References and Notes
For recent reviews, see:
<A NAME="RW10809ST-1A">1a</A>
Krause N.
Hoffmann-Roder A.
Synthesis
2001,
171
<A NAME="RW10809ST-1B">1b</A>
Berner OM.
Tedeschi L.
Enders D.
Eur. J. Org. Chem.
2002,
1877
<A NAME="RW10809ST-1C">1c</A>
Sibi MP.
Manyem S.
Tetrahedron
2000,
56:
8033
<A NAME="RW10809ST-1D">1d</A>
Sulzer-Mossé J.
Alexakis A.
Chem. Commun.
2007,
3123
<A NAME="RW10809ST-1E">1e</A>
Vicario JL.
Badía D.
Carillo L.
Synthesis
2007,
2065
<A NAME="RW10809ST-2">2</A>
Sakthivel K.
Notz W.
Bui T.
Barbas CF.
J. Am. Chem. Soc.
2001,
123:
5260
<A NAME="RW10809ST-3">3</A>
List B.
Pojarlier P.
Martin HJ.
Org.
Lett.
2001,
3:
2423
For recent reviews, see:
<A NAME="RW10809ST-4A">4a</A>
Tsogoeva SB.
Eur. J. Org. Chem.
2007,
1701
<A NAME="RW10809ST-4B">4b</A>
Almasi D.
Alonso DA.
Nájera C.
Tetrahedron: Asymmetry
2007,
18:
299
Very recent references for organocatalyzed
asymmetric nitro-Michael reaction:
<A NAME="RW10809ST-5A">5a</A>
Zhu SL.
Yu SY.
Ma DW.
Angew.
Chem. Int. Ed.
2008,
47:
545
<A NAME="RW10809ST-5B">5b</A>
Garcia P.
Ladepeche A.
Halder R.
List B.
Angew. Chem. Int. Ed.
2008,
47:
4719
<A NAME="RW10809ST-5C">5c</A>
Hayashi Y.
Itoh T.
Ohkubo M.
Ishikawa H.
Angew. Chem. Int. Ed.
2008,
47:
4722
<A NAME="RW10809ST-5D">5d</A>
Rabalakos C.
Wulff WD.
J. Am. Chem. Soc.
2008,
130:
13524
<A NAME="RW10809ST-5E">5e</A>
Dong XQ.
Teng HL.
Wang CJ.
Org. Lett.
2009,
11:
1265
<A NAME="RW10809ST-5F">5f</A>
Peng FZ.
Shao ZH.
Fan BM.
Song H.
Li GP.
Zhang HB.
J.
Org. Chem.
2008,
73:
5202
<A NAME="RW10809ST-5G">5g</A>
Luo J.
Xu LW.
Hay RAS.
Lu YX.
Org. Lett.
2009,
11:
437
<A NAME="RW10809ST-5H">5h</A>
Zhou W.
Liu H.
Du DM.
Org. Lett.
2008,
10:
2817
<A NAME="RW10809ST-5I">5i</A>
Ni BK.
Zhang QY.
Dhungana K.
Headley AD.
Org. Lett.
2009,
11:
1037
<A NAME="RW10809ST-5J">5j</A>
Tan B.
Zeng XF.
Lu YP.
Chua PJ.
Zhong GF.
Org.
Lett.
2009,
11:
1927
<A NAME="RW10809ST-5K">5k</A>
Chandrasekhar S.
Tiwari B.
Parida B.
Reddy C.
Tetrahedron: Asymmetry
2008,
19:
495
<A NAME="RW10809ST-5L">5l</A>
Quintard A.
Bournaud C.
Alexakis A.
Chem.
Eur. J.
2008,
14:
7504
<A NAME="RW10809ST-5M">5m</A>
Xu D.
Yue H.
Luo S.
Xia A.
Zhang S.
Xu Z.
Org.
Biomol. Chem.
