,3´ 8.4 Hz, H4´; 7.83, d, J 8.1 Hz,
(13). δ 2.39 and 2.73, each s, Me; 3.83, s, OMe; 4.74 and 4.86, each d, J
H
7
11.8 Hz, CH OH; 7.16, s, H3´; 7.27, s, H4; 7.42–7.68, m, H6,6´,7,7´;
2
ArH; 7.88, br d, J 8.2 Hz, ArH; 7.93, d, J 8.4 Hz, ArH; 8.10, d, J 8.4 Hz,
ArH. δC 16.17, Me; 26.24, NMe; 55.67, OMe; 106.39, 124.42, 124.68,
7.87,brd, J8.1 Hz, ArH;8.09–8.15,m, 2× ArH;8.26, br d,J 8.0Hz,ArH.
δ 15.88 and 19.44, each Me; 55.60, OMe, 59.61, CH ; 105.88, 124.39,
C
2

Atropisomerism of 2,2´-Binaphthalenes
935
1
1
1
24.59, 124.71, 124.90, 125.31, 125.71, 126.28 and 127.26, each CHAr;
27.61, CAr; 128.76, CHAr; 130.72, 131.75, 132.28, 132.80, 133.06,
H, 5.6; N, 2.6%). [α] 25 –102.7° (c, 1.8). λmax 232, 277, 341 (log ε
D
4.97, 4.03, 2.90). C.d. λmax nm/∆ε 217 (+63), 233.5 (–66.5). δH –0.21
33.27, 134.56 and 135.13, each CAr; 155.31, COMe.
and 0.66, each d, J 6.9 Hz, HC(CH ) ; 1.99–2.03; m; CHMe ; 2.17, d,
3 2 2
1
The e.e. was estimated by H n.m.r. spectroscopy in CDCl solution
J 0.8 Hz, Me; 2.34, s, Me; 3.27, s, NMe; 4.31, dd, J 7.7, 9.7 Hz, CHH5;
5.55, dd, J 9.7, 11.1 Hz, CHH5; 5.83, m, H4; 7.44–7.47, m, ArH; 7.53–
7.58, m, 2 × ArH; 7.65, br s, H4´; 7.75, ddd, J 1.0, 7.0, 8.1 Hz, ArH;
7.78–7.81, m, ArH; 7.93–8.03, m, 2 × ArH; 8.05, br d, J 8.3 Hz, ArH;
8.27, d, J 8.2 Hz, ArH; 8.55, dd, J 8.5 Hz, ArH. δC 12.81, 17.44, 17.55
3
in presence of 1.27 mol equiv. of (+)-(S)-1-(anthracen-9-yl)-2,2,2-
trifluoroethanol. For the (R)-diastereomer: δH 2.36 and 2.70, each s,
Me; 3.81, s, OMe; 4.68 and 4.82, each d, J 11.8 Hz, CH OH; 7.10,
2
s, H3´; 7.24, s, H4; 7.44–7.63, m, 4 × ArH; 7.85, d, J 8.2 Hz, ArH;
8
.07–8.15, m, 2 × ArH; 8.20, d, J 8.3 Hz, ArH. The n.m.r. spectrum of
and 21.59, each Me; 26.31, CHMe ; 34.56, NMe; 68.97, C4; 73.28, C5;
2
the (S)-diastereomer included δH 2.35 and 2.70, each s, Me; 3.81, s,
OMe; 4.70, d, J 11.6 Hz, CHHOH; 7.13, s, H3´; 7.25, s, H4.
116.75, CAr; 124.31, 125.83, 126.44, 126.95, 127.18, 127.26, 127.79,
128.40 and 128.60, each CHAr; 129.20, CAr; 130.85, CHAr; 131.21,
1
31.87, 132.78, 133.46 and 133.76, each CAr; 134.12. CHAr; 134.34
(
–)-(S)-3-Methoxy-1´,4´-dimethyl-2,2´-binaphthalene-1-carbonitrile
and 140.77, each CAr; 174.27, C2.
(27)
(
–)-(R)-1´,3´-Dimethyl-2,2´-binaphthalene-1-carbaldehyde (30)
Prepared from the aldehyde (25) by a manner similar to that employed
for compound (21), it was purified by radial chromatography with 5%
ethyl acetate/light petroleum as eluent, which gave the nitrile (27)
Reduction and hydrolysis of the (R)-methiodide (29) gave a crude
product which was subjected to radial chromatography with 1–20%
ethyl acetate/light petroleum as eluent. The aldehyde (30) was obtained
as a solid (50%) which crystallized from acetone as prisms, m.p. 172–
(
88%) as a solid which crystallized from ethyl acetate/light petroleum
+
•
12
1
14 16
as needles, m.p. 236–238° (Found: M , 337.1461. C24 H19
N O
+
•
30
+•
requires M , 337.1467). [α]
–55.4° (c, 2.4). λmax nm/∆ε 229.5,
87, 346 nm (log ε 4.80, 3.96, 3.83). λinfl 252 nm (log ε 4.55). C.d.
λmax nm/∆ε 205.5 (+15), 220.5 (+34.5), 242.5 (–20), 293.5 (+7.5), 313
174° (Found: C, 89.3; H, 6.0%. M , 310.1351. C H O requires C,
D
23 8 12
1
16
+•
31
2
89.0; H, 5.8%. 12C23 H18 O requires M , 310.1358). [α]D –144.2°
(c, 2.2). λmax 231, 248.5, 254, 287, 319, 313 nm (log ε 5.07, 4.82, 4.84,
4.09, 4.12, 4.05). λinfl 216 nm (log ε 4.84). C.d. λmax nm/∆ε 213 (+36),
228.5 (+17.4), 251 (–35.2). λmin/∆ε 196 (+1.4), 222 (+13.5). m/z 310
+
(
(
–10). λmin/∆ε 211 (+13). m/z 337 (M , 100%), 336 (32), 322 (23), 321
12), 307 (19), 306 (22), 290 (11), 153 (18), 139 (10). δH 2.47 and 2.74,
+
each s, Me; 3.88, s, OMe; 7.22, s, H3´; 7.48, s, H4; 7.58–7.64, m,
× ArH; 7.89–7.91, 8.08–8.10, 8.15–8.17 and 8.24–8.26, each m, ArH.
