3140 J . Org. Chem., Vol. 63, No. 9, 1998
Notes
CDCl3) δ 1.23 (3H, t, J ) 7 Hz), 1.98-2.03 (2H, m), 2.32 (2H, t,
J ) 8 Hz), 2.75 (2H, t, J ) 8 Hz), 4.11 (2H, q, J ) 7 Hz), 5.02
(1H, s), 5.10 (1H, s), 7.08 (1H, d, J ) 9 Hz), 7.16 (2H, d, J ) 9
Hz), 7.27-7.42 (4H, m), 7.58 (1H, s), 7.85-7.90 (2H, m), 7.97
(1H, d, J ) 9 Hz); 13C NMR (CDCl3, 75 MHz) δ 173.9, 152.9,
152.3, 137.5, 133.8, 132.2, 131.3, 130.8, 129.8, 129.6, 128.8, 128.4,
127.4, 127.2, 124.4, 124.3, 124.0, 117.8, 117.7, 111.3, 111.2, 60.4,
34.9, 33.7, 26.4, 14.2; MS (ES-) m/z 399 (M+ - 1); IR (solid) νmax
3328.3, 2934.9, 1725.8, 1594.1, 1245.5, 1143.3. Anal. Calcd for
C26H24O4: C, 77.98; H, 6.04. Found: C, 78.30; H, 6.57.
137.4, 135.8, 135.1, 134.9, 134.8, 134.4, 134.1, 133.9, 133.7, 133.6,
133.5, 133.4, 133.3, 132.3, 132.2, 131.0, 130.6, 128.6, 128.2, 128.0,
127.9, 127.8, 127.2, 126.6, 60.4, 35.1, 33.6, 26.3, 14.3; MS (ES+)
m/z 737 (M+ + 1); IR (solid) νmax 2933.0, 1731.6, 1432.2, 1307.5,
1025.4.
(R)-4-[2,2′-(Dip h en ylp h osp h in o)-1,1′-b in a p h t h -6-yl]b u -
ta n oic a cid (5). To a solution of ester (R)-4 (1.48 g, 2.01 mmol)
in THF (15 mL) was added 15 mL of aqueous LiOH (4.0 g, 0.10
mol) and the mixture heated at reflux for 20 h. After being
cooled to room temperature, the solution was acidified to pH 3
with 2.0 M aqueous HCl and extracted with EtOAc (3 × 20 mL).
The combined organic extracts were dried over anhydrous
Na2CO3, and the solvent was removed in vacuo. Recrystalliza-
(R)-E t h yl 4-[2,2′-b is(t r iflu or om et h a n esu lfoxy)-1,1′-b i-
n a p h th -6-yl]bu ta n oa te. To a cooled (0 °C) mixture of (R)-3
(0.67 g, 1.68 mmol), 2,6-lutidine (0.45 g, 4.19 mmol), and
(dimethylamino)pyridine (0.020 g, 0.169 mmol) was added
dropwise trifluoromethanesulfonic anhydride (1.04 g, 3.69 mmol).
The resulting orange solution was warmed to room temperature,
stirred for 20 h, and then poured onto saturated aqueous
NaHCO3 (20 mL). The layers were separated, and the aqueous
phase was extracted with CH2Cl2 (3 × 15 mL). The combined
organic layers were washed with 0.5 M aqueous HCl (20 mL)
and H2O (20 mL) and then dried over anhydrous Na2CO3.
