bulky electron donating substituents on L4. In addition, we first
extended reaction (1) to a ruthenium complex, which contains
the dianion of 1b. The crystal structural determination of
[RuII(1b Ϫ 2H)(NO)Cl], the first isolated ruthenium binaphthyl
Schiff base complex, is also described.
(R)-2,2Ј-Bis(3-tert-butyl-2-hydroxybenzylideneamino)-1,1Ј-
binaphthyl 1g. Yield: 72%. [α]D20 = Ϫ289.5 (c 0.3, CHCl3), mp
184–187 ЊC (Found: C, 83.03; H, 6.60; N, 4.16. C21H20NO
requires C, 83.44; H, 6.62; N, 4.63%). MS: m/z 604 (Mϩ), 589
(Mϩ Ϫ CH3) and 547 (Mϩ Ϫ C4H9). HRMS: m/z 604.3058
(Mϩ) (calc. for C42H40N2O2: 604.3089). 1H NMR (CDCl3,
300 MHz): δ 12.9 (s, 2 H, OH), 8.6 (s, 2 H, CH᎐N), 8.05 (d,
᎐
Experimental
Instrumentation
2 H, J = 8.80, Ph), 7.95 (d, 2 H, J = 8.15, aryl H), 7.58 (d, 2 H,
J = 8.80, aryl H), 6.90–7.5 (m, 10 H, aryl H), 6.67 (t, 2 H,
J = 7.62 Hz, aryl H) and 1.2 (s, 18 H, But). 13C NMR (CDCl3,
300 MHz): δ 162.2, 160.5, 143.8, 137.3, 133.4, 132.6, 130.3,
129.8, 129.3, 128.2, 126.9, 126.6, 125.6, 123.4, 118.9, 117.6,
117.1, 34.7 and 29.0.
The 1H and 13C NMR spectra were recorded on a Bruker DPX
300 FT-NMR spectrometer (300 MHz). Chemical shifts (δ in
ppm) are reported relative to tetramethylsilane (TMS). The
UV-visible spectra were recorded on a Perkin-Elmer Lambda
19 spectrophotometer, infrared spectra on a Shimadzu-470
spectrometer, FAB mass spectra on a Finnigan MAT 95 spec-
trometer, electrospray mass spectrum on a Finnigan LCQ
quadrupole ion trap mass spectrometer and CD spectra on a
JASCO spectrophotometer. The GC analyses were carried out
on an HP 5890 series II system equipped with an HP 5890A
flame ionization detector and an HP 3395 integrator. A capil-
lary column containing β-cyclodextrin was used to analyse the
cyanohydrins after derivatization. All melting points are un-
corrected. Elemental analyses were performed by Butterworth
Laboratories Ltd. or Institute of Chemistry, Chinese Academy
of Sciences.
(R)-2,2Ј-Bis(3-ethyl-2-hydroxybenzylideneamino)-1,1Ј-
binaphthyl 1j. Yield: 78%. [α]D20 = Ϫ448.0 (c 0.66, CHCl3), mp
223–225 ЊC (Found: C, 83.01; H, 5.78; N, 4.83. C19H16NO
1
requires C, 83.21; H, 5.83; N, 5.10%). MS: m/z 548 (Mϩ). H
NMR (CDCl3, 300 MHz): δ 12.3 (s, 2 H, OH), 8.55 (s, 2 H,
CH᎐N), 8.05 (d, 2 H, J = 7.50, aryl H), 7.93 (d, 2 H, J = 7.35,
᎐
aryl H), 6.90–7.50 (m, 12 H, aryl H), 6.68 (t, 2 H, J = 7.45 Hz,
aryl H), 2.5 (q, 4 H, CH2CH3) and 1.1 (t, 6 H, CH2CH3). 13C
NMR (CDCl3, 300 MHz): δ 162.9, 158.9, 144.6, 133.3, 132.4,
132.1, 131.9, 129.9, 128.6, 128.2, 126.8, 126.5, 125.6, 124.6,
118.6, 118.2, 117.8, 22.5 and 13.5.
