4134 J. Am. Chem. Soc., Vol. 121, No. 17, 1999
Murakami et al.
) 26.6 min, (S) t2 ) 29.7 min]. 1H NMR NMR δ 1.45-1.70 (m, 1 H),
2.05 (s, 3 H), 2.31 (s, 3 H), 2.40-2.53 (m, 1 H), 2.90-3.14 (m, 3 H),
7.00 (d, J ) 2.3 Hz, 1 H), 7.12-7.28 (m, 3 H), 7.60-7.70 (m, 1 H);
13C{1H} NMR δ 20.5, 23.8, 24.3, 30.0, 51.5, 122.1, 123.9, 126.4, 128.1,
129.4, 131.4, 134.6, 137.2, 139.0, 143.2, 206.9; HRMS m/e calcd for
C16H16O 224.1201, found 224.1199.
(5R)-4,5-Diethyl-2-isopropylidene-3-cyclopentenone (2d). Oil. [R]20
D
-77.9 (c 1.40, CHCl3), 76.6% ee [HPLC, CHIRALCEL OD-H (4.6φ
× 250 mm), 0.5 mL/min, hexane, (S) t1 ) 15.0 min, (R) t2 ) 17.1
min]. 1H NMR δ 0.72 (t, J ) 7.4 Hz, 3 H), 1.13 (t, J ) 7.4 Hz, 3 H),
1.51-1.75 (m, 2 H), 1.80-2.00 (m, 1 H), 1.91 (s, 3 H), 2.10-2.35
(m, 1 H), 2.21 (s, 3 H), 2.76 (t, J ) 4.5 Hz, 1 H), 6.48 (d, J ) 1.5 Hz,
1 H); 13C{1H} NMR δ 9.5, 11.6, 20.2, 21.4, 23.2, 23.5, 55.0, 125.7,
134.0, 140.0, 146.4, 209.2; HRMS m/e calcd for C12H18O 178.1358,
found 178.1372.
Conclusion
(5R)-4,5-Dibutyl-2-isopropylidene-3-cyclopentenone (2e). Oil. [R]20
D
Asymmetric cycloaddition is a powerful tool to construct
complex chiral molecules.19 The asymmetric carbonylative [4
+ 1] cycloaddition of vinylallenes documented herein adds a
new promising example which achieves enantioselectivities up
to 95% ee. The studies illustrate that either enantiomer of the
[4 + 1] cycloadduct can be obtained with good selectivity using
a single enantiomer of a chiral diphosphine ligand by appropriate
choice of a metal catalyst. Although the origin of the reversal
of the induced chirality according to the metal employed is only
partially interpreted at this time, the ability to carry out
enantioselective cycloaddition in two distinct ways enhances
the synthetic utility of the present reaction.
-75.4 (c 1.22, CHCl3), 70.7% ee [HPLC, CHIRALPAK AS (4.6φ ×
250 mm), 0.5 mL/min, hexane, (R) t1 ) 10.5 min, (S) t2 ) 12.7 min].
1H NMR δ 0.85 (t, J ) 7.3 Hz, 3 H), 0.93 (t, J ) 6.7 Hz, 3 H), 1.00-
1.85 (m, 10 H), 1.91 (s, 3 H), 2.10-2.30 (m, 2 H), 2.22 (s, 3 H), 2.77
(t, J ) 4.4 Hz, 1 H), 6.46 (d, J ) 1.5 Hz, 1 H); 13C{1H} NMR δ 14.2,
14.2, 20.2, 22.8, 23.3, 23.6, 27.6, 28.4, 29.5, 30.1, 54.1, 126.3, 133.9,
140.1, 145.5, 209.2; HRMS m/e calcd for C16H26O 234.1982, found
234.1981.
(5R)-4,5-Diethyl-2-(1-ethylpropylidene)-3-cyclopentenone (2f). Oil.
[R]20D -72.9 (c 1.20, CHCl3), 74.8% ee [HPLC, CHIRALCEL OD-H
(4.6φ × 250 mm), 0.5 mL/min, hexane, (S) t1 ) 11.9 min, (R) t2 )
1
13.3 min]. H NMR δ 0.72 (t, J ) 7.5 Hz, 3 H), 1.02 (t, J ) 7.5 Hz,
3 H), 1.07 (t, J ) 7.6 Hz, 3 H), 1.13 (t, J ) 7.4 Hz, 3 H), 1.54-1.73
(m, 1 H), 1.78-1.96 (m, 1 H), 2.10-2.40 (m, 4 H), 2.55-2.83 (m, 3
H), 6.48 (d, J ) 1.6 Hz, 1 H); 13C{1H} NMR δ 9.5, 11.6, 12.9, 13.3,
21.5, 23.3, 24.1, 27.8, 55.0, 125.5, 132.8, 146.8, 151.8, 209.1; HRMS
m/e calcd for C14H22O 206.1670, found 206.1667.
