scholarly journals Synthesis of New Di- and Triamides as Potential Organocatalysts for Asymmetric Aldol Reaction in Water

2020 ◽  
Vol 67 (4) ◽  
pp. 1014-1023
Author(s):  
Elif Keskin ◽  
Cigdem Yolacan ◽  
Feray Aydogan
Keyword(s):  
Benzoic Acid ◽  
Aldol Reaction ◽  
Aromatic Aldehydes ◽  
Reaction Conditions ◽  
Asymmetric Aldol ◽  
Co Catalyst ◽  
Aliphatic Ketones ◽  
Asymmