Novel route to enantiopure 2,2′-diaryl-1,1′-binaphthalenes by stereoconservative Suzuki arylation at positions 2 and 2′

Article abstract of DOI:10.1135/cccc20041517

The Suzuki arylation of enantiopure 2,2′-diiodo-1,1′- binaphthalene affords the 2,2′-diarylated products in considerable yields (up to 52%), however, significantly racemized. The reversed-polarity approach, using novel enantiopure 1,1′-binaphthalene-2,2′-diyldiboronic acid, prepared either by resolution or by stereoconservative boronation, allowed, after optimization of coupling conditions, to obtain the model 2,2′-ditolylated product in good yield (56%) as well, but in addition, without impairing of enantiomeric purity (i.e. stereo-conservatively). The developed synthetic approach was found to be an expedient method for the synthesis of enantiopure 2,2′-diaryl-1,1′-binaphthalenes, especially for those with electron-neutral and electron-deficient poor aryl groups. Observing that the diboronic acid decomposes by hydrodeboronation under the reaction conditions, 2-aryl-1,1′-binaphthalenes were isolated as the main products from the reaction with less reactive electron-rich aryl iodides.

Full text of DOI:10.1135/cccc20041517

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1517
NOVEL ROUTE TO ENANTIOPURE 2,2′-DIARYL-1,1′-BINAPHTHALENES BY
STEREOCONSERVATIVE SUZUKI ARYLATION AT POSITIONS 2 AND 2′+
1
2
3
Henrich BRATH , Margaréta DUBOVSKÁ, Michal JURÍČEK , Peter KASÁK and
4,
Martin PUTALA *
Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University,
1
Mlynská dolina CH-2, 842 15 Bratislava, Slovak Republic; e-mail: henrichbrath@hotmail.com,
2
3
4
mrmojo@pobox.sk, kasak@pobox.sk, putala@fns.uniba.sk
Received April 16, 2004
Accepted Jun e 7, 2004
Th e Suzuki arylation of en an tiopure 2,2′-diiodo-1,1′-bin aph th alen e affords th e 2,2′-di-
arylated products in con siderable yields (up to 52%), h owever, sign ifican tly racem ized. Th e
reversed-polarity approach , usin g n ovel en an tiopure 1,1′-bin aph th alen e-2,2′-diyldiboron ic
acid, prepared eith er by resolution or by stereocon servative boron ation , allowed, after opti-
m ization of couplin g con dition s, to obtain th e m odel 2,2′-ditolylated product in good yield
(56%) as well, but in addition , with out im pairin g of en an tiom eric purity (i.e. stereo-
con servatively). Th e developed syn th etic approach was foun d to be an expedien t m eth od
for th e syn th esis of en an tiopure 2,2′-diaryl-1,1′-bin aph th alen es, especially for th ose with
electron -n eutral an d electron -deficien t poor aryl groups. Observin g th at th e diboron ic acid
decom poses by h ydrodeboron ation un der th e reaction con dition s, 2-aryl-1,1′-bin aph th ale-
n es were isolated as th e m ain products from th e reaction with less reactive electron -rich aryl
iodides.
Keyw ord s: Biaryls; Bin apth yls; Boron ic acids; C-C couplin g; C2-Sym m etry; Palladium ; Steric
h in dran ce; Cross-couplin g reaction s; Stereoselective syn th esis.
Despite th e in ten sive atten tion paid to th e syn th esis an d application of axi-
ally ch iral 1,1′-bin aph th alen e derivatives2–4, 2,2′-diarylated-1,1′-bin aph th a-
len es 1 h ave n ot been readily accessible. On ly specific approach es h ave
been successful for th e syn th esis of particular n on racem ic derivatives 1
with aryl, h eteroaryl or oth er cyclic groups attach ed th rough C(sp2) to th e
position s 2 an d 2′ (Sch em e 1).
A. stereoselective h om ocouplin g of n aph th alen es 2 already substituted at
position 2 (to 2,2′-bisoxazolyl-1,1′-bin aph th alen es 1A)5;
+ Prelim in ary com m un ication : see ref.1
Collect. Czech. Chem. Commun. (Vol. 69) (2004)
doi:10.1135/cccc20041517

1518
Brath et al.:
B. n on stereoselective h om ocouplin g of n aph th alen e 3 already substituted
at position 2 followed by resolution (to 2,2′-dipyridyl-1,1′-bin aph th alen es
1B)6;
SCHEME 1
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Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1519
C. build-up of h eterocyclic m oieties from carboxy groups of racem ic
diacid 4 with n on racem ic am in o alcoh ol 5, followed by separation of
diasteroisom ers (to 2,2′-bisoxazolyl-1,1′-bin aph th alen es 1C)7;
D. alm ost stereocon servative substitution at position s 2 an d 2′ of en an tio-
m erically pure dibrom ide 6a via lith iation , quen ch in g of lith ium in term edi-
ate with cyclic en on es 7, followed by arom atization an d m etallation (to
ansa-m etallocen es 1D)8 (Th is approach is specific because it uses an
electroph ile n ot readily reactin g with butyllith ium , so th e electroph ile can
be added before lith iation is com pleted an d th e substitution takes place
stepwise – as th e first at position 2, th en at position 2´ – avoidin g sign ifi-
can t racem ization via con figuration ally un stable dilith ium in term ediate.);
E. approach sim ilar to D, from racem ic dibrom ide 6a via lith iation an d
reaction with xan th en on e 8 or its th io an alogue, followed by resolution
an d arom atization (to 2,2′-bis(xan th ylium /th ioxan th ylium )-1,1′-bin aph th a-
len es 1E)9;
F. stereocon servative Negish i cross-couplin g at position s 2 an d 2′ of
en an tiopure diiodide 6b (to ansa-ferrocen e 1F)10.
Th e approach F, direct cross-couplin g arylation s at position s 2 an d 2′,
would be th e best can didate for th e sim ple an d effective syn th esis. How-
ever, in m an y variation s (Kum ada, Negish i, Suzuki or Stille), it did n ot af-
forded di-2-pyridyl derivative 1B 6. Also attem pts of Suzuki arylation s of
diboron ic acid 9 or dibrom ide 6a gave n o or on ly traces of desired diaryl-
ated products, respectively11, an d m on oarylated derivatives 10 were iso-
lated as th e m ain products in th ese cases. All th e attem pts m en tion ed h ere
were reported to be perform ed on ly from racem ic bin aph th alen e substrates.
However, reported cross-couplin g reaction s (Suzuki, Stille, Negish i) on
1,1′-bin aph th alen e derivatives at an y oth er position s th an 2 an d 2′ (m ost
often at position s 3 an d 3′ 12 or 6 an d 6′ 13 on derivatives substituted at po-
sition s 2 an d 2′ to en sure con figuration al stability), as a rule proceed
sm ooth ly, affordin g correspon din g diarylated products in good to h igh
yields with out im pairin g en an tiopurity (stereocon servatively).
Th e peculiarity of th e cross-couplin g reaction s (or an y substitution s) at
position s 2 an d 2′ con sist in substan tial steric h in dran ce (due to bulky
2-substituted 1-n aph th yl group at position adjacen t to th e reaction site)
an d th e risk of racem ization durin g th e reaction , sin ce th ese reaction s take
place at position s wh ere a n on bon din g in teraction between groups (bein g
replaced in th e course of th e reaction ) is decisive for con figuration al stabil-
ity of th ese derivatives.
