Electronic Molecular Devices
J . Org. Chem., Vol. 63, No. 9, 1998 2937
poured into cold HCl solution (1%, 25 mL) and extracted with
EtOAc (3 × 25 mL). The organic extracts were quickly washed
with saturated NaHCO3 (2 × 25 mL) and brine (25 mL), and
the solvent was removed in vacuo. SGC (95:5 hexanes/EtOAc)
yielded 19 as an orange oil (2.9 g, 96%): 1H NMR (300 MHz,
CDCl3) δ 5.4-5.6 (m, 3H), 5.15 (m, 2H), 3.43 (m, 1H), 0.75-
1.85 (m, 18H), 0.13 (s, 9H); 13C NMR (75 MHz, CDCl3) δ 233.7,
123.6, 95.2, 94.6, 94.5, 89.8, 88.9, 74.2, 54.8, 46.2, 39.8, 34.6,
31.4, 29.1, 27.2, 24.8, 22.0, 1.2; IR (neat, cm-1) 1950, 1870;
[R]D ) +63.6 (c ) 0.06, EtOAc).
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)-1-cycloh exa n ol-
η6-Dicar bon ylm on o(tr iph en ylph osph in o)ch r om iu m Com -
p lex (21d ). Complex 19 (0.37 g, 0.84 mmol) and Ph3P (1.31
g, 5.0 mmol) were dissolved in dry benzene (4 mL). The
mixture was degassed (triple freeze-thaw cycles) and then
irradiated with ultraviolet light for 4 h under an argon
atmosphere. The solvent was removed in vacuo, the residue
was suspended in MeOH (5 mL), K2CO3 (0.7 g, 5.1 mmol) was
added, and the mixture was stirred at 25 °C for 3 h. The
K2CO3 was then filtered off and the solvent removed in vacuo.
SGC (8:2 hexanes/EtOAc) yielded the title compound as an
orange oil (0.44 g, 87%): 1H NMR (300 MHz, (CD3)2CO) δ
7.34-7.52 (m, 15H), 5.34 (d, J ) 6.5 Hz, 1H), 5.14 (d, J ) 6.5
Hz, 1H), 4.4-4.6 (m, 3H), 3.3 (m, 1H), 0.75-1.85 (m, 18H);
13C NMR (75 MHz, (CD3)2CO) δ 242.4, 242.2, 141.0, 140.6,
133.8, 133.6, 129.6, 128.6, 115.7, 94.8, 92.0, 91.0, 89.5, 89.1,
72.9, 60.0, 56.0, 47.3, 40.7, 35.6, 32.4, 32.2, 28.7, 27.7, 25.7,
22.3; IR (neat, cm-1) 3422, 1878, 1831; [R]D ) +16.1 (c ) 0.06,
EtOAc). Anal. Calcd for C36H39CrO3P: C, 71.75; H, 6.52.
Found: C, 71.61; H, 6.44.
ch r om iu m Com p lex (22b). 22b was similarly prepared from
21b in 82% yield as a yellow solid: mp 88-90 °C; 13C NMR
(75 MHz, (CD3)2CO) δ 237.8, 237.4, 165.3, 153.3, 130.8, 130.6,
130.2, 128.8, 126.5, 126.1, 125.2, 122.5, 121.5, 120.8, 92.8, 92.3,
89.0, 88.5, 75.0, 74.9, 52.7, 51.1, 42.3, 42.1, 34.9, 32.0, 30.3,
28.7, 27.5, 26.5, 21.8; IR (neat, cm-1) 1900, 1851, 1718, 1715;
[R]D ) -2.9 (c ) 0.05, MeOH). Anal. Calcd for C39H41CrO7P:
C, 66.47; H, 5.86. Found: C, 66.81; H, 5.98.
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)cycloh exyl Acr y-
l a t e -η6 -D i c a r b o n y l m o n o ( t r i p h e n y l p h o s p h i n o ) -
ch r om iu m Com p lex (22d ). 22d was similarly prepared from
21d in 88% yield as a yellow oil: 13C NMR (75 MHz, (CD3)2CO)
δ 242.1, 241.8, 165.3, 152.1, 140.7, 140.3, 133.7, 133.5, 130.7,
130.2, 129.6, 128.6, 128.5, 115.8, 95.2, 91.4, 90.8, 89.1, 88.8,
75.0, 53.0, 42.3, 40.0, 35.1, 32.2, 31.9, 27.6, 26.8, 26.2, 22.0;
IR (solution in THF, cm-1) 1891, 1837, 1722; [R]D ) +141 (c )
