6250 J . Org. Chem., Vol. 61, No. 18, 1996
Benincori et al.
separated, dried (Na2SO4), and concentrated in vacuo. The
crude reaction product was tritured with petroleum ether to
give (()-1b (10.35 g, 82%): mp 177 °C; 1H NMR (CDCl3) δ
7.25 (m, 26H), 7.78 (d, 2H); 31P NMR (CDCl3) δ -23; mass
spectrum m/z 634 (M+). Anal. Calcd for C40H28P2S2: C, 75.69;
H, 4.45. Found: C, 75.47; H, 4.39.
P r ep a r a tion of 3,3′-Biben zo[b]fu r a n (5c). A solution of
4c (9 g) in dry THF (100 mL) was dropped into a solution of
BuLi (0.055 mol, 1.6 M solution in hexane) in THF (150 mL)
at -105/110 °C under N2. After 20 min of stirring, CuCl2 (7.4
g) was added, the mixture was stirred for 5 h at 105/110 °C,
then allowed to warm to 0 °C, quenched with 2 M HCl solution,
and stirred overnight. The mixture was concentrated and
extracted with CH2Cl2, and the organic layer was dried (Na2-
SO4) and concentrated in vacuo. Chromatography (SiO2,
eluted by petroleum ether) provided pure 5c (1.5 g, 26%): mp
110/115 °C; 1H NMR (CDCl3) δ 7.33 (t, 1H, J ) 8 Hz), 7.39 (t,
1H, J ) 7.3 Hz), 7.58 (d, 1H, J ) 8 Hz), 7.74 (d, 1H, J ) 7.3
Hz), 8 (s, 1H). Anal. Calcd for C16H10O2: C, 82.04; H, 4.30.
Found: C, 82.34; H, 4.28.
P r ep a r a tion of (()-2,2′-Bis(d ip h en ylp h osp h in yl)-3,3′-
biben zo[b]th iop h en e (6b). H2O2 (16 mL, 35%) was dropped
into a solution of (()-1b (10.35 g) in CH2Cl2 (200 mL) at 0 °C.
The mixture was stirred for 1 h at 0 °C and for 1 h at 25 °C
and then water was added. The organic layer was separated,
dried (Na2SO4), and concentrated in vacuo. Chromatography
(SiO2, eluted by AcOEt/CH2Cl2/Et3N 3:7:0.1) provided pure (()-
1
6b (10.65, 98%): mp 286 °C; H (CDCl3) δ 6.99 (d, 4H, J ) 4
Hz), 7.10 (dt, 4H, J ) 3.8 Hz), 7.28 (m, 4H), 7.38 (dt, 4H, J )
3.8 Hz), 7.47 (m, 2H), 7.58 (d, 2H, 7 Hz), 7.62 (d, 2H, 7 Hz),
7.69 (d, 2H, 8 Hz), 7.82 (d, 2H, 7 Hz), 7.85 (d, 2H, 7 Hz); 31P
(CDCl3) δ 21.00; mass spectrum m/z 666 (M+). Anal. Calcd
for C40H28O2P2S2: C, 72.06; H, 4.23. Found: C, 72.26; H, 4.39.
Op tica l r esolu tion of (()-2,2′-Bis(d ip h en ylp h osp h i-
n yl)-3,3′-biben zo[b]th iop h en e (6b) w ith (-)- or (+)-2,3-
P r ep a r a tion of (()-2,2′-Bis(d ip h en ylp h osp h in o)-3,3′-
biben zo[b]fu r a n (1c). BuLi (0.013 mol, 1.6 M solution in
hexane) was dropped into a solution of 5c (1.36 g) and TMEDA
(1.94 mL) in THF (15 mL) at -50 °C under N2, and then the
temperature was allowed to warm to 0 °C. After 30 min
diphenylphosphinous chloride (2.6 mL) was added. The
mixture was stirred 2 h and then concentrated in vacuo. The
residue was treated with water and CHCl3; the organic layer
was separated, dried (Na2SO4), and concentrated in vacuo. The
residue was treated with isopropyl ether to give 1c (0.48 g,
60%): mp 198-202 °C; 1H NMR (CDCl3) δ 7.20 (m, 14H), 7.35
(m, 12H), 7.50 (d, 2H); 31P NMR (CDCl3) δ -31.11. Anal.