Removal of the solvent in vacuo and purification by flash column
chromatography (silica gel, EtOAc-hexane, 15%) gave the title
tion from methanol afforded the title compound as a white solid
1
(1.43 g, 99%): mp 150-153 °C; [R]20 179.4 (c 0.3, toluene); H
D
NMR (300 MHz, CDCl3) δ 1.27 (3H, t, J ) 7 Hz), 1.92-2.01 (2H,
m), 2.35 (2H, t, J ) 8 Hz), 2.72 (2H, t, J ) 8 Hz), 4.16 (2H, q, J
) 7 Hz), 6.71 (2H, s), 6.86 (1H, d, J ) 9 Hz), 6.94 (1H, t, J ) 9
Hz), 7.02-7.24 (10H, m), 7.35 (1H, t, J ) 9 Hz), 7.44 (2H, d, J
) 9 Hz), 7.60 (1H, s), 7.82-7.87 (2H, m), 7.90 (1H, d, J ) 9 Hz);
13C NMR (CDCl3, 75 MHz) δ 180.0, 145.8, 145.6, 145.4, 145.0,
144.8, 139.5, 138.2, 138.1, 137.9, 137.8, 137.7, 137.5, 135.5, 135.4,
135.0, 134.9, 134.6, 134.3, 134.1, 133.5, 133.3, 133.0, 132.9, 132.1,
130.9, 130.6, 128.6, 128.5, 128.3, 128.2, 127.9, 127.7, 127.6, 127.1,
126.3, 126.0, 35.0, 33.4, 26.0; MS (ES+) m/z 709 (M+ + 1); IR
(solid) νmax 3049.1, 2925.7, 1703.2, 1432.4, 1239.0, 815.1. Anal.
Calcd for C48H37O2P2: C, 81.46; H, 5.27. Found: C, 81.14; H,
5.49.
product as a colorless oil (0.92 g, 83%): [R]20 -120.5 (c 0.3,
D
toluene); 1H NMR (300 MHz, CDCl3) δ 1.26 (3H, t, J ) 7 Hz),
2.02-2.10 (2H, m), 2.37 (2H, t, J ) 8 Hz), 2.82 (2H, t, J ) 8
Hz), 4.13 (2H, q, J ) 7 Hz), 7.18 (1H, d, J ) 9 Hz), 7.24-7.29
(2H, m), 7.41 (1H, t, J ) 9 Hz), 7.58-7.66 (3H, m), 7.79 (1H, s),
8.01 (1H, d, J ) 9 Hz), 8.07 (1H, d, J ) 9 Hz), 8.14 (1H, d, J )
9 Hz); 13C NMR (CDCl3, 75 MHz) δ 173.4, 145.4, 145.0, 140.8,
133.1, 132.6, 132.3, 132.0, 131.7, 131.5, 129.5, 128.4, 128.0, 127.3,
127.0, 126.8, 123.6, 123.3, 119.9, 119.4, 119.3, 116.4, 113.1, 60.4,
35.0, 33.6, 26.1, 14.2; MS (CI) m/z 664 (M+); IR (film) νmax 2935.3,
1729.2, 1418.3, 1204.4, 1135.0.
Cou p lin g of Acid to Am in om eth ylp olystyr en e. To a flask
containing aminomethylated polystyrene resin (1.0 g, 0.21 mmol,
1% cross-linked with divinylbenzene, 75-150 µm mesh size) was
added CH2Cl2 (10 mL). (R)-5 (0.223 g, 0.315 mmol) was added
as a solution in DMF (5 mL) followed by hydroxybenzotriazole
(0.064 g, 0.42 mmol), diisopropylethylamine (0.030 g, 0.21 mmol),
and diisopropylcarbodiimide (0.056 g, 0.44 mmol). The resulting
mixture was stirred slowly for 24 h. The resin was collected by
filtration and washed sequentially with DMF (2 × 5 mL), CH2Cl2
(2 × 5 mL), MeOH (2 × 5 mL), and Et2O (2 × 5 mL). Drying
under vacuum afforded (R)-6 as a white solid (1.15 g, new loading
of 0.18 mmol/g).
Asym m etr ic Hyd r ogen a tion s, Ca ta lyst P r ep a r a tion . To
a mixture of diphosphine (R)-6 (30 mg, 0.0054 mmol) and bis(2-
methylallyl)cycloocta-1,5-dieneruthenium(II) complex (1.7 mg,
0.0054 mmol) in anhydrous degassed acetone (0.5 mL) was added
0.29 M methanolic HBr (0.043 mL, 0.0125 mmol). The amber
mixture was stirred at room temperature for 1 h and the solvent
removed thoroughly in vacuo to leave the active catalyst, which
was used immediately as a hydrogenation catalyst.
