Palladium-catalysed reactions of 6-halogeno-1,1′-binaphthyl derivatives. A detailed investigation of structure/reactivity and structure/selectivity relationships

Article abstract of DOI:10.1016/j.tet.2011.06.011

Five 6-halogeno-binaphthyl derivatives of different structure were synthesised starting from 2,2′-dihydroxy-1,1′-binaphthyl 1. Several new 6-substituted binaphthyl compounds were obtained via the palladium-catalysed reactions of these derivatives. The rea

Full text of DOI:10.1016/j.tet.2011.06.011

Tetrahedron 67 (2011) 6327e6333
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Palladium-catalysed reactions of 6-halogeno-1,10-binaphthyl derivatives.
A detailed investigation of structure/reactivity and structure/selectivity
relationships
a
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b
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Csaba Feher , Bela Urban , Laszlo Urge , Ferenc Darvas , Jozsef Bakos , Rita Skoda-Foldes
a
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University of Pannonia, Institute of Chemistry, Department of Organic Chemistry, H-8201 Veszprem, PO Box 158, Hungary
ThalesNano Inc., H-1031 Budapest, Zahony u. 7., Hungary
b
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a r t i c l e i n f o
a b s t r a c t
Five 6-halogeno-binaphthyl derivatives of different structure were synthesised starting from 2,20-dihy-
droxy-1,10-binaphthyl 1. Several new 6-substituted binaphthyl compounds were obtained via the
palladium-catalysed reactions of these derivatives. The reactivity of 6-iodo derivatives was much greater
in most cases. In cross-coupling reactions the 6-bromo compounds were converted into the products
using longer reaction times and/or higher temperatures. The reactivity difference between the two types
of substrates was especially marked in aminocarbonylation and Heck reactions.
Article history:
Received 4 January 2011
Received in revised form 16 May 2011
Accepted 6 June 2011
Available online 23 June 2011
Keywords:
1,10-Binaphthyl derivatives
Palladium
Ó 2011 Elsevier Ltd. All rights reserved.
Coupling reactions
Carbonylation
1. Introduction
Recently, we have developed a high-yielding procedure for se-
lective monoiodination of BINOL (Scheme 1) and have shown that
Asymmetric synthesis remains a challenge to synthetic chemists
as the demand for enantiomerically pure compounds continues to
increase. Optically active 2,20-dihydroxy-1,10-binaphthyl (BINOL)
and its derivatives are among the most widely used ligands for both
stoichiometric and catalytic asymmetric reactions.1
6-iodo-2,20-dipivaloyloxy-1,10-binaphthyl (4) is a highly reactive
substrate for palladium-catalysed functionalisation under very
mild reaction conditions.14
Deactivation of one of the naphthol rings via monoester for-
mation is
a prerequisite of selective monohalogenation of
Accordingly, a great variety of functionalised BINOL or BINAP
(2,20-bis(diphenylphosphino)-1,10-binaphthyl) derivatives have
beenprepared, especiallytoenablethe attachmentof the binaphthyl
core to various supports.2 Many of these heterogenisation methods
incorporate a palladium-catalysed coupling reaction of halogeno-
BINOL derivatives as the key step.3e6 Both di- and mono-
halogenated BINOL derivatives were successfully used as substrates
in these reactions. According to the literature, BINOL and its de-
rivatives can be halogenated at the 6,60-,7 3,30-8 and 5,50-9 positions.
There are several reports on the synthesis of 6-bromo-,3,10ꢀ12 3-
iodo-4 and 6-iodo BINOL derivatives.13 The iodo derivatives are
usually synthesised by multistep methods involving deiodination of
a diiodo derivative,4 or halogen exchange of a bromo compound.13
BINOL.3,12,14 After the halogenation step, compound 3 was con-
verted into the dipivaloyloxy derivative 4,14 because the in-
corporation of electron-withdrawing groups into the aromatic ring
of aryl halides warrants high reactivity in palladium-catalysed re-
actions. At the same time, although aryl halides bearing electron-
donating groups are known to be less reactive substrates in
palladium-catalysed couplings, there are some examples for the
successful conversion of halogenophenol derivatives15 and even for
the Heck reaction of 6-bromo-2-hydroxy-20-pivaloyloxy-1,10-
binaphthyl.3
Based on these findings, the applicability of 3 as substrate in
various palladium-catalysed couplings was also investigated. Al-
though 3 could be converted into the coupling products, the re-
actions took place with poor selectivity. Because of the great
importance of such couplings in the immobilisation of BINOL de-
rivatives, a more detailed investigation of the effect of the pro-
tecting and leaving groups on the outcome of the palladium-
catalysed reactions has been carried out.
* Corresponding author. Tel.: þ36 88 624719; fax: þ36 88 624469; e-mail address:
€
skodane@almos.uni-pannon.hu (R. Skoda-Foldes).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.06.011

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
I
I
OH
OH
OH
i)
ii)
OPiv
OPiv
OH
OPiv
i)
OPiv
97%
95 %
96%
2
1
3
4
84 %
iii)
Br
Br
Br
OEt
OPiv
OPiv
OPiv
i)
97%
OH
OPiv
iv)
90%
7
5
6
Scheme 1. Synthesis of 6-halogeno-1,10-binaphthyl derivatives. Reaction conditions: (i) (CH3)3CCOCl, Et3N, CH3CN, 1 h, 0 ꢁC, then 4 h at rt; (ii) Ag2SO4, I2, EtOH, 12 h, rt; (iii) Br2,
CH3CN, 0 ꢁC, 3 h; (iv) EtBr, K2CO3, acetone, reflux, 18 h.
2. Results and discussion
lower temperature and reactions were completed in shorter re-
action times (entries 6, 7 and 11, 12).
Five 6-halogeno-binaphthyl derivatives of different structure
were synthesised starting from 2,20-dihydroxy-1,10-binaphthyl 1
(Scheme 1). Selective monoiodination leading to compounds 3 and
4 was reported in our previous paper.14 The bromo-derivatives, 6-
bromo-2,20-dipivaloyloxy-1,10-binaphthyl (6) and 6-bromo-2-
ethoxy-20-pivaloyloxy-1,10-binaphthyl (7) were obtained by deri-
vatisation of the known 6-bromo-2-hydroxy-20-pivaloyloxy-1,10-
binaphthyl 5.