0.075, MeOH). Anal. Calcd for C39H41CrO4P: C, 71.33; H,
6.29. Found: C, 71.51; H, 6.38.
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)cycloh exyl Acr y-
la t e-η6-Dica r b on ylm on o(t r iet h ylp h osp h it o)ch r om iu m
Com p lex (22c). 21c was similarly prepared from 21c in 85%
yield as a yellow oil: 1H NMR (300 MHz, C6D6) δ 6.25 (br d, J
) 17 Hz, 1H), 5.81 (m, 1H), 5.27 (d, J ) 10.1 Hz, 1H) 4.4-5.0
(m, 6H), 3.44 (m, 6H), 0.5-2.0 (m, 25H); 13C NMR (75 MHz,
C6D6) δ 238.7, 238.4, 164.8, 117.5, 92.4, 90.8, 90.4, 86.5, 86.3,
74.5, 52.6, 51.0, 41.9, 39.4, 34.6, 31.0, 27.3, 27.1, 26.2, 21.8,
16.6; IR (neat, cm-1) 1901, 1823, 1720; [R]D ) +291 (c ) 0.076,
MeOH). Anal. Calcd for C27H41CrO7P: C, 57.85; H, 7.37.
Found: C, 58.21; H, 6.99.
5-M e t h y l-2-(1-m e t h y l-1-p h e n y le t h y l)c y c lo h e x y l-
bicyclo[2.2.1]h ept-5-en e-2-car boxylate (23). Gen er al P r o-
ced u r e. 5-Methyl-2-(1-methyl-1-phenylethyl)cyclohexyl acry-
late (0.029 g, 0.1 mmol) was dissolved in CH2Cl2 (5 mL), the
solution was then cooled to 0 °C, and freshly distilled cyclo-
pentadiene (1 mL) was added. The mixture was stirred at 0
°C for 20 min, then freshly distilled BF3‚Et2O (0.012 mL, 0.1
mmol) added dropwise down the sides of the flask over a 10
min period. The reaction was stirred at 0 °C for an additional
3.5 h, the solution was poured into saturated NaHCO3 (25 mL)
and extracted with EtOAc (3 × 25 mL), the organic extracts
were washed with water (25 mL) and brine (25 mL), and the
solvent was evaporated to yield 23 as an essentially pure oil
(0.032 g, 97%) spectroscopically identical with known material:
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)-1-cycloh exa n ol-
η6-Dicar bon ylm on o(tr iph en ylph osph ito)ch r om iu m Com -
p lex (21b). 21b was similarly prepared from 19 in 91% yield
as a yellow oil: 1H NMR (300 MHz, (CD3)2CO) δ 7.1-7.4 (m,
15H), 5.20 (br, 1H), 5.09 (br, 1H), 3.8-4.2 (br m, 3H), 3.15 (br
m, 1H), 0.75-1.85 (m, 18H); 13C NMR (75 MHz, (CD3)2CO) δ
238.0, 237.5, 153.3, 130.2, 129.8, 124.8, 122.5, 119.3, 93.6, 92.8,
92.2, 88.8, 88.4, 72.7, 55.5, 47.1, 40.5, 35.4, 32.1, 28.2, 27.5,
26.4, 22.2; IR (neat, cm-1) 3336, 1909, 1839; [R]D ) +269 (c )
0.048, MeOH). Anal. Calcd for C36H39CrO6P: C, 66.45; H,
6.04. Found: C, 66.61; H, 6.28.
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)-1-cycloh exa n ol-
η6-Dica r bon ylm on o(tr ieth ylp h osp h ito)ch r om iu m Com -
p lex (21c). 21c was similarly prepared from 19 in 93% yield
as a yellow oil: 13C NMR (75 MHz, (CD3)2CO) δ 240.0, 239.6,
117.8, 93.3, 92.0, 91.1, 88.4, 87.7, 73.0, 60.0, 55.9, 47.3, 40.6,
35.6, 32.3, 27.8, 25.8, 22.3, 16.6; IR (Neat, cm-1) 3503, 1901,
1823; [R]D ) +143 (c ) 0.057, MeOH). Anal. Calcd for
38
1H NMR (300 MHz, CDCl3) δ 7.1-7.4 (m, 5H), 5.96-6.12
(m, 2H), 4.77 (m, 1H), 0.5-3.0 (br m, 24H); 13C NMR (75 MHz,
CDCl3) δ 174.0, 151.4, 137.1, 132.9, 127.8, 125.7, 125.4, 125.0,
74.3, 50.2, 49.3, 45.1, 43.7, 42.3, 41.8, 39.8, 34.5, 31.2, 29.6,
26.8, 26.6, 26.5, 21.8; HPLC Diacel OD column; 98:2 hexane/
isopropyl alcohol eluent; flow rate 1.0 mL/min; endo 1 ) 4.44
min, endo 2 ) 5.00 min. In the case of the arenechromium
carbonyl-complexed acrylates, the crude product was then
dissolved in Et2O (20 mL) and allowed to decomplex (sunlight)
completely over a 3 h period. The resulting greenish precipi-
tate was then filtered through a small plug of silica gel and
the filtrate condensed in vacuo to yield the cycloadduct 23 as
a colorless oil.