With th e aim to prepare th e diarylated bin aph th alen es 1 with poten tial
application eith er in stereoselective syn th esis (as n ew ch iral ligan ds), supra-
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1520
Brath et al.:
m olecular ch em istry (as ch iral buildin g blocks), or in m aterials scien ce
(ch iral com poun ds with specific optical or electron ic properties), th e
m eth od used for th eir syn th esis sh ould be toleran t of fun ction al groups in
order to allow direct in troduction of already fun ction alized aryl groups.
Th is requirem en t togeth er with th e kn own low sen sitivity to steric h in -
dran ce14 (required as m en tion ed above) is fulfilled by th e Suzuki reaction 15
.
Th is reaction is of special in terest, sin ce organ oboron ic acids, used as an
organ om etallic com pon en t in th is reaction , are easily available, n on -toxic
an d in ert to air an d water. Th erefore we focused our effort on th e elabo-
ration of an access to en an tiopure derivatives 1 usin g th is cross-couplin g
reaction .
RESULTS AND DISCUSSION
2,2′-Dih alo-1,1′-bin ap h talen es Ap p roach (6)
2,2′-Dih alo-1,1′-bin aph th alen es (dibrom ide 6a, diiodide 6b) an d bistriflate
6c (as th eir syn th etic equivalen t), available in en an tiopure form , are suit-
able as poten tial substrates for cross-couplin g reaction s. First, we tried th e
Suzuki arylation of m ore easily accessible bistriflate 6c with ph en ylboron ic
acid, but it did n ot gave detectable am oun ts (TLC) of desired diarylated
product 1G un der an y con dition s (various Ni an d Pd catalysts, solven ts
an d bases). Traces of m on oarylated product an d bin aph th ol m on otriflate as
a product of partial h ydrolysis of bistriflate 6c, if barium h ydroxide was
used as a base, were iden tified as th e on ly n ew com poun ds in th e reaction
m ixture.
Usin g barium h ydroxide as base, we succeeded in obtain in g th e desired
diarylated products 1G an d 1H eith er from dibrom ide 6a or diiodide 6b in
con siderable yields (up to 52%, in con trast to on ly traces reported so far11),
togeth er with sm all am oun ts of m on oarylated products 10G an d 10H
(Table I).
However, startin g from en an tiopure diiodide 6b, th e obtain ed product
1H was foun d to be alm ost racem ic (Table I, 7% e.e.). Racem ization durin g
th is reaction is m ost probably caused by specific m ech an istic path way in -
cludin g con figuration ally un stable Pd(IV) in term ediate wh ich h as been re-
ported elsewh ere10
.
On th e oth er h an d, on ly m in or racem ization was observed in th e form a-
tion of m on oarylated product 10H (80% e.e.). Th e form ation of m on o-
tolylated product 10H is prevailin gly stereocon servative (con servin g spatial
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1521
arran gem en t of th e bin aph th alen e m oiety) alth ough th e stereoch em ical
descriptor h as ch an ged2,16 (applyin g CIP system rules).
TABLE I
Suzuki arylation of bin aph th alen e precursors 6a
Isolated, %
En try
Substrate
Ar
1
10
1
2
3
4
5
6c
6a
G, ph en yl
–
–
G, ph en yl
38
44
46
52c
11
19
32
10d
6b
G, ph en yl
6a
(R)-6bb
H, 4-m eth ylph en yl
H, 4-m eth ylph en yl
a
0.5 m m ol 6, 1.2 m m ol ArB(OH)2, 0.05 m m ol [Pd(PPh 3)4], 3 m m ol Ba(OH)2·8H2O, 4 m l
b
THF–H2O (1:1), reflux, 24 h ; acid work-up followed by flash ch rom atograph y. >99% e.e.
(HPLC). 7% e.e. (HPLC). 80% e.e. (HPLC).
c
d
1,1′-Bin ap h th alen e-2,2′-d iyld iboron ic Acid Ap p roach
Bein g en couraged by acceptable yields in th e Suzuki arylation of diiodide
6b m en tion ed above (sign ifican tly h igh er th an th ose reported so far), we
decided to in vestigate an approach with reversed polarity of th e substrates
for cross-couplin g, startin g from diboron ic acid 9 an d aryl h alides. In addi-
tion , th e assum ed m ech an ism for th is approach sh ould be a stan dard on e,
with out an y in term ediate causin g atropisom erization of th e bin aph th alen e
m oiety, with th e reaction s takin g place in depen den tly at both th e posi-
tion s. However, th e preparation of th e required en an tiom erically pure di-
boron ic acid 9 h as n ot been described. On th e oth er h an d, a greater variety
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1522
Brath et al.:
of aryl h alides th at can be used as reagen ts in th is approach , are available
th an th ose of arylboron ic acids applicable in th e form er polarity approach .
Preparation of Enantiopure Diboronic Acid 9
Racem ic diboron ic acid 9 was prepared by Kaufm an n et al.17 by lith iation of
racem ic dibrom ide 6a an d quen ch in g of th e gen erated dilith io derivative
with a large excess of trim eth yl borate. Th e approach usin g quen ch in g of
2,2′-dilith io-1,1′-bin aph th alen e, prepared from en an tiopure dibrom ide 6a
below –40 °C (wh ich is an aproxim ate lim it for con figuration al stability of
th e dilith ium com poun d18), with electroph iles was successfull in prepara-
tion of n on racem ic silicon 19, m ercury20 an d tin 21 2,2′-dim etallo-1,1′-bi-
n aph th alen es. However, quen ch in g with m ost of electroph iles, for in stan ce
with ch lorodiph en ylph osph in e even at –95 °C 22, gives alm ost racem ic
bin aph th alen e derivatives. Usin g th is approach , startin g from en an tiopure
dibrom ide 6a an d perform in g th e lith iation an d quen ch in g with trim eth yl
borate at low tem peratures, allowed us to isolate alm ost racem ic diboron ic
acid 9 (Sch em e 2).
SCHEME 2
Th erefore we exam in ed an oth er approach – th e m ost frequen tly used al-
tern ative route to arylboron ic acids, wh ich con sist in palladium -catalyzed
boron ation of aryl h alides in th e presen ce of am in e as a base23. Startin g
from a m ore reactive dih alobin aph th alen e – diiodide 6b, we used pin acol
boron ate (14) as a boron ation agen t, m ost often applied palladium catalysts
an d am in es, an d various solven ts (Table II). Mon oboron ates 15a an d 15b
togeth er with com pletely h ydrodeh alogen ated product – bin aph th alen e 16,
were prevailin g products in th e reaction m ixture in all cases. Full con ver-
sion of diiodide 6b was observed on ly in toluen e (en tries 4–6). Desired
diboron ate 17 was isolated in low yield usin g th e com bin ation of catalyst,
am in e an d solven t given in en try 6. Neverth eless, wh en takin g en an tiopure
diiodide (S)-6b, th e isolated diboron ate 17 was foun d to be en an tiopure
(determ in ed with diboron ic acid 9, obtain ed from diboron ate 17 by alka-
lin e h ydrolysis).
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Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1523
TABLE II
Atem pts of boron ation of 6b with dioxaborolan e 14a
Isolated, %
En try
Catalyst
Base
Solven t
17
15a
15b
16
1
2
3
4
5
6
[PdCl2(dppf)]
[PdCl2(dppf)]
[PdCl2(dppf)]
[PdCl2(PPh 3)2]
[PdCl2(dppf)]
[PdCl2(dppf)]
Et3N
ClCH2CH2Cl
1,4-dioxan e
THF
–
–
10
12
5
5
2
10
12
38
35
15
5
i-Pr2NH
i-PrEt2N
Et3N
–
–
toluen e
<3
<3
17
35
21
67
5
i-Pr2NEt
Et3N
toluen e
30
2
toluen e
a
0.5 m m ol (S)-6b, 2–3 m m ol 14, 0.05 m m ol catalyst, 3 m m ol base, 3 m l solven t, stirrin g at
90 °C for 18 h ; m ild acid work-up followed by flash ch rom atograph y.