Calcd for C40H28P2O2: C, 79.73; H, 4.68. Found: C, 79.65; H,
4.65.
P r epar ation of 2,2′-Bis(diph en ylph osph in yl)-3,3′-biben -
zo[b]fu r a n (6c). BuLi (0.013 mol, 1.6M solution in hexane)
was dropped into a solution of 1c (1.36 g) and TMEDA (1.94
mL) in THF (15 mL) at -50 °C under N2, and then the
temperature was allowed to warm to 0 °C. After 30 min
diphenylphosphinic acid chloride (2.4 mL) was added. The
mixture was stirred 2 h and then concentrated in vacuo. The
residue was treated with water and CHCl3; the organic layer
was separated, dried (Na2SO4), and concentrated in vacuo.
Chromatography (SiO2, eluted by AcOEt/CH2Cl2 1:1) provided
pure 6c (2.3 g, 60%): mp 206-207 °C; 1H NMR (CDCl3) δ 6.97
(m, 4H), 7.10 (t, 2H, J ) 7 Hz), 7.19 (m, 4H), 7.33 (t, 2H, J )
7 Hz), 7.45 (m, 6H), 7.53 (dd, 2H, J ) 7 Hz), 7.63 (m, 4H),
7.82 (m, 4H); 31P NMR (CDCl3) δ 16.7; mass spectrum m/z 634
(M+). Anal. Calcd for C40H28P2O4: C, 75.71; H, 4.45. Found:
C, 75.67; H, 4.37.
O,O′-Diben zoylta r ta r ic Acid Mon oh yd r a te [DBTA].
A
mixture of (()-6b (2.15 g) and (-)-DBTA (1.20 g) was dissolved
into a solution of AcOEt/CHCl3 9:4.3 (133 mL), refluxed for a
few minutes, and allowed to stand at rt for 24 h. An adduct
between (+)-6b and (-)-DBTA was collected, and the filtrate
was stored for recovery of (-)-6b. Chromatography (SiO2,
eluted by AcOEt/CH2Cl2/Et3N 3:7:0.1) of the above complex
[0.54 g, mp 185-190 °C, [R]25 ) +100.6° (c ) 0.50, EtOH)]
D
provided (+)-6b [0.2 g, mp 206 °C, [R]25 ) +325° (c ) 0.48,
D
C6H6)].
The mother liquor from the first resolution was concentrated
to dryness to give a solid (3 g), and chromatography (SiO2,
AcOEt/CH2Cl2/Et3N 3:7:0.1) gave a residue of (-)-6b enriched
in the dextrorotatory enantiomer. The recovered solid (1.9 g)
and (+)-DBTA (1.07 g) were dissolved into a mixture of AcOEt/
CHCl3 26:16 (402 mL) and refluxed for a few minutes. After
24 h an adduct between (-)-6b and (+)-DBTA was collected
[0.8 g, mp 190 °C dec, [R]25 ) -97.4° (c ) 0.47, EtOH)].
D
Chromatography (SiO2, eluted by AcOEt/CH2Cl2/Et3N 3:7:0.1)
of the adduct provided (-)-6b [0.54 g, mp 206 °C, [R]25
-329° (c ) 0.50, C6H6)].
)
D
P r ep a r a tion of (-)-2,2′-Bis(d ip h en ylp h osp h in o)-3,3′-
biben zo[b]th iop h en e [(-)-1b]. In three-necked flask
a
P r ep a r a tion of P d (II) Dich lor id e Com p lexes (9a -c).