Typ ica l Hyd r ogen a tion P r oced u r e. A solution of methyl
propionylacetate (41 mg, 0.314 mmol) in degassed THF (0.3 mL)
and MeOH (0.3 mL) was added to the catalyst in a glass vial
and placed into a stainless steel pressure vessel. The system
was thoroughly purged with hydrogen by three cycles of pres-
surizing and stirred magnetically with heating at 70 °C under
10 atm of hydrogen pressure for 18 h. After cooling, the reaction
mixture was filtered and the resin washed with THF (3 × 1 mL).
Removal of solvent in vacuo furnished the â-hydroxy ester, which
was analyzed without purification: 1H NMR (300 MHz, CDCl3)
δ 0.95 (3H, t, J ) 6 Hz), 1.43-1.60 (2H, m), 2.42 (1H, dd, J ) 9,
12 Hz), 2.53 (1H, dd, 4, 12 Hz), 2.96 (1H, s), 3.72 (3H, s), 3.90-
4.00 (1H, m).
(R)-E t h yl 4-[2,2′-(Dip h en ylp h osp h in o)-1,1′-b in a p h t h -6-
yl]bu ta n oa te (4). A solution of NiCl2dppe (2.12 g, 4.01 mmol)
in anhydrous DMF (10 mL) was degassed thoroughly using
seven pump/argon cycles. HPPh2 (1.24 g, 6.68 mmol) was added
and the red mixture aged at 100 °C for 1 h. In a separate flask,
(R)-ethyl 4-[2,2′-bis(trifluoromethanesulfoxy)-1,1′-binaphth-6-
yl]butanoate (2.22 g, 3.34 mmol) and 1,4-diazabicyclo[2.2.2]octane
(1.50 g, 0.0134 mol) were degassed in DMF (10 mL) and added
to the nickel solution via cannula. The resulting deep green
solution was heated at 100 °C, a further portion of HPPh2 (1.24
g, 6.68 mmol) added after 4 h, and the solution continued heating
for a further 16 h. After being cooled to room temperature, the
mixture was diluted with EtOAc (50 mL), poured onto 50 mL of
aqueous NaCN (1.64 g, 0.0334 mmol), and stirred vigorously for
1 h. The layers were separated, the organic phase was washed
with H2O (3 × 20 mL) and dried over anhydrous Na2SO4, and
the solvents were removed in vacuo. The resulting brown solid
was then dissolved in anhydrous toluene (50 mL), treated with
trichlorosilane (13.42 g, 0.099 mol), and heated at reflux for 18
h. The mixture was quenched by pouring carefully onto 2.0 M
aqueous NaOH (100 mL) and stirring vigorously for 30 min. The
layers were separated, and the aqueous phase was extracted
with CH2Cl2 (3 × 20 mL). The combined organic layers were
dried over anhydrous Na2CO3 and the volatiles removed in
vacuo. Purification was affected by flash column chromatogra-
phy (silica gel, EtOAc-hexane, 10%) to give the title product as
a white solid (1.64 g, 66%): mp 200 °C dec; [R]20 185.2 (c 0.3,
D
toluene); 1H NMR (300 MHz, CDCl3) δ 1.30 (3H, t, J ) 7 Hz),
1.94-2.03 (2H, m), 2.31 (2H, t, J ) 8 Hz), 2.72 (2H, t, J ) 8
Hz), 4.16 (2H, q, J ) 7 Hz), 6.71 (2H, s), 6.89 (1H, d, J ) 9 Hz),
6.95 (1H, t, J ) 9 Hz), 7.06-7.25 (10H, m), 7.37 (1H, t, J ) 9
Hz), 7.48 (2H, d, J ) 9 Hz), 7.62 (1H, s), 7.83-7.88 (2H, m),
7.92 (1H, d, J ) 9 Hz); 13C NMR (CDCl3, 75 MHz) δ 173.9, 145.8,
145.6, 145.5, 145.0, 144.9, 139.8, 138.3, 138.0, 137.8, 137.6, 137.5,
Ack n ow led gm en t. D.J .B. would like to thank Pro-
fessor S. G. Davies for his invaluable advice. All
enantiomeric excess measurements were conducted by
the analytical department at Oxford Asymmetry.
J O972330G