Studies towards the N-Acylative kinetic resolution of NOBIN

Article abstract of DOI:10.1135/cccc2011034

An investigation into the N-acylation of atropisomeric anilines 8 and 2, which are related to NOBIN (1), catalysed by small molecule chiral pyridine-based nucleophilic catalysts is described. The first organocatalytic kinetic resolution (KR) of an atropis

Full text of DOI:10.1135/cccc2011034

Towards the Acylative Kinetic Resolution of NOBIN
1239
STUDIES TOWARDS THE N-ACYLATIVE KINETIC RESOLUTION OF
NOBIN
1
2
3
4
Stellios ARSENIYADIS , Mohan MAHESH , Paul McDAID , Thomas HAMPEL ,
5
6,
Stephen G. DAVEY and Alan C. SPIVEY *
Department of Chemistry, Imperial College London, South Kensington Campus,
1
2
London, SW7 2AZ, UK; e-mail: stellios.arseniyadis@espci.fr, mahesh.mohan@imperial.ac.uk,
3 paul.mcdaid@pfizer.com, 4 thhampel@web.de, 5 s.davey@nature.com, 6 a.c.spivey@imperial.ac.uk
Received February 2, 2011
Accepted May 24, 2011
Published online September 26, 2011
Dedicated to Professor Pavel Kočovský on the occasion of his 60th birthday.
An investigation into the N-acylation of atropisomeric anilines 8 and 2, which are related to
NOBIN (1), catalysed by small molecule chiral pyridine-based nucleophilic catalysts is de-
scribed. The first organocatalytic kinetic resolution (KR) of an atropisomeric aniline is de-
scribed.
Keywords: Kinetic resolution; Atropisomerism; Asymmetric synthesis; Organocatalysis.
2-Amino-2′-hydroxy-1,1′-binaphthyl [NOBIN (1); Fig. 1] was first prepared
as a racemate by Kočovský in 1991 via oxidative coupling of 2-naphthol
and 2-naphthylamine in MeOH using stoichiometric tert-butylamine/
copper(II) chloride1–3. Subsequently, a variant employing aqueous iron(III)
chloride was reported4,5, and ( )-NOBIN has been prepared from ( )-BINOL
(3; Fig. 1) by a Bucherer reaction6. Kočovský has also shown that partial op-
tical resolution concomitant with oxidative coupling can be achieved by in-
clusion of a stoichiometric amount of various chiral amines in place of
tert-butylamine during oxidative coupling. This allows for initial precipita-
tion of a complex of NOBIN, the copper salt and the chiral amine in up to
46% ee and subsequent fractional crystallisation can yield product with high
levels of optical purity7–11. Optical resolution of scalemic or ( )-NOBIN by
classical crystallisation with camphor sulfonic acid12,13, by imine exchange
of achiral imine derivatives with chiral amines14 and by inclusion com-
plexation with N-benzyl cinchonidinium chloride15 are alternative methods
to obtain enantiomerically highly enriched (R)- or (S)-NOBIN. Alterna-
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253
© 2011 Institute of Organic Chemistry and Biochemistry
doi:10.1135/cccc2011034

1240
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
tively, enantiomerically highly enriched NOBIN can be obtained by multi-
step Functional Group Interconversion (FGI) from enantiomerically pure
BINOL 16,17 or from enantiomerically pure 2′-methoxy-1,1′-binaphthylene-
2-carboxylate via conversion to its acyl azide, Curtius rearrangement to give
NOMBIN 18 (2; Fig. 1) then demethylation with BBr3 19. Both enantiomers
of BINOL are commercially available whereas enantiomerically pure (S)-2′-
methoxy-1,1′-binaphthylene-2-carboxylate [which leads to (S)-NOBIN] is
prepared by a diastereoselective ′Meyers-type′20 SNAr reaction of 2-methoxy-
1-naphthylmagnesium bromide with (–)-menthyl 1-(–)-menthoxynaphthylene-
2-carboxylate then hydrolysis18,19,21–23. These synthetic approaches, and the
applications of (S)- and (R)-NOBIN as ligands and auxiliaries for asymmetric
catalysis, have been reviewed (Fig. 1)24–26
.
OH
OH
NH2
NH2
OH
OMe
3 (S)-BINOL
1 (S)-NOBIN
2 (S)-NOMBIN
FIG. 1
Interestingly, although the synthesis of enantiomerically enriched BINOL
via asymmetric catalysis is known [e.g. via enzymatic kinetic resolution (KR)
of diester derivatives and via chiral ligand/metal-complex catalysed oxida-
tive 2-naphthol coupling]27 no direct asymmetric catalysis approach to
NOBIN has been reported. Spurred by an interest in non-enzymatic, cata-
lytic acylative KR of alcohols and amines28, and the knowledge that enzy-
matic N-acylative KR of 2-amino-1,1′-binaphthyls has not yet proved
possible29,30 we became interested in developing the KR of NOBIN and
its derivatives via chiral nucleophile catalysed non-enzymatic N-acylative
KR. Efficient procedures for O-acylative KR/asymmetric desymmetrisation
of alcohols/diols catalysed by small molecule chiral nucleophiles have been
developed for many structurally diverse substrate classes, but corresponding
N-acylative processes for amines are still rather rare28,31. This undoubtedly
reflects the fact that it is difficult to design catalysts that are substantially
more nucleophilic than many potential amine substrates and explains why
almost all successful reports of N-acylative KR reactions to date have been
applied to amine classes of moderate nucleophilicity32–38. It was our cogni-
sance of this situation, and the aforementioned substrate limitation of en-
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1241
zymatic amine KR processes, that led us to consider that an investigation of
atropisomeric anilines such as ( )-NOBIN and congeners as substrates for
small molecule chiral nucleophile N-acylative KR could be interesting.
Herein, we describe our preliminary results towards this end.
The starting point for our investigation was our previous successful
O-acylative KR of various classes of alcohols using the atropisomeric chiral
4-(dialkylamino)pyridine derivative (S)-DEAP-Ph (–)-11 (Scheme 2, below)39
Specifically, we planned initially to investigate this catalyst as a chiral
nucleophilic catalyst for effecting the N-acylative KR of atropisomeric ani-
line 8. This substrate was selected as it could be readily prepared from
2-methoxynaphthalene-1-boronic acid (4) using a Suzuki cross-coupling40
with 2-nitro-1-bromobenzene (5) to give nitro biaryl 7, followed by nitro to
amine reduction using Raney nickel (→ 8; Scheme 1).