The other substrate with the bromo leaving group 7 gave
comparable results with the bromo derivative 6. In the Heck re-
action, the reactivities of both compounds were low (entries 4 and
5). In Stille and Sonogashira couplings the conversion of 7 (entries 9
and 14) was lower than that of 6 under the same reaction condi-
tions (entries 8 and 13). In the Suzuki coupling, the phenyl de-
rivatives 16 and 17 could be produced in good yields starting from 6
and 7, respectively (entries 16 and 17).
Compounds 3e7 were used as substrates in various palladium-
catalysed coupling and carbonylation reactions (Schemes 2 and 3,
Table 1). The reactions were followed by GC.
All of the reactions were completely selective except for the
aminocarbonylation, when a double carbonylation accompanied
the formation of the amide product 8. The products 8 and 10e17
were isolated by column chromatography and their structures were
proved by 1H, 13C NMR and MS. The formation of the side product of
the aminocarbonylation, ketoamide 9, was confirmed by the
GCeMS measurements of the reaction mixtures.16
Heck and cross-coupling reactions of 6-halogeno-BINOL de-
rivatives with one unprotected OH group (3, 5) were also in-
vestigated (Table 2). Conversions were lower in Stille (entries 1 and
4) and Heck couplings (entries 5e7) than those obtained in the
Except for the Suzuki coupling (entries 15 and 16), the iodo
derivative 4 gave uniformly better results than the corresponding
bromo compound 6. The reactivity difference between the two
substrates was especially marked in the aminocarbonylation (en-
tries 1 and 2) and Heck reactions (entries 3 and 4). In the Sono-
gashira and Stille couplings, the products could be obtained in good
yields starting from compound 6 (entries 8 and 13), but the use of
the iodo derivative 4 made it possible to carry out the reactions at
X
OR
OPiv
4
X = I, R = Piv
X = Br, R = Piv
X = Br, R = Et
6
7
[Pd]
[Pd]
[Pd]
[Pd]
[Pd]/CuI
Ph
CH2=CHCO2Me
Et3N
PhB(OH)2
K2CO3
O
NH, CO
Et3N
CH2=CHSnBu3
Ph
O
MeO2C
Ph
N
n
O
OR
OPiv
OR
OPiv
OR
OPiv
OR
OPiv
OR
OPiv
8
9
,
R = Piv n = 1
12 R = Piv
13 R = Et
10
14 R = Piv
15 R = Et
R = Piv
16
R = Piv
R = Piv, n = 2
11 R = Et
17 R = Et
Scheme 2. Palladium-catalysed reactions of 6-halogeno-1,10-binaphthyl derivatives 4, 6, 7.

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
6329
X
R
OH
OPiv
OH
OPiv
3
X = I
18
R = CH=CH2
5
X = Br
19 R = CH=CHCO2Me
20 R = CC-Ph
[Pd]
OH
OH
OPiv
OPiv
R
X
3a
X = I
18a
R = CH=CH2
5a X = Br
19a R = CH=CHCO2Me
20a R = CC-Ph
Scheme 3. Formation of isomeric products in the Stille, Heck and Sonogashira couplings of 3 and 5.
reactions of the corresponding dipivaloyl derivatives 4 and 6 (Table
1, entries 11e13 and 3 and 4) and comparable in the Sonogashira
coupling (compare entry 8 in Table 2 and entry 6 in Table 1). The
iodo compound 3 was more reactive in each case than the corre-
sponding bromo derivative 5.
iodo compound 3, the signal of another component with a similar
mass spectrum appeared in chromatograms obtained by GC and
GCeMS.
The main steps of Stille coupling involve oxidative addition of
the halide, transmetallation and reductive elimination. It can be
assumed that in the presence of the palladium catalyst, an iso-
merisation of the BINOL halide takes place prior to the trans-
metallation step. As in most cases transmetallation is the rate
determining step of Stille coupling, the extent of isomerisation
might be reduced by accelerating this step by the use of less do-
nating ligands, or by an excess of the organometallic reagent.17
Indeed, the products were obtained as a 70/30 mixture of two
isomers in the presence of the Pd2(dba)3$CHCl3/AsPh3 catalyst
system (entry 2). However, the selectivity of the reaction could not
be improved further by increasing the ratio of the organometallic
reagent (entry 3). Isolation of the two products by column chro-
matography was attempted but complete separation could not be
achieved. Mixtures with 95/5 and 35/65 product ratios were
obtained from the reactions carried out using the conditions de-
scribed in entries 2 and 1, respectively. The main product was
identified as 6-vinyl-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl 18
using 2D NMR techniques (1He1H COSY, HSQC and HMBC). Fig. 1
shows the regions of aromatic/olefinic protons of 18 (below) and
the 35/65 product mixture (above). Unfortunately, the exact posi-
tion of the vinyl substituent in 18a could not be determined from
the 2D NMR spectra of the latter sample because of the overlap of
the signals of the two isomers.
Table 1
Palladium-catalysed coupling and carbonylation reactions of 4, 6 and 7.
Entry Products Substrate Temp [ꢁC] Time [h] Yielda [%]
1b
8þ9
8þ9
10
10
11
12
12
12
13
14
14
14
15
16
16
17
4
6
4
6
7
4
4
6
7
4
4
6
7
4
6
7
100
100
100
100
100
60
rt
60
60
100
60
100
100
60
60
60
2
92 (8/9¼94/6)
2b
2 (12)
2
2
2 (24)
2
0.5
2 (8)
2
2
2
2 (4)
4
2
2
2
16 (23)g (8/9¼90/10)
3c
100
21
22 (89)
100
4c
5c
6d
7d
100
8d
50 (81)g
36
9d
11e
12e
13e
14e
15f
16f
17f
100
100
60 (100)g
75
92
93
92
a
Determined by GC.
b
Pd(OAc)2 (5 mol %), 10 mol % PPh3, substrate/morpholine/Et3N¼1/5/2 in DMF
under a CO atmosphere.
c
Pd(OAc)2 (5 mol %), 10 mol % PPh3, substrate/methyl acrylate/Et3N¼1/2.5/2 in
DMF.
d
PdCl2(PPh3)2 (5 mol %), 5 mol % CuI, substrate/phenylacetylene/Et3N¼1/2.5/2 in
Similar isomerisation was observed in the Sonogashira and Heck
reactions of 3 and also in the palladium-catalysed reactions of 5.