We succeeded in m ore effective preparation of en an tiopure diboron ic
acid 9 by resolution of racem ic 9, perform ed by ch rom atograph ic separa-
tion of th e diastereoisom ers of its ester 18 with ch iral diol 19 accessible
from L-tartaric acid (Sch em e 3). Th e diastereoisom eric purity of diboron ate
SCHEME 3
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1524
Brath et al.:
1
18 was easily determ in ed from its H NMR spectra an d, after flash ch rom a-
tograph y twice on silica gel, it was foun d to be >98% d.e. (Fig. 1). Both acid
an d alkalin e h ydrolysis afforded en an tiopure diboron ic acid 9. Th e yield
an d purity of th e isolated product were h igh er in th e case of acid h ydro-
lysis, sin ce prolon ged h eatin g of diboron ic acid 9 leads to partial decom po-
sition by h ydrodeboron ation .
En an tiom eric purity of diboron ic acid 9, obtain ed from each experim en t
m en tion ed above, was determ in ed at first by com parison of its optical rota-
tion with th at of en an tiopure 9, obtain ed by resolution , an d th en by
en an tioselective HPLC of product 1H of th e subsequen t Suzuki arylation .
Th e absolute con figuration s of com poun ds 9 an d 18 were assign ed on th e
basis of th e sign of optical rotation of product 1H prepared from 9, com -
pared with th at of th e partly en rich ed product 1H obtain ed from diiodide
6b of kn own con figuration .
Isolation an d ch aracterization of diboron ic acid 9 is quite troublesom e, as
was already m en tion ed by Kaufm an n et al.17 Its precipitation from aqueous
acid m edium is n ot com plete, an d a very fin e precipitate is form ed. Precipi-
tation s with h exan es from con cen trated dich lorom eth an e solution yield a
m ixture of diboron ic acid 9 with its an h ydrides. Ch rom atograph ic purifica-
tion of 9 on silica gel causes partial h ydrodeboron ation . However, esters of
9, i.e. 17 an d 18 do n ot decom pose durin g ch rom atograph y. Th erefore it is
m ost advan tageous to purify 9 in th e form of an ester, to isolate crude
diboron ic acid 9 after h ydrolysis by precipitation from dich lorom eth an e
an d to directly use th e crude product in th e Suzuki reaction .
a
b
c
4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4
FIG. 1
Expan sion s of 1H NMR spectra of (aR,R,R,R,R)-18 (a), (aS,R,R,R,R)-18 (b) an d th eir m ixture (c)
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1525
Cross-Couplings
Optim ization of Couplin g Con dition s
Over th ousan d papers dealin g with th e Suzuki cross-couplin g reaction h ave
been already publish ed, wh ere a wide variety of com bin ation s of catalysts,
bases an d solven ts were used15,24. For optim ization of couplin g con dition s
in th e reaction of diboron ic acid 9 with m odel tolyl iodide, we exam in ed
th e m ost frequen tly used palladium catalysts (Table III), bases (Table IV)
TABLE III
Optim ization of catalyst for th e Suzuki arylation of diboron ic acid 9a
En try
Catalyst
Isolated, %
1
2
3
4
5
6
[Pd(dba)2]
[Pd(OAc)2]
[Pd(dppe)2]
[Pd(dppp)2]
[Pd(dppf)2]
[Pd(PPh 3)4]
<3
<3
10
10
25
56
a
0.5 m m ol 9, 1.2 m m ol 4-CH3C6H4I, 0.05 m m ol catalyst, 3 m m ol Ba(OH)2·8H2O, 5 m l
THF–H2O (5:1), reflux, 24 h ; acid work-up followed by flash ch rom atograph y.
TABLE IV
Optim ization of base for th e Suzuki arylation of diboron ic acid 9a
Base
Isolated, %
En try
1
2
3
4
5
6
7
KF
7
<3
0
CsF
Na2CO3
Cs2CO3
28
<3
39
52
b
K3PO4
Bu4NOHc
Ba(OH)2
a
0.5 m m ol 9, 1.2 m m ol 4-CH3C6H4I, 0.05 m m ol [Pd(PPh 3)4], 3 m m ol base, 5 m l THF,
b
reflux, 24 h ; acid work-up followed by flash ch rom atograph y. Toluen e used as solven t, th e
reaction tem perature 70 °C. 3 m m ol Bu4NOH in 1 m l of m eth an ol was used as base.
c
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1526
Brath et al.:
an d solven ts (Table V). Alth ough m on oarylated product 10H an d bin aph -
th alen e 16 were observed in th e resultin g reaction m ixtures, on ly th e target
diarylated product 1H were m on itored. Th e results obtain ed clearly sh owed
th e com bin ation of [Pd(PPh 3)4], barium h ydroxide an d aqueous tetrah ydro-
furan bein g th e best, allowin g to obtain th e desired product 1H in con sider-
able 56% yield (com pared with failure of th is approach reported so far11).
TABLE V
Optim ization of solven t for th e Suzuki arylation of diboron ic acid 9a
En try
Solven t
Isolated, %
1
2
3
4
5
6
MeOH
44
54
25
52
52
56
Ph Me
dioxan e
THF
THF–MeOH (5:1)
THF–H2O (5:1)
a
0.5 m m ol 9, 1.2 m m ol 4-CH3C6H4I, 0.05 m m ol [Pd(PPh 3)4], 3 m m ol Ba(OH)2·8H2O, 5 m l
solven t, stirrin g at 70 °C for 24 h ; acid work-up followed by flash ch rom atograph y.
In addition , wh en usin g th ese optim ized con dition s in th e reaction start-
in g from en an tiopure diboron ic acid 9 (prepared by resolution , >98% e.e.),
th e isolated product 1H was foun d to be en an tiopure as well (HPLC on
Ch iralcel Daicel OD-H colum n , >99% e.e.) (Sch em e 4).
SCHEME 4
Th e Suzuki couplin g of tolyl iodide with th e stereoisom erically pure
diboron ates (S)-17 an d (aS,R,R,R,R)-18, perform ed un der th e sam e con di-
tion s as with diboron ic acid 9, afforded en an tiopure desired diarylated
product (S)-1H in 42 an d 12% yields, respectively. Th erefore, it is advan ta-
geous to perform th e couplin gs with free diboron ic acid 9, givin g th e de-
sired product (S)-1H in h igh er yield (56%).