PCy2
6
(2.4 mol%)
B(OH)2
OMe
NMe2
X
Pd2(dba)3 (1 mol%)
OMe
NO2
+
Br
K3PO4 (3 eq.)
toluene, 70 °C
5
H2, Raney-Ni
EtOH, rt
(±)-7 X = NO2, 82%
(±)-8 X = NH2, 95%
4
SCHEME 1
Gratifyingly, aniline 8 proved unreactive towards isobutyric anhydride
(1.0 equiv.) and Hünig’s base (1.0 equiv.) at –78 °C in toluene in the ab-
sence of a catalyst but showed ~30% conversion to its isobutyramide 9 after
8 h at this temperature in the presence of 1 mole % of 4-(dimethylamino)-
pyridine (4-DMAP; 12) as catalyst. Moreover, aniline 8 and its isobutyr-
amide 9 were verified as being sufficiently atropisomerically stable to allow
for analysis without racemisation by chiral stationary phase (CSP) high per-
formance liquid chromatography (HPLC)41. We also developed a quenching
protocol in which an excess of n-propylamine (6 equiv.) was added to the
reaction mixture at –78 °C to react with any unreacted isobutyric anhydride
(→ 10) prior to warming to room temperature for work-up and analysis by
CSP-HPLC. The use of a Chiralpak AD column allowed for baseline separa-
tion of both enantiomers of aniline 8 and isobutyramide 9 in a single injec-
tion (see Experimental). The stage was therefore set to attempt the KR of
aniline 8. To our surprise, however, no N-isobutyrylation occurred when
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1242
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
chiral 4-(dialkylamino)pyridine (S)-DEAP-Ph (–)-11 (1 mole %) was used as
a catalyst in place of 4-DMAP (12) for the attempted KR of aniline 8
(Scheme 2).
1) (iPrCO)2O (1.0 eq)
EtNiPr2 (1.0 eq)
O
toluene, -78 °C
H
NEt2
N
NH2
N
H
OMe
N
NH2
+
+
cat
1 mol%
OMe
OMe
O
Ph
10
2)
NH2
(6 eq)
(-)-11 (S)-DEAP-Ph
-78 °C (1 h) to rt
(±)-8
(±)-8
100%
70%
(±)-9
without catalyst:
with 4-DMAP (12):
with (S)-DEAP-Ph [(-)-11]:
C = 0%
C = 30%
C = 0%
@ 8 h
@ 8 h
100%
@ 8 h (NB. in situ 1-(1-naphthyl)ethanol is acylated)
SCHEME 2
Clearly our atropisomeric chiral 4-(dialkylamino)pyridine 11 was insuffi-
ciently active to catalyse N-acylation under conditions that 4-DMAP (12) it-
self could. In order to determine whether this reflected lack of formation of
the required acyl pyridinium salt under the reaction conditions or whether
the salt itself was less reactive than that formed from 4-DMAP (12), a com-
petition reaction in which both aniline 8 and 1-(1-naphthyl)ethanol were
present as potential substrates was carried out. The alcohol was O-acylated
cleanly and the aniline remained unreacted proving that the requisite acyl
pyridinium salt was formed42 and implicating an intrinsic lack of reactivity
towards aniline 8 of the acylpyridinium salt derived from (S)-DEAP-Ph
(–)-11 relative to that derived from 4-DMAP (12). We formulated two hy-
potheses for this – either steric hindrance was precluding attack by the
aniline on the salt or partial conjugation across the biaryl axis was electron-
ically deactivating the salt towards attack. We therefore undertook a survey
of the effect of catalyst structure on the ability to catalyse isobutyrylation
of aniline 8 using a panel of racemic 4-(dialkylamino)pyridines (13–17 and
20) and N-methyl-5-azaindolines (18, 19 and 21) that we had prepared pre-
viously during our development of alcohol KR (Fig. 1)43–45
.
Catalysts 11, 13, 14 and 15, which form a series displaying successively
reduced levels of steric bulk around their biaryl axes, all failed to catalyse
the N-isobutyrylation reaction and so steric hindrance was concluded not
to account for the lack of reactivity. However, the nature of the catalyst
core was more decisive: those catalysts based on 4-PPY (16 and 17) and par-
ticularly those based on N-methyl-5-azaindoline (18, 19 and 21) gave levels
of catalysis comparable to that of 4-DMAP (12) itself. Both of these cores
are known to exhibit greater nucleophilicity at the pyridyl nitrogen as the
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1243
NEt2
N
N
N
NEt2
NEt2
N
NEt2
N
Ph
Ph
Ph
N
11 DEAP-Ph
C = 0% @ 8 h
13
14
15
16
C = 0% @ 8 h
C = 0% @ 8 h
C = 0% @ 8 h
C = 5% @ 8 h*
Me
MeO
Me
N
N
N
NEt2
MeN
MeO
OBn
OBn
Ph
N
N
N
N
N
17
18
19
20
C = 0% @ 8 h*
21 NMe-AI-Ph
C = 30% @ 8 h*
C = 34% @ 8 h*
C = 28% @ 8 h*
C = 35% @ 8 h*
C = conversion (8 -> 9) under the conditions shown in Scheme 3. An asterix denotes the use of 5 eq of (iPrCO)2O in CH2Cl2.
FIG. 2
result of superior conjugation of the non-pyridyl nitrogen lone pair and the
pyridine ring π-system and this presumably compensates for the deactiva-
tion resulting from partial conjugation across the biaryl axis46,47. Armed with
these findings we returned to the KR of the atropisomeric aniline substrate
8 and were pleased to find that we could achieve KR of atropisomeric ani-
line ( )-8 using N-methyl-5-azaindoline (S)-NMe-AI-Ph (–)-21 (1 mole %)39,45
,
Hünig’s base (1 equiv.) and isobutyric anhydride (5.0 equiv.) in CH2Cl2 at
–50 °C for 12 h with a selectivity factor48 s = 4.4 1.0 at 31.4% conversion
(Scheme 3).
1) (iPrCO)2O (5.0 eq)
EtNiPr2 (1.0 eq)
O
MeN
N
H
CH2Cl2, -50 °C, 12 h
N
NH2
N
H
+
NH2
+
Ph
cat
1 mol%
OMe
O
OMe
OMe
10
2)
NH2
(-)-21 (S)-NMe-AI-Ph
(6 eq)
8
9
(±)-8
s = 4.4±1.0
C = 31.4%
68.6% (25.3% ee)
31.4% (55.1% ee)
SCHEME 3
The absolute stereochemistry of neither the substrate 8 nor the isobutyr-
amide product 9 were determined and so the sense of stereoinduction in
this KR process was not ascertained; the enantiomers depicted in Scheme 3
are therefore arbitrary. Encouraged by these results, and hoping that in-
creased levels of selectivity would be displayed by the 1,1-binaphthyl con-
gener, NOMBIN (2), we prepared this compound as a racemate via ′Meyers-
type′ SNAr coupling between 1-methoxy-2-nitronaphthalene (23) and the
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1244
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
Grignard reagent derived from 2-methoxy-1-bromonaphthalene (24) ac-
cording to the method of Miyano49 (Scheme 4).
