References and Notes
1 For a review of the chemistry of enaminones, see: Elassar A.-ZA.
El-Khairb AA.
Tetrahedron
2003,
59:
8463
For selected reviews, see:
2a
Dehaen W.
Becher J.
Acta Chem. Scand.
1993,
47:
244
2b
Lue P.
Greenhill JV. In Advances in Heterocyclic Chemistry
Vol. 67:
Katritzky AR.
Academic Press;
New York:
1997.
p.207
2c
Kascheres CM.
J. Braz. Chem. Soc.
2003,
14:
945
3
Michael JP.
Koning CB.
Gravestock D.
Hosken GD.
Howard AS.
Jungmann CM.
Krause RWM.
Parsons AS.
Pelly SC.
Stanbury TV.
Pure Appl. Chem.
1999,
71:
979
4
Felice E.
Fioravanti S.
Pellacani L.
Tardella PA.
Tetrahedron Lett.
1999,
40:
4413
5
Cimarelli C.
Palmieri G.
Volpini E.
Synth. Commun.
2001,
31:
2943
6
Beholz LG.
Benovsky P.
Ward DL.
Barta NS.
Stille JR.
J. Org. Chem.
1997,
62:
1033
7
Dalpozzo R.
De Nino A.
Bartoli G.
Bosco M.
Sambri L.
Marcantoni E.
J. Org. Chem.
1998,
63:
3745
8
Cimarelli C.
Giuli S.
Palmieri G.
Eur. J. Org. Chem.
2006,
1017
9
Figueiredo LJO.
Kascheres C.
J. Org. Chem.
1997,
62:
1164
10
Aceña JL.
Arjona O.
Mañas R.
Plumet J.
J. Org. Chem.
2000,
65:
2580
11
Brandt CA.
Da Silva ACMP.
Pancote CG.
Brito CL.
Da Silveira MAB.
Synthesis
2004,
1557
12
Braibante MEF.
Braibante HS.
Missio L.
Andricopulo A.
Synthesis
1994,
898
13
Gao Y.
Zhang Q.
Xu J.
Synth. Commun.
2004,
34:
909
14
Texier-Bouliet F.
Synthesis
1985,
679
15a
Khorospour AR.
Khodaei MM.
Kookhazadeh M.
Tetrahedron Lett.
2004,
45:
1725
15b
Khodaei MM.
Khorospour AR.
Kookhazadeh M.
Can. J. Chem.
2005,
83:
209
16
Bartoli G.
Bosco M.
Locatelli M.
Marcantoni E.
Melchiorre P.
Sambri L.
Synlett
2004,
239
17
Khodaei MM.
Khosropour AR.
Kookhazadeh M.
Synlett
2004,
1980
18
Zhang Z.-H.
Yin L.
Wang Y.-M.
Adv. Synth. Catal.
2006,
348:
184
19
Cartaya-Marin CP.
Henderson DG.
Soeder RW.
Synth. Commun.
1997,
27:
4275
20
Stefane B.
Polanc S.
Synlett
2004,
696
21a
Karthikeyan G.
Perumal PT.
Can. J. Chem.
2005,
83:
1746
21b
Stefani HA.
Costa IM.
Silva DO.
Synthesis
2000,
1526
22
Brandt CA.
da Silva ACMP.
Pancote CG.
Brito CL.
da Silveira MAB.
Synthesis
2004,
1157
23
Katritzky AR.
Fang Y.
Donkor A.
Xu J.
Synthesis
2000,
2029
24
Haak E.
Synlett
2006,
1847
25a Nitriles: Lee AY.-S.
Cheng R.-Y.
Tetrahedron Lett.
1997,
38:
443
25b Tosylimines: Jiang N.
Qu Z.
Wang J.
Org. Lett.
2001,
3:
2989
25c Imidoyl halides: Fustero S.
Pina B.
Salavert E.
Navarro A.
Ramírez de Arellano C.
Simón A.
J. Org. Chem.
2002,
67:
4667
26
Cimarelli C.
Palmieri G.
Volpini E.
Tetrahedron Lett.
2004,
45:
6629
27
Kobayashi S.
Manabe K.
Pure Appl. Chem.
2000,
72:
1373
Some examples are:
28a CeCl3·nH2O/NaI: Bartoli G.
Marcantoni E.
Sambri L.
Synlett
2003,
2101
28b Ce(OTf)3: Bartoli G.
De Nino A.
Dalpozzo R.
Maiuolo L.
Nardi M.
Procopio A.
Tagarelli A.
Lett. Org. Chem.
2005,
2:
51
Some reviews on CAN-promoted synthetic transformations:
29a
Nair V.