C
24H34CrO6P: C, 57.48; H, 6.83. Found: C, 57.75; H, 6.59.
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)cycloh exyl Acr y-
la te. To a solution of 5-methyl-2-(1-methyl-1-phenylethyl)cy-
clohexanol (18) (0.2 g, 0.86 mmol) and Et3N (0.6 mL, 4.3 mmol)
in CH2Cl2 (3 mL) at -10 °C was added neat acryloyl chloride
(0.175 mL 2.15 mmol) dropwise down the sides of the flask
over a 5 min period. The deep red solution was warmed to 25
°C and filtered directly, followed by solvent evaporation in
vacuo to yield the essentially pure product. SGC (9:1 hexanes/
EtOAc) gave the title compound (0.22 g, 91%) as a colorless
oil spectroscopically identical with known material:38 1H NMR
(300 MHz, CDCl3) δ 7.30-7.20 (m, 5H), 5.98 (m, 1H), 5.56 (m,
2H), 4.95 (m, 1H), 0.84-1.95 (m, 18H); IR (solution in THF,
cm-1) 1721 cm-1; [R]D ) -16.5° (c ) 1, CH2Cl2).
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)cycloh exyl Acr y-
la te-η6-Tr ica r bon ylch r om iu m Com p lex (22a ). 22a was
similarly prepared from 21a in 80% yield as a pale yellow
solid: mp 242-244 °C dec; 1H NMR (300 MHz, CDCl3) δ 6.27
(d, J ) 17.4 Hz, 1H), 5.79 (m, 2H), 5.47 (m, 3H), 5.07 (m, 2H),
4.73 (m, 1H), 0.84-1.87 (m, 18H); 13C NMR (75 MHz, (CD3)2CO)
δ 235.1, 165.3, 131.1, 130.1, 125.4, 97.0, 96.9, 96.5, 91.6, 91.4,
75.0, 52.8, 42.3, 39.9, 35.0, 31.7, 27.9, 27.8, 21.9; IR (solution
in THF, cm-1) 1960, 1885, 1724; [R]D ) +209 (c ) 0.09, MeOH).
Anal. Calcd for C22H26CrO5: C, 62.55; H, 6.20. Found: C,
62.31; H, 6.47.
(4S)-4-Ben zyl-1,3-oxa zola n -2-on e (24). (2S)-2-Amino-3-
phenylpropan-1-ol (0.95 g, 6.29 mmol) and urea (0.42 g, 6.92
mmol) were dissolved in dimethylacetamide (5 mL) in a 10
mL Erlenmeyer flask. The mixture was then placed in the
center of an unmodofied domestic microwave oven (Kenmore,
650 W) and irradiated on full power for 1 min, allowed to cool
for 1 min, and then irradiated again for 1 min. The resulting
oil was diluted with EtOAc (100 mL), washed with HCl (1%,
50 mL), H2O (50 mL), and brine (50 mL), and the solvent
removed in vacuo to yield 24 (1.0 g, 90%) spectroscopically
identical to known material.31
(4S)-4-Ben zyl-1,3-oxa zola n -2-on e-η6-Tr ica r bon ylch r o-
m iu m Com p lex (25a ). In a round-bottom flask fitted with a
reflux condenser was placed oxazolidione 24 (3.0 g, 16.95
mmol), naphthalene (0.44 g,3.4 mmol), and Cr(CO)6 (7.5 g, 34
mmol). The flask was then charged with Bu2O (60 mL) and
THF (6 mL) and placed in a 140 °C oilbath for 40 h. Upon
cooling, the mixture was filtered through a small plug of silica
gel and the solvent removed in vacuo. SGC (7:3 EtOAc/
5-Meth yl-2-(1-m eth yl-1-p h en yleth yl)cycloh exyl Acr y-
l a t e -η6 -D i c a r b o n y l m o n o ( t r i p h e n y l p h o s p h i t o ) -