Gen er a l P r oced u r e. A mixture of (()-tetraMe-bitianp (1a )
(0.069 g, 0.1 mmol) and (C6H5CN)2PdCl2 (0.038 g, 0.1 mmol)
in CH2Cl2 (5 mL) was stirred at rt for 18 h; the solvent was
removed in vacuo to leave 9a as a yellow solid. Recrystalli-
zation of the crude product by slow diffusion of ether into a
CH2Cl2-saturated solution afforded crystals suitable for X-ray
structure analysis. An identical procedure was employed for
the preparation of crystals of 9c, while crystals of 9b were
obtained by diffusion of ether into an acetone saturated
solution.
equipped with a thermometer and a reflux condenser, which
is connected to an argon inlay tube, were placed (-)-6b (2.7
g), dry xylene (100 mL), trichlorosilane (4 g), and triethylamine
(2.9 g). The mixture was stirred and heated at 100 °C for 10
h. After cooling to rt, the mixture was concentrated in vacuo,
and the residue was treated with water and extracted with
CH2Cl2. The organic layer was dried (Na2SO4) and concen-
trated under reduced pressure. Toluene (2 mL) and methanol
(10 mL) were added to the residue, and the precipitate was
collected to give (-)-1b (2.06 g): mp ) 187-190 °C (DSC);
[R]25 ) -193° (c ) 0.50, C6H6).
D
9a : 31P NMR (CDCl3) δ 21.22; 13C NMR (CDCl3) δ 19.93,
21.35, 119.25, 123.21, 124.46, 128.07, 129.68, 131.60, 133.95,
134.12, 135.15, 136.34, 137.76, 140.05, 144.38.
(+)-(6b) was reduced by following the same procedure
followed for (-)-6b: mp ) 187-189 °C (DSC); [R]25D ) + 195°
(c ) 0.48, C6H6).
9b: 31P NMR (CDCl3) δ 19.65; 13C NMR (CDCl3) δ 122.49,
124.00, 124.52, 125.62, 126.99, 128.88, 128.98, 131.00, 132.34,
134.35, 135.74, 135.86, 135.90, 135.93, 136.00, 137.92, 140.00,
P r ep a r a tion of 2,3-Dibr om oben zo[b]fu r a n (3c). A solu-
tion of bromine (71.34 mL) in CHCl3 (150 mL) was dropped
into a mixture of benzo[b]furan (2b) (82 g) and AcOK (13.7 g)
in CHCl3 (300 mL) at rt. The mixture was heated at 50 °C,
and a 5% NaHSO3 solution was added after 5 h. The organic
layer was separated, washed with a 5% NaHCO3 solution,
dried (Na2SO4), and concentrated in vacuo. Chromatography
(SiO2, eluted by petroleum ether) provided pure (3c) (115 g,
60%): 1H NMR (CDCl3) δ 7.3 (m, 2H), 7.45 (m, 2H).
1
144.02; H NMR (CDCl3) δ 7.4 (m, 24H), 8.00 (m, 4H).
9c: 31P NMR (CDCl3) δ 11.19; 13C NMR (DMSO) δ 11.82,
120.62, 121.44, 124.26, 125.53, 125.96, 127.30, 128.04, 128.73,
129.00, 130.06, 130.77, 131.30, 132.46, 133.36, 135.19, 135.29,
1
157.36; H NMR (CDCl3) δ 7.30 (m, 24H), 8.12 (m, 4H).
P r ep a r a t ion of [(+)- a n d (-)-t et r a Me-b it ia n p ]R u Cl2
(10a ).17 To a Schlenk tube charged with (R)-tetraMe-bitianp
(2.3 × 10-2 mmol) and red brown [RuCl2(C6H6)]2 (1.15 × 10-2),
prepared according to the procedure reported in the litera-
ture,18 was added freshly distilled argon-degassed DMF. The
mixture was stirred at 100 °C for 15 min. The resulting orange
yellow solution was cooled to 50 °C and concentrated under
reduced pressure to give 10a . The residue was left under
vacuum for 1 h and then argon pressurized. The obtained
ruthenium complex, was utilized without other purification
P r epar ation of 3-Br om oben zo[b]fu r an (4c). BuLi (0.072
mol, 1.6 M solution in hexane) was dropped into a solution of
3c (17.94 g) in dry THF (100 mL) at -70 °C under N2. The
mixture was stirred for 30 min, treated with methanol (2 mL),
and concentrated in vacuo. The residue was treated with
water and CH2Cl2. The organic layer was separated, dried
(Na2SO4), and concentrated in vacuo. Chromatography (SiO2,
eluted by petroleum ether) provided pure 4c (11 g, 86%): mp
1
34 °C; H NMR (CDCl3) δ 7.30 (m, 2H), 7.45 (m, 2H).