2008,
6:
2054
<A NAME="RW10809ST-6">6</A>
Hayashi Y.
Okano T.
Aratake S.
Hazelard D.
Angew. Chem. Int. Ed.
2007,
46:
4922
<A NAME="RW10809ST-7">7</A>
Tan B.
Chua P.
Li Y.
Zhong G.
Org.
Lett.
2008,
10:
2437
<A NAME="RW10809ST-8">8</A>
Evans DA.
Mito S.
Seidel D.
J.
Am. Chem. Soc.
2007,
129:
11583
<A NAME="RW10809ST-9">9</A>
Belot S.
Massaro A.
Tenti A.
Mordini A.
Alexakis A.
Org.
Lett.
2008,
10:
4557
<A NAME="RW10809ST-10A">10a</A>
Tsogoeva SB.
Wei S.-W.
Chem.
Commun.
2006,
1451
<A NAME="RW10809ST-10B">10b</A>
Huang H.
Jacobsen EN.
J. Am. Chem. Soc.
2006,
128:
7170
<A NAME="RW10809ST-11">11</A>
All reactions were conducted in solvent
(2 mL) using nitrodiene 2a (0.2 mmol) and
acetophenone 3a (1 mmol, 5 equiv) in the
presence of 10 mol% of catalyst 1d.
Results of different solvent: toluene (30% yield, 97% ee), n-hexane (25% yield, 92% ee), i-PrOH (18% yield, 85% ee),
EtOH (5% yield, 88% ee), CH2Cl2 (15% yield,
97% ee), CHCl3 (16% yield, 97% ee),
THF (5% yield, 95% ee), Et2O (17% yield,
96% ee).
<A NAME="RW10809ST-12A">12a</A>
Yalalov DA.
Tsogoeva SB.
Schmatz S.
Adv. Synth. Catal.
2006,
348:
826
<A NAME="RW10809ST-12B">12b</A>
Wei S.-W.
Yalalov DA.
Tsogoeva SB.
Schmatz S.
Catal. Today
2007,
121:
151
<A NAME="RW10809ST-13">13</A>
General Procedure
for Enantioselective Conjugate Addition of Ketone with Nitrodiene
Organocatalyst 1d (43.32 mg, 0.12 mmol) was added to a vial
containing acetophenone 3 (4 mmol) and
toluene (2 mL) at r.t. The mixture was stirred vigorously for 10
min, and then the corresponding nitrodiene 2 (0.4mmol)
was added. The reaction mixture was stirred at r.t. for 96 h. Then
the solvent was evaporated, and the residue was purified by flash
silica gel chromatography (PE-EtOAc, 10:1) to afford the
corresponding product. The ee value was determined by chiral HPLC.
Characterization Data of Representative Compounds
Compound 4a: 63% yield, 97% ee, [a]D
²0 +3.5
(c 1.0, CHCl3). HPLC analysis [Chiralpak
AD-H column, l = 254 nm, hexane-i-PrOH (90:10), flow rate 1.0 mL/min]: t
R = 16.0
min(major), 18.4 min(minor). ¹H NMR (500 MHz, CDCl3):
d = 7.96 (d, J = 7.8
Hz, 2 H), 7.61-7.58 (m, 1 H), 7.50-7.47 (m, 2
H), 7.34-7.28 (m, 4 H), 7.25-7.23 (m, 1 H), 6.58
(d, J = 15.8
Hz, 1 H), 6.17 (dd, J = 15.8,
7.6 Hz, 1 H), 4.74-4.70 (m, 1 H), 4.64-4.60 (m,
1 H), 3.76 (m, 1 H), 3.30 (d, J = 6.3
Hz, 2 H). IR (film): n = 2958, 2918, 2850, 1679, 1542,
1450, 1410, 1379, 1365, 1271, 1218, 969, 758, 691 cm-¹.
HRMS: m/z calcd for C18H17NO3 [M]:
295.1208; found: 295.1210.