MgBr
Me2SO4
OMe
K2CO3
acetone
H2, 10% Pd/C
MeOH, rt
NO2
NH2
24
OMe
OMe
NO2
NO2
THF, 70 °C
OH
22
OMe
23 95%
(±)-25 71%
(±)-2 NOMBIN 69%
SCHEME 4
Attempted KR of 1,1′-binaphthyl aniline ( )-2 (NOMBIN) under identical
conditions to those that had proved successful for its 1-phenylnaphthyl
congener ( )-8 (cf. Scheme 3) resulted in just 14.0% conversion after 43 h
at –50 °C in CH2Cl2. Moreover, the reaction displayed a selectivity factor
of just s = 1.4 0.2. As previously, there was no background reaction in
the absence of catalyst and the reaction could be conveniently monitored
and the selectivity analysed by CSP-HPLC following a single injection onto
TABLE I
MeN
H
1) Conditions
N
O
Ph
see Table 1
O
N
AcO
NH2
NH2
N
R
cat
10
28
+
+
H
(-)-21 (S)-NMe-AI-Ph
OMe
tBu
O
O
O
OMe
OMe
or
tBu
HN
N
2)
NH2
(6 eq)
Ph
N
Ph
MeN
H
Ph
29
26 R = iPr
27 R = Me
2
(±)-2 NOMBIN
N
(+)-21 (R)-NMe-AI-Ph
Entry Conditions
Additives
–
t, h T, °C
Yields, % (ee, %)a
1
(–)-21 (1.2 mol %)
(i-PrCO)2O (4.3 eq)
EtNi-Pr2 (1 eq) CH2Cl2
(0.4 ml)
43
–50
(S)-2 86.0
(R)-26 14.0
(2.8 0.5)
(17.0 0.5)
2
3
(+)-21 (5 mol %)
29 (0.5 eq) tol (0.7 ml)
LiBr (1.5 eq);
18-c-6 (0.75 eq)
44
54
–10
–10
2 94.0
(0.0 0.5)
27 6.0
(0.0 0.5)
(+)-21 (20 mol %)
29 (3.0 eq) tol/CH2Cl2
(1:1, 0.5 ml)
–
2 23.0
(0.0 0.5)
27 72.0
(0.0 0.5)
a
In all cases control reactions were conducted under identical conditions but in the absence
of catalyst and no reaction was observed (e.g. see Fig. 3, below).
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1245
a chiralpak AD column. The absolute configuration of both the substrate 2
and the isobutyramide product 26 were assigned by reference to correla-
tions established by Hattori49 (Table I, entry 1).
Pursuing further the hypothesis that the efficiency of catalysis is critically
dependent upon the structure and reactivity of the acyl pyridinium salt de-
rived from the N-methyl-5-azaindoline catalyst 21 we explored alternative
a
b
FIG. 3
a CSP-HPLC time-course for the uncatalysed background reaction corresponding to Table I, en-
try 3. A – 9-methylanthracene (internal standard), B – first enantiomer of 2 (unreacted
NOMBIN), B′ – second enantiomer of 2 (unreacted NOMBIN); analytical Chiralpak AD-H
column (0.46 cm × 25 cm), mobile phase: n-hexane/2-propanol (9:1), flow rate: 1 ml/min @ 25
°C, UV: λ = 250 nm (ref. = 360 nm), injection: 2 µl solution in 2-propanol (25 µl of the reac-
tion mixture was quenched with n-propyl amine overnight). b CSP-HPLC time-course for the
catalysed reaction corresponding to Table I, entry 3. A – 9-methylanthracene (internal stan-
dard), B – first enantiomer of 2 (unreacted NOMBIN), B′ – second enantiomer of 2 (unreacted
NOMBIN), C – first enantiomer of amide 27, C′ – second enantiomer of amide 27; same condi-
tions as above
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1246
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
acylating reagents in place of isobutyric anhydride. After considerable
experimentation we found that use of conditions closely similar to those
disclosed by Fu et al. for the acylative KR of indolines34 allowed for N-
acetylation even at –10 °C without the intervention of a background reac-
tion (Table I, entry 2). These conditions feature O-acetylazlactone derivative
29 as acylating agent in conjunction with LiBr and 18-crown-6 as additives
in toluene. However, even when employing 5 mole % catalyst (cf. 1.2 mole %
in entry 1), conversion remained just 6.0% after 44 h and no enantio-
selectivity was measurable. Good levels of conversion could be achieved
under modified conditions in which 20 mole % catalyst was employed in
a toluene/CH2Cl2 mixed solvent system at –10 °C with an excess of the
acylating agent 29 (3 equiv. cf. 0.5 equiv. in entry 2) and no additives
(Table I, entry 3). This allowed for 72% conversion after 54 h but again no
enantioselectivity was discernable. HPLC time-courses for the uncatalysed
and catalysed reactions corresponding to this experiment are shown below
(Fig. 3).
In conclusion, we have described an investigation into the N-acylation of
atropisomeric anilines 8 and 2, which are related to NOBIN (1), catalysed
by small molecule chiral pyridine-based nucleophilic catalyst 21. Although
conditions for the N-acylation of 1,1′-binaphthyl aniline ( )-2 (NOMBIN)
catalysed by 20 mole % N-methyl-5-azaindoline catalyst (S)-NMe-AI-Ph
(–)-21 have been established, the reaction proceeds without enantio-
selectivity. By contrast, conditions for the N-acylative KR of its 1-phenyl-
naphthyl congener ( )-8 (s = 4.4 1.0 @ C = 31.7%) using just 1 mole % of
the same catalyst has been achieved; this is the first example of an organo-
catalytic acylative KR of an atropisomeric substrate. Clearly, there is a sig-
nificant difference in reactivity and propensity for chiral recognition
between these topologically related substrates. We are currently exploring
the role of the nature of the ether group in NOMBIN-type substrates and
further structural variants of the nucleophilic catalyst and acylating agent
in order to discover conditions for an efficient KR protocol leading to
NOBIN itself and these studies will be reported in due course.