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Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1527
Scope an d Lim itation s – Variation of Aryl Substrates
After optim ization of couplin g con dition s an d verifyin g of stereocon ser-
vative course of th is reaction , we in ten ded to determ in e th e scope an d lim i-
tation s of th e discovered m eth od for th e preparation of en an tiopure
2,2′-diaryl-1,1′-bin aph th alen es (1). First, we exam in ed th e effect of leavin g
group of tolyl substrates (Table VI). Th e foun d depen den ce of th e yield of
th e desired diarylated product 1H in palladium -catalyzed reaction s (en tries
1–4) correspon ds to th e kn own gen eral reactivity of aryl h alides an d
triflates in th e palladium -catalyzed Suzuki reaction decreasin g in th e order:
I > Br > OTf > Cl, resultin g from th e relative reactivity of respective aryl sub-
strates in oxidative addition to a palladium (0) com plex25. Sin ce slow de-
com position of diboron ic acid 9, wh ich takes place un der th e reaction con -
dition s (h eatin g in stron gly alkalin e m edium ), is a com petitive reaction , rel-
ative reactivity of aryl substrates affects th e yield of th e diarylated product
1H. In accordan ce, in creasin g am oun ts of h ydrodeboron ated products
(m on oarylated 10H an d bin aph th alen e 16) were observed in th e reaction
m ixture with decreasin g yield of th e diarylated product 1H. Th e use of a
TABLE VI
Suzuki arylation of diboron ic acid 9 with various tolyl electroph ilesa
Isolated, %
En try
X
Catalyst
Base
1Hb
10H
1
2
3
4
5
6
I
[Pd(PPh 3)4]
[Pd(PPh 3)4]
[Pd(PPh 3)4]
[Pd(PPh 3)4]
[Ni(PPh 3)4]
[Ni(PPh 3)4]
Ba(OH)2
Ba(OH)2
Ba(OH)2
Ba(OH)2
Ba(OH)2
CsF
54
40
3
<3
10
27
41
23
38
Br
Cl
OTf
Cl
21
–
OTf
–
a
0.5 m m ol 9, 1.2 m m ol 4-CH3C6H4X, 3 m m ol base, 0.05 m m ol [Pd(PPh 3)4], 5 m l Ph Me,
b
reflux, 24 h ; acid work-up followed by flash ch rom atograph y. >99% e.e. (HPLC).
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1528
Brath et al.:
n ickel catalyst in th e case of less reactive aryl substrates in palladium -
catalyzed arylation s – tolyl ch loride an d triflate (en tries 5, 6) – did n ot lead
to th e form ation of detectable am oun ts of th e diarylated product 1H.
Th e stereocon servative course of th e tolylation reaction was proved by
en an tioselective HPLC for both ditolylated an d m on otolylated products
1H an d 10H. Despite th e spatial arran gem en t of th e bin aph th alen e m oi-
ety does n ot ch an ge durin g th e form ation of both th e products, th e stereo-
descriptor den otin g its absolute con figuration h as ch an ged in th e case of
10H.
Th ereafter, we exam in ed exploitability of th is reaction for th e prepara-
tion of various en an tiopure 2,2′-diaryl-1,1′-bin aph th alen es (1) by variation
of aryl groups in aryl h alides (Table VII). Based on th e results given above,
we preferably used aryl iodides.
TABLE VII
Suzuki arylation of diboron ic acid 9 with various aryl h alidesa
Isolated, %
En try
Ar
X
1
10
1
2
3
4
5
6
7
ph en yl (G)
I
I
I
I
46b
56b
–
12b
15b
35b
43b
<5
<5
35
37
24
<5
<5
4-m eth ylph en yl (H)
2-m eth oxyph en yl (I)
3-m eth oxyph en yl (J)
(dim eth ylam in o)ph en yl (K)
4-cyan oph en yl (L)
2-th ien yl (M)
Br
I
I
a
0.5 m m ol (S)-9, 1.2 m m ol ArX, 0.05 m m ol [Pd(PPh 3)4], 3 m m ol Ba(OH)2·8H2O, 6 m l
b
THF–H2O (5:1), reflux, 24 h ; acid work-up followed by flash ch rom atograph y. >99% e.e.
(HPLC).
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1529
Th e desired diarylated products 1 were obtain ed in con siderable yields
from th e reaction s of 9 with aryl iodides possessin g sufficien t reactivity in
oxidative addition to a palladium (0) com plex: in th e h igh est yields (from
35 to 56%) in th e case of electron -n eutral an d electron -deficien t aryls
(ph en yl G, tolyl H, cyan oph en yl L an d th ien yl M; en tries 1, 2, 6 an d 7),
an d in lower yields (12–15%) with aryls bearin g electron -don atin g groups
(3-m eth oxy J an d 4-(dim eth ylam in o) K, en tries 4 an d 5). Form ation of
diarylated product 1 was n ot observed in th e reaction of m ore sterically de-
m an din g ortho-substituted aryl iodide (2-m eth oxyph en yl I; en try 4). In all
cases, th e reaction m ixtures were quite com plex, con tain in g m on oarylated
derivatives 10 (bein g th e m ain products in th e case of electron -rich aryls
I–K, en tries 3–5), bin aph th alen e 16, h om ocouplin g products – biaryls 20
an d low am oun ts of oth er n ot iden tified products in separable by flash
ch rom atograph y in sufficien tly pure form . Th e yields of arylated products 1
were n ot rem arkably im proved wh en th e correspon din g aryl h alides were
used in a h igh er excess (4 m m ol, i.e. four-fold excess relative to on e boron ic
group). All arylated products 1 an d 10 obtain ed in sufficien t am oun t were
fully ch aracterized. Particular sign als (of m eth oxy group an d n eigh bourin g
h ydrogen or carbon atom s) in NMR spectra of m on oarylated 2-m eth oxy-
ph en yl derivative 10I were broad due to atropisom erization (rotation
aroun d th e bin aph th alen e-aryl bon d) an d th erefore th e spectra are given at
50 °C, at wh ich all sign als were sh arp.
Th e subsequen t en an tioselective HPLC of all diarylated products 1 (1G,
1H, 1J, 1K, 1L an d 1M), prepared from en an tiopure diboron ic acid 9,
proved th e stereocon servative course of th e reaction , fin din g th em to be
en an tiopure (>99%).
CONCLUSION
We h ave developed an expedien t m eth od for th e syn th esis of a n ew group
of en an tiopure 1,1′-bin aph th alen e derivatives – 2,2′-diarylated derivatives
1. On ly few of th em h ave been prepared by special m eth ods so far. Proper
ch oice of th e reaction con dition s an d th e polarity of th e substrates were
foun d to be crucial for obtain in g th ese derivatives in en an tiopure form s
an d con siderable yields (up to 56%). Th is approach is expedien t especially
for th e syn th esis of diaryl derivatives 1 with electron -n eutral or electron -
deficien t aryl groups. It is lim ited to th e syn th esis of diaryl derivatives 1
th at do n ot bear ortho-substituen t on aryl group bein g in troduced. Applica-
tion s of th e prepared fun ction alized diarylated derivatives 1 after tran sfor-
m ation to suitable ch iral ligan ds, supram olecular syn th on s or fun ction al
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1530
Brath et al.:
m aterials, are th e subject of in ten sive study in our laboratory. Oth er appli-
cation s of th e n ovel en an tiom erically pure diboron ic acid 9 are also un der
in vestigation .
EXPERIMENTAL
Flash colum n ch rom atograph y was perform ed on Merck Silica Gel (60H). Merck Silica Gel
F254 plates were used for th in layer ch rom atograph y an d visualization was effected with UV
ligh t (254 n m ). Meltin g poin ts were m easured on a Kofler block; th ey are un corrected. Spe-
cific optical rotation s were m easured on a Perkin –Elm er 241 polarim eter an d are given in
deg cm 3 g–1 dm –1. HPLC an alysis was m ade on a Ch iralcel Daicel OD-H colum n usin g a
Jasco CD-995 detector (CD an d UV detection ) or UV-VIS detector LCD 5000. UV-VIS spectra
(in n m ) were m easured on a Hewlett–Packard diode array 8245 spectroph otom eter. CD spec-
trum (in n m ) was m easured on a Jasco J710 in strum en t. IR data were recorded on a Specord
M 80 spectroph otom eter. 1H an d 13C NMR spectra were recorded on Varian Gem in i 300
in strum en t at 298 K. Ch em ical sh ifts (δ) are reported in ppm down field to in tern al stan dard
TMS (δ 0.00 ppm ) an d th e solven t was used as a referen ce. Workin g frequen cy was 300 MHz
for 1H an d 75.5 MHz for 13C NMR. Couplin g con stan ts (J) are given in Hz. GC-MS spectra
(70 eV, 150 µA, EI) were recorded on a Voyager GC/MS Fin n igan in strum en t. Elem en tal
an alyses were determ in ed with an Erba Scien ce 1106 in strum en t.
