1450
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 8, August, 2006
Lyubimov et al.
their absolute configurations were determined by HPLC on a
Varian 5000 chromatograph with a Daicel Chiralcel ODꢀH chiral
column; data18 were taken into account. Elemental analysis was
performed at the organic microanalysis laboratory of the A. N.
Nesmeyanov Institute of Organoelement Compounds, Russian
Academy of Sciences.
All reactions were carried out under dry argon in anꢀ
hydrous solvents. The phosphorylating reagent (Sax)ꢀ2ꢀchlorodiꢀ
naphtho[2,1ꢀd:1´,2´ꢀf ][1,3,2]dioxaphosphepine, the starting
complex [Rh(COD)2]BF4, and methyl (Z )ꢀ2ꢀacetamidoꢀ3ꢀ
phenylacrylate (6) were prepared as described earlier.19—21 Comꢀ
mercial methyl itaconate (5), BINOL, and 2ꢀ(dimethylamiꢀ
no)ethanol (Fluka) were used.
Nꢀ(2ꢀHydroxyethyl)ꢀN,Nꢀdimethylheptylammonium tetraꢀ
fluoroborate (1). Heptyl bromide (10 g, 56 mmol) was added to a
solution of 2ꢀ(dimethylamino)ethanol (5 g, 56 mmol) in a mixꢀ
ture of benzene (15 mL) and ethanol (15 mL). The reaction
mixture was stirred at 20 °C for 12 h and concentrated in vacuo
(40 Torr). Bromide 2 was washed with hexane (2×20 mL), dried
in vacuo (1 Torr), and used in the next step without further
characterization. Bromide 2 (10 g, 37 mmol) was dissolved in
acetonitrile (30 mL) and refluxed with an excess of KBF4 (14 g,
111 mmol) while stirring for 48 h. The solution was filtered
through a short column with silica gel and concentrated in vacuo
(40 Torr). The residue was dried in vacuo (1 Torr) to give comꢀ
pound 1 (8.652 g, 85%) as white crystals, m.p. 40—43 °C.
Found (%): C, 47.86; H, 9.64; N, 5.17. C11H26BF4NO. Calcuꢀ
lated (%): C, 48.02; H, 9.52; N, 5.09. 1H NMR, δ: 0.85 (t, 3 H,
3JH,H = 6.8 Hz); 1.24—1.32 (m, 8 H); 1.71 (m, 2 H); 3.23 (s,
6 H); 3.42 (m, 2 H); 3.58 (t, 2 H, 3JH,H = 4.8 Hz); 4.05 (s, 2 H);
4.61 (s, 1 H). ESI MS, m/z (Irel (%)): 188 [M – BF4]+ (100),
87 [BF4]– (100).
0.140 g (95%), an orange powder, m.p. 110—121 °C (decomp.).
Found (%): C, 57.09; H, 5.67; N, 1.81. C70H86B3F12N2O6P2Rh.
Calculated (%): C, 56.93; H, 5.87; N, 1.90. 31P NMR, δ: 124.22
(d, 1JP,Rh = 260.5 Hz). ESI MS, m/z (Irel (%)): 405 [M – 3 BF4]3+
(5), 397 [M – 3 BF4 – COD + 2 MeCN]3+ (100).
Asymmetric hydrogenation of methyl itaconate (5). Methyl
itaconate 5 (0.1 g, 0.6 mmol) was added to a solution of rhodium
complex 4 (9.3 mg, 0.006 mmol) in CH2Cl2 or ethyl acetate
(4 mL). The closed autoclave was purged with argon and then
three times with hydrogen. The reaction mixture was stirred
under a hydrogen pressure of 5 atm. for 24 h, diluted with hexꢀ
ane (4 mL), and filtered through a short column with silica gel.
The solvent was removed in vacuo (40 Torr) and the residue was
dried in vacuo (10 Torr) to give product 7 as a colorless oil.
1H NMR and MS data for compound 7 were in full agreement
with the literature data.22
Asymmetric hydrogenation of methyl (Z )ꢀ2ꢀacetamidoꢀ3ꢀ
phenylacrylate (6). Compound 6 (0.1 g, 0.46 mmol) was added
to a solution of rhodium complex 4 (6.7 mg, 0.0046 mmol) in
CH2Cl2 (4 mL). The closed autoclave was purged with argon
and then three times with hydrogen. The reaction mixture was
stirred under a hydrogen pressure of 5 atm. for 24 h, diluted with
hexane (4 mL), and filtered through a short column with silica
gel. The solvent was removed in vacuo (40 Torr) and the residue
was dried in vacuo (10 Torr) to give product 8 as a white powder.
1H NMR and MS data for compound 8 were in full agreement
with the literature data.22
We are grateful to Daicel Chemical Industries Ltd
(Japan) for providing the Daicel Chiralcel ODꢀH chiral
HPLC column.
This work was financially supported in part by the
Russian Science Support Foundation.
(Sax)ꢀNꢀ(Dinaphtho[2,1ꢀd:1´,2´ꢀf ][1,3,2]dioxaphosphepinꢀ
2ꢀyloxyethyl)ꢀN,Nꢀdimethylheptylammonium tetrafluoroborate
(3). Triethylamine (0.4 mL, 2.8 mmol) and quaternized amino
alcohol 1 (0.784 g, 2.8 mmol) were added to a solution of
(Sax)ꢀ2ꢀchlorodinaphtho[2,1ꢀd:1´,2´ꢀf][1,3,2]dioxaphosphepine
(1 g, 2.8 mmol) in CH2Cl2 (15 mL). The reaction mixture was
stirred at 20 °C for 3 h and washed with water (45 mL). The
organic phase was separated, dried with Na2SO4, filtered, and
concentrated in vacuo (40 Torr). The product was purified by
flash chromatography on silica gel (CH2Cl2, 300 mL). The yield
of compound 3 was 0.84 g (50%), a white powder, m.p.
80—81 °C. Found (%): C, 63.29; H, 6.16; N, 2.44.
C31H37BF4NPO3. Calculated (%): C, 63.17; H, 6.33; N, 2.38.
References
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2
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2
131.7, 132.4, 132.7, 133.9, 146.8, 147.9 (d, C arom., JC,P
=
5.1 Hz). ESI MS, m/z (Irel (%)): 503 [M – BF4]+ (100),
87 [BF4]– (100).
[1,2:5,6ꢀηꢀ(1,5ꢀCyclooctadiene)],[bis{(Sax)ꢀNꢀ(diꢀ
naphtho[2,1ꢀd:1´,2´ꢀf ][1,3,2]dioxaphosphepinꢀ2ꢀyloxyethyl)ꢀ
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(40 Torr). The product was washed with ether (2×5 mL)
and dried in vacuo (1 Torr). The yield of complex 4 was
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