δ 15.96 and 19.43, each Me; 55.97, OMe; 110.45, CHAr; 112.03, C1;
(M , 100%), 296 (24), 295 (100), 293 (13), 282 (12), 281 (23), 280
4
(11), 278 (13), 267 (26), 266 (28), 265 (47), 263 (12), 252 (27), 147
(11), 133 (19), 132 (24), 131 (11), 126 (18). δH 2.17, d, J 0.6 Hz, Me;
2.39, s, Me; 7.34, d, J 8.3 Hz, H3; 7.55–7.58, m, 2 × ArH; 7.65, ddd, J
1.1, 6.9, 8.1 Hz, ArH; 7.70, br s, H4´; 7.76, ddd, J 1.4, 6.9, 8.4 Hz, ArH;
7.86–7.89, m, ArH; 7.99, br d, J 8.1 Hz, ArH; 8.05–8.08, m, ArH; 8.17,
C
116.44, CN; 124.74, 125.09, 125.24, 125.80, 125.81, 126.22, 127.12,
127.69 and 127.80, each CHAr; 127.89, 131.02, 131.09, 132.18,
132.77, 132.81, 133.56 and 139.86, each CAr; 154.87, COMe.
d, J 8.3 Hz, H4; 9.41, dd, J 0.6, 8.5 Hz, ArH; 10.11, s, CHO. δ 16.74
C
(
4S)-4-Isopropyl-2-(1´,3´-dimethyl-2,2´-binaphthalen-1-yl)-4,5-
and 21.94, each Me; 124.21, 125.77, 125.97, 126.08, 126.33, 126.81,
dihydrooxazole
1
1
27.86, 128.08 and 128.34, each CHAr; 128.51, CAr; 128.38, CHAr;
30.52, 131.03, 132.21, 133.18, 133.24 and 133.70, each CAr; 134.96,
This diasteromeric mixture of oxazolines was prepared from 2-bromo-
1
CHAr; 136.35 and 148.68, CAr; 194.26, CHO.
,3-dimethylnaphthalene (8) and the oxazoline (4) in the usual way
except that the reactants were stirred and heated under reflux for 60 h.
Flash chromatography with 1–20% ethyl acetate/light petroleum as
(–)-(R)-1´,3´-Dimethyl-2,2´-binaphthalene-1-methanol (31)
eluent gave the product as
a
solid (76%, 39.9% d.e.). The
Reduction of the (R)-aldehyde (30) gave a crude product which was
purified by radial chromatography with 1–10% ethyl acetate/light
petroleum as eluent to give the alcohol (31) as a solid (96%)
which crystallized from ethyl acetate/light petroleum as prisms, m.p.
(R)-diastereomer (28) was separated by fractional crystallization from
dichloromethane/light petroleum, the purity of fractions being
1
monitored by H n.m.r. spectroscopy, whereupon it was obtained as
+
•
12
1
14 16
+•
needles, m.p. 133–136° (Found: M , 393.2100. C28 H27
N
O
197–200º (Found: C, 88.3; H, 6.6%. M , 312.503. C23H20O requires
+
•
27
12
1
16
+•
30
requires M , 393.2093). [α]
–195.4° (c, 1.0). λmax 233.5, 275.5 nm
nm/∆ε 222 (+135), 234.5 (–137). m/z 393
C, 88.4; H, 6.4%. C23 H20 O requires M , 312.1514). [α]
D
D
(
log ε 4.81, 3.78). C.d. λ
–122.1° (c, 2.4). λmax 232, 273, 282 nm (log ε 5.08, 4.21, 4.20). C.d.
λmax nm/∆ε 220.5 (+163), 234.5 (–147). m/z 312 (M , 16%), 296 (11),
max
+
+
(
1
M , 31%), 378 (11), 281 (26), 280 (100), 279 (13), 266 (12), 265 (41),
49 (12), 114 (15). δH 0.62 and 0.68, each d, J 6.7 Hz, CH(CH ) ; 1.32,
295 (26), 294 (84), 281 (11), 280 (27), 279 (100), 278 (27), 277 (16),
276 (20), 266 (11), 265 (20), 149 (26), 139 (27), 138 (14), 126 (11). δH
2.15, d, J 0.8 Hz, Me; 2.39, s, Me; 4.77 and 4.85, each d, J 11.6 Hz,
3 2
m, CHMe ; 2.24 and 2.39, each s, Me; 3.63, dd, J 8.2, 8.2 Hz, CHH5;
2
3
.89–3.95, m, H4; 4.04, dd, J 8.2, 9.6 Hz, CHH5; 7.33, d, J3,4 8.3 Hz,
H3; 7.49–7.52, m, 2 × ArH; 7.61, br s, H4´; 7.56–7.63, m, 2 × ArH;
CH OH; 7.28, d, J 8.3 Hz, H3; 7.56-7.62, m, 3 × Ar; 7.67, ddd, J 1.4,
6.9, 8.3 Hz, ArH; 7.71, br s, H4´; 7.88–7.91, m, ArH; 7.95, d, J 8.3 Hz,
H4; 7.99, br d, J 8.1 Hz, ArH; 8.08–8.11, m, ArH; 8.37, d, J 8.5 Hz,
2
7
.81–7.85, m, ArH; 7.95, br d, J 8.2 Hz, ArH; 8.01, d, J 8.5 Hz, ArH;
.04–8.10, m, ArH; 8.12, br d, J 8.0 Hz, ArH. δC 16.52, 18.21, 18.49
8
and 21.71, each Me; 32.40, CHMe ; 69.86, C5; 72.96, C4; 124.29 and
ArH. δC 16.62 and 21.92, each Me; 59.67, CH ; 124.30, 124.62,
2
2
1
1
1
1
24.89, each CHAr; 125.37, 2 × CHAr; 125.47 and 126.10, each CHAr;
26.39, CAr; 127.11, 127.22, 127.61, 128.01 and 129.94, each CHAr;
31.00, 131.55 and 131.86, each CAr; 132.33, CAr; 133.14, 135.17,
38.44 and 139.50, each CAr; 162.46, C2.
125.36, 125.65, 125.71, 126.06, 126.77, 127.54, 127.77, 128.58 and
128.90, each CHAr; 131.19, 131.63, 132.34, 132.79, 133.04, 133.28
and 134.34, each CAr; 138.77, 2 × CAr.