All ch em icals were used as purch ased if n ot stated oth erwise. Dich lorom eth an e was dried
with calcium ch loride un der argon . THF, toluen e, dioxan e an d dieth yl eth er were dried with
sodium /ben zoph en on e. All solven ts for couplin g reaction s were degassed with a th aw-freeze
pum p in 3 cycles an d th ese reaction s were perform ed un der n itrogen usin g th e Sch len k
tech n ique. Dibrom ide (RS)- an d (R)-6a 26, diiodide (RS)-, (R)- an d (S)-6b 26, bistriflate
17
28
(RS)-6c 27, diboron ic acid (RS)-9
an d diol (R,R)-19
were prepared accordin g to th e litera-
ture procedures.
(R)-2,2′-Dibrom o-1,1′-bin aph th alen e (6a)
M.p. 155–157 °C (h exan es–toluen e), [α ]2D3 33.2 (c 1.24, pyridin e), >98% e.e. (polarim etry)
(lit.26 m .p. 157–157.5 °C, [α ]2D1.4 +33.1 (c 1.00, pyridin e)).
(R)- an d (S)-2,2′-Diiodo-1,1′-bin aph th alen e (6b)
(R)-6b: m .p. 227–229 °C (h exan es), [α ]2D3 +16.7 (c 1.75, pyridin e), >99% e.e. (determ in ed
by HPLC) (lit.26 m .p. 225–227 °C, [α ]D23 +16.4 (c 1.725, pyridin e)). (S)-6b: [α ]2D2 –16.2 (c 1.75,
pyridin e), >99% e.e. (determ in ed by HPLC). (RS)-6b: HPLC: Ch iralcel Daicel OD-H colum n ,
eluen t n-h eptan e with 1% 1,2-dim eth oxyeth an e (DME), tem perature 16 °C, flow rate 1.0
m l/m in , pressure 31 bar, detector (UV) λ = 280 n m ; k′: 6.52 (S)-6b, 7.35 (R)-6b.
Non racem ic 1,1′-Bin aph th alen e-2,2′-diyldiboron ic Acid (9)
A dry two-n ecked flask was ch arged with 0.480 g of (R)-6a (1.17 m m ol, >96% e.e.). Th e flask
was evacuated, filled with argon an d capped with septum . 20 m l of absolute THF was added
an d cooled to –78 °C. 1.25 m l of 2 M BuLi in h exan es (2.5 m m ol, 2.14 equiv.) was added
dropwise to th e stirred reaction m ixture. After addition , th e m ixture was stirred for 1 h at
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1531
–60 °C. An oth er dry flask was ch arged with 1.2 g B(OMe)3 (1.35 m l, 11.8 m m ol, 10 equiv.)
an d 30 m l absolute THF an d th e stirred solution was cooled to –78 °C. Th e solution of
dilith iated dibrom ide was added dropwise via can n ula to th e latter solution at –78 °C durin g
1 h . Th e reaction m ixture was stirred at –78 °C for an oth er h our an d th en was allowed to
warm up to room tem perature an d stirred at th is tem perature for 10 h . Th e solven t was
evaporated an d 50 m l of dieth yl eth er, 50 m l of aqueous 1 M HCl were added to th e yellow
residue, th e m ixture was vigorously stirred to h ydrolyze for on e h our an d th en th e layers
were separated. Th e water layer was extracted th ree tim es with 30 m l portion s of dieth yl
eth er. Com bin ed organ ic layers were wash ed with saturated aqueous NaHCO3 (30 m l) an d
water (30 m l) an d dried over an h ydrous Na2SO4. After filtration an d evaporation , th e yel-
lowish residue was dissolved in 2–3 m l CH2Cl2, precipitated with ca. 20 m l of h exan es an d
cen trifuged several tim es. Product 9 was obtain ed as a wh ite solid 184 m g (46%) (m eltin g
poin t determ in ation is n ot possible because of th e form ation of oligom eric an h ydrides). 1H
an d 13C NMR spectra were in agreem en t with literature values17. En rich ed (R)-9: [α ]2D3 +5.4
(c 0.34, CHCl3), 6% e.e.
(S)-2,2′-Bis(4,4,5,5-tetram eth yl-1,3,2-dioxaborolan -2-yl)-1,1′-bin aph th alen e (17)
A dry Sch len k flask, capped with a rubber septum , was flam e-dried un der vacuum , backfilled
with argon an d cooled to room tem perature. Th e flask was ch arged with (S)-6b (253 m g,
0.5 m m ol, >98% e.e.) an d [PdCl2(dppf)] (36.7 m g, 0.05 m m ol) an d th e flask was evacuated
again an d backfilled with argon . 2 m l toluen e, 420 µl Et3N (305 m g, 3 m m ol, 6 equiv.) were
successively in jected in to th e flask, followed by 14 (78 m g, 346 µl, 2 m m ol, 2 equiv.). Th e
reaction m ixture switch ed from oran ge to brown ish an d was h eated to 90 °C an d stirred
overn igh t. After coolin g, th e reaction m ixture was poured in to 10% aqueous NH4Cl an d ex-
tracted th ree tim es with CH2Cl2 (10 m l portion s). Com bin ed organ ic fraction s were wash ed
twice with water an d brin e an d dried over an h ydrous Na2SO4. After filtration an d evapora-
tion of th e solven t, th e residue was ch rom atograph ed on silica gel (eluen t h exan es–eth yl
acetate, gradien t 10:0–9:1) (Table II).
(S)-17: colorless oil, [α ]2D2 –35.5 (c 0.83, CHCl3) (product 1H of subsequen t Suzuki reaction :
>99% e.e. as determ in ed by HPLC). Spectral data were in agreem en t with literature values17
(RS)-17: m .p. 63–65 °C (lit.17 m .p. 65 °C).
.
(S)-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,1′-binaphthalene (15a). Wh ite crystallin e
solid, m .p. 110–112 °C, [α ]2D2 –50.4 (c 1, CHCl3). Spectral data were in agreem en t with litera-
ture values17. (RS)-15a: m .p. 54–56 °C (lit.16 m .p. 53–54 °C).