Although an acceleration in the Heck reaction of 5 was observed
using o-tolyl-phosphine (entry 7) instead of PPh3 (entry 6) but
isomerisation could not be suppressed.
DMF.
e
Pd(PPh3)4 (2 mol %), substrate/CH2]CHSnBu3¼1/1.1, in DMF.
f
Pd(PPh3)4 (5 mol %) substrate/PhB(OH)2/K2CO3¼1/2/5 in THF/H2O (1:1).
g
Yield obtained after heating the reaction mixture for the total time given in
parenthesis in the previous column.
According to GCeMS measurements, an isomer of 5 was
obtained in 36% yield upon heating it at 100 ꢁC in DMF in the
presence of the Pd(OAc)2/2 PPh3 catalyst for half an hour. Although
the two isomers could not be separated, the 1H NMR spectrum of
the mixture showed that the isomer had a very similar substitution
pattern to that of 5 (Fig. 2) with a doublet (J¼2 Hz) at 8.11 ppm. The
pattern of the signal and the coupling constant corresponds to
Stille coupling of 3 resulted in a 65% conversion of the substrate
in 4 h (Table 2, entry 1). Surprisingly, the formation of two products
(18, 18a) with almost identical mass spectra was observed in 52/48
ratio. At the same time, an isomerisation of the unreacted starting
material was also observed. Beside the peak corresponding to the

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
6330
Table 2
Palladium-catalysed coupling reactions of 3 and 5 with vinyltributylstannane, methyl acrylate or phenylacetylene.
Entry
Product
Substrate
Catalyst (mol % Pd)
Temp [ꢁC]
Time [h]
Conv.a [%]
Distribution of isomersa (%)
Product
Substrate
1b
2b
3c
4b
5d
6d
7d
8e
18þ18a
18þ18a
18þ18a
18þ18a
19þ19a
19þ19a
19þ19a
20þ20a
3
3
3
5
3
5
5
3
Pd(PPh3)4 (2)
100
100
100
100
100
100
100
60
4
4
4
4
2
12
2
2
65
100
100
25
63
39
52/48
70/30
65/35
64/36
56/44
53/47
56/44
57/43
55/45 (3/3a)
d
Pd2(dba)3$CHCl3þ4 AsPh3 (5)
Pd2(dba)3$CHCl3þ4 AsPh3 (5)
Pd(PPh3)4 (2)
Pd(OAc)2þ2PPh3 (5)
Pd(OAc)2þ2PPh3 (5)
Pd(OAc)2þ2P(o-Tol)3 (5)
PdCl2(PPh3)2/CuI (5)
d
65/35 (5/5a)
60/40 (3/3a)
55/45 (5/5a)
52/48 (5/5a)
d
41
100
a
Determined by GC.
b
c
Substrate/CH2]CHSnBu3¼1/1.1, in DMF.
Substrate/CH2]CHSnBu3¼1/1.65, in DMF.
d
e
Substrate/methyl acrylate/Et3N¼1/2.5/2 in DMF.
CuI (5 mol %), substrate/phenylacetylene/Et3N¼1/2.5/2 in DMF.
Although there is no mention of isomerisation in this paper, the
coupling product was found to give complicated NMR spectra with
overlappingsignals,despitethefactthatitwasanalyticallypure. Upon
hydrolysis of the pivaloyl group, the product gave satisfactory NMR
spectra corresponding to a 6-substituted 2,2-dihydroxy compound.3
Based on these observations, the mixture obtained by the
palladium-catalysed isomerisation of 5 was reacted with pivaloyl
chloride. Pivaloylation resulted in the formation of a single com-
pound that was found to be identical with 6 according to the 1H
NMR spectrum of the reaction mixture. Similarly, pivaloylation of
isomeric mixtures of products obtained by the Stille (18/18a), Heck
(19/19a) and Sonogashira reactions (20/20a) led to products iden-
tical with compounds 14, 10 and 12, respectively.
These observations support the assumption that in the coupling
reactions of 3 and 5, an isomerisation of the substrates to 3a and 5a
takes place prior to transmetallation, leading to the formation of
a mixture of 6- and 60-substituted 2-hydroxy-2-pivaloyloxy-1,10-
binaphthyl derivatives (Scheme 3).
There are two possible explanations for this isomerisation: (i)
a 6/60 palladium migration of palladium after the oxidative ad-
dition step or (ii) the migration of the pivaloyl group to the OH
oxygen of the 6-substituted naphthyl ring.
Fig. 1. Regions of aromatic/olefinic protons of 1H NMR spectra of 18/18a mixtures
(below: 18/18a¼95/5, above: 18/18a¼35/65).
However, both of these explanations have some weaknesses. A
well-known and interesting aspect of the chemistry of aryl cou-
pling is that it can take place at an arene position different from that
of the original CePd bond.18 Various aryl to aryl,19 aryl to benzylic20
and vinylic to aryl21 palladium migrations have been described in
the literature for biaryl compounds19 or naphthalene derivatives.20
Although according to DFT/B3LYP calculations of Dedieu,22 various
1/n aryl-to-aryl palladium shifts (n¼3e6) are feasible, to the best
of our knowledge, no such migrations involving binaphthyl de-
rivatives have been reported before.
On the other hand, although acyl-transfer under acidic, basic or
even neutral conditions is a known reaction in e.g., carbohydrate
chemistry, the pivaloyl group is generally regarded as less prone to
such migrations.23 Besides, according to our own results, other 2-
hydroxy-20-pivaloyloxy-1,10-binaphthyl derivatives without a ha-
lide group, such as 6-nitro-2-hydroxy-20-pivaloyloxy-1,10-
binaphthyl,14 do not undergo isomerisation in the presence of
a palladium catalyst under similar conditions.