When the 1H n.m.r. spectrum was determined in CDCl3 in the
presence of 1.92 mol equiv. of (+)-(S)-1-(anthracen-9-yl)-2,2,2-
trifluoroethanol no signals due to the (S)-enantiomer could be
detected. Enantio-enriched alcohol was prepared from the enantio-
enriched oxazoline (39.9% d.e.), via the enantio-enriched aldehyde,
Then.m.r.spectraoftheminor(S)-diastereomerincluded δ 0.58and
H
0
.61, each d, J 6.7 Hz, CH(CH) ) ; 1.25, m, CHMe ; 2.20 and 2.42, each
3 2 2
s, Me; 3.54, dd, J 8.4, 8.4 Hz, CHH5; 3.89–3.95, m, H4; 4.10, dd, J 8.4,
9
1
1
1
.6Hz,CHH5;7.35,d,J3,48.3Hz,H3;8.11,brd,J7.8Hz,ArH.δ 16.68,
C
3
2
32
8.14, 18.49 and 21.53, each Me; 32.32, CHMe ; 69.89, C5; 73.05, C4;
[α]D 32.0° (c, 2.6); the alcohol had [α]D –30.0° (c, 1.0) and the
2
1
24.32, 124.92, 125.30 and 127.52, each CHAr; 131.09, 131.57, 132.29,
33.06, 134.83, 138.31 and 139.52, each CAr; 162.38, C2.
e.e. was determined to be 22.8% by the H n.m.r. method. Under these
conditions the (R)-enantiomer (31) had δH 2.07 and 2.33, each s,
Me; 4.73 and 4.81, each d, J 11.6 Hz, CH OH; 7.24, d, J 8.3 Hz, ArH;
2
(–)-(R,4S)-4-Isopropyl-3-methyl-(1´,3´-dimethyl-2,2´-binaphthalen-1-
7
.47–7.63, m, 4 × ArH; 7.65, s, H4´; 7.84–7.86, m, ArH; 7.92, d, J 8.3
Hz, ArH; 7.95, br d, J 8.5 Hz, ArH; 8.01–8.03, br m, ArH; 8.29, d, J
.3 Hz, ArH. The n.m.r. spectrum of the minor (S)-enantiomer
included δH 2.09 and 2.31, each s, Me; 4.72 and 4.83, each d, J 11.6
Hz, CH OH.
yl)-4,5-dihydrooxazolium Iodide (29)
8
Methylation of the (R)-oxazoline (28) gave the methiodide (29) (83%)
which crystallized from acetone/dichloromethane as prisms, m.p.
2
08–210° (Found: C, 65.2; H, 5.6; N, 2.5. C29H30INO requires C, 65.0;
2

9
36
R. W. Baker et al.
(
–)-(R)-1,1´,3´-Trimethyl-2,2´-binaphthalene (32)
petroleum as eluent to give the alcohol (35) (93%, 35.5% e.e.) which
precipitated from ethyl acetate/light petroleum in amorphous form,
m.p. 150–152° (Found: C, 84.3; H, 6.7%. M , 342.1626. C24H22O2
This was prepared from the (R)-alcohol (31) and was purified by radial
chromatography with light petroleum as eluent, which gave the
hydrocarbon (32) as a solid (76%) that crystallized from ethyl acetate/
light petroleum as prisms, m.p. 165–167° (Found: C, 93.0; H, 6.8%.
M , 296.1559. C23H20 requires C, 93.2; H, 6.8%. C23 H20 requires
M , 296.1565). [α]
2
+
•
1
2
1
16
+•
requires C, 84.2; H, 6.5%. C24 H22 O2 requires M , 342.1620).
[
24
α]D –26.2° (c, 2.3). λmax 236, 266.5, 277, 316.5, 331 nm (log ε 5.06,
+
•
12
1
4.08, 4.07, 3.50, 3.58). C.d. λ nm/∆ε 224 (+50), 239 (–40). m/z 342
max
+
+
•
32
(M , 55%), 326 (19), 325 (30), 324 (100), 310 (12), 309 (35), 295 (12),
94 (13), 281 (12), 279 (17), 278 (17), 266 (18), 265 (27), 253 (10), 252
(18), 171 (19), 149 (25), 133 (12), 129 (11), 127 (14), 126 (15), 113
–126.2° (c, 2.1). λmax (C H12) 236, 274.5,
D
6
2
84.5 nm (log ε 5.09, 4.15, 4.13). C.d. λ
nm/∆ε 221 (+135), 235.5
max
+
(–120). m/z 296 (M , 100%), 282 (15), 281 (64), 267 (12), 266 (52),
(
10). δH 2.09, d, J 0.8 Hz, Me; 2.34, s, Me; 3.82, s, OMe; 4.68 and 4.76,
2
65 (50), 139 (12), 133 (20), 132 (21). δH 2.14, 2.38 and 2.40, each s,
each d, J 11.6 Hz, CH OH; 7.30, s, ArH; 7.49–7.56, m, 4 × ArH; 7.68,
s, ArH; 7.84–7.90, m, 2 × ArH; 8.04–8.07, m, ArH; 8.23–8.27, br d, J
8
1
2
Me; 7.27, d, J3,4 8.3 Hz, H3; 7.53–7.65, m, 4 × ArH; 7.71, s, H4´; 7.84,
d, J 8.3 Hz, H4; 7.87–7.90, m, ArH; 7.97, d, J 8.0 Hz, ArH; 8.09–8.10,
m, ArH; 8.16, d, J 8.0 Hz, ArH. δC 15.25, 16.04 and 21.59, each Me;
1
1
1
.7 Hz, ArH. δC 16.28 and 21.34, each Me; 55.63, OMe; 59.55, CH2;
06.07, 124.23, 124.57, 125.10, 125.52; 125.91; 126.27 and 127.33,
24.34, 124.37, 125.17, 125.33, 125.44, 125.93, 126.00, 126.28,
27.73, 127.77 and 128.56, each CHAr; 131.35, 131.39, 131.49,
32.79, 132.91, 132.97, 134.60, 138.80 and 140.01, each CAr.
each CHAr; 127.77, CAr; 127.85, CHAr; 131.25, 131.83, 132.20,
33.23, 134.62, 134.68 and 134.87, each CAr; 155.09, COMe. One
1
CHAr and one CAr were not located.
The enantio-enriched alcohol (13.7 mg, 40 µmol) and (+)-(S)-
Mosher acid chloride (15 µl, 88 µmol) were stirred together in
anhydrous dichloromethane (3 drops) and pyridine (3 drops) under
argon for 18 h. The solution was diluted with dichloromethane and
washed in turn with dilute hydrochloric acid, saturated aqueous sodium
hydrogen carbonate and saturated brine. The product was purified by
radial chromatography with 5–10% ethyl acetate/light petroleum to
give the diastereomeric α-trifluoromethyl-α-methoxyphenylacetates as
a solid (18.3 mg, 35.5% d.e.).
(
4S)-4-Isopropyl-2-(3-methoxy-1´,3´-dimethyl-2,2´-binaphthalen-1-
yl)-4,5-dihydrooxazole
This diastereomeric mixture of oxazolines was prepared from 2-bromo-
1
except that the reactants were stirred and heated under reflux for 19 h.
Flash chromatography with 2–20% ethyl acetate/light petroleum as
eluent gave the binaphthalene as a foam (82%, 37.0% d.e.) (Found:
M , 423.2209. C29 H29
–
3
,3-dimethyl-naphthalene (8) and the oxazoline (5) in the usual way
+
•
12
1
14 16
+•
32
N O2 requires M , 423.2198). [α]D
52.4° (c, 3.0). λmax 236, 268, 277, 318, 332 nm (log ε 5.23, 4.30, 4.30,
.85, 3.92). C.d. λmax nm/∆ε 224 (+48), 237 (–36).