(R)-2-Iodo-2′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,1′-binaphthalene (15b). Isolated
on ly as a m ixture with 15a. 1H NMR (300 MHz, CDCl3): 7.94–7.82 m , 4 H; 7.98–7.75 m ,
2 H; 7.15–7.50 m , 5 H; 7.05 d, 1 H, 3J = 8.4; 0.93 s, 6 H (CH3); 0.83 s, 6 H (CH3).
(aS,R,R,R,R)- an d (aR,R,R,R,R)-2,2′-Bis[4,5-bis(1-m eth oxy-1-m eth yleth yl)-
1,3,2-dioxaborolan -2-yl]-1,1′-bin aph th alen e (18)
A dry flask was ch arged with (RS)-9 (300 m g, 0.88 m m ol), (R,R)-19 (400 m g, 1.95 m m ol) an d
a grain of TsOH. Th e flask was evacuated an d back-filled with n itrogen . Deoxygen ated tolu-
en e 40 m l was in jected an d a Dean –Stark apparatus was attach ed. Th e reaction m ixture was
refluxed for 24 h un der n itrogen with rem oval of water. Th en th e solven t was evaporated
un der vacuum . A crude residue was purified by flash ch rom atograph y. Com bin ed esters were
obtain ed from th e th ird fraction (198 m g) of th e first ch rom atograph y on silica gel (eluen t
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

1532
Brath et al.:
h exan es–eth yl acetate, gradien t from 100:0 to 80:20), th e ratio of esters was 10:8. Th e n ext
two flash ch rom atograph ies on silica gel (eluen t h exan es–eth er 6:1) first gave (aS,R,R,R,R)-18
(86 m g, 38%) as a colorless oil, [α ]D27 +25.7 (c 0.27, CHCl3), >98% d.e. (determ in ed by 1H
NMR), RF 0.38 (h exan es–dieth yl eth er, 4:1). UV-VIS (MeOH): 228, 286, 296, 321. IR (CHCl3):
3055, 1715, 1608, 1550, 1520, 1480, 1432, 1422, 1402, 1380, 1352, 1245, 1210, 1113, 1105,
1012, 950, 846, 712, 680, 648. 1H NMR (300 MHz, CDCl3): 7.93 d, 2 H, 3J = 8.3 (Ar-H); 7.87
d, 2 H, 3J = 8.2 (Ar-H); 7.85 d, 2 H, 3J = 8.3 (Ar-H); 7.41 ddd, 2 H, J = 2.2, 6.6, 8.3 (Ar-H);
7.15 m , 4 H (Ar-H); 3.78 s, 4 H (C-H); 3.04 s, 12 H (OCH3); 0.80 s, 12 H (CH3); 0.72 s, 12 H
(CH3). 13C NMR (75 MHz, CDCl3): 146.69, 134.50, 133.74, 130.60, 127.68, 127.38, 126.33,
126.23, 125.33, 82.40, 75.59, 49.53, 20.88, 18.77. For C40H52B2O8 (682.4) calculated: 70.40%
C, 7.68% H; foun d: 70.69% C, 7.74% H. As a secon d was eluted (aR,R,R,R,R)-18 (72 m g,
25%), colorless oil, [α ]2D7 –41.1 (c 0.44, CHCl3), >98% d.e. (determ in ed by 1H NMR), RF 0.36
(h exan es–dieth yl eth er, 4:1). UV-VIS (MeOH): 228, 286, 296, 320. CD (MeOH): 332 (–m ),
313 (+m ), 302 (+s), 278 (–s), 272 (+m ), 266 (–w), 262 (+m ), 254 (–m ), 249 (+w). IR (CHCl3):
3050, 1725, 1605, 1550, 1520, 1485, 1432, 1417, 1402, 1380, 1340, 1250, 1210, 1113, 1100,
1012, 950, 846, 712, 680, 650. 1H NMR (300 MHz, CDCl3): 8.05 d, 2 H, 3J = 8.3 (Ar-H);
7.90 d, 2 H, 3J = 8.3 (Ar-H); 7.86 d, 2 H, 3J = 8.2 (Ar-H); 7.40 ddd, 2 H, J = 2.2, 5.6, 8.3
(Ar-H); 7.13 m , 4 H (Ar-H); 3.86 s, 4 H (CH); 2.98 s, 12 H (OCH3); 0.76 s, 12 H (CH3); 0.56 s,
12 H (CH3). 13C NMR (75 MHz, CDCl3): 147.14, 134.85, 133.58, 131.12, 127.55, 127.42,
126.37, 126.22, 125.47, 82.20, 75.51, 49.47, 20.95, 18.37. GC-MS (EI), m/z (%): [M+] n ot ob-
servable, 341 (26), 340 (92), 267 (73), 265 (100), 252 (60). C40H52B2O8 (682.4) calculated:
70.40% C, 7.68% H; foun d: 70.25% C, 7.62% H.
Acid Hydrolysis of 18
A solution of BBr3 (906 m g, 350 µl, 3.6 m m ol) in 2 m l of absolute CH2Cl2 was added
dropwise to a cool solution (–20 °C) of eith er (aS,R,R,R,R)- or (aR,R,R,R,R)-18 (76 m g,
0.11 m m ol, >98% d.e.) in 3 m l of absolute CH2Cl2. Wh ile stirrin g un der n itrogen , th e reac-
tion m ixture was warm ed up to room tem perature overn igh t. Th en it was carefully poured
on to ice an d extracted th ree tim es with CH2Cl2 (10 m l portion s). Com bin ed organ ic layers
were wash ed with 2% aqueous HCl, water an d dried over an h ydrous Na2SO4. After filtration ,
th e solution was con cen trated to ca. 1 m l an d th is solution was precipitated with h exan es
several tim es. Th e wh ite precipitate was dried un der vacuum , yieldin g 28 m g (74%) of pure
(S)- or (R)-3. (R)-3: [α ]2D5 +86.3 (c 0.27, CHCl3). (S)-3: [α ]D25 –87.3 (c 0.31, CHCl3).
Alkalin e Hydrolysis of 18
A m ixture of eith er (aS,R,R,R,R)- or (aR,R,R,R,R)-18 (89 m g, 0.13 m m ol, >98% e.e.) an d 5 m l
of aqueous 20% NaOH was stirred at 50 °C overn igh t. After coolin g, th e reaction m ixture
was acidified with 6 M HCl an d extracted th ree tim es with CH2Cl2 (10 m l portion s). Com -
bin ed organ ic layers were wash ed with water an d dried over an h ydrous Na2SO4. Th e filtrate
was con cen trated to ca. 1 m l an d precipitated with h exan es several tim es to yield wh ite pre-
cipitate 31.5 m g (72%), im pure (S)- or (R)-9.
Gen eral Procedure for th e Suzuki Couplin g of 6
A Sch len k flask, capped with a rubber septum , was ch arged with 6a or 6b (0.5 m m ol),
ph en yl- or (4-m eth ylph en yl)boron ic acid (1.2 m m ol), Ba(OH)2·8H2O (946.4 m g, 3 m m ol)
Collect. Czech. Chem. Commun. (Vol. 69) (2004)

Novel Route to Enantiopure 2,2 D-iaryl-1,1′-binaphthalenes
1533
an d [Pd(PPh 3)4] (57.8 m g, 0.05 m m ol), th e flask was evacuated an d backfilled with argon .
2 m l of water an d 2 m l of THF were succesively in jected in to th e flask an d th e m ixture was
h eated to 60 °C overn igh t wh ile stirrin g. After coolin g, th e reaction m ixture was poured in to
5% aqueous HCl an d extracted th ree tim es with CH2Cl2 (10 m l portion s). Com bin ed organ ic
fraction s were wash ed twice with water an d brin e an d dried over an h ydrous Na2SO4. After
filtration an d evaporation of th e solven t, th e residue was ch rom atograph ed on silica gel
(Table I).