Fig. 2. Regions of aromatic protons of 1H NMR spectra of 5 (below) and that of the
reaction mixture after isomerisation in the presence of Pd(OAc)2/PPh3 (above).
3. Conclusions
a coupling with only one proton in the meta position. That means
that the bromo substituent of the isomer can only be attached to
the 7, 60 or 70 positions of the binaphthyl core.
Uozumi reported that the Heck reaction of 5 and butyl acrylate
afforded the coupling product in 87% yield in the presence of the
Pd(OAc)2/P(o-Tol)3 catalytic system after heating for 36 h at 130 ꢁC.3
6-Iodo-1,10-binaphthyl derivatives were shown to be excellent
substrates for the palladium-catalysed functionalisation of the
binaphthyl core. Reactivities of 6-bromo derivatives were compa-
rable only in Suzuki couplings. The reactivity difference between
the two types of substrates was especially marked in amino-
carbonylation and Heck reactions. Coupling reactions of 2,20-

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
6331
dipivaloyloxy and 2-ethoxy-20-pivaloyloxy derivatives were com-
pletely selective. However, an isomerisation of the substrates was
found to take place when using 2-hydroxy-20-pivaloyloxy de-
rivatives as substrates.
in 5 mL DMF under argon. Triethylamine (139
m
L, 1 mmol) was
added and the mixture was heated at 100 ꢁC for 2e24 h. Then the
solvent was removed in vacuo. The residue was dissolved in chlo-
roform (20 mL) and washed twice with 5% HCl (20 mL), saturated
NaHCO3 (20 mL), brine (20 mL), dried over Na2SO4 and concen-
trated. The products were purified by chromatography (silica,
toluene).
4. Experimental
4.1. General
4.2.1. 6-((E)-(1-Methoxycarbonyl)-ethen-2-yl)-2,20-dipivaloyloxy-
1,10-binaphthyl (10). Yield: 256 mg (95%, starting from 4), white
solid. [Found: C, 75.69; H, 6.28, C34H34O6 requires C, 75.82; H,
Gas chromatographic analyses were performed on an HP 4890D
instrument with FID, using a 30 m, 0.32 mm ID, 0.25 mm SPB 1
column. 1H and 13C NMR spectra were recorded in CDCl3 on a Var-
ian Inova 400 spectrometer at 400.13 MHz and 100.62 MHz, re-
spectively. Mass spectra of were recorded on an HP-5971A MSD
connected to an HP-5890/II gas chromatograph. Elemental analyses
were measured on a 1108 Carlo Erba apparatus.
6.36%]; Rf (toluene) 0.18; nmax (KBr) 1750, 1721, 1115 cmꢀ1
; dH
(400.13 MHz, CDCl3) 7.97 (d, J 8.8 Hz, 1H), 7.96 (d, J 1.5 Hz, 1H), 7.95
(d, J 8.9 Hz, 1H), 7.90 (dd, J 8.1, 1.2 Hz, 1H), 7.82 (d, J 16.0 Hz, 1H),
7.43e7.50 (m, 2H), 7.41 (d, J 8.9 Hz, 1H), 7.36 (d, J 8.8 Hz, 1H),
7.23e7.33 (m, 3H), 6.48 (d, J 16.0 Hz, 1H), 3.80 (s, 3H), 0.73 (s, 9H),
0.72 (s, 9H); dC (100.62 MHz, CDCl3) 176.2, 176.1, 167.3, 148.1, 146.9,
144.5, 134.5, 134.4, 134.3, 133.2, 131.6, 131.4, 131.2, 129.7, 129.6,
129.4, 127.9, 126.8, 126.7, 125.7, 125.6, 124.2, 122.8, 121.8, 118.1, 51.7,
38.6, 38.5, 26.3, 26.2; m/z (EI) 538 (11, Mþ), 454 (38), 370 (95), 57
(100).
Compounds 2, 53 and 3, 4, 614 were obtained as described
previously.
4.1.1. 6-Bromo-2-ethoxy-20-pivaloyloxy-1,10-binaphthyl(7). 6-Bromo-
2-hydroxy-20-pivaloyloxy-1,10-binaphthyl (5) (6.7 mmol, 3.01 g) and
K2CO3 (13.4 mmol, 1.85 g) were dissolved in acetone (30 mL) under
argon. In an inert atmosphere 13.4 mmol (1.46g) EtBr was added and
the mixture was refluxed for 18 h. The solvent was removed in vacuo
and the residue was dissolved in CHCl3 (30 mL). The solution was
washed with saturated Na2S2O3 (30 mL) and brine (30 mL) and then
dried over Na2SO4. After evaporation of the solvent, the product was
purified by column chromatography (silica, n-hexane/EtOAc¼6/1) to
give 3.10 g of 7 (97% yield) as a yellow solid. [Found: C, 67.88; H 5.35,
C27H25BrO3 requires C, 67.93; H, 5.28%]; Rf (toluene) 0.60; nmax (KBr)
4.2.2. 6-((E)-(1-Methoxycarbonyl)-ethen-2-yl)-2-ethoxy-20-piv-
aloyloxy-1,10-binaphthyl (11). Yield 152 mg (63%), white solid.
[Found: C, 77.31; H 6.42, C31H30O5 requires C, 77.16; H, 6.27%]; Rf
(toluene) 0.12; nmax (KBr) 1749, 1716, 1115 cmꢀ1
; dH (400.13 MHz,
CDCl3) 7.96 (d, J 8.8 Hz, 1H), 7.93 (d, J 9.0 Hz, 1H), 7.92 (dd, J 8.3,
1.2 Hz, 1H), 7.90 (d, J 1.8 Hz, 1H), 7.79 (d, J 16.0 Hz, 1H), 7.43 (ddd, J
8.3, 6.4, 1.6 Hz, 1H), 7.39 (dd, J 8.9, 1.8 Hz, 1H), 7.38 (d, J 9.0 Hz, 1H),
7.37 (d, J 8.8 Hz, 1H), 7.24e7.28 (m, 2H), 7.10 (d, J 8.9 Hz, 1H), 6.42 (d,
J 16.0 Hz, 1H), 4.05 (q, J 7.1 Hz, 2H), 1.09 (t, J 7.1 Hz, 3H), 0.73 (s, 9H);
m/z (EI) 482 (70, Mþ), 398 (100), 370 (17), 57 (35).