For the major (S,R)-diastereomer the n.m.r. spectra included δH
.97, d, J 0.7 Hz, Me; 2.09, s, Me; 3.40, m, OMe; 3.79, s, OMe; 5.34
1
The major (S)-diastereomer (33) had: δH 0.58 and 0.67, each d, J 6.7
and 5.37, each d, J 11.8 Hz, CH . δ –72.558. For the (R,R)-
2
F
Hz, CH(CH ) ; 1.19, m, CHMe ; 2.21, d, J 0.8 Hz, Me; 2.37, s, Me;
3
dd, J 8.2, 9.7 Hz, CHH5; 7.36, s, H4´; 7.42–7.54, m, H6,6´,7,7´; 7.59,
s, H4; 7.79–7.82, m, ArH; 7.85, br d, J 8.2 Hz, ArH; 7.94–7.96 and
8
3
1
1
1
3
2
2
diastereomer the n.m.r. spectra included δH 1.84, d, J 0.7 Hz, Me; 2.20,
.56, dd, J 8.2, 8.2 Hz, CHH5; 3.81-3.89, m, H4; 3.84, s, OMe; 3.98,
s, Me. δ –72.558.
F
(–)-(S)-3-Methoxy-1,1´,3´-trimethyl-2,2´-binaphthalene (36)
.02–8.05, each m, ArH. δC 16.36, 18.23, 18.69 and 21.14, each Me;
This was prepared from the foregoing enantio-enriched alcohol (35) and
the crude product was purified by radial chromatography with 1–5%
ethyl acetate/light petroleum as eluent which gave the hydrocarbon (36)
2.39, CHMe ; 55.68, OMe, 69.94, C4; 72.91, C5; 107.12, 124.26 and
2
24.59, each CHAr; 125.23, 2 × CHAr; 126.56 and 126.74, each CHAr;
26.98, CAr; 127.64, CHAr; 128.28, 131.05, 132.22, 132.45, 133.32,
34.08, 134.28 and 135.77, each CAr; 154.84, COMe; 162.02, C2. Two
(
79%) as a solid which precipitated from ethyl acetate/light petroleum
+
•
in amorphous form (Found: C, 87.9; H, 6.9%. M , 326.1663. C24H22O
requires C, 88.3; H, 6.8%. C24 H22 O requires M , 362.1671).
CHAr were not located.
12
1
16
+•
The n.m.r. spectra of the (R)-diastereomer included δ 0.53 and 0.59,
H
28
[
3
α]D –26.9° (c, 1.2). λmax 237, 277, 315.5, 329.5 nm (log ε 5.15, 4.33,
each d,J 6.7 Hz, CH(CH ) ;2.23, m, CHMe ;2.17, d,J 0.8 Hz, Me; 2.40,
s, Me; 3.44, dd, J 8.5, 8.5 Hz, CHH5; 3.81–3.89, m, H4; 3.84, s, OMe;
4
3
1
1
3
2
2
.66, 3.71). C.d. λ nm/∆ε 223 (+45), 235 (infl.) (–10), 241 (–20). m/
max
+
z 326 (M , 100%), 311 (24), 296 (20), 295 (10), 279 (13), 265 (13), 252
11), 149 (12), 148 (13), 133 (12), 126 (11). δH (300 MHz) 2.09, d,
J 0.7 Hz, Me; 2.29 and 2.34, each s, Me; 3.81, s, OMe; 7.19, s, H4´;
.06,dd,J8.5,9.7Hz,CHH5.δ 16.44,18.16,18.63and21.02, eachMe;
C
(
2.29, CHMe ; 55.68, OMe; 69.98, C5; 73.04, C4; 124.32, 124.61 and
2
25.03, each CHAr; 127.01, CAr; 127.55, CHAr; 128.26, CAr; 131.14,
32.90, 133.23 and 135.44, each CAr; 154.84, COMe; 161.93, C2.
7
.43–7.56, m, 4 × ArH; 7.68, s, H4; 7.84–7.88, m, 2 × ArH; 8.03–8.09,
m, 2 × ArH. δ 15.35, 15.77 and 21.14, each Me; 55.56, OMe; 103.66,
C
(–)-(S)-3-Methoxy-1´,3´-dimethyl-2,2´-binaphthalene-1-carbaldehyde
123.63, 124.42, 124.47, 124.95, 125.34, 125.85, 126.01, 127.35 and
127.91, each CHAr; 128.61, 131.05, 131.48, 132.10, 133.22, 133.53,
(34)
1
34.26, 135.14 and 136.08, each CAr; 155.55, OMe.
The diastereomeric mixture of oxazolines was converted into the
methiodide and this was reduced and hydrolysed. Radial
chromatography of the crude product with 1–10% ethyl acetate/light
petroleum as eluent gave the product as a solid (56%) which
precipitated from acetone in amorphous form, m.p. 180–182° (Found:
(4S)-4-Isopropyl-2-(1´,3´,4´-trimethyl-2,2´-binaphthalen-1-yl)-4,5-
dihydrooxazole
This diastereomeric mixture of oxazolines was prepared from 2-bromo-
1,3,4-trimethylnaphthalene (10) and the oxazoline (4). Flash chro-
matography with 1–20% ethyl acetate/light petroleum as eluent gave
the binaphthalene as a solid (82%, 30.8% d.e.) which crystallized from
+
•
C, 84.4; H, 6.1%. M , 340.1465. C 4H O requires C, 84.7; H, 5.9%.
2
20 2
1
2
1
16
+•
25
C24 H20 O requires M , 340.1463). [α]
32, 268, 329.5, 352.5 nm (log ε 5.14, 4.39, 3.88, 3.94). C.d. λmax nm/
ε 220 (+19), 231 (–11). m/z 340 (M , 68%), 325 (36), 282 (13), 281
22), 266 (11), 265 (17), 252 (13), 126 (14), 86 (64), 84 (100), 83 (11).
–34.5° (c, 2.0). λmax
2
D
2
∆
(
+
+•
acetone/light petroleum as plates, m.p. 125–130° (Found: M ,
12
1
14 16
+•
32
4
07.2239. C29 H29
N
O requires M , 407.2249). [α]D –22.7°
δ
7
9
5
2.16 and 2.37, each s, Me; 3.88, s, OMe; 7.54–7.63, m, 4 × ArH;
+
H
(c, 2.8). m/z 407 (M , 40%), 295 (32), 294 (100), 280 (15), 279 (54),
.56 and 7.70, each s, ArH; 7.87–7.92, 2 × ArH; 8.05–8.07 and
.22–9.24, each m, ArH; 9.98, s, CHO. δC 16.45 and 21.39, each Me;
5.87, OMe; 111.96, 124.20, 125.46 and 125.74, each CHAr; 125.84,
278 (14), 114 (68).