Gen eral Procedure for th e Suzuki Couplin g of 9
A Sch len k flask was ch arged with (R)- or (S)-9 (170.5 m g, 0.5 m m ol), aryl iodide (1.2 m m ol),
Ba(OH)2·8H2O (946.4 m g, 3 m m ol) an d [Pd(PPh 3)4] (57.8 m g, 0.05 m m ol). Th e flask was
evacuated an d backfilled with argon . 1 m l water an d 5 m l THF were succesively in jected
in to th e flask an d th e m ixture was h eated to reflux overn igh t wh ile stirrin g. After coolin g,
th e reaction m ixture was poured on to aqueous 5% HCl an d extracted th ree tim es with
CH2Cl2 (10 m l portion s). Com bin ed organ ic fraction s were wash ed twice with water an d
brin e an d dried over an h ydrous Na2SO4. After filtration an d evaporation th e solven t, th e
residue was ch rom atograph ed on silica gel (Table VII).
(S)-2,2′-Diphenyl-1,1′-binaphthalene (1G). Wh ite solid, m .p. 125–128 °C, [α ]2D2 –128.5 (c 1,
CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.42 (h exan es–eth yl acetate, 10:1). UV (h ex-
an es): 226, 248, 290. IR (CHCl3): 1620 m , 1520 m , 1470 w, 1280 w, 1050 m , 880 w, 840 s,
720 s, 680 w. 1H NMR (300 MHz, CDCl3): 7.92 d, 2 H, 3J = 8.0; 7.88 d, 2 H, 3J = 8.4;
7.50–7.28 m , 8 H; 7.00 dd, 2 H, 3J = 7.3, 7.3; 6.86 dd, 4 H, 3J = 7.7, 8.4; 6.43 d, 4 H, 3J = 7.7.
13C NMR (75 MHz, CDCl3): 141.4, 139.6, 134.6, 134.3, 132.3, 129.1, 128.5, 128.1, 128.0,
127.5, 127.0, 126.5, 126.1, 125.5. GC-MS (EI), m/z (%): 406 (100) [M+], 329 (36), 326 (31),
315 (23). For C32H22 (406.4) calculated: 94.08% C, 5.92% H; foun d: 93.02% C, 6.61% H.
(RS)-1G: m .p. 228–230 °C. HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h eptan e with 1%
DME, tem perature 21 °C, flow rate 1.0 m l/m in , pressure 47 bar, detector (UV) λ = 280 n m ;
k′: 0.84 (S)-1G, 1.19 (R)-1G.
(S)-2,2′-Bis(4-methylphenyl)-1,1′-binaphthalene (1H). Wh ite solid, m .p. 179–183 °C, [α ]D22
–169.8 (c 1.01, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.45 (h exan es–eth yl acetate,
10:1). UV (h exan es): 226, 256, 294. IR (CHCl3): 3045, 1620, 1600, 1520, 1510, 1220, 1120,
1030, 870, 820, 720. 1H NMR (300 MHz, CDCl3): 7.91 d, 2 H, 3J = 8.1; 7.97 d, 2 H, 3J = 8.4;
7.23–7.48 m , 8 H; 6.69 d, 4 H, 3J = 7.8; 6.36 d, 4 H, 3J = 8.1; 2.18 s, 6 H (CH3). 13C NMR
(75 MHz, CDCl3): 140.0, 139.0, 136.0, 135.0, 134.6, 132.6, 129.4, 129.0, 128.4, 128.2, 128.1,
127.9, 126.8, 125.7, 31.3. GC-MS (EI), m/z (%): 434 (100) [M+], 326 (26), 343 (24), 163 (18).
For C34H26 (434.58) calculated: 93.94% C, 6.06% H; foun d: 94.04% C, 5.57% H. (RS)-1H:
m .p. 184–186 °C. HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h eptan e with 1.5% DME,
tem perature 21 °C, flow rate 1.0 m l/m in , pressure 50 bar, detector (UV) λ = 280 n m ; k′: 4.03
(S)-1H, 4.96 (R)-1H.
(R)-2,2′-Bis(3-methoxyphenyl)-1,1′-binaphthalene (1J). Wh ite solid, m .p. 126–130 °C, [α ]D21
+143.3 (c 1, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.32 (petroleum eth er–eth yl
acetate, 10:1). IR (CHCl3): 3015 m , 1590 s, 1480 m , 1460 s, 1420 m , 1280 m , 920 m , 820 s,
690 m . UV (MeOH (log ε)): 226 (5.86); 252 (5.60); 296 (5.28). 1H NMR (300 MHz, CDCl3):
7.96 d, 2 H, 3J = 8.1; 7.92 d, 2 H, 3J = 8.4; 7.36–7.52 m , 8 H; 6.85 dd, 2 H, 3J = 7.9, 9.1;
6.66 d, 2 H, J = 8.1; 6.10 d, 2 H, 3J = 7.6; 6.00 s, 2 H; 3.15 s, 6 H (OCH3). 13C NMR (75 MHz,
CDCl3): 158.3, 142.6, 139.6, 134.6, 134.3, 132.3, 128.4, 128.1, 128.0, 127.5, 126.6, 125.6,
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124.8, 121.6, 113.5, 113.1, 54.1. GC-MS (EI), m/z (%): 466 (100) [M• +], 313 (26), 326 (16).
(RS)-1J: m .p. 135–138 °C. HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h eptan e with 20%
DME, tem perature 21 °C, flow rate 1.0 m l/m in , pressure 47 bar, detector (UV) λ = 280 n m ;
k′: 2.09 (S)-1J, 2.67 (R)-1J.
(R)-2,2′-Bis[4-(dimethylamino)phenyl]-1,1′-binaphthalene (1K). Wh ite solid, m .p. 195–198 °C,
[α ]2D0 +12.1 (c 0.01, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.29 (h exan es–eth yl acetate,
4:1). UV-VIS (c 1.30 × 10–5 M, MeOH (log ε)): 222 (4.41), 290 (3.97). IR (CHCl3): 1610, 1520,
1420, 1410, 1350, 1220, 925, 700. 1H NMR (300 MHz, CDCl3): 7.90 d, 2 H, 3J = 8.2; 7.9 d,
2 H, 3J = 8.5; 7.48–7.35 m , 6 H, 3J = 8.5; 7.28 m , 2 H, 3J = 6.7; 6.42 d, 4 H, 3J = 8.8; 6.29 d,
4 H, 3J = 8.8; 2.81 s, 12 H (CH3). 13C NMR (75 MHz, CDCl3): 149.1, 139.0, 134.8, 134.3,
132.2, 130.4, 130.0, 129.1, 128.1, 127.8, 127.6, 126.4, 125.2, 111.8, 40.8. For C36H32N2
(492.7) calculated: 87.77% C, 6.55% H, 5.69% N; foun d: 87.22% C, 6.57% H, 5.55% N.
(RS)-1K: m .p. 270–280 °C with decom position . HPLC: Ch iralcel Daicel OD-H colum n , eluen t
n-h exan e with 10% propan -2-ol, tem perature 16 °C, flow rate 0.5 m l/m in , pressure 18 bar,
detector (UV) λ = 254 n m ; k′: 3.97 (S)-1K, 4.91 (R)-1K.
(R)-2,2′-Bis(4-cyanophenyl)-1,1′-binaphthalene (1L). Wh ite solid, m .p. 86–90 °C, [α ]2D0 +105.8
(c 0.01, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.15 (h exan es–eth yl acetate, 4:1).