EXPERIMENTAL
General Directions
Solvents and reagents: Solvents were dried as follows – CH2Cl2 (CaH2), benzene (CaH2),
toluene (Na), Et2O (Na/benzophenone ketyl), MeOH [Mg(OMe)2] and EtOH [Mg(OEt)2]. Re-
agents were used as commercially supplied unless otherwise stated and handled in accor-
dance with COSHH regulations50. Chromatography: Flash chromatography was performed on
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1247
silica gel (60 F254, 230–400 mesh) according to the method of W. C. Still51. Thin layer chro-
matography (TLC) was performed on aluminium plates pre-coated with silica (60 F254
,
0.2 mm) which were developed using standard visualising agents: ultraviolet fluorescence
(254 nm), KMnO4/∆ or vanillin/∆. Chiral stationary phase (CSP)-high performance liquid
chromatography (HPLC) – An Agilent 1100 instrument was employed with elution with
commercial HPLC grade, degassed solvents. Spectra: 1H NMR spectra were recorded at 250
and 400 MHz. Chemical shifts (δH) are quoted in parts per million (ppm) referenced to the
appropriate residual solvent peak, with the abbreviations s, d, t and m denoting singlet,
doublet, triplet and multiplet, respectively. 13C NMR spectra were recorded at 62.5 and
100 MHz. Chemical shifts (δC) are quoted in parts per million (ppm) referenced to the ap-
propriate residual solvent peak, with the abbreviations s, d, t and q denoting C, CH, CH2
and CH3, respectively. Coupling constants J are given in Hz. Infra red (IR) spectra were re-
corded as thin films or as solids. Only selected absorbencies (νmax, cm–1) are reported. Mass
spectra (MS) – Molecular ions and major peaks only are reported for low resolution spectra.
Intensities are given as percentages of the base peak. HRMS values are valid to 5 ppm.
Melting points: Analyses were carried out using a hot stage and are uncorrected.
( )-2-Methoxy-1-(2′-nitrophenyl)naphthalene (7)40,52
A mixture of 2-methoxynaphthalene-1-boronic acid53 (4; 750.5 mg, 3.72 mmol), 2-nitro-
1-bromobenzene (5; 500 mg, 2.48 mmol), Pd2(dba)3 (22.6 mg, 0.02 mmol, 1 mole %),
2-dicyclohexylphosphino-2′-(N,N′-dimethylamino)biphenyl54 (6; 23.4 mg, 0.06 mmol,
2.4 mole %) and K3PO4 (1.05 mg, 4.46 mmol) in dry toluene (10 ml) was stirred under
nitrogen at 70 °C for 1 h 30 min. The mixture was diluted with EtOAc, washed with sat.
NaHCO3 (aq.), water, brine, dried over Na2SO4 and the solvent was removed in vacuo. Flash
chromatography eluting with CH2Cl2 then hexane/EtOAc (20:1) gave nitroaryl compound 7
as brown needles (570 mg, 82%). M.p. 133–134 °C (hexane/EtOAc) [lit.52 133–134 °C]; RF
0.42 (hexane/EtOAc, 10:1). 1H NMR (400 MHz, CDCl3): 3.83 (3 H, s, OCH3), 7.35 (1 H, d, J =
8.9, ArH), 7.36–7.42 (3 H, m, ArH), 7.45 (1 H, dd, J = 7.5, 1.4, ArH), 7.60 (1 H, ddd, J = 7.8,
7.7, 1.4, ArH), 7.73 (1 H, ddd, J = 7.7, 7.5, 1.3, ArH), 7.84–7.90 (1 H, m, ArH), 7.95 (1 H, d,
J = 8.9, ArH), 8.14 (1 H, dd, J = 7.8, 1.3, ArH). IR (neat): 3064, 2941, 2840, 1622, 1594, 1524,
1512, 1464, 1353, 1340, 1276, 1262, 1251, 1149, 1126, 1067, 1022, 909, 857, 810, 787, 750.
MS (EI) m/z (rel. int., %): 279 (100, M•+), 220 (52), 189 (48), 165 (23), 109 (18), 95 (21), 77
(7). HRMS (EI) m/z: found: (M+) 279.0904, C17H13NO3 requires 279.0895 (∆ = +3.2 ppm).
( )-2-(2′-Methoxynaphthalene-1-yl)phenylamine (8)52
To a suspension of 2-methoxy-1-(2-nitrophenyl)naphthalene (7; 2.41 mg, 8.6 mmol) in etha-
nol (120 ml) was added Raney Nickel as a 50% slurry in water (1 g). The reaction flask was
evacuated and backfilled with H2 (3×) and the reaction mixture allowed to stir under 1 at-
mosphere of H2 at room temperature for 16 h. The catalyst was removed by filtration
through Celite®, washed through repeatedly with ethanol. The solvent was removed under
reduced pressure to give yellow oil. Purification by flash chromatography eluting with
CH2Cl2 then hexane/EtOAc (5:1) gave aniline 8 as pale yellow needles (2.04 g, 95%). M.p.
81.5–82.5 °C (hexane/EtOAc) [lit.52 83–84 °C]; RF 0.27 (petrol ether/EtOAc, 7:1). 1H NMR
(400 MHz, CDCl3): 3.78 (3 H, s), 6.83 (2 H, m), 7.03 (1 H, dd, J = 7.0, 1.5), 7.19 (1 H, m),
7.25–7.29 (3 H, m), 7.36 (1 H, m), 7.82 (1 H, d, J = 9.0). IR (neat): 3457, 3375, 3053, 2938,
2837, 1614, 1592, 1507, 1496, 1453, 1382, 1332, 1298, 1262, 1250, 1179, 1147, 1120, 1067,
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1248
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
1020, 905, 812, 749. MS (EI) m/z (rel. int., %): 249 (97, M•+), 218 (100), 217 (89), 204 (22),
189 (12), 178 (10), 165 (4), 125 (6), 117 (7), 109 (9), 102 (11), 93 (4), 77 (4). HRMS (EI) m/z:
found: (M+) 249.1161, C17H15NO requires 249.1154 (∆ = +2.8 ppm).
Kinetic Resolution of Biaryl Aniline ( )-8 (Scheme 3)
A solution of the atropisomeric aniline ( )-8 (80 mg, 0.32 mmol), Hünig’s base (55 µl,
0.32 mmol) and catalyst (–)-(S)-NMe-AI-Ph 21 39,45 (1.1 mg, 0.0032 mmol, 1 mole %) in
CH2Cl2 (0.65 ml) was cooled to –50 °C using a cryostat. During vigorous stirring, isobutyric
anhydride (270 µl, 1.6 mmol) was then added dropwise over 2 min and the resulting mix-
ture stirred at –50 °C for 12 h. n-Propylamine (0.16 ml, 1.92 mmol) was then added
dropwise with rapid stirring and the mixture was stirred for a further 1 h at –50 °C before al-
lowing the reaction mixture to warm to room temperature. The reaction mixture was diluted
with CH2Cl2 (50 ml) and washed sequentially with sat. NaHCO3 (aq.) (2 × 50 ml) and brine
(50 ml). The organic layer was dried over MgSO4 and the solvent removed in vacuo. The
crude mixture of products 8, 9 and 10 was analysed by 1H NMR spectroscopy and by
CSP-HPLC: Chiralpak AD (4.6 mm × 25 cm); hexane/EtOH (99:1); 0.6 ml/min; 40 °C; UV de-
tection at 230 nm, reference at 360 nm. Retention times: aniline 8: 25.5 min (minor) and
31.8 min (major); isobutyramide 9: 19.3 min (major) and 20.5 min minor). NB. The absolute
stereochemistry of the enantiomers were not assigned; by product 10 is not detected at this
wavelength.