Experimental Section20
Materials. [Rh(cod){(R,R)-Me-DuPHOS}]PF6 was prepared from
[Rh(cod)2]PF621 by a method analogous to that reported for [Rh(cod)-
{(R,R)-Me-DuPHOS}]OTf.7a
(7R)-9-Isopropylidenebicyclo[5.3.0]dec-1(10)-en-9-one (2g). Oil.
[R]20D -144.3 (c 1.92, CHCl3), 76.9% ee [HPLC, CHIRALCEL OD-H
(4.6φ × 250 mm), 0.5 mL/min, hexane, (S) t1 ) 20.6 min, (R) t2 )
22.1 min]. 1H NMR δ 1.40-1.55 (m, 3 H), 1.55-1.85 (m, 4 H), 1.91
(s, 3 H), 1.90-2.20 (m, 1 H), 2.21 (s, 3 H), 2.45-2.60 (m, 2 H), 2.75-
2.90 (m, 1 H), 6.40-6.50 (m, 1 H); 13C{1H} NMR δ 20.1, 23.4, 28.0,
28.6, 30.2, 30.9, 31.7, 56.3, 126.0, 133.7, 139.8, 147.4, 208.5; HRMS
m/e calcd for C13H18O 190.1358, found 190.1366.
(6S)-8-Isopropylidenebicyclo[4.3.0]non-1(9)-en-7-one (2b). A mix-
ture of [Rh(cod){(R,R)-Me-DuPHOS}]PF6 (4.5 mg, 6.8 µmol) and 1b
(20.0 mg, 135 µmol) in DME (3 mL) under 5 atm of CO in an autoclave
was stirred in an oil bath at 58 °C for 9 h. After the mixture was cooled,
the solvent was removed under vacuum. The residue was subjected to
preparative thin-layer chromatography (silica gel, ether:hexane ) 1:10)
to afford 2b (23.5 mg, 99%): oil, [R]20D +57.7 (c 1.24, CHCl3), 78.0%
ee [HPLC, CHIRALPAK AS (4.6φ × 250 mm), 0.5 mL/min, hexane,
(R) t1 ) 19.3 min, (S) t2 ) 22.9 min]. 1H NMR δ 0.80-1.50 (m, 4 H),
1.80-2.40 (m, 3 H), 1.92 (s, 3 H), 2.22 (s, 3 H), 2.45-2.70 (m, 2 H),
6.36 (s, 1 H); 13C{1H} NMR δ 20.0, 23.5, 25.3, 27.3, 28.9, 29.8, 52.8,
122.6, 133.4, 140.6, 145.0, 208.3; MS m/e 176 (M+). Anal. Calcd for
C12H16O: C, 81.77; H, 9.15. Found: C, 81.92; H, 9.38.
1
(4Z,6E)-2-Methyl-5-propyl-2,4,6-nonatriene (3). Oil. H NMR δ
0.92 (t, J ) 7.3 Hz, 3 H), 1.04 (t, J ) 7.4 Hz, 3 H), 1.40-1.59 (m, 2
H), 1.77 (s, 3 H), 1.83 (s, 3 H), 2.10-2.26 (m, 4 H), 5.77 (dt, J )
15.5, 6.7 Hz, 1 H), 6.02 (d, J ) 11.6 Hz, 1 H), 6.27 (d, J ) 11.6 Hz,
1 H), 6.52 (d, J ) 15.5 Hz, 1 H); 13C{1H} NMR δ 14.1, 14.4, 18.3,
22.6, 26.7, 36.9, 120.6, 123.2, 125.2, 132.4, 134.6, 135.6.
General Procedure for the Synthesis of 5 and 6. After the
asymmetric [4 + 1] cycloaddition reactions of 4 were carried out
according to the procedure for 2b, the [4 + 1] cycloadducts 5a-c were
isolated by passing the reaction mixture through a short pad of silica
gel. The cycloadducts 5a-c thus isolated were subsequently subjected
to reduction with NaBH4/CeCl3 in MeOH to give 6a-c.
