Transition-Metal Aqua Complexes of DBFOX/Ph
J. Am. Chem. Soc., Vol. 120, No. 13, 1998 3087
1.67 (1H, m, one of H-7), 1,99 (1H, m, the other of H-7), 2.63 (1H, br
s, H-4), 3.26 (1H, br s, H-1), 3.59 (1H, t, J ) 4.0, H-2), 3.8-4.1 (2H,
m, H-4′), 4.41 (2H, t, Jgem ) J5′-4′ ) 8.1 Hz, H-5′), 5.78 (1H, dd, J5-6
) 5.5 Hz and J5-4 ) 2.6 Hz, H-5), and 6.36 (1H, dd, J6-5 ) 5.5 Hz
and J6-1 ) 3.3 Hz, H-6); 13C NMR (CDCl3) δ ) 14.25 (Me of n-Pr),
22.02 (C-2 of n-Pr), 37.84 (C-7), 42,46, 43.04, 47.13, 47.60, 47.66
(C-1, C-2, C-3, C-4, and C-3 of n-Pr), 49.99 (C-7), 61.88 (C-5′), 131.09,
139.71 (C-5 and C-6), 153.50 (C-2′), and 174.55 (CON); MS (70 eV,
relative intensity, %) m/z 250 (21), 249 (28, M+), 186 (46), 164 (34),
163 (base peak), 162 (97), 161 (14), 148 (17), 147 (12), 144 (17), 141
(28), 135 (20), 134 (67), 133 (42), 130 (12), 129 (12), 121 (15), 120
(82), 119 (83), 118 (27), 107 (27), 106 (64), 104 (42), 103 (37), 99
(10), 95 (32), 93 (29), 92 (70), 90 (24), 89 (55), 87 (15), 81 (25), 80
(21), 79 (48), 78 (35), and 77 (56). Anal. Calcd for C14H19NO3: C,
67.45; H, 7.68; N, 5.62. Found: C, 67.13; H, 7.63; N, 5.40.
hexane-2-PrOH, 9:1 v/v), c ) 1.00, CHCl3); IR (KBr) 3000, 2900,
1760, 1680, 1320, 1200, 1110, 1040, 910, 850, 800, 750, and 700 cm-1
;
1H NMR (CDCl3) δ ) 1.66 (3H, s, Me), 1.5-2.2 (6H, m, H-3, H-5,
and H-6), 3.66 (1H, m, H-4), 4.02 (2H, t, J4′-5′ ) 8.0 Hz, H-4′), 4.41
(2H, t, J5′-4′ ) 8.0 Hz, H-5′), and 5.39 (1H, m, H-2); 13C NMR (CDCl3)
δ ) 23.42 (Me), 25.94, 27.47, 29.52 (C-3, C-5, and C-6), 38.20 (C-4),
42.84 (C-4′), 61.94 (C-5′), 119.09 (C-2), 133.73 (C-1), 153.21 (C-2′),
and 176.72 (CO); MS (70 eV, relative intensity, %) m/z 209 (66, M+),
122 (81), 107 (26), 95 (12), 94 (43), 91 (13), 88 (32), 79 (base peak),
77 (19), and 67 (17). Anal. Calcd for C11H15NO3: C, 63.14; H, 7.23;
N, 6.69. Found: C, 62.75; H, 7.13; N, 6.62.
(2S)-2-Bromobicyclo[2.2.1]hept-5-ene-2-carboxaldehyde (19). Prod-
uct 19 was characterized by comparison of the spectral data with those
of the authentic sample.51 Its enantioselectivity (86% ee) was based
on the 1H NMR spectral analysis using a chiral shift reagent, europium-
(III) (-)-tris[3-(heptafluoropropylhydroxymethylene)camphorate (Eu-
(hfc)3).52
Preparation of the Anhydrous DBFOX/Ph Nickel Complex. A
mixture of (R,R)-1 (32.5 mg, 0.071 mmol), anhydrous NiBr2 (15.5 mg,
0.071 mmol), and anhydrous AgClO4 (29.4 mg, 0.142 mmol) in dry
dichloromethane (4.4 mL) was stirred under dry nitrogen at room
temperature for 6 h, during which time a gray precipitate of silver
bromide appeared. The resulting suspension was used without filtration
for the Diels-Alder reactions as follows: At -40 °C, 3-acryloyl-2-
oxazolidinone (0.1 g, 0.71 mmol) and freshly distilled cyclopentadiene
(0.468 g, 0.571 mL, 7.09 mmol) were added to this suspension. The
reaction was performed at the same temperature (monitored by TLC).
After the completion of reaction, similar quenching and purification
procedures were applied.