( )-N-[2-(2-Methoxynaphthalen-1-yl)phenyl]isobutyramide (9)
A colourless viscous oil. RF 0.38 (petrol/EtOAc, 4:1). 1H NMR (400 MHz, CDCl3): 0.81 (3 H,
d, J = 7.0), 0.90 (3 H, d, J = 7.0), 2.10 (1 H, m), 3.90 (3 H, s), 6.96 (1 H, br s), 7.27–7.52
(7 H), 7.87 (1 H, m), 8.01 (1 H, d, J = 9.0), 8.43 (1 H, d, J = 8.0). 13C NMR (100 MHz,
CDCl3): 19.1 (2 × q), 36.5 (d), 56.6 (q), 113.3 (d), 119.6 (s), 121.1 (d), 123.8 (d), 124.1 (d),
124.9 (d), 126.0 (s), 127.2 (d), 128.0 (d), 128.6 (d), 129.1 (s), 130.5 (d), 131.5 (d), 133.3 (s),
136.5 (s), 154.1 (s), 174.7 (s). IR (neat): 3414, 2966, 1690, 1511. MS (EI+) m/z (rel. int., %):
319 (30, M•+), 217 (100). HRMS (EI+) m/z: found: (M+) 319.1569, C20H21NO2 requires
319.1572 (∆ = –0.9 ppm).
n-Propylisobutyramide (10)55
A low-melting white solid, m.p. 36 °C. 1H NMR (400 MHz, CDCl3): 0.93 (3 H, t, J = 7.4,
CH2CH3), 1.16 (6 H, d, J = 6.9, 2 × CH3), 1.53 (2 H, tq, J = 7.0, 7.4, CH2CH3), 2.35 (1 H, sep,
J = 6.9, CH), 3.21 (2 H, app q, J = 7.0, NCH2), 5.63 (1 H, broad s, NH). 13C NMR (100 MHz,
CDCl3): 11.3 (q), 19.7 (2 × q), 22.9 (t), 35.7 (d), 41.0 (t), 177.0 (s). IR (neat): 3293, 3092,
2966, 2933, 2875, 1644, 1547, 1465, 1376, 1242, 1151, 1094, 942, 778. MS (EI+) m/z (rel.
int., %): 129 (33, M•+), 114 (9), 100 (7), 86 (17), 72 (21), 71 (35), 55 (5), 43 (100). HRMS
(EI+) m/z: found: (M+) 129.1158, C7H15NO requires 129.1154 (∆ = +3.1 ppm).
1-Methoxy-2-nitronaphthalene (23)56
To a solution of 2-nitro-1-naphthol (22; 2.79 g, 14.7 mmol) in acetone (20 ml) were added
K2CO3 (3.8 g, 27.5 mmol) and dimethylsulfate (2.0 ml, 21.1 mmol). The resulting reaction
mixture was stirred at reflux for 20 h before being cooled to room temperature, concen-
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1249
trated in vacuo and the residue partitioned between CH2Cl2 (20 ml) and sat. NaHCO3 (aq.)
(40 ml). The phases were separated, the organic phase washed with brine (30 ml), dried over
Na2SO4 and then concentrated in vacuo to give a brown solid. Recrystallisation of this solid
from hexane/EtOAc (3:1) yielded methyl ether 23 as bright yellow needles (2.85 g, 95%).
M.p. 78–79 °C (hexane/EtOAc) [lit.56 80 °C]; RF 0.36 (hexane/EtOAc, 19:1). 1H NMR
(400 MHz, CDCl3): 4.17 (3 H, s, OCH3), 7.62–7.73 (3 H, m, ArH), 7.88–7.95 (2 H, m, ArH),
8.30–8.37 (1 H, m, ArH). 13C NMR (100 MHz, CDCl3): 63.7 (q), 121.0 (d), 124.2 (d),
124.3 (d), 127.6 (d), 128.2 (d), 128.6 (s), 129.5 (d), 136.5 (s), 139.1 (s), 151.7 (s). IR (neat):
3102, 2990, 2947, 2861, 1620, 1584, 1521, 1498, 1460, 1439, 1427, 1375, 1340, 1321, 1262,
1214, 1144, 1086, 1027, 976, 913, 859, 874, 816. MS (EI+) m/z (rel. int., %): 203 (100, M•+),
156 (76), 142 (20), 129 (33), 128 (43), 127 (92), 114 (53), 102 (20), 88 (14), 77 (12), 63 (12),
51 (7). HRMS (EI+) m/z: found: (M+) 203.0587, C11H9NO3 requires 203.0582 (∆ = +2.5 ppm).
( )-2-Methoxy-2′-nitro-1,1′-binaphthyl (25)57
To a solution of 2-methoxy-1-bromonaphthalene (24; 1.40 g, 5.91 mmol) in diethyl ether
(40 ml) were added magnesium turnings (0.57 g, 23.6 mmol), dibromomethane (0.62 g,
0.30 ml, 0.30 mmol) and a small crystal of iodine. The reaction mixture was sonicated for
3 h after which time a white slurry had formed; this was dissolved by addition of benzene
(40 ml). An aliquot of the resulting solution containing the Grignard reagent (55 ml) was
added via cannula to a solution of 1-methoxy-2-nitronaphthalene (23; 800 mg, 3.94 mmol)
in benzene (55 ml). A red colouration appeared and the reaction mixture was allowed to stir
for 1 h at room temperature before the remaining solution of Grignard reagent (25 ml) was
added dropwise. The reaction mixture was stirred for further 30 min then the solution was
cooled to 0 °C and water (10 ml) added dropwise. The phases were separated and the or-
ganic layer was dried over Na2SO4. The solvent was evaporated under reduced pressure. Col-
umn chromatography eluting with CH2Cl2 then hexane/EtOAc (20:1) gave nitroaryl
compound 25 as yellow crystals (923 mg, 71%). M.p. 169–171 °C (hexane/EtOAc) [lit.57
170–171 °C]; RF 0.15 (hexane/EtOAc, 10:1). 1H NMR (400 MHz, CDCl3): 3.79 (3 H, s),
6.93–8.14 (12 H, m). 13C NMR (100 MHz, CDCl3): 56.6 (q), 113.3 (d), 117.6 (s), 120.6 (d),
123.9 (d), 124.4 (d), 127.1 (d), 127.9 (d), 128.0 (s), 128.26 (2 × d), 128.30 (d), 128.7 (d),
129.0 (s), 129.3 (d), 130.6 (d), 132.8 (s), 133.4 (s), 135.1 (s), 147.5 (s), 154.4 (s). IR (neat):
3056, 3006, 2939, 2839, 1621, 1593, 1524, 1506, 1464, 1345, 1273, 1263, 1179, 1132, 1083,
1021, 810, 759, 750. MS (EI+) m/z (rel. int., %): 329 (97, M•+), 314 (21), 299 (13), 270 (100),
241 (49), 239 (50), 226 (18), 215(16), 188 (12), 158 (10), 155 (9), 134 (18), 120 (26), 113
(12), 102 (9), 89 (10), 43 (27). HRMS (EI+) m/z: found: (M+) 329.1058, C21H15NO3 requires
329.1052 (∆ = +1.8 ppm).