The major (R)-diastereomer (37) had δH 0.57 and 0.60, each d, J
6
3
.7 Hz, CH(CH ) ; 1.19, m, CHMe ; 2.19, 2.33 and 2.66, each s, Me;
3 2 2
CAr; 125.93, 126.05, 126.63, 126.96, 127.11 and 127.88, each CHAr;
29.97, 131.02, 131.84, 133.00, 133.38, 134.30, 134.37 and 140.56,
each CAr; 154.45, COMe; 194.29, CHO.
.56, dd, J 8.2, 8.2 Hz, CHH5; 3.91, ddd, J 6.7, 8.2, 9.7 Hz, H4; 4.06,
1
dd, J 8.2, 9.7 Hz, m, CHH5; 7.33, d, J3,4 8.3 Hz, H3; 7.48–7.61, m,
× ArH; 7.94, dd, J 0.8, 7.3 Hz, ArH; 8.00, d, J4,3 8.3, H4; 8.05–8.09,
4
m, 2 × ArH; 8.13, dd, J 1.1, 8.4 Hz, ArH. δC 14.90, 16.80, 18.16, 18.32
and 18.85, each Me; 32.28, CHMe ; 69.89, C5; 72.88, C4; 124.15,
(–)-(S)-3-Methoxy-1´,3´-dimethyl-2,2´-binaphthalene-1-methanol (35)
2
Reduction of the aldehyde (34) yielded a crude product which was
purified by radial chromatography with 5–20% ethyl acetate/light
124.46, 124.78, 125.23; 125.34 and 126.05, each CHAr; 126.33, CAr;
127.13, 127.38 and 128.01, each CHAr; 128.82 and 129.65, each CAr;

Atropisomerism of 2,2´-Binaphthalenes
937
1
1
29.86, CHAr; 130.95, 131.53, 132.25, 132.32, 132.72, 138.47 and
40.59, each CAr; and 162.58, C2.
The n.m.r. spectra of the (S)-diastereomer included δH 0.54 and
(+)-(S)-1´,3´,4´-Trimethyl-2,2´-binaphthalene-1-carbaldehyde (41)
This was prepared in the same way as its enantiomer from the (S,4S)-
methiodide (39). The aldehyde crystallized from acetone as prisms,
0.57, each d, J 6.7 Hz, CH(CH ) ; 1.24, m, CHMe ; 2.14, 2.37 and
25
3
2
2
m.p. 199–201°. [α]D +117.7° (c, 1.4). C.d. λmax nm/∆ε 217 (–24),
2.67, each s, Me; 3.53, dd, J 8.4, 8.4 Hz, CHH5; 4.08, dd, J 8.4, 9.7
2
31 (–35), 252 (+34). λmin nm/∆ε 222 (–21).
Hz, CHH5. δC 14.95, 16.95, 18.04, 18.42 and 18.71, each Me; 32.23,
CHMe ; 69.81, C5; 72.94, C4; 124.04, 124.48, 124.85 and 125.39,
each CHAr; 126.27, CAr; 127.44, CHAr; 128.64, CAr; 129.98,
CHAr; 131.06, 131.55, 132.35, 138.39 and 140.64, each CAr;
2
(–)-(R)-1´,3´,4´-Trimethyl-2,2´-binaphthalene-1-methanol (42)
Reduction of the (R)-aldehyde (40) gave a crude product which was
purified by radial chromatography with 5–30% ethyl acetate/light
petroleum as eluent. This gave the alcohol (42) as a solid (93%) which
crystallized from ethyl acetate/light petroleum as clusters of needles,
1
62.48, C2.
(R,4S)-(38) and (S,4S)-4-Isopropyl-3-methyl-2-(1´,3´,4´-trimethyl-
+
•
12
1
16
+•
m.p. 99–101°C (Found: M , 326.1682. C24 H22 O requires M
2
,2´-binaphthalen-1-yl)-4,5-dihydrooxazolium Iodide (39)
3
3
1
26.1671). [α]D30 –89.2° (c, 1.6). λmax 237, 273, 282 nm (log ε 4.73,
Methylation of the diastereomeric mixture of oxazolines gave the
methiodides as a foam (97%) which was fractionally crystallized from
acetone/dichloromethane to afford the pure diastereomers.
+
.74, 3.75). C.d. λmax nm/∆ε 224 (+150), 239 (–113). m/z 326 (M ,
3%), 310 (11), 309 (17), 308 (56), 294 (26), 293 (100), 279 (19), 278
(53), 277 (13), 276 (16), 265 (11), 155 (14), 139 (16), 138 (11), 127
The major (R)-diastereomer (38) crystallized as prisms, m.p.
(
24). δH 2.10, 2.33 and 2.70, each s, Me; 4.79 and 4.85, each d, J 11.7
+
•
2
04–207º (Found: C, 65.4; H, 5.8; N, 2.4%. M , 549.1528.
Hz, CH OH; 7.25, d, J 8.4 Hz, H3; 7.54–7.67, m, H6,6´,7,7´; 7.93, d,
1
2
1
127 14 16
2
3,4
C30H32INO requires C, 65.5; H, 5.8, N, 2.5%. C30 H32
requires M , 549.1529). [α]
I N O
J4,3 8.4 Hz, H4; 7.97, dd, J 0.6, 8.1 Hz, ArH; 8.09, br d, J 8.0 Hz, ArH;
+
•
27
–71.7º (c, 2.8). λmax 236, 284.5 nm
nm/∆ε 223 (+81.5), 238 (–78). m/z 549
D
8
1
1
1
1
.18, br d, J 8.4 Hz, ArH; 8.36, d, J 8.4 Hz, ArH. δC 15.16, 16.90 and
(
log ε 5.10, 4.16). C.d. λ
max
8.83, each Me; 59.77, CH ; 124.34, 126.63, 124.80, 124.97, 125.53,
+
2
(M , 19%), 446 (22), 423 (19), 377 (58), 362 (9), 324 (23), 323 (90),
25,70, 126.84, 127.80, 128.62 and 128.88, each CHAr; 129.34,
29.66, 131.13, 131.89, 132.28, 132.36, 132.83, 133.26, 138.86 and
39.96, each CAr.