Other anhydrous DBFOX/Ph complexes were prepared according
to a similar procedure by using anhydrous metal halides such as MnBr2,
FeCl2, CoBr2, CuCl2, and ZnI2. The DBFOX/Ph complexes bearing
counteranions other than perchlorate were prepared in one of the
following ways: (1) treatment of (R,R)-1 with MgBr2, MgI2, Mg(OTf)2,
or Cu(OTf)2; (2) treatment of (R,R)-1 with MgBr2, MgI2, or FeCl2,
followed by treatment with I2; or (3) treatment of the anhydrous nickel-
(II) or copper(II) complex with AgSbF6.
Preparation of the 1:1 Hydroxo Complex [R-DBFOX/Ph‚NiClO4-
(OH)‚2H2O] (A). Ligand (R,R)-1 (65 mg, 0.142 mmol) and Ni-
(ClO4)2‚6H2O (52 mg, 0.142 mmol) were stirred in dichloromethane
(4 mL) at room temperature for 5 h, during which time the insoluble
nickel salt became dissolved and then a pale blue solid started to
precipitate. The precipitate was filtered off, and the filtrate was
evaporated in vacuo. The residue was washed with dichloromethane
and dried in a vacuum at room temperature for 3 days to give a pale
blue solid (95 mg, 100%): mp >300 °C; FAB-MS (matrix: m-
nitrobenzyl alcohol) (relative intensity, %) m/z 619 (15), 618 (18), 617
(51, DBFOX/Ph + NiClO4), 616 (24), 615 (65), 518 (17), 517 (17),
and 516 (39). Anal. Found: C, 53.15; H, 4.25; N, 4.27%. Calcd for
C30H27N2O10ClNi: C, 53.77; H, 4.06; N, 4.18.
Preparation of the 1:1 Aqua Complex [R-DBFOX/Ph‚Ni(ClO4)2‚-
3H2O] (R,R)-9). A mixture of (R,R)-1 (32.5 mg, 0.071 mmol), NiBr2
(15.5 mg, 0.071 mmol), and AgClO4 (29.4 mg, 0.142 mmol) in dry
dichloromethane (4 mL) was stirred overnight under dry nitrogen at
room temperature. Filtration to remove the silver salt that precipitated
gave a filtrate, which was treated in one of the following manners: (1)
To the filtrate was added benzene, and this solution was allowed to
stand at room temperature to give cubic crystals of the above complex
(82 mg, 71%). (2) The dichloromethane was evaporated in vacuo, the
residue was dissolved in acetone, dichloromethane was added, and
finally the solution was allowed to stand at room temperature to give
prism crystals of the above complex. (3) To the dichloromethane filtrate
(1S,2R,3R,4R)-3-(3-Phenylbicyclo[2.2.1]hept-5-en-2-ylcarbonyl)-
2-oxazolidinone (8d); colorless solid; [R]25D -45.23 (51% ee estimated
on the basis of HPLC using a chiral column (Daicel Chiralcel AD with
hexane-2-PrOH, 19:1 v/v), c ) 0.37, CCl4); IR (KBr) 3000, 1780,
1
1690, 1490, 1400, 1220, 1110, 1030, 730, and 700 cm-1; H NMR
(CDCl3) δ ) 1.2-2.0 (2H, m, H-7), 3.00, 3.34, 3.47 (each 1H, m,
H-1, H-3, and H-4, 3.9-4.3 (3H, m, H-2 and H-4′), 4.3-4.5 (2H, H-5′),
5.93 (1H, dd, J ) 5.5 and 2.9 Hz, H-5 or H-6), and 6.53 (1H, dd, J )
5.5 and 2.9 Hz, H-6 or H-5), and 7.1-7.4 (5H, m, Ph); 13C NMR
(CDCl3) δ ) 43.02, 46.94, 47.50, 48.16, 49.75 (C-1, C-2, C-3, C-4,
and C-4′), 50.31 (C-7), 61.94 (C-5′), 126.16, 127.63, 128.02, 128.51
(Ar), 132.18, 140.23 (C-5 and C-6), 153.40 (C-2′), and 173.85 (CO);
MS (70 eV) (relative intensity, %) m/z 283 (12, M+), 221 (16), 220
(11), 216 (40), 198 (10), 197 (62), 196 (65), 195 (20), 189 (14), 177
(62), 176 (73), 174 (20), 173 (30), 172 (20), 169 (36), 164 (19), 155
(14), 154 (35), 151 (12), 147 (20), 146 (27), 142 (18), 141 (19), 140
(17), 134 (12), and 84 (10). Anal. Calcd for C17H17NO3: C, 72.07;
H, 6.05; N, 4.94. Found: C, 70.60; H, 6.05; N, 4.48.