( )-2-Amino-2′-methoxy-1,1′-binaphthyl (NOMBIN; 2)49
A solution of 2-methoxy-2′-nitro-1,1′-binaphthyl (25; 688 mg, 2.09 mmol) in methanol
(30 ml) and CH2Cl2 (10 ml) was sonicated for 2 min and then 10% Pd/C (206.4 mg) was
added. The reaction mixture was stirred under an atmosphere of H2 at room temperature for
3 h. The reaction mixture was filtered through Celite® and the solvent was evaporated un-
der reduced pressure. Flash chromatography eluting with CH2Cl2 then hexane/EtOAc (10:1)
gave the aminobinaphthyl 2 as a violet solid (609 mg, 69%). M.p. 138–139 °C (hexane/
EtOAc) [lit.49 139–141°C]; RF 0.19 (hexane/EtOAc, 5:1). 1H NMR (400 MHz, CDCl3): 3.14 (br,
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1250
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
2 H), 3.76 (s, 3 H), 6.95–8.01 (m, 12 H). 13C NMR (100 MHz, CDCl3): 56.9 (q), 114.0 (s),
114.4 (d), 118.3 (d), 118.9 (s), 122.2 (d), 124.0 (d), 124.3 (d), 125.1 (d), 126.3 (d), 127.0 (d),
128.05 (d), 128.10 (d), 128.3 (s), 129.0 (d), 129.6 (s), 130.0 (d), 133.7 (s), 134.2 (s), 141.9 (s),
155.5 (s). IR (neat): 3466, 3377, 3200, 3054, 3007, 2936, 2837, 1617, 1590, 1505, 1476,
1463, 1430, 1380, 1351, 1329, 1259, 1245, 1178, 1146, 1075, 1048, 1019, 904, 809, 747,
735. MS (EI+) m/z (rel. int., %): 299 (100, M•+), 284 (10), 267 (27), 254 (11), 239 (10), 226
(6), 156 (14), 143 (4), 134 (12), 127 (6), 120 (5), 113 (4), 101 (3), 91 (2), 57 (2). HRMS (EI+)
m/z: found: (M+) 299.1319, C21H17NO requires 299.1310 (∆ = +3.0 ppm).
Kinetic Resolution of NOMBIN ( )-2 (Table I)
Entry 1: A solution of NOMBIN ( )-2 (25.7 mg, 0.086 mmol), Hunig’s base (15.0 µl,
0.087 mmol) and catalyst (–)-(S)-NMe-AI-Ph 21 39,45 (0.29 mg, 0.8 µmol, 1.2 mole %) in
CH2Cl2 (0.4 ml) was cooled to –50 °C using a cryostat. During vigorous stirring, isobutyric
anhydride (70 µl, 0.42 mmol) was then added dropwise over 2 min and the resulting mix-
ture stirred at –50 °C for 12 h. n-Propylamine (42 ml, 0.52 mmol) was then added dropwise
with rapid stirring and the mixture was stirred for a further hour at –50 °C before allowing
the reaction mixture to warm to room temperature. The reaction mixture was diluted with
CH2Cl2 (50 ml) and washed sequentially with sat. NaHCO3 (aq.) (2 × 50 ml) and brine
(50 ml). The organic layer was dried over MgSO4 and the solvent removed in vacuo. The
crude residue containing compounds 2, 26 and 10 was analysed by 1H NMR spectroscopy
and by CSP-HPLC: Chiralpak AD (4.6 mm × 25 cm); hexane/i-PrOH (80:20); 1.0 ml/min;
20 °C; UV detection at 250 nm, reference at 525 nm. Retention times: NOMBIN (2): 7.1 min
[(R)-(+)-minor] and 12.9 min [(S)-(–)-major]; NOMBIN isobutyramide 26: 5.5 min [(R)-major]
and 9.4 min [(S)-minor]. NB. The absolute stereochemistry of the enantiomers of NOMBIN
(2) were assigned by reference to those determined by Hattori et al.49 using identical
CSP-HPLC conditions; by product 10 is not detected at this wavelength.
N-[2-Amino-2′-methoxy-1,1′-binaphthyl]isobutyramide (26)
A pale brown solid. 1H NMR (400 MHz, CDCl3): 0.80 (3 H, d, J = 6.9, CH3), 0.88 (3 H, d, J =
6.9, CH3), 2.12 (1 H, tt, J = 6.9, 6.9, CH), 6.97 (1 H, broad s, NH), 7.11 (1 H, app d, J = 8.5,
ArH), 7.14 (1 H, app d, J = 8.5, ArH), 7.22–7.31 (2 H, m, ArH), 7.35–7.44 (2 H, m, ArH), 7.52
(1 H, d, J = 9.0, ArH), 7.89–7.96 (2 H, m, ArH), 8.01 (1 H, d, J = 9.0, ArH), 8.10 (1 H, d, J =
9.0, ArH), 8.63 (1 H, app d, J = 9.0, ArH). 13C NMR (100 MHz, CDCl3): 19.1 (2 × q), 36.4 (d),
56.6 (q), 113.5 (d), 117.1 (s), 120.8 (d), 121.3 (s), 124.2 (d), 124.6 (d), 124.8 (d), 125.7 (d),
126.2 (d), 127.5 (d), 128.10 (d), 128.14 (d), 128.7 (d), 129.3 (s), 130.9 (d), 132.9 (s), 133.5 (s),
134.5 (s), 155.1 (s), 174.9 (s). MS (CI) m/z (rel. int., %) 387 (10, M + NH4+), 370 (100, M +
H+), 299 (5). HRMS (CI) m/z: found: (M + H+) 370.1819, C25H23NO2 requires 370.1807 (∆ =
+3.3 ppm).