3
1
1
1
4
22 (27), 308 (24), 256 (22), 213 (22), 199 (38), 185 (30), 171 (60),
57 (20), 153 (21), 152 (16), 129 (59), 128 (32), 127 (36); 126 (11),
15 (21). 101 (15). δH –0.28 and 0.58, each d, J 6.8 Hz, CH(CH3)2;
This alcohol was converted into the (R,R)-Mosher ester (98.7% e.e)
.98–2.02, m, CHMe ; 2.08, 2.23 and 2.58, each s, Me; 3.20, s, NMe;
2
by treatment with (+)-(S)-Mosher acid chloride. Its n.m.r. spectra
included δH 1.97, 2.05 and 2.66, each s, Me; 3.41, br d, J 0.9 Hz, OMe;
.19, dd, J 7.8, 9.6 Hz, CHH5; 5.48, dd, J 9.6, 11.1 Hz, CHH5; 5.78,
m, H4; 7.39, d, J3,4 8.4 Hz, H3; 7.50–7.57, m, 2 × ArH; 7.65, ddd, J
5
.39 and 5.51, each d, J 11.9 Hz, CH . δ –72.75.
2 F
0
2
8
.9, 7.0, 8.1 Hz, ArH; 7.85, ddd, J 1.2, 7.0, 8.3 Hz, ArH; 7.97–8.00, m,
× ArH; 8.05, d, J 8.3 Hz, ArH; 8.22, d, J 8.3 Hz, ArH; 8.52, dd, J 0.7,
.4 Hz, ArH. δC 12.25, 17.24, 17.39, 17.42 and 19.02, each Me; 25.89,
(+)-(S)-1´,3´,4´-Trimethyl-2,2´-binaphthalene-1-methanol (43)
This was prepared in an analogous manner to its enantiomer from
CHMe ; 34.31, NMe; 68.47, C4; 72.93, C5; 116.48, CAr; 124.02,
2
28
the (S)-aldehyde (41). [α]
+88.5° (c, 2.1). C.d. λmax nm/∆ε 222.5
D
1
24.58, 125.55, 125.69, 126.49, 127.22, 127.90 and 128.43, each
CHAr; 128.80 and 129.66, each CAr; 130.27, CHAr, 130.79, 130.89,
31.06, 131.52, 132.43, each CAr; 133.80, CHAr; 134.14 and 141.75,
(
–120), 238 (+82).
The diastereomeric mixture of methiodides (38) and (39) was
1
converted sequentially, as above, into the enantiomeric mixture of
alcohols (42) and (43), and finally into the derived Mosher esters. The
n.m.r. spectra of the (S,R)-Mosher ester included δH 1.90, 2.18 and
2.61, each s, Me; 3.39, br d, J 1.0 Hz, OMe; 5.43 and 5.49, each d, J
11.9 Hz, CH . δ –72.75.
each CAr; 173.88, C2.
The (S)-diastereomer (39) crystallized as prisms, m.p. 232–235º
+
•
12
1
127 14 16
+•
(Found: M , 549.1507.
C30 H32
I
N
O
requires M ,
2
7
5
49.1529). [α]D +133.0º (c, 2.9). C.d. λmax nm/∆ε 218 (–86), 238
+
2
F
(
(
(
+77). m/z 549 (M , 24%), 423 (22), 422 (66), 353 (12), 324 (25), 323
100), 322 (30), 308 (29), 294 (15), 265 (10), 236 (16), 171 (21), 139
15), 128 (25), 127 (31), 111 (16). δH –0.30 and 0.62, each d, J 6.8 Hz,
(4S)-4-Isopropyl-2-(3-methoxy-1´,3´,4´-trimethyl-2,2´-binaphtha-
lenen-1-yl)-4,5-dihydrooxazole
CH(CH ) ; 1.97–2.03, m, CHMe ; 2.03, 2.31 and 2.63, each s, Me;
3
2
2
This was prepared as a mixture of diastereomers from the oxazoline (5)
and 2-bromo-1,3,4-trimethylnaphthalene (10) in the usual way except
that the reactants were stirred and heated under reflux for 18 h. Radial
chromatography with 5–20% ethyl acetate/light petroleum as eluent
3
5
.23, s, NMe; 4.22–4.26, m, CHH5; 5.50, br dd, J 10.0, 10.0 Hz, CHH5;
.87, m, H4;7.42, d, J 8.4 Hz, ArH; 7.50–7.59, m, 2 × ArH; 7.69, br dd,
J 7.6, 7.6 Hz, ArH; 7.89–7.95, m, 2 × ArH; 8.02, br d, J 8.2 Hz, ArH;
.09, br d, J 8.4 Hz, ArH; 8.25, d, J 8.4 Hz, ArH; 8.59, d, J 8.4 Hz, ArH.
δC 12.39, 14.99, 17.44, 17.45 and 18.86, each Me; 25.86, CHMe2;
8
+•
gave the binaphthalene as a foam (23%, 20.8% d.e.) (Found: M ,
4
4
37.2345. 12C30 H31
1
14 16
N
O requires M , 437.2355). [α]
+•
26
–0.9° (c,
3
1
4.28, NMe; 68.62, C4; 72.97, C5; 116.48, CAr; 124.22, 124.36,
25.70, 125.76, 126.55, 127.25, 128.04 and 128.53, each CHAr; 128.89
2
D
.8). λmax 239.5, 279.5, 316.5, 332 nm (log ε 5.20, 4.20, 3.82, 3.86).
+
C.d. λ
3
nm/∆ε 227 (+33), 241 (–24). m/z 437 (M , 14%), 351 (10),
max
and 129.19, each CAr; 130.56, CHAr; 130.70, 130.75, 131.55, 131.64
and 132.60, each CAr; 134.04, CHAr; 134.96 and 141.97, each CAr;
1
25 (28), 324 (100), 310 (11), 309 (36), 114 (39).
The major (S)-diastereomer (44) had δH 0.62 and 0.70, each d, J 6.7
Hz, CH(CH ) ; 1.17, m, CHMe ; 2.29, 2.44 and 2.74, each s, Me; 3.54,
73.88, C2.
3
2
2
dd, J 8.3, 8.3 Hz, CHH5; 3.88, s, OMe; 3.89–3.94, m, CHH5; 4.09, ddd,
J 6.7, 8.3, 9.7 Hz, H4; 7.42, s, H4; 7.50–7.62, m, 4 × ArH; 7.92, d, J 8.1
Hz, ArH; 8.03, br d, J 8.3 Hz, ArH; 8.16, br d, J 8.2 Hz, ArH; 8.20, d, J
8.5 Hz, ArH. δC 14.84 and 16.54, each Me; 18.16, 2 × MeAr; 18.37,
(
–)-(R)-1´,3´,4´-Trimethyl-2,2´-binaphthalene-1-carbaldehyde (40)
Reduction and subsequent hydrolysis of the (R,4S)-methiodide (38)
yielded the aldehyde (40) as a solid (56%) which crystallized from
acetone as prisms, m.p. 199–202º (Found: M , 324.1499. C24 H20
+
•
12
1
O
MeAr; 32.34, CHMe ; 55.54, OMe, 69.87, C4; 72.81, C5; 106.92,
2
+
•
28
requires M , 324.1514). [α]
–118.6º (c, 2.4). λmax 214, 233.5, 282,
CHAr, 124.09, 2 × CHAr; 124.48, 124.62, 125.01, 125.12, 126.41 and
126.65, each CHAr; 126.92, 128.18, 128.32, 130.13, 130.95, 132.45,
133.13, 133.23, 133.93 and 134.22, each CAr; 154.89, C3; 161.95, C2.