(5S)-4-(Ethoxycarbonyl)-2-isopropylidene-5-phenyl-3-cyclopen-
tenone (5a). Oil. 1H NMR δ 1.16 (d, J ) 7.1 Hz, 3 H), 2.15 (s, 3 H),
2.32 (s, 3 H), 4.06-4.22 (m, 2 H), 4.28 (d, J ) 1.6 Hz, 1 H), 7.10-
7.20 (m, 2 H), 7.20-7.40 (m, 3 H), 7.90 (d, J ) 1.6 Hz, 1 H); 13C{1H}
NMR δ 14.3, 21.3, 24.6, 58.4, 60.7, 127.3, 127.8, 128.8, 132.7, 132.8,
137.2, 141.5, 154.8, 164.6, 202.5; HRMS m/e calcd for C17H18O3
270.1255, found 270.1252.
The following rhodium-catalyzed asymmetric [4 + 1] cycloaddition
reactions producing 2 were carried out according to the preceding
procedure for 2b. The platinum-catalyzed reactions were carried out
analogously except that the catalyst was prepared in situ from [Pt(cod)2]
(5 mol %) and (R,R)-Me-DuPHOS (or Et-DuPHOS, 6 mol %).
(5S)-4,5-Dipropyl-2-isopropylidene-3-cyclopentenone (2a). Oil.
64.5% ee [HPLC, CHIRALCEL OD-H (4.6φ × 250 mm), 0.5 mL/
min, hexane, (S) t1 ) 15.8 min, (R) t2 ) 19.6 min]. 1H NMR δ 0.86 (t,
J ) 7.1 Hz, 3 H), 0.96 (t, J ) 7.3 Hz, 3 H), 1.05-1.40 (m, 2 H),
1.40-1.65 (m, 3 H), 1.70-1.90 (m, 1 H), 1.91 (s, 3 H), 2.10-2.25
(m, 2 H), 2.22 (s, 3 H), 2.76 (t, J ) 4.4 Hz, 1 H), 6.46 (d, J ) 1.4 Hz,
1 H); 13C{1H} NMR δ 15.3, 15.6, 19.9, 21.2, 21.6, 24.6, 32.0, 33.5,
55.1, 127.4, 134.8, 141.1, 146.3, 210.2; HRMS m/e calcd for C14H22O
206.1670, found 206.1655.
(1S,5S)-4-(Ethoxycarbonyl)-2-isopropylidene-5-phenyl-3-cyclo-
pentenol (6a). Oil. [R]20 +68.2 (c 3.99, CHCl3), 92.0% ee [HPLC,
D
(6S)-2,3-Benzo-8-isopropylidenebicyclo[4.3.0]non-1(9)-en-7-one
(2c). Oil. [R]20D -19.6 (c 1.30, CHCl3), 74.6% ee [HPLC, CHIRALCEL
OD-H (4.6φ × 250 mm), 0.5 mL/min, hexane-iPrOH (250:1), (R) t1
SUMICHIRAL OA-2500I (4.0φ × 250 mm), 1.0 mL/min, hexane-
ClCH2CH2Cl-EtOH (500:20:1), (1S,5S) t1 ) 31.9 min, (1R,5R) t2 )
1
37.2 min]. H NMR (400 MHz) δ 1.057 (d, J ) 6.4 Hz, 1 H), 1.063
(18) Trost, B. M.; Belletire, J. L.; Godleski, S.; Baldwin, J. J.; Christy,
M. E.; Ponticello, G. S. J. Org. Chem. 1986, 51, 2370.
(19) (a) Lautens, M.; Klute, W.; Tam, W. Chem. ReV. 1996, 96, 49. (b)
Ojima, I.; Tzamarioudaki, M.; Li, Z.; Donovan, R. J. Chem. ReV. 1996, 96,
635.
(t, J ) 7.1 Hz, 3 H), 1.95 (s, 6 H), 3.93-4.19 (m, 2 H), 4.37 (dd, J )
7.7, 1.8 Hz, 1 H), 5.01 (dd, J ) 7.7, 6.4 Hz, 1 H), 7.12-7.16 (m, 2 H),
7.20-7.33 (m, 3 H), 7.46 (d, J ) 1.8 Hz, 1 H); 13C{1H} NMR δ 14.0,
21.3, 22.0, 54.7, 60.0, 72.5, 127.1, 128.4, 129.1, 135.7, 136.9, 138.6,
139.7, 140.7, 165.2; HRMS m/e calcd for C17H20O3 272.1411, found
272.1427.
(20) General experimental details have been described.4c
(21) Green, M.; Kuc, T. A.; Taylor, S. H. J. Chem. Soc. (A) 1971, 2334.