1748, 1115 cmꢀ1
; dH (400.13 MHz, CDCl3) 7.99e8.04 (m, 2H), 7.96 (d, J
8.2 Hz,1H), 7.87 (d, J 8.9 Hz,1H), 7.46e7.51 (m, 3H), 7.26e7.35 (m, 3H),
7.05 (d, J 9.1 Hz, 1H), 4.07 (q, J 7.0 Hz, 2H), 1.11 (t, J 7.0 Hz, 3H), 0.80 (s,
9H); dC (100.62 MHz, CDCl3) 176.4, 154.6, 147.0, 133.6, 132.5, 131.7,
130.0, 129.7, 129.6, 129.1, 128.8, 128.2, 127.4, 126.5, 126.0, 125.4, 124.7,
122.0, 118.9, 117.5, 116.0, 65.1, 38.7, 26.6, 14.9; m/z (EI) 476/478 (53,
Mþ),392/394(100), 364/366(28),284(24), 255(26), 226(33), 57(56).
4.3. General procedure for the Sonogashira coupling of 4, 6
and 7
A solution of the 6-halogeno-1,10-binaphthyl derivative (4, 6 or
7) (0.5 mmol), PdCl2(PPh3)2 (17.5 mg, 0.025 mmol), CuI (4.8 mg,
4.1.2. 6-(Morpholino-carbonyl)-2,20-dipivaloyloxy-1,10-binaphthyl
(8). A solution of 6-iodo-2,20-pivaloyloxy-1,10-binaphthyl (4)
(290 mg, 0.5 mmol), Pd(OAc)2 (5.6 mg, 0.025 mmol), PPh3 (13.1 mg,
0.05 mmol) and morpholine (218
5 mL DMF under argon. Triethylamine (139
0.025 mmol) and phenylacetylene (137
mL, 1.25 mmol) was dis-
solved in 5 mL DMF under argon. Triethylamine (139
mL, 1 mmol)
was added and the mixture was heated at 60 ꢁC for 2 h. Then the
solvent was removed in vacuo. The residue was dissolved in chlo-
roform (20 mL) and washed twice with 5% HCl (20 mL), saturated
NaHCO3 (20 mL), brine (20 mL), dried over Na2SO4 and concen-
trated. The products were purified by chromatography (silica,
toluene).
m
L, 2.5 mmol) was dissolved in
mL, 1 mmol) was added
and the atmosphere was changed to carbon monoxide. The mixture
was heated at 100 ꢁC for 4 h, then the solvent was removed in
vacuo. The residue was dissolved in chloroform (20 mL) and
washed twice with 5% HCl (20 mL), saturated NaHCO3 (20 mL),
brine (20 mL), dried over Na2SO4 and concentrated. The product
was purified by chromatography (silica, toluene, toluene/EtOAc¼8/
1) to give 235 mg of 8 (83%) as a light yellow solid. [Found: C, 74.22;
H, 6.51; N, 2.41, C35H37NO6 requires C, 74.05; H, 6.57; N, 2.47%]; Rf
4.3.1. 6-((1-Phenyl)-ethyn-2-yl)-2,20-dipivaloyloxy-1,10-binaphthyl
(12). Yield: 268 mg (97%, starting from 4), light orange solid.
[Found: C, 82.11; H, 6.09, C38H34O4 requires C, 82.28; H, 6.18%]; Rf
(toluene) 0.58; nmax (KBr) 1751, 1116 cmꢀ1
; dH (400.13 MHz, CDCl3)
(toluene/EtOAc¼8/1) 0.81; nmax (KBr) 1750, 1634, 1100 cmꢀ1
;
dH
8.11 (d, J 1.4 Hz, 1H), 7.96 (d, J 8.9 Hz, 1H), 7.92 (d, J 9.1 Hz, 1H), 7.90
(d, J 8.9 Hz, 1H), 7.52e7.56 (m, 2H), 7.45 (ddd, J 1.4, 6.5, 8.1 Hz, 1H),
7.25e7.41 (m, 9H), 0.75 (s, 9H), 0.72 (s, 9H); dC (100.62 MHz, CDCl3)
176.3, 176.2, 147.7, 147.0, 133.4, 132.9, 131.7, 131.5, 131.4, 131.1, 129.4,
129.3, 129.1, 128.4, 128.3, 128.0, 126.8, 126.3, 125.9, 125.7, 123.9,
123.3, 123.2, 122.8, 121.9, 120.5, 90.1, 89.6, 38.7, 26.4, 26.3; m/z (EI):
554 (3, Mþ), 470 (20), 386 (61), 57 (100).
(400.13 MHz, CDCl3) 8.00 (d, J 1.3 Hz, 1H), 7.98 (d, J 8.8 Hz, 1H), 7.96
(d, J 8.9 Hz,1H), 7.90 (dd, J 8.1,1.2 Hz,1H), 7.48e7.61 (m, 2H), 7.44 (d,
J 8.9 Hz, 1H), 7.37 (d, J 8.8 Hz, 1H), 7.27e7.33 (m, 3H), 3.47e3.74 (m,
8H), 0.74 (s, 9H), 0.72 (s, 9H); dC (100.62 MHz, CDCl3) 176.2, 176.1,
170.1, 148.0, 146.9, 133.8, 133.2, 132.2, 131.4, 130.7, 129.6, 129.4,
127.9, 127.2, 126.7, 126.5, 125.7, 125.6, 124.9, 123.9, 123.0, 122.9,
121.8, 66.8, 66.3, 45.8, 40.4, 38.6, 38.5, 26.3, 26.2; m/z (EI) 567 (7,
Mþ), 483 (29), 399 (70), 313 (90), 57 (100).