UV-VIS (c 9.98 × 10–5 M, MeOH (log ε)): 222 (4.83), 272 (4.70). IR (CHCl3): 2220, 1600,
1490, 1440, 1200, 1030, 920, 840, 820, 690. 1H NMR (300 MHz, CDCl3): 8.00 d, 2 H, 3J =
8.2; 7.98 d, 2 H, 3J = 8.2; 7.58 d, 2 H, 3J = 8.2; 7.40 2 × d, 2 × 2 H; 7.33 d, 2 H, 3J = 8.2; 7.19
dd, 4 H, 3J = 8.2; 6.50 d, 4 H, 3J = 8.2. 13C NMR (75 MHz, CDCl3): 146.0, 137.8, 134.4,
134.1, 132.9, 131.3, 129.8, 129.4, 128.7, 127.7, 127.6, 127.4, 126.8, 119.0, 110.4. GC-MS
(EI), m/z (%): 456 (100) [M+], 351 (22), 338 (10). (RS)-1L: 300–310 °C with decom position .
HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h exan e with 10% propan -2-ol, tem perature
16 °C, flow rate 0.75 m l/m in , pressure 27 bar, detector (UV) λ = 254 n m ; k′: 5.23 (S)-1L, 6.78
(R)-1L.
(S)-2,2′-Di-2-thienyl-1,1′-binaphthalene (1M). Wh ite off solid, m .p. 155–159 °C, [α ]2D1 +15.7
(c 1, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.32 (h exan es–eth yl acetate, 10:1). UV-VIS
(c 9.98 × 10–5 M, MeOH (log ε)): 222 (4.83), 272 (4.70), 302 (4.39). Spectral data were in
agreem en t with literature values29. For C28H20S2 (418.6) calculated: 80.35% C, 4.33% H,
15.32% S; foun d: 79.47% C, 4.04% H, 14.56% S. (RS)-1O: m .p: 195–200 °C (aceton e–water)
(lit.29 m .p. 204–206 °C). HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h eptan e with 1%
DME, tem perature 21°C, flow rate 1.0 m l/m in , pressure 47 bar, detector (UV) λ = 280 n m ; k′:
5.84 (S)-1M, 6.35 (R)-1M.
2-Phenyl-1,1′-binaphthalene (10G). Wh ite solid, m .p. 131–133 °C (lit.11 m .p. 133 °C), RF
0.52 (h exan es–ch loroform , 4:1). Spectral data were in agreem en t with literature values11
.
(R)-2-(4-Methylphenyl)-1,1′-binaphthalene (10H). Wh ite solid, m .p. 110–111 °C, [α ]2D2.5 –133
(c 1, CHCl3), >99% e.e. (determ in ed by HPLC), RF 0.52 (h exan es–ch loroform , 4:1). Spectral
data were in agreem en t with literature values11. (RS)-10H: m .p. 121–123 °C (lit.11 m .p.
123 °C). HPLC: Ch iralcel Daicel OD-H colum n , eluen t n-h exan e with 1% DME, tem perature
17 °C, flow rate 1.0 m l/m in , pressure 32 bar, detector (UV) λ = 254 n m ; k′: 3.03 (R)-10H,
4.29 (S)-10H.
2-(2-Methoxyphenyl)-1,1′-binaphthalene (10I). Wh ite solid, m .p. 54–58 °C, RF 0.38 (h exan es–
ch loroform , 4:1). UV-VIS (c 5.08 × 10–5 M, MeOH (log ε)): 222 (4.97), 285 (3.14). IR (CHCl3):
1590, 1580, 1490, 1460, 1430, 1370, 1200, 1120, 1020, 920, 700. 1H NMR (50 °C, 300 MHz,
CDCl3): 7.99 d, 1 H, 3J = 8.2; 7.95 d, 1 H, 3J = 8.2; 7.80 d, 1 H, 3J = 8.2; 7.73 d, 1 H, 3J = 8.2;
7.57 d, 1 H, 3J = 8.2; 7.55–7.15 m , 9 H, 3J = 8.2; 7.0 dd, 1 H, 3J = 8.2, 7.7; 6.60 br, 2 H;
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3.8–3.0 br s, 3 H (OCH3). 13C NMR (50 °C, 75 MHz, CDCl3): 156.5, 137.2, 136.9, 136.8,
133.4, 133.3, 132.9, 130.9, 129.1, 128.3, 128.1, 128.1, 128.0, 127.5, 127.5, 127.4, 127.3,
126.8, 126.2, 126.0, 125.7, 125.6, 125.5, 125.1, 119.8, 110.3, 54.9. GC-MS (EI), m/z (%): 360
(100) [M+], 345 (10), 326 (19), 313 (17), 252 (15), 156, (21).
2-(3-Methoxyphenyl)-1,1′-binaphthalene (10J). Wh ite solid, m .p. 89–94 °C, RF 0.42 (h exan es–
ch loroform , 4:1). UV-VIS (c 2.54 × 10–5 M, MeOH (log ε)): 224 (4.50), 292 (4.42). IR (CHCl3):
1580, 1580, 1460, 1420, 1370, 1280, 1200, 1020, 900, 690. 1H NMR (300 MHz, CDCl3): 8.05 d,
1 H, 3J = 8.6; 7.94 d, 1 H, 3J = 8.2; 7.85 d, 1 H, 3J = 8.6; 7.80 d, 1 H, 3J = 8.2; 7.68 d, 1 H, 3J =
8.6; 7.35–7.48 m , 4 H; 7.18–7.30 m , 4 H; 6.75 ddd, 1 H, J = 8.6, 1.7, 1.0; 6.60–6.52 m , 2 H;
3.2 s, 3 H (OCH3). 13C NMR (75 MHz, CDCl3): 158.7, 143.4, 139.5, 137.3, 135.9, 134.0,
133.5, 133.4, 132.8, 129.1, 128.7, 128.4, 128.2, 128.1, 128.0, 127.7, 127.4, 126.8, 126.5,
126.3, 125.9, 125.8, 125.7, 121.9, 114.2, 113.3, 54.8. GC-MS (EI), m/z (%): 360 (100) [M+],
326 (15), 313 (27), 300 (10), 289 (11), 252 (18), 156 (24).
2-[4-(Dimethylamino)phenyl]-1,1′-binaphthalene (10K). Yellowish solid, m .p. 95–99 °C, RF
0.45 (h exan es–eth yl acetate, 4:1). UV-VIS (c 1.38 × 10–5 M, MeOH (log ε)): 224 (5.13), 284
(3.65). IR (CHCl3): 1680, 1610, 1530, 1500, 1350, 1210, 1130, 1010, 940, 900, 810, 690, 660.
1H NMR (300 MHz, CDCl3): 7.97 d, 1 H, 3J = 8.8; 7.91 d, 1 H, 3J = 8.2; 7.87 d, 1 H, 3J = 8.2;
7.81 d, 1 H, 3J = 8.2; 7.67 d, 1 H, 3J = 8.2; 7.45–7.36 m , 4 H; 7.30–7.14 m , 4 H; 6.95 d, 2 H,
3J = 8.8; 6.38 d, 2 H, 3J = 8.7; 2.78 s, 6 H (N(CH3)2). 13C NMR (75 MHz, CDCl3): 137.4,
135.2, 133.6, 133.4, 133.3, 132.3, 131.7, 130.1, 129.1, 129.0, 128.6, 128.2, 128.1, 128.0,
127.9, 127.8, 127.4, 127.0, 126.7, 126.1, 126.0, 125.5, 125.4, 112.8, 41.2. GC-MS (EI), m/z
(%): 373 (100) [M+], 327 (12), 313 (9), 163 (14).
The authors are thankful to Prof. A. Mannschreck and Prof. G. Uray for HPLC analysis. This work
was supported by the Grant Agency for Science of the Slovak Republic (grant No. 1/0091/03) and
Comenius University (grants No. UK/149/2002 and No. UK/175/2003).
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