(R)-2-Amino-2Ј-(3,5-di-tert-butyl-2-hydroxybenzylidene-
amino)-1,1Ј-binaphthyl 2a. Yield: 63%. [α]D20 = Ϫ4.5 (c 0.378,
CHCl3), mp 89–90 ЊC (Found: C, 82.79; H, 7.44; N, 5.53.
C35H36N2Oؒ0.5H2O requires C, 82.51; H, 7.27; N, 5.50%). MS:
m/z 500 (Mϩ). 1H NMR (CDCl3, 300 MHz): δ 11.6 (s, 1 H, OH),
Materials
Acetonitrile and dichloromethane were distilled over calcium
hydride, benzene, tetrahydrofuran, and toluene over sodium–
benzophenone. Acetone and methanol (AR, Merck) were used
as received. All aldehydes except those indicated as follows were
freshly distilled before use. 3,5-Dichlorosalicylaldehyde, 3,5-
dibromosalicylaldehyde, 5-nitrosalicylaldehyde, trimethylsilyl
cyanide, (S)-(Ϫ)-1-(1-naphthyl)ethylamine, (S)-(Ϫ)-α-methyl-
benzylamine, AgPF6 (all Aldrich products), and (R)- and
(S)-2,2Ј-diamino-1,1Ј-binaphthyl (BINAM) (both Fluka prod-
ucts) were used as received. Racemic BINAM,26 the ligands
1a–1f25,27,28 and 2b,29 and the complex [RuII(NO)Cl3(PPh3)2]30
were all prepared by the literature methods.
8.65 (s, 1 H, CH᎐N), 6.9–8.1 (m, 14 H, aryl H), 1.25 (s, 9 H, But)
᎐
and 1.24 (s, 9 H, But). 13C NMR (CDCl3, 300 MHz): δ 163.1,
158.7, 144.8, 143.1, 142.2, 140.3, 133.1, 130.2, 129.9, 129.7,
128.6, 128.4, 128.1, 127.9, 127.6, 127.3, 126.9, 126.84, 126.82,
124.3, 122.8, 122.5, 118.7, 118.5, 118.3, 112.9, 35.3, 34.6, 31.8
and 29.7.
(R)-2,2Ј-Bis(3,5-di-tert-butyl-2-hydroxybenzylideneamino)-
5,5Ј,6,6Ј,7,7Ј,8,8Ј-octahydro-1,1Ј-binaphthyl 3c. Yield: 68%.
[α]D20 = ϩ47.5 (c 1.15, CHCl3), mp 202–204 ЊC (Found: C, 83.16;
H, 9.15; N, 3.50. C25H32NO requires C, 82.87; H, 8.84; N,
3.86%). HRMS: m/z 724.4963 (Mϩ) (calc. for C50H64N2O2:
724.4968). 1H NMR (CDCl3, 300 MHz): δ 13.1 (s, 2 H, OH), 8.5
Preparations
(s, 2 H, CH᎐N), 7.3 (d, 2 H, J = 2.5, aryl H), 7.12 (d, 2 H,
J = 5.3, aryl H), 7.08 (d, 2 H, J = 2.5, aryl H), 7.0 (d, 2 H, J = 5.3
᎐
(R)-5,5Ј,6,6Ј,7,7Ј,8,8Ј-Octahydro-1,1Ј-binaphthyl-2,2Ј-
Hz, aryl H), 2.8–2.9 (m, 4 H, CH2), 2.3–2.6 (m, 4 H, CH2), 1.7–
diamine [(R)-H8BINAM]. This compound was prepared by a
procedure analogous to that for its diol analogue.31 A mixture
of (R)-BINAM (200 mg), PtO2 (20 mg), and glacial acetic acid
(20 ml) was stirred in a 50 ml autoclave under hydrogen (3 atm)
at room temperature for 3 d. After releasing the hydrogen gas
and removing solid by filtration, the mixture was neutralized
with 10% NaHCO3 solution (200 ml) followed by extraction
with chloroform (3 × 30 ml). The solvent of the organic layer
dried with Na2SO4 was then removed by evaporation to give a
crude product, which was purified by column chromatography.