4.3.2. 6-((1-Phenyl)-ethyn-2-yl)-2-ethoxy-20-pivaloyloxy-1,10-bi-
naphthyl (13). Yield: 239 mg (96%), light orange solid. [Found: C,
84.49; H, 6.12, C35H30O3 requires C, 84.31; H, 6.06%]; Rf (toluene)
4.2. General procedure for the Heck reactions of 4, 6 and 7
0.48; nmax (KBr) 1748, 1114 cmꢀ1
; dH (400.13 MHz, CDCl3) 8.06 (d, J
A solution of the 6-halogeno-1,10-binaphthyl derivative (4, 6 or
7) (0.5 mmol), Pd(OAc)2 (5.6 mg, 0.025 mmol), PPh3 (13.1 mg,
0.05 mmol) and methyl acrylate (112 mL, 1.25 mmol) was dissolved
1.3 Hz, 1H), 7.99 (d, J 8.9 Hz, 1H), 7.95 (d, J 8.3 Hz, 1H), 7.92 (d, J
9.2 Hz, 1H), 7.54e7.58 (m, 2H), 7.25e7.49 (m, 9H), 7.12 (d, J 8.8 Hz,
1H), 4.06 (q, J 6.9 Hz, 2H), 1.10 (t, J 6.9 Hz, 3H), 0.78 (s, 9H); dC

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
6332
(100.62 MHz, CDCl3) 176.3, 155.1, 147.0, 133.7, 133.5, 131.6, 131.3,
129.7, 129.0, 129.0, 128.5, 128.4, 128.2, 128.1, 126.4, 126.3, 126.1,
125.6, 125.4, 124.9, 123.5, 122.0, 118.7, 118.2, 115.5, 90.0, 89.3, 65.0,
38.7, 26.5, 14.8; m/z (EI): 498 (100, Mþ), 414 (96), 368 (30), 281 (63),
57 (39).
126.2, 126.0, 125.6, 125.5, 123.6, 123.5, 122.3, 121.9, 38.6, 38.5, 26.4,
26.3; m/z (EI) 530 (10, Mþ), 446 (31), 362 (87), 57 (100).
4.5.2. 6-Phenyl-2-ethoxy-20-pivaloyloxy-1,10-binaphthyl (17). Yield:
197 mg (83%), yellow powder. [Found: C, 83.66; H, 6.21, C33H30O3
requires C, 83.52; H, 6.37%]; Rf (toluene) 0.42; nmax (KBr) 1748,
1111 cmꢀ1
; dH (400.13 MHz, CDCl3) 8.04 (d, J 1.9 Hz, 1H), 7.98 (d, J
4.4. General procedure for the Stille coupling of 4, 6 and 7
9.0 Hz, 2H), 7.93 (d, J 8.3 Hz, 1H), 7.66e7.71 (m, 2H), 7.50 (dd, J
8.8 Hz, 1.9 Hz, 1H), 7.39e7.47 (m, 5H), 7.28e7.36 (m, 3H), 7.21 (d, J
8.8 Hz, 1H), 4.05 (q, J 7.0 Hz, 2H), 1.08 (t, J 7.0 Hz, 3H), 0.76 (s, 9H); dC
(100.62 MHz, CDCl3) 175.3, 153.4, 145.9, 140.0, 135.1, 132.7, 132.1,
130.6, 128.9, 128.2, 127.8, 127.7, 127.0, 126.1, 126.0, 125.2, 125.1,
125.0, 124.9, 124.4, 124.3, 124.2, 121.0, 117.5, 114.5, 64.0, 37.6, 25.5,
13.8; m/z (EI): 474 (98, Mþ), 390 (100), 362 (35), 344 (32), 57 (30).
In a typical reaction, a solution of the 6-halogeno-1,10-binaphthyl
derivative (4, 6 or 7) (0.5 mmol), Pd(PPh3)4 (11.5 mg, 0.01 mmol) and
vinyltributylstannane (161 mL, 0.55 mmol) was dissolved in 5 mL
DMF under argon. The mixture was heated at 100 ꢁC for 2e4 h, then
the solvent was removed in vacuo. The residue was dissolved in
toluene (20 mL), 10 mL of saturated aqueous solution of KF was
added and the mixture was stirred overnight. The organic phase was
dried over Na2SO4 and concentrated. The products were purified by
chromatography (silica, toluene).
4.6. Stille coupling of 3 in the presence of the
Pd2(dba)3$CHCl3/AsPh3 catalyst
A solution of 6-iodo-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl
(3) (248 mg, 0.5 mmol), Pd2(dba)3$CHCl3 (12.9 mg, 0.0125 mmol),
4.4.1. 6-Vinyl-2,20-dipivaloyloxy-1,10-binaphthyl (14). Yield: 180 mg
(75%), light yellow solid. [Found: C, 79.78; H, 6.91, C32H32O4 re-
quires C, 79.97; H, 6.71%]; Rf (toluene) 0.51; nmax (KBr) 1750,
AsPh3 (30 mg, 0.1 mmol) and vinyltributylstannane (161
mL,
0.55 mmol) was dissolved in 5 mL DMF under argon. The mixture
was heated at 100 ꢁC for 4 h, then the solvent was removed in
vacuo. The residue was dissolved in toluene (20 mL), 10 mL of
saturated aqueous solution of KF was added and the mixture was
stirred overnight. The organic phase was dried over Na2SO4 and
concentrated. The residue was purified by chromatography (silica,
toluene) to give 101 mg of 18/18a¼95/5 mixture (51%).24
1108 cmꢀ1
; dH (400.13 MHz, CDCl3) 7.95 (d, J 8.9 Hz, 1H), 7.92 (d, J
8.9 Hz, 1H), 7.90 (d, J 8.2 Hz, 1H), 7.81 (d, J 1.4 Hz, 1H), 7.41e7.46 (m,
2H), 7.37 (d, J 8.9 Hz, 1H), 7.36 (d, J 8.9 Hz, 1H), 7.25e7.31 (m, 2H),
7.23 (d, J 8.6 Hz, 1H), 6.85 (dd, J 11.0, 17.0 Hz, 1H), 5.80 (dd, J 0.6,
17.0 Hz, 1H), 5.30 (dd, J 0.6, 11.0 Hz, 1H), 0.75 (s, 9H), 0.73 (s, 9H); dC
(100.62 MHz, CDCl3) 176.4, 176.3, 147.1, 147.0, 136.6, 134.7, 133.4,
133.1,131.6,131.5,129.3,129.2,128.2,127.9,127.8,126.7,126.3,126.2,
126.0, 125.6, 124.0, 122.3, 121.9, 114.4, 38.7, 26.4, 26.3; m/z (EI): 480
(9, Mþ), 396 (33), 312 (86), 57 (100).