(1S,2S,4S)-1-(Bicyclo[2.2.1]hept-5-en-2-ylcarbonyl)-2-pyrrolidi-
none (14): colorless solid; mp 86-89 °C; [R]25 -170.83 (98% ee
D
estimated on the basis of HPLC using a chiral column (Daicel Chiralcel
OD with hexane-2-PrOH, 99:1 v/v), c ) 1.57, CHCl3); IR (KBr) 2900,
1
1900, 1510, 1200, 1150, 920, 850, 720, 650, and 590 cm-1; H NMR
(CDCl3) δ ) 1.3-1.6 (3H, m, H-7 and one of H-3), 1.92 (1H, ddd,
J3-2 ) 8.0 Hz, J3-4 ) 3.6 Hz, and Jgem ) 11.0 Hz, the other of H-3),
1.9-2.2 (2H, m, H-4′), 2.62 (2H, t, J4′-3′ ) 8.0 Hz, H-3′), 2.92 (1H,
m, H-4), 3.26 (1H, m, H-1), 3.6-3.9 (2H, m, H-2 and one of H-5′),
3.98 (1H, ddd, Jgem ) 8.9 Hz and J5′-4′ ) 4.4 and 3.6 Hz, the other of
H-5′), 5.85 (1H, dd, J5-6 ) 5.5 and J5-4 ) 2.9 Hz, H-5) and 6.25 (1H,
dd, J6-5 ) 5.5 Hz and J6-1 ) 2.9 Hz, H-6); 13C NMR (CDCl3) δ )
17.23 (C-4′), 29.56 (C-3), 34.03, 42.88, 44.64, 45.67, 46.11 (C-1, C-2,
C-4, C-3′, and C-5′), 50.09 (C-7), 131.83, 137.88 (C-5 and C-6), 175.02,
and 175.61 (C-2′ and CO); MS (70 eV, relative intensity, %) m/z 205
(21, M+), 140 (68), 139 (26), 120 (base peak), 111 (14), 99 (13), 98
(29), 92 (19), 91 (40), and 86 (54). Anal. Calcd for C12H15NO2: C,
70.22; H, 7.37; N, 6.82. Found: C, 69.26; H, 7.26; N, 6.55.
Methyl (1S,2R,3R,4R)-3-Phenylbicyclo[2.2.1]hept-5-en-2-ylgly-
oxylate (16): colorless oil; [R]25 -111.35 (68% ee estimated on the
D
basis of HPLC using a chiral column (Daicel Chiralcel AD with
hexane-2-PrOH, 50:1 v/v), c ) 1.57, CHCl3); IR (KBr) 3000, 1720,
1600, 1440, 1240, 1080, 1320, 900, 700 cm-1; 1H NMR (CDCl3) δ )
1.63 (1H, dd, Jgem ) 8.7 Hz and J ) 1.7 Hz, H-7), 1.93 (1H, d, Jgem
8.7 Hz, the other of H-7), 3.05 (1H, m, H-4), 3.24 (1H, d, J3-2 ) 4.9
Hz, H-3), 3.48 (1H, m, H-1), 3.73 (1H, dd, J2-3 ) 4.9 Hz and J2-1
)
)
3.4 Hz, H-2), 3.84 (3H, s, COOMe), 5.94 (1H, dd, J6-5 ) 5.5 Hz and
J6-1 ) 2.7 Hz, H-6), 6.44 (1H, dd, J5-6 ) 5.5 Hz and J5-4 ) 3.1 Hz,
H-5), and 7.4-7.1 (5H, m, Ph); 13C NMR (CDCl3) δ ) 45.56, 47.20,
47.73, 49.10, 52.82, 56.69 (Me, C-1, C-2, C-3, C-4, and C-7), 126.25,
127.43, 128.57, 132.70 (each Ph), 139.91, 143.41 (C-5 and C-6), 162.27
(COCOOMe), and 194.12 (COCOOMe); MS (70 eV, relative intensity,
%) m/z 256 (0.23, M+), 191 (66), 131 (base peak), 103 (23), 77 (10),
and 66 (17). Anal. Calcd for C16H16O3: C, 74.98; H, 6.29. Found:
C, 72.70; H, 6.18.
(51) Corey, E. J.; Loh, T.-P. J. Am. Chem. Soc. 1991, 113, 8966-8967.
(52) Fraile, J. M.; Garcia, J. I.; Mayoral, J. A.; Royo, A. J. Tetrahedron
Asymmetry 1996, 7, 2263-2276.
(53) (a) CAD-4 Software. Version 5. Enraf-Nonius: Delft, The Neth-
erlands, 1989. (b) Fair, C. K. MolEN. An Interactive Intelligent System
for Crystal Structure Analysis. Enraf-Nonius: Delft, The Netherlands, 1990.
(c) Altomare, M. C.; Burla, M.; Camalli, G.; Cascarano, C.; Giacovazzo,
A.; Guagliardi, G.; Polidori, J. J. Appl. Crystallogr. 1994, 27, 435. (d)
Sheldrick, G. M. SHELXL93. Program for the Refinement of Crystal
Structures. University of Go¨ttingen, Germany, 1993.
3-(1-Methylcyclohexen-4-ylcarbonyl)-2-oxazolidinone (17): color-
less solid; mp 51-53 °C; [R]25 -71.29 (56% ee estimated on the
D
basis of HPLC using a chiral column (Daicel Chiralcel ODH with