Yield: 83%. [α]D20 = ϩ133 (c 1.0, pyridine), mp 210 ЊC. HRMS:
m/z 292.1935 (Mϩ) (calc. for C20H24N2: 292.1939). IR (KBr,
cmϪ1): 3456, 3365, 2925, 1609, 1479, 1442, 1300, 1286, 826 and
1.9 (m, 8 H, CH2), 1.33 (s, 18 H, But) and 1.24 (s, 18 H, But). 13
C
NMR (CDCl3, 300 MHz): δ 162.5, 160.2, 145.1, 141.5, 138.5,
137.6, 136.0, 130.9, 128.9, 128.1, 120.1, 116.1, 36.8, 35.9, 33.3,
32.8, 31.8, 31.0, 25.0 and 24.7.
General procedure for Schiff bases 1h, 1i, 3a, 3b, and 4. A
mixture of the corresponding chiral amine (0.1 mmol) and sub-
stituted salicylaldehyde (1.05 equivalents for 4 and 2.1 equiv-
alents for the others) in ethanol (20 ml) was refluxed for 2 h.
After concentrating the solution to 5 ml, the product pre-
cipitated was collected by filtration and washed with cold
methanol.
(R)-2,2Ј-Bis(3-tert-butyl-5-chloro-2-hydroxybenzylidene-
amino)-1,1Ј-binaphthyl 1h. Yield: 78%. [α]D20 = Ϫ327.9 (c 0.372,
CHCl3), mp 214–215 ЊC (Found: C, 74.82; H, 5.59; N, 3.87.
C21H19ClNO requires C, 74.88; H, 5.64; N, 4.16%). MS: m/z
673 (Mϩ). 1H NMR (CDCl3, 300 MHz): δ 12.9 (s, 2 H, OH), 8.5
1
808. H NMR (CDCl3, 300 MHz): δ 6.90 (d, 2 H, J = 8.2, aryl
H), 6.60 (d, 2 H, J = 8.1 Hz, aryl H), 3.31 (s, 4 H, NH2), 2.70 (m,
4 H, CH2), 2.22 (t, 4 H, J = 6.02 Hz, CH2) and 1.67 (m, 8 H,
CH2). 13C NMR (CDCl3, 300 MHz): δ 141.5, 136.2, 129.2,
127.7, 122.0, 113.1, 29.4, 27.0, 23.4 and 23.2.
(s, 2 H, CH᎐N), 8.08 (d, 2 H, J = 8.85, aryl H), 7.97 (d, 2 H,
᎐
J = 8.23, aryl H), 7.59 (d, 2 H, J = 8.87, aryl H), 7.2–7.5 (m, 6 H,
aryl H), 7.12 (d, 2 H, J = 2.52, aryl H), 6.99 (d, 2 H, J = 2.57 Hz,
aryl H) and 1.15 (s, 18 H, But). 13C NMR (CDCl3, 300 MHz):
δ 160.7, 159.0, 143.1, 139.6, 133.2, 132.8, 129.9, 129.6, 128.8,
128.2, 127.1, 126.5, 125.9, 122.4, 119.5, 116.6, 34.9 and 28.8.
(R)-2,2Ј-Bis(5-tert-butyl-3-chloro-2-hydroxybenzylidene-
amino)-1,1Ј-binaphthyl 1i. Yield: 80%. [α]D20 = Ϫ375.0 (c 0.36,
CHCl3), mp 159–160 ЊC (Found: C, 74.86; H, 5.61; N, 4.22.
General procedure for Schiff bases 1g, 1j, 2a and 3c
The compound (R)-BINAM (284 mg, 0.1 mmol) and the cor-
responding salicylaldehyde (1.05 equivalents for 2a and 2.1
equivalents for the others) were dissolved in ethanol–acetic acid
(7:1 v/v, 20 ml) and stirred at 60 ЊC for 2 h. Upon removal of
solvent, the residue was recrystallized from dichloromethane–
ethanol.
3304
J. Chem. Soc., Dalton Trans., 1999, 3303–3309