The n.m.r. spectra of the (R)-diastereomer included δH 0.59 and
D
2
2
3
93.5 nm (log ε 4.64, 4.83, 3.90, 3.91). C.d. λmax nm/∆ε 215.5 (+21),
+
31 (+32), 252.5 (–37.5). λmin nm/∆ε 221 (+19). m/z 324 (M , 100%),
10 (18), 309 (77), 285 (11), 294 (14), 281 (14), 279 (13), 260 (20), 265
(37), 155 (11), 149 (14), 133 (14). δH 2.12, 2.33 and 2.69, each Me;
0.65, each d, J 6.7 Hz, CH(CH ) ; 2.25, 2.48 and 2.76, each Me; 3.48,
3 2
7
6
8
1
1
1
1
.33, d, J 3,4 8.3 Hz, H3; 7.54–7.65, m, 3 × ArH; 7.74, ddd, J 1.3,
.9, 8.4 Hz, ArH; 7.97, br d, J 8.1 Hz, ArH; 8.07, br d, J 8.3 Hz, ArH;
dd, J 8.3, 8.3 Hz, CHH5; 3.88, s, OMe; 3.89–3.94, m, CHH5; 4.09, ddd,
J 6.7, 8.3, 9.7 Hz, H4; 8.05, br d, J 8.3Hz, ArH; 8.16, br d, J 8.5 Hz,
ArH. δC 14.86 and 16.60, each Me; 18.04, 18.11, 18.46, each MeAr;
.15–8.18, 2 × m, ArH; 9.37, d, J 8.6 Hz, ArH; 10.07, s, CHO. δ 15.10,
C
7.05 and 19.04, each Me; 124.43, 124.73, 125.34; 125.93, 126.00,
26.78, 128.33 and 128.37, each CHAr; 128.62, CAr; 129.40, CHAr;
29.93, 130.02, 130.54, 130.96, 131.40, 132.50 and 133.13, CAr;
34.88, CHAr; 136.49 and 149.91, each CAr; 194.48, CHO.
32.15, CHMe ; 55.54, OMe; 69.79, C4; 72.90, C5; 106.94, 123.98,
2
124.50, 124.72, 125.00 and 125.17, each CHAr; 126.94, 128.11,
128.12, 129.43, 131.07, 132.37, 133.27, 133.95 and 134.09, each CAr;
154.89, C3; 161.85, C2.

9
38
R. W. Baker et al.
Structure Determinations, (38), (38).2S and (22).0.5S (S = (H C) CO)
References
3
2
1
Pu, L., Chem. Rev., 1998, 98, 2405 and references therein.
Cooke, A. S., and Harris, M. M., J. Chem. Soc. (C), 1967, 988 and
references therein.
Longmore, L., Indian J. Chem., 1886, 5, 200.
Adams, R., Geissman, T. A., and Edwards, J. D., Chem. Rev., 1960,
Unique room-temperature single-counter diffractometer data sets,
2
together with ‘Friedel pairs’, were measured (2θ/θ scan mode, 2θ
max
5
0º; monochromatic Mo Kα radiation, λ 0.7107 Å; T c. 295 K), for N
3
3
4
hkl, N with I > nσ(I) being considered ´observed’ and used in the full-
o
matrix least-squares refinements on |F|, with anisotropic thermal
6
0, 555.
parameters forms refined C, N, O, I and (x, y, z, U
) constrained at
iso H
5
6
King, T. J., and de Silva, L. B., Tetrahedron Lett., 1968, 261.
Segal, J. S., ‘Gossypol, a Potential Contraceptive for Men’ (Plenum
Press: New York 1985).
Meyers, A. I., and Willemsen, J. J., Chem. Commun., 1997, 1573.
Jaroszewski, J. W., Strom-Hansen, T., and Hansen, L. L., Chirality,
estimated values, after gaussian absorption correction. Conventional
2
2 1/2
residuals R (= Σ∆/Σ|F |), Rw (=Σw∆ /ΣwF ) ) on |F| are quoted at
o
o
2
2
convergence, statistical weights being derivative of σ (I) = σ (Idiff) +
.0004σ (I ). Neutral atom complex scattering factors were
employed within the XTL 3.4 program system. Atomic parameters are
deposited. Copies are available, until 31 December 2005, on application
to the Australian Journal of Chemistry, P.O. Box 1139, Collingwood,
Vic. 3066, or the Cambridge Crystallographic Data Centre, deposition
7
8
4
0
diff
3
8
1
992, 4, 216.
9
0
Huang, L., Si, Y.-K., Snatzke, G., Zheng, D.-K., and Zhou, J., Coll.
Czech. Chem. Commun., 1988, 53, 2664.
Harada, N., and Nakanishi, K., ‘Circular Dichroic Spectroscopy:
Exciton Coupling in Organic Stereochemistry’ (University
Science Books: Mill Valley 1983).
Tsipouras, A., Goetz, M. A., Hensens, O. D., Liesch, J. M., Ostlind,
D. A., Williamson, J. M., Dombrowski, A. W., Ball, R. G., and
Singh, S. B., Biorg. Med. Chem. Lett., 1997, 7, 1279.
Buchanan, M. S., Gill, M., and Gimenez, A., Aust. J. Chem., 1998,
51, 103.
1
1
numbers 000000. All compounds are orthorhombic, space group
4
P2 2 2 (D , No. 19).
1
1
1
2
1
Crystal/Refinement Data
(
2
×
38). C30H22INO, M 549.5. a 21.666(8), b 13.971(5), c 8.705(3) Å, V
3
–3
–1
12
13
14
635 Å . D (Z = 4) 1.38 g cm . µMo 12.4 cm ; specimen: 0.45 × 0.52
c 5
0.80 mm; Tmin,max 0.55, 0.61. N 2647, N (n = 2) 2398; R 0.040,
o
–
3
Rw 0.051. |∆ρmax| = 0.79 (3) e Å . xabs –0.01(1).
38).2S. C36H44INO , 665.7. 18.365(4),
c 10.723(5) Å, V 3419 Å . D (Z = 4) 1.29 g cm . µMo 9.7 cm
Buchanan, M. S., Gill, M., and Yu, J., J. Chem. Soc., Perkin Trans.