4.6.1. 6-Vinyl-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl
(18). (Ob-
tained as a 95/5 mixture of 18 and 18a) as a light yellow solid.
[Found: C, 81.62; H, 6.25, C27H24O3 requires C, 81.79; H, 6.10%]; Rf
4.4.2. 6-Vinyl-2-ethoxy-20-pivaloyloxy-1,10-binaphthyl (15). Yield:
151 mg (71%), light yellow solid. [Found: C, 81.83; H, 6.72, C29H28O3
requires C, 82.05; H, 6.65%]; Rf (toluene) 0.50; nmax (KBr) 1750,
(toluene) 0.11; nmax (KBr) 3410, 1750, 1122 cmꢀ1
; dH (400.13 MHz,
CDCl3) 8.07 (d, J 8.9 Hz,1H), 7.97 (d, J 8.2 Hz,1H), 7.85 (d, J 9.0 Hz,1H),
7.75 (br s,1H), 7.51 (ddd, J 1.3, 6.5, 8.2 Hz,1H), 7.28e7.44 (m, 5H), 7.02
(d, J 8.8 Hz, 1H), 6.83 (dd, J 10.9, 17.6 Hz, 1H), 5.77 (d, J 17.6 Hz, 1H),
5.26 (d, 10.9 Hz, 1H), 4.85 (br s, 1H), 0.81 (s, 9H); dC (100.62 MHz,
CDCl3) 177.9, 152.0, 148.3, 136.8, 133.5, 133.4, 132.8, 132.2, 130.7,
130.4, 129.0, 128.3, 127.5, 126.4, 126.2, 125.6, 124.9, 124.1, 122.9, 121.8,
118.6, 114.4, 113.3, 38.8, 26.5; m/z (EI) 396 (30, Mþ), 312 (95), 252
(14), 239 (16), 57 (100).
1114 cmꢀ1
; dH (400.13 MHz, CDCl3) 7.95 (d, J 8.8 Hz, 1H), 7.91 (d, J
8.2 Hz, 1H), 7.88 (d, J 8.9 Hz, 1H), 7.71 (d, J 1.6 Hz, 1H), 7.33e7.45 (m,
2H), 7.38 (d, J 8.8 Hz, 1H), 7.34 (d, J 8.9 Hz, 1H), 7.25e7.27 (m, 2H),
7.06 (d, J 8.9 Hz, 1H), 6.81 (dd, J 18.2, 10.9 Hz, 1H), 5.74 (d, J 18.2 Hz,
1H), 5.23 (d, J 10.9 Hz, 1H), 4.01 (q, J 7.0 Hz, 2H), 1.06 (t, J 7.0 Hz, 3H),
0.73 (s, 9H); dC (100.62 MHz, CDCl3) 176.4, 154.5, 146.9, 136.8, 133.7,
133.6, 132.8, 131.6, 129.8, 129.0, 128.8, 128.1, 126.4, 126.3, 126.2,
126.1, 125.7, 125.3, 123.8, 122.0, 118.7, 115.3, 113.3, 65.0, 38.6, 26.5,
14.9; m/z (EI): 424 (88, Mþ), 340 (100), 312 (39), 294 (23), 57 (21).
In another experiment, the mixture obtained by the Stille cou-
pling of 3 was dissolved in toluene and washed with saturated KF.
The organic phase was dried over Na2SO4 and concentrated. Et3N
(139
MeCN (6 mL) under argon. The solution was cooled to 0 ꢁC and
pivaloyl chloride (93 L, 0.75 mmol) was added. The solution was
mL, 1 mmol) was added and the mixture was dissolved in
4.5. General procedure for the Suzuki coupling of 4, 6 and 7
m
A solution of the 6-halogeno-1,10-binaphthyl derivative (4, 6 or
7) (0.5 mmol), Pd(PPh3)4 (28.9 mg, 0.025 mmol), phenylboronic
acid (122 mg, 1.0 mmol) and K2CO3 (345 mg, 2.5 mmol) was dis-
solved in THF/H2O¼1/1 mixture (5 mL) under argon. The mixture
was heated at 100 ꢁC for 2 h, then the solvent was removed in
vacuo. The residue was dissolved in chloroform (20 mL) and
washed twice with 5% HCl (20 mL), saturated NaHCO3 (20 mL),
brine (20 mL), dried over Na2SO4 and concentrated. The products
were purified by chromatography (silica, toluene).
stirred for 1 h at 0 ꢁC and then for 4 h at room temperature. The
solvent was removed in vacuo and the residue was dissolved in
CHCl3 (10 mL), washed with 5% HCl (2ꢂ10 mL), saturated NaHCO3
(10 mL) and brine (10 mL) and then dried over Na2SO4. Removal of
the solvent gave a single product identical with 14 according to
GCeMS and 1H NMR.
