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DOI: 10.1055/s-0028-1087349
N-Tosyl-(S a)-binam-l-prolinamide as Highly Efficient Bifunctional Organocatalyst for the General Enantioselective Solvent-Free Aldol Reaction
Publication History
Publication Date:
12 November 2008 (online)
Abstract
N-Tosyl-(S a)-binam-l-prolinamide (5 mol%) and benzoic acid (1 mol%) were used as catalysts in the enantioselective direct aldol reaction between different ketones and aldehydes under solvent-free conditions in the presence or absence of water. Under these reaction conditions it was possible to reduce the amount of required ketone to two equivalents to give the corresponding aldol products with high yields, regio-, diastereo- and enantioselectivities. The aldol reaction between aldehydes or the intramolecular aldol reaction can be also performed with excellent results.
Key words
organocatalyzed - aldol reactions - solvent-free - enantioselective - ketone
- For comprehensive books and selected reviews, see:
-
1a
Dalko PI.Moisan L. Angew. Chem. Int. Ed. 2004, 43: 5138 -
1b
Berkessel A.Gröger H. Asymmetric Organo-catalysis: From Biomimetic Concepts to Applications in Asymmetric Synthesis Wiley-VCH; Weinheim: 2005. -
1c
Seayad J.List B. Org. Biomol. Chem. 2005, 3: 719 -
1d
Kočovský P.Malkov AV. Tetrahedron 2006, 62: 255 -
1e
Lelais G.McMillan DWC. Aldrichimica Acta 2006, 39: 79 -
1f
Marigo M.Jørgensen KA. Chem. Commun. 2006, 2001 -
1g
Guillena G.Ramón DJ. Tetrahedron: Asymmetry 2006, 17: 1465 -
1h
List B. Chem. Commun. 2006, 819 -
1i
Gaunt MJ.Johansonn CCC.McNally A.Vo NT. Drug Discovery Today 2007, 12: 8 -
1j
Pellissier H. Tetrahedron 2007, 63: 9267 -
1k
Enantioselective
Organocatalysis
Dalko PI. Wiley-VCH; Weinheim: 2007. -
1l
List B. Chem. Rev. 2007, 107: 5413 -
1m
Enders D.Grondal C.Hüttl MRM. Angew. Chem. Int. Ed. 2007, 46: 1570 -
1n
Guillena G.Ramón DJ.Yus M. Tetrahedron: Asymmetry 2007, 18: 693 -
1o
de Figueiredo RM.Christmann M. Eur. J. Org. Chem. 2007, 2575 -
1p
Kotsuki H.Ikishima H.Okuyama A. Heterocycles 2008, 75: 493 -
1q
Kotsuki H.Ikishima H.Okuyama A. Heterocycles 2008, 75: 757 - 2
Guillena G.Nájera C.Ramón DJ. Tetrahedron: Asymmetry 2007, 18: 2249 -
3a
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2006, 17: 729 -
3b
Gryko D.Kowalczyk B.Zawadzki L. Synlett 2006, 1059 -
3c
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2006, 17: 1493 -
3d
Corrigendum:
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2007, 18: 1031 -
3e
Guizzetti S.Benaglia M.Pignataro L.Puglisi A. Tetrahedron: Asymmetry 2006, 17: 2754 -
3f
Ma G.-N.Zhang Y.-P.Shi M. Synthesis 2007, 197 -
3g
Guizzetti S.Benaglia M.Raimondi L.Celentano G. Org. Lett. 2007, 9: 1247 -
4a
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2006, 17: 1027 -
4b
Corrigendum:
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2007, 18: 1030 -
4c
Guillena G.Hita MC.Nájera C. Arkivoc 2007, (iv), 260 -
4d
Corrigendum:
Guillena G.Hita MC.Nájera C. Arkivoc 2007, (i): 146 -
4e
Guillena G.Hita MC.Nájera C. Tetrahedron: Asymmetry 2007, 18: 1272 -
5a
Guillena G.Hita MC.Nájera C.Viózquez SF. Tetrahedron: Asymmetry 2007, 18: 2300 -
5b
Guillena G.Hita MC.Nájera C.Viózquez SF. J. Org. Chem. 2008, 73: 5933 - 6
Chen T.Gao J.Shi M. Tetrahedron 2006, 62: 6289 - For some other organacatalyzed enantioselective aldol reactions under solvent-free conditions, see:
-
7a
Rodríguez B.Rantanen T.Bolm C. Angew. Chem. Int. Ed. 2006, 45: 6924 -
7b
Hayashi Y.Aratake S.Itoh T.Okano T.Sumiya T.Shoji M. Chem. Commun. 2007, 957 -
7c
Rodríguez B.Bruckmann A.Bolm C. Chem. Eur. J. 2007, 13: 4710 - 8
Nyberg AI.Usano A.Pinko PM. Synlett 2004, 1891 - 9
Chen J.-R.Li X.-Y.Xing X.-N.Xiao W.-J. J. Org. Chem. 2006, 71: 8198 -
10a
Eder U,Wiechert R, andSauer G. inventors; Ger. Patent, DE 2014757. ; Chem. Abstr. 1972, 76, 14180 -
10b
Hajos ZG, andParrish DR. inventors; Ger. Patent, DE 2102623. ; Chem. Abstr. 1972, 76, 59072 -
10c
Eder U.Sauer G.Wiechert R. Angew. Chem. Int. Ed. Engl. 1971, 10: 496 -
10d
Hajos ZG.Parrish DR. J. Org. Chem. 1974, 39: 1615 -
10e
Hajos ZG.Parrish DR. In Org. Synth., Coll. Vol. VIIFreeman JP. Wiley; New York: 1990. p.363 -
10f
Buchschacher P.Fürst A.Gutzwiller J. In Org. Synth., Coll. Vol. VIIFreeman JP. Wiley; New York: 1990. p.368 -
10g
Kwiatkowski S.Syed A.Brock CP.Watt DS. Synthesis 1989, 818 -
10h
Tietze LF.Utecht J. Synthesis 1993, 927 - 11
Wieland P.Miescher K. Helv. Chim. Acta 1950, 33: 2215
References and Notes
Representative
Experimental Procedure:
Anhydrous
Solvent-Free Conditions: To a mixture of the corresponding
aldehyde (0.25 mmol), catalyst 2 (0.0125 mmol,
6.5 mg) and benzoic acid (0.0025 mmol, 0.3 mg) at
0 ˚C
was added the corresponding ketone (0.5 mmol). The reaction was
stirred until the aldehyde was consumed (monitored by TLC). Then,
the crude product was diluted in CH2Cl2 (10
mL), silica gel was added and the solvent was evaporated in vacuo.
The resulting residue was purified by flash chromatography (hexanes-EtOAc)
to yield the pure aldol product.
Wet
Solvent-Free Conditions: To a mixture of the corresponding
aldehyde (0.25 mmol), catalyst 2 (0.0125 mmol,
6.5 mg), benzoic acid (0.0025 mmol, 0.3 mg), H2O (33 µL)
was added at 0 ˚C followed by the corresponding ketone
(0.5 mmol). The reaction was stirred until the aldehyde was consumed.
The crude product was diluted in CH2Cl2 (10
mL), MgSO4 was added and filtered. To the filtrate, silica
gel was added and the above purification procedure was followed
to obtain the aldol product.