Matthew J.
Prabhakaran J.
Chem. Soc. Rev.
1997,
26:
127
29b
Hwu JR.
King K.-Y.
Curr. Sci.
2001,
81:
1043
29c
Nair V.
Panicker SB.
Nair LG.
George TG.
Augustine A.
Synlett
2003,
156
29d
Nair V.
Balagopal L.
Rajan R.
Mathew J.
Acc. Chem. Res.
2004,
37:
21
29e
Dhakshinamoorty A.
Synlett
2005,
3014 ; Spotlight 143
Some synthetically useful CAN-catalyzed reactions have been described very recently. See:
30a
Zeng X.-F.
Ji S.-J.
Wang SY.
Tetrahedron
2005,
61:
10235
30b
Wang SY.
Ji S.-J.
Tetrahedron
2006,
62:
1527
30c
Savitha G.
Perumal PT.
Tetrahedron Lett.
2006,
47:
3589
30d
Nair V.
Mohanan K.
Suja TD.
Suresh E.
Tetrahedron Lett.
2006,
47:
705
30e
Varala R.
Enugala R.
Nuvula S.
Adapa SR.
Synlett
2006,
1009
30f
Varala R.
Sreelatha N.
Adapa SR.
Synlett
2006,
1549
30g
Sridharan V.
Avendaño C.
Menéndez JC.
Tetrahedron
2007,
63:
673
31
General Experimental Procedure for β-Enaminone Synthesis
To a stirred solution of 3 mmol of amine 1 and 3 mmol of β-dicarbonyl compound 2 in 3 mL of EtOH was added 5 mol% of CAN. The mixture was stirred at r.t. for the time periods specified in Tables
[1]
and
[2]
. After completion of the reaction the mixture was dissolved in CH2Cl2, washed with H2O, dried, and evaporated. Analytically pure compounds 3 were obtained by a rapid column chromatography on Et3N-pretreated silica gel, eluting with PE-EtOAc mixtures. Characterization data for two representative, previously unknown enamines follow.
Ethyl 2-(4-methylphenylamino)cyclohex-1-enecarboxylate (3b): viscous liquid. IR (neat): 3228.5, 2935.4, 2858.6, 1650.6, 1603.4, 1515.9, 1236.9, 1175.8, 1077.8 cm-1. 1H NMR (250 MHz, CDCl3): δ 1.33 (t, J = 7.1 Hz, 3 H), 1.61-1.63 (m, 4 H), 2.26-2.40 (m, 7 H), 4.21 (q, J = 7.1 Hz, 2 H), 6.98 (d, J = 8.2 Hz, 2 H), 7.13 (d, J = 8.2 Hz, 2 H), 10.69 (br s, 1 H). 13C NMR (62.9 MHz, CDCl3, DEPT-135): δ = 15.1 (CH3), 21.3 (CH3), 22.7 (CH2), 23.1 (CH2), 24.3 (CH2), 28.5 (CH2), 59.5 (CH2), 92.7 (CH), 125.7 (CH), 129.8 (CH), 134.6 (C), 137.5 (C), 157.5 (C), 171.3 (C). Anal. Calcd for C16H21NO2: C, 74.10; H, 8.16; N, 5.40. Found: C, 74.06; H, 8.32; N, 5.71.
tert-Butyl 3-(butylamino)but-2-enethioate (3ac): viscous liquid. IR (neat): 3253.3, 2960.1, 2928.2, 1606.0, 1582.8, 1499.8, 1360.6, 1266.3, 1084.5 cm-1. 1H NMR (250 MHz, CDCl3): δ = 0.94 (t, J = 7.3 Hz, 3 H), 1.37-1.56 (m, 4 H), 1.50 (s, 9 H), 1.87 (s, 3 H), 3.20 (q, J = 7.3 Hz, 2 H), 4.86 (s, 1 H), 9.34 (br s, 1 H). 13C NMR (62.9 MHz, CDCl3, DEPT-135): δ = 14.2 (CH3), 19.2 (CH3), 20.4 (CH2), 31.0 (CH3), 32.8 (CH2), 43.3 (CH2), 46.8 (C), 94.2 (CH), 160.1 (C), 188.9 (C). Anal. Calcd for C12H23NOS: C, 62.83; H, 10.11; N, 6.11; S, 13.98. Found: C, 62.76; H, 9.96; N, 5.86; S, 13.74.
32
Markó IE.
Ates A.
Gautier A.
Leroy B.
Plancher J.-M.
Quesnel Y.
Vanherck J.-C.
Angew. Chem. Int. Ed.
1999,
12:
2653