4.7. General procedure for the Heck reaction of 3 and 5
A solution of 6-iodo-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl
(3) or 6-bromo-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl (5)
(0.5 mmol), Pd(OAc)2 (5.6 mg, 0.025 mmol), PPh3 (13.1 mg,
4.5.1. 6-Phenyl-2,20-dipivaloyloxy-1,10-binaphthyl (16). Yield: 225 mg
(85%), brownish yellow powder. [Found: C, 81.61; H, 6.37, C36H34O4
requires C, 81.48; H, 6.46%]; Rf (toluene) 0.48; nmax (KBr) 1750,
0.05 mmol) and methyl acrylate (112
mL, 1.25 mmol) was dissolved
1117 cmꢀ1
;
dH (400.13 MHz, CDCl3) 8.10 (d, J 1.9 Hz, 1H), 8.01 (d, J
in 5 mL DMF under argon. Triethylamine (139 mL, 1 mmol) was
8.8 Hz, 1H), 7.97 (d, J 8.9 Hz, 1H), 7.91 (d, J 8.3 Hz, 1H), 7.67e7.71 (m,
2H), 7.57 (dd, J 1.9, 8.8 Hz, 1H), 7.42e7.48 (m, 3H), 7.40 (d, J 8.8 Hz,
1H), 7.39 (d, J 8.9 Hz,1H), 7.31e7.37 (m, 4H), 0.75 (s, 9H), 0.73 (s, 9H);
dC (100.62 MHz, CDCl3) 176.3, 176.2, 147.0, 146.9, 140.6, 138.1, 133.4,
132.6, 131.7, 131.4, 129.4, 129.2, 128.8, 127.8, 127.4, 127.2, 126.7, 126.6,
added and the mixture was heated at 100 ꢁC. The mixture was
analysed by GC and GCeMS.25
The GC analysis of the reaction mixture obtained by the Heck
reaction of 3 showed complete conversion of the substrate after 6 h.
Then the solvent was removed in vacuo. The residue was dissolved

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C. Feher et al. / Tetrahedron 67 (2011) 6327e6333
6333
in chloroform (20 mL) and washed twice with 5% HCl (20 mL),
saturated NaHCO3 (20 mL), brine (20 mL), dried over Na2SO4 and
concentrated. The residue and Et3N (139 L 1 mmol) was dissolved
in MeCN (6 mL) under argon. The solution was cooled to 0 ꢁC and
pivaloyl chloride (93 L, 0.75 mmol) was added. The solution was
References and notes
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2. (a) Trindade, A. F.; Gois, P. M. P.; Afonso, C. A. M. Chem. Rev. 2009, 109, 418e514;
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3. Hocke, H.; Uozumi, Y. Tetrahedron 2003, 59, 619e630.
4. Meng, Y.; Slaven, W. T., IV; Wang, D.; Liu, T. J.; Chow, H. F.; Li, C. J. Tetrahedron:
m
stirred for 1 h at 0 ꢁC and then for 4 h at room temperature. The
solvent was removed in vacuo and the residue was dissolved in
CHCl3 (10 mL), washed with 5% HCl (2ꢂ10 mL), saturated NaHCO3
(10 mL) and brine (10 mL) and then dried over Na2SO4. Removal of
the solvent gave a single product identical with 10 according to
GCeMS and 1H NMR.
Asymmetry 1998, 9, 3693e3707.
5. (a) Hocke, H.; Uozumi, Y. Tetrahedron 2004, 60, 9297e9306; (b) Wu, L.; Zheng,
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H. Y.; Hodge, P.; Kilner, M.; Tastard, C. Y.; Zhang, Z. P. Tetrahedron: Asymmetry
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M. S.; Pu, L. J. Org. Chem. 1996, 61, 8370e8377.
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4.8. Sonogashira coupling of 3
A solution of 6-iodo-2-hydroxy-20-pivaloyloxy-1,10-binaphthyl
(3) (248 mg, 0.5 mmol), PdCl2(PPh3)2 (17.5 mg, 0.025 mmol), CuI
(4.8 mg, 0.025 mmol) and phenylacetylene (137
dissolved in 5 mL DMF under argon. Triethylamine (139
m
L, 1.25 mmol) was
9. Zhang, S.; Liu, Y.; Huang, H.; Zheng, L.; Wu, L.; Cheng, Y. Synlett 2008, 853e856.
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mL,1 mmol)
was added and the mixture was heated at 60 ꢁC for 2 h. The mixture
was analysed by GC and GCeMS.26 Then the solvent was removed
in vacuo. The residue was dissolved in chloroform (20 mL) and
washed twice with 5% HCl (20 mL), saturated NaHCO3 (20 mL),
brine (20 mL), dried over Na2SO4 and concentrated. The residue and
€
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Et3N (139
m
L 1 mmol) was dissolved in MeCN (6 mL) under argon.
16. MS of 9 (m/z (rel int. %)): 595 (10) (Mþ), 511 (25), 427 (55), 285 (10), 57 (100).
17. Farina, V. Pure Appl. Chem. 1996, 68, 73e78.
The solution was cooled to 0 ꢁC and pivaloyl chloride (93
mL,
0.75 mmol) was added. The solution was stirred for 1 h at 0 ꢁC and
then for 4 h at room temperature. The solvent was removed in
vacuo and the residue was dissolved in CHCl3 (10 mL), washed with
5% HCl (2ꢂ10 mL), saturated NaHCO3 (10 mL) and brine (10 mL) and
then dried over Na2SO4. Removal of the solvent gave a single
product identical with 12 according to GCeMS and 1H NMR.
18. Chiusoli, G. P.; Catellani, M.; Costa, M.; Motti, E.; Della Ca’, N.; Maestri, G. Coord.
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23. Berces, A.; Whitfield, D. M.; Nukada, T.; Do Santos, I.; Obuchowska, A.;
Acknowledgements
Krepinsky, J. J. Can. J. Chem. 2004, 82, 1157e1171.
24. MS of 18a (m/z (rel int. %)): 396 (22) (Mþ), 312 (90), 252 (15), 239 (17), 57 (100).
25. MS of 19 (m/z (rel int. %)): 454 (4) (Mþ), 370 (15), 286 (32), 57 (100). MS of 19a
(m/z (rel int. %)): 454 (7) (Mþ), 370 (18), 286 (30), 57 (100).
The authors thank the Hungarian National Science Foundation
(OTKA NK71906) and the National Office for Research and Tech-
nology (NKFP 07 A2 FLOWREAC) for financial support.
26. MS of 20 (m/z (rel int. %)): 470 (50) (Mþ), 386 (100), 281 (23), 57 (25). MS of 20a
(m/z (rel int. %)): 470 (55) (Mþ), 386 (100), 281 (26), 57 (35).