1, 1997, 919.
(
M
a
b 17.365(4),
3
3
–3
–1
;
Bao, J., Wulff, W. D., Dominy, J. B., Fumo, M. J., Grant, E. B., Rob,
A. C., Whitcomb, M. C., Yeung, S.-M., Ostrander, R. L., and
Rheingold, A. L., J. Am. Chem. Soc., 1996, 118, 3392.
Eliel, E. L., and Wilen, S. H., ‘Stereochemistry of Organic
Compounds’ (Wiley: New York 1994).
Cooke, A. S., and Harris, M .M., J. Chem. Soc., 1963, 2365.
Baraldi, I., Bruni, M. C., Caselli, M., and Ponterini, G., J. Chem.
Soc., Faraday Trans. 2, 1989, 85, 65.
Baker, R. W., Lui, S, and Sargent, M. V., Aust. J. Chem., 1998, 51,
255.
Meyers, A. I., J. Heterocycl. Chem., 1998, 34, 991 and references
therein.
Sunthankar, S. V., and Gilman, H., J. Org. Chem., 1951, 16, 8.
McKennon, M. J., Meyers, A. I., Dranz, K., and Schwann, M., J.
Org. Chem., 1993, 58, 3586.
Degman,A.P.,andMeyers,A.I.,J.Am.Chem.Soc.,1999,121,2762.
Mitchell, R. H., Lai, Y.-H., and Williams, R. V., J. Org. Chem.,
1979, 44, 4733.
Brain, E. G., Doyle, F. P., Mehta, M. D., Miller, D., Nayler, J. H. C.,
and Stove, E. V., J. Chem. Soc., 1963, 491.
Cassebaum, H., Chem. Ber., 1957, 50, 1537.
Pearson, D. E., Wysong, R. D., and Breder, C. V., J. Org. Chem.,
1967, 32, 2358.
Parham, W. E., Reiff, H. E., and Swartzentruber, J. Am. Chem. Soc.,
1956, 78, 1437 and references therein.
Parham, W. E., Davenport, R. W., and Rinhart, J. K., J. Org. Chem.,
1970, 35, 2662.
Cologne, J., and Weinstein, G., Bull. Soc. Chim. Fr., 1952, 462.
Riemschneider, R., Nolde, K., and Henning, K., Monatsh., 1973,
104, 9872.
Campaigne, E., and Ashby, J., J. Heterocycl. Chem., 1971, 8, 487.
Aslam, F. M., Gore, P. H., and Jehangir, M., J. Chem. Soc., Perkin
Trans. 1, 1972, 892.
Nordin, I. C., J. Heterocycl. Chem., 1966, 3, 351.
Oki, M., ‘Application of Dynamic NMR Spectroscopy to Organic
Chemistry’ (VCH: Weinheim 1985).
Meyers, A. I., and Himmelsbach, R. J., J. Am. Chem. Soc., 1985,
107, 682.
Adams, R., and Yuan, H. C., Chem. Rev., 1933, 12, 261.
Bott, G., Field, L. D., and Sternhell, S., J. Am. Chem. Soc., 1980,
102, 5618.
c
1
specimen:0.18×0.18×0.58mm(capillary);Tmin,max0.83,0.85.N 3383,
–
3
N (n = 3) 1742; R 0.057, R 0.064; |∆ρmax| 0.92 (3) e Å . xabs –0.01 (6).
o
w
1
5
The latter structure determination of (38).2S, derivative of rather
weak data, was ultimately followed by the determination of the
unsolvated form (38), as a precautionary corroboration of the absolute
configuration; the two determinations are consistent.
1
1
6
7
(
22).0.5S. C30.5H34NO , M 470.6. a 12.127(2), b 16.919(2),
3.5
3
–3
18
19
c 25.065(3) Å, V 5143 Å . D (Z = 8) 1.21 g cm ; F (000) 2016.
µMo 0.8 cm ; specimen: 0.4 × 0.24 × 0.16 mm (no correction). R 0.053,
Rw 0.054. |∆ρmax| 0.29 (3) e Å
c
5
–
1
–
3
Variata.—For this compound only, a full sphere of CCD area
detector data was measured on a somewhat twinned specimen (Bruker
AXS instrument, T c. 153 K, ω-scan, 2θmax 58º) yielding 51234 total
reflections merging (inclusive of ‘Friedel pairs’ since no significant
anomalous scatterer was present) to 7391 unique (Rint 0.063), 5306
with F > 4σ(F) used in the refinement. Chirality was set according to
the internal reference (C(15)). Difference map residues were modelled
in terms of a fully populated ordered acetone, for which all hydrogen
atoms were located in difference maps.
2
2
0
1
2
2
2
3
2
4
2
2
5
6
Comment.—The results of the room-temperature single-crystal
X-ray studies are consistent with the formulation of (38) in both cases in
terms of stoichiometry, stereochemistry, connectivity and absolute
configurations as given above; in each case, one molecule, devoid of
crystallographic or intrinsic symmetry, comprises the asymmetric unit
of the structure, (38).2S solvated with two molecules of acetone.
Substituent dispositions are similar in both, dihedral angles between
peripheral and central naphthyl (n /n ) and oxazole planes (o ) being,
2
2
7
8
2
3
9
0
p
c
p
respectively, for (38), (38).2S: n /n 68.5(2), 88.5(5)°; o /n 85.5(2),
c
p
p
c
7
4.6(5)°; o /n 59.7(2), 59.1(6)°, the variation in n /np inclination
p
p
c
3
3
1
2
perhaps accompanied by a concomitant variation N(1)–C(5)–C(51)–
C(52) torsion (57.1(7), 62.2(2)º). In both cases, the iodide anion
approaches the oxazole plane with closest contacts to H(8´, 4B) at 3.18,
3
3
3
4
3
.27 (est.) (38), 3.15, 3.20 (est.) ((38).2S), suggestive of an
´electrostatic’ interaction between the anion and the charged region of
the cation substituent rather than with the aromatic charge-transfer
implications.
In (22).0.5S, the dihedral angles between the pairs of naphthalene
planes are 85.06(8) and77.39(8)º, the C.CO.N planes lying at 77.96(9),
3
5
3
3
6
7
80.9(1)º, to their associated central planes. H(14) hydrogen bonds
to O(13) (x – ½, 1½ – y, 2 – z) 1.8 Å and H(24) to O(23) (½ + x, ½ – y,
8
3
8
2
– z) both 1.9 Å, so that molecules 1 and 2 form distinct strings
Hall, S. R., King, G. S. D., and Stewart, J. M. (Eds), ‘The XTAL 3.4
User’sManual’(UniversityofWesternAustralia,Lamb:Perth,1995).
generated by 2 screw axes parallel to c.
1