Entry 2: An oven-dried 0.5 ml microwave glass vial (0.7 cm ID × 7.5 cm, Biotage Ltd.)
equipped with a Teflon® magnetic stirring bar was charged with catalyst (+)-(R)-NMe-AI-Ph
21 39,45 (0.8 mg, 5 mole %), NOMBIN (2; 0.015 g, 0.05 mmol), 18-crown-6 (0.010 g,
0.0375 mmol), anhydrous LiBr (0.0065 g, 0.075 mmol), and the vial was sealed with an
air-tight aluminium/rubber septum using a crimper. The contents in the vial was dried in
vacuo and purged with argon gas (3×). Toluene (0.4 ml) was added and the reaction mixture
was stirred vigorously for 0.5 h at room temperature with occasional sonication to afford a
heterogeneous mixture containing a white precipitate in a clear pale brown solution. It was
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1251
then cooled to –10 °C using a cold isopropanol bath and stirred for 30 min. A solution of
the acylating reagent 29 34 (0.0065 g, 0.025 mmol) in dry toluene (0.3 ml) at –10 °C was
added to the reaction mixture under an argon atmosphere. The contents were stirred at
–10 °C for stipulated reaction time, after which the reaction mixture was quenched with ex-
cess n-propylamine (25 µl, 0.3 mmol) and stirred at –10 °C for 1 h and slowly warmed to
room temperature overnight. The reaction mixture was then extracted with EtOAc (50 ml)
and washed sequentially with sat. NaHCO3 solution (2 × 25 ml) and brine (50 ml). The or-
ganic layer was dried over anhydrous Na2SO4 and evaporated to dryness. The crude residue
containing compounds 2, 27 and 28 was analysed by 1H NMR spectroscopy and by
CSP-HPLC: Chiralpak AD-H (4.6 mm × 25 cm); hexane/i-PrOH (90:10); 1.0 ml/min; 25 °C;
UV detection at 250 nm, reference at 360 nm. Retention times: NOMBIN (2): 11.6 min
[(R)-(+)] and 28.2 min [(S)-(–)]; NOMBIN acetamide 27: 19.0 min (R) and 25.3 min (S). NB.
The absolute stereochemistry of the enantiomers of NOMBIN (2) were assigned by analogy
with those from entry 1; by product 28 is not detected at this wavelength.
2-Amino-2′-methoxy-1,1′-binaphthyl acetamide (27)
A brown solid; m.p. 178–180 °C (CH2Cl2); RF 0.53 (n-hexane/EtOAc, 1:1). 1H NMR (400 MHz,
CDCl3): 1.84 (3 H, s, COCH3), 3.81 (3 H, s, OCH3), 6.92 (1 H, broad s, NH), 7.01–7.11 (2 H,
m, ArH), 7.20–7.31 (2 H, m, ArH), 7.35–7.45 (2 H, m, ArH), 7.52 (1 H, app d, J = 9.0, ArH),
7.89–7.96 (2 H, m, ArH), 8.00 (1 H, d, J = 9.0, ArH), 8.09 (1 H, d, J = 9.0, ArH), 8.58 (1 H, d,
J = 9.0, ArH). 13C NMR (100 MHz, CDCl3): 24.6 (q), 56.7 (q), 113.7 (d), 117.1 (s), 120.8 (d),
124.2 (d), 124.7 (d), 124.9 (d), 125.7 (d), 126.3 (d), 127.4 (d), 128.1 (d), 128.2 (d), 128.7 (d),
129.3 (s), 130.9 (d), 131.7 (s), 132.9 (s), 133.5 (s), 134.4 (s), 155.2 (s), 168.3 (s), (1 × s ab-
sent). IR (neat): 3408, 3263, 3057, 2935, 1677, 1619, 1593, 1495, 1425, 1353, 1263, 1249,
1147, 1083, 1055, 1018, 864, 811, 746. MS (EI) m/z (rel. int., %) 341 (100, M•+), 299 (79),
267 (49), 239 (12), 198 (21), 156 (21), 105 (20). HRMS (EI+) m/z: found: (M+) 341.1419,
C
23H19NO2 requires 341.1416 (∆ = +0.9 ppm).
N-Benzoyl-tert-butylglycine propylamide (28)34
Colourless needles (EtOAc/n-hexane, 1:1); m.p. 186.5–187.5 °C; RF 0.39 (n-hexane/EtOAc,
4:1). 1H NMR (400 MHz, CDCl3): 0.92 (3 H, t, J = 7.4, CH2CH3), 1.09 (9 H, s, 3 × CH3), 1.54
(2 H, q, J = 7.4, CH2CH3), 3.14 (1 H, m, NCH2), 3.34 (1 H, m, NCH2), 4.66 (1 H, d, J = 9.2,
CH), 6.84 (1 H, broad s, NH), 7.05 (1 H, d, J = 9.2, NH), 7.42–7.45 (2 H, m, ArH), 7.50–7.55
(1 H, m, ArH), 7.80–7.85 (2 H, m, ArH). 13C NMR (100 MHz, CDCl3): 11.5 (q), 22.7 (t), 26.8
(3 × q), 35.3 (s), 41.3 (t), 60.8 (d), 127.1 (d), 128.6 (d), 131.7 (d), 134.3 (s); 167.2 (s), 170.5
(s). IR (neat): 3308, 2962, 2935, 2872, 1670, 1629, 1578, 1529, 1491, 1481, 1389, 1367,
1335, 1278, 1241, 1188, 1149, 802, 751. MS (ESI) m/z (rel. int., %): 299 (19, M + Na+), 277
(100, M + H+), 218 (20), 190 (7). MS (EI) m/z (rel. int., %): 276 (11, M•+), 261 [22, (M-CH3)+],
220 [16, (M-tBu)+], 202 (5), 190 (72), 176 (16), 161 (10), 115 (14), 105 (100), 77 (41), 60
(23), 51 (7). HRMS (ESI+ve) m/z: found: (M + H+) 277.1917, C16H25N2O2 requires 277.1916
(∆ = +0.4 ppm).
REFERENCES AND NOTES
1. Smrčina M., Lorenc M., Hanuš V., Kočovský P.: Synlett 1991, 231.
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

1252
Arseniyadis, Mahesh, McDaid, Hampel, Davey, Spivey:
2. Smrčina M., Vyskočil Š., Máca B., Polášek M., Claxton T. A., Abbott A. P., Kočovský P.:
J. Org. Chem. 1994, 59, 2156.
3. Lipshutz B. H., Buzard D. J., Olsson C., Noson K.: Tetrahedron 2004, 60, 4443.
4. Ding K., Xu Q., Wang Y., Liu J., Yu Z., Du B., Wu Y., Koshima H., Matsuura T.: Chem.
Commun. 1997, 693.
5. Vyskočil S., Smrčina M., Lorenc M., Kočovský P., Hanuš V., Polášek M.: Chem. Commun.
1998, 585.
6. Körber K., Tang W., Hu X., Zhang X.: Tetrahedron Lett. 2002, 43, 7163.
7. Smrčina M., Lorenc M., Hanuš V., Sedmera P., Kočovský P.: J. Org. Chem. 1992, 57, 1917.
8. Smrčina M., Poláková J., Vyskočil Š., Kočovský P.: J. Org. Chem. 1993, 58, 4534.
9. Vyskočil S., Jaracz S., Smrčina M., Sticha M., Hanuš V., Polášek M., Kočovský P.: J. Org.
Chem. 1998, 63, 7727.
10. Hon S.-W., Li C.-H., Kuo J.-H., Barhate N. B., Liu Y.-H., Wang Y., Chen C.-T.: Org. Lett.
2001, 3, 869.
11. Yusa Y., Kaito I., Akiyama K., Mikami K.: Chirality 2010, 22, 224.
12. Smrčina M., Vyskočil Š., Polívková J., Poláková J., Kočovský P.: Collect. Czech. Chem.
Commun. 1996, 61, 1520.
13. Singer R. A., Brock J. R., Carreira E. M.: Helv. Chim. Acta 2003, 86, 1040.
14. Mahmoud H., Han Y., Segal B. M., Cai L.: Tetrahedron: Asymmetry 1998, 9, 2035.
15. Ding K., Wang Y., Yun H., Liu J., Wu Y., Terada M., Okubo Y., Mikami K.: Chem. Eur. J.
1999, 5, 1734.
16. Singer R. A., Buchwald S. L.: Tetrahedron Lett. 1999, 40, 1095.
17. Salinger D., Bruckner R.: Synlett 2009, 109.
18. Hattori T., Hotta H., Suzuki T., Miyano S.: Bull. Chem. Soc. Jpn. 1993, 66, 613.
19. Brunner H., Henning F., Weber M.: Tetrahedron: Asymmetry 2002, 13, 37.
20. Meyers A. I., Lutomski K. A.: Synthesis 1983, 105.
21. Ito Y., Miyake T., Hatano S., Shima R., Ohara T., Suginome M.: J. Am. Chem. Soc. 1998,
120, 11880.
22. Van Veldhuizen J. J., Garber S. B., Kingsbury J. S., Hoveyda A. H.: J. Am. Chem. Soc.
2002, 124, 4954.
23. Brunner H., Weber M., Zabel M.: Z. Naturforsh. B: Chem. Sci. 2003, 58, 821.
24. Kočovský P., Vyskočil Š., Smrčina M.: Chem. Rev. 2003, 103, 3213.
25. Ding K. L., Guo H. C., Li X., Yuan Y., Wang Y.: Top. Catal. 2005, 35, 105.
26. Ding K. L., Li X., Ji B. M., Guo H. C., Kitamura M.: Curr. Org. Synth. 2005, 2, 499.
27. Brunel J. M.: Chem. Rev. 2007, 107, PR1-PR45.
28. Spivey A. C., Arseniyadis S.: Top. Curr. Chem. 2010, 291, 233.
29. Aoyagi N., Izumi T.: Tetrahedron Lett. 2002, 43, 5529.
30. van Rantwijk F., Sheldon R. A.: Tetrahedron 2004, 60, 501.
31. Wurz R. P.: Chem. Rev. 2007, 107, 5570.
32. Arai S., Bellemin-Laponnaz S., Fu G. C.: Angew. Chem. Int. Ed. 2001, 40, 234.
33. Birman V. B., Jiang H., Li X., Guo L., Uffman E. W.: J. Am. Chem. Soc. 2006, 126, 6536.
34. Arp F. O., Fu G. C.: J. Am. Chem. Soc. 2006, 128, 14264.
35. Anstiss M., Nelson A.: Org. Biomol. Chem. 2006, 4, 4135.
36. De C. K., Klauber E. G., Seidel D.: J. Am. Chem. Soc. 2009, 131, 17060.
37. Fowler B. S., Mikochik P. J., Miller S. J.: J. Am. Chem. Soc. 2010, 132, 2870.
38. Klauber E. G., De C. K., Shah T. K., Seidel D.: J. Am. Chem. Soc. 2010, 132, 13624.
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253

Towards the Acylative Kinetic Resolution of NOBIN
1253
39. Spivey A. C., Zhu F., Mitchell M. B., Davey S. G., Jarvest R. L.: J. Org. Chem. 2003, 68,
7379.
40. Yin J., Buchwald S. L.: J. Am. Chem. Soc. 2000, 122, 12051.
41. For example, enantiomerically pure biaryls 8 and 9 (obtained by separation using chiral
stationary phase HPLC, see Experimental) were found to lose <5% ee on standing for 1
week at 25 °C and to be essentially configurationally stable over this time period in a
–20 °C freezer.
42. Previous studies on catalyst 11 had established that there is no background reaction
between 1-(1-naphthyl)ethanol and isobutyric anhydride under these conditions (see
ref.39).
43. Spivey A. C., Fekner T., Adams H.: Tetrahedron Lett. 1998, 39, 8919.
44. Spivey A. C., Fekner T. S., Spey S. E., Adams H.: J. Org. Chem. 1999, 64, 9430.
45. Spivey A. C., Fekner T. S., Spey S. E.: J. Org. Chem. 2000, 65, 3154.
46. Heinrich M. R., Klisa H. S., Mayr H., Steglich W., Zipse H.: Angew. Chem. Int. Ed. 2003,
42, 4826.
47. Rycke N. D., Berionni G., Couty F. O., Mayr H., Goumont R., David O. R. P.: Org. Lett.
2010, 13, 530.
48. Kagan H. B., Fiaud J. C.: Top. Stereochem. 1988, 18, 249.
49. Hattori T., Takeda A., Yamabe O., Miyano S.: Tetrahedron 2002, 58, 233.
50. http://www.hse.gov.uk/coshh/index.htm.
51. Still W. C., Kahn M., Mitra A.: J. Org. Chem. 1978, 43, 2923.
52. Stubbs H. W. D., Tucker S. H.: J. Chem. Soc. 1954, 227.
53. Genov M., Almorín A., Espinet P.: Chem. Eur. J. 2006, 12, 9346.
54. Wolfe J. P., Singer R. A., Yang B. H., Buchwald S. L.: J. Am. Chem. Soc. 1999, 121, 9550.
55. Tanaka K.-I., Yoshifuji S., Nitta Y.: Chem. Pharm. Bull. 1987, 35, 364.
56. Troja E.: Org. Prep. Proc. Int. 1988, 253.
57. Hattori T., Takeda A., Yamabe O., Miyano S.: Tetrahedron 2002, 58, 233.
Collect. Czech. Chem. Commun. 2011, Vol. 76, No. 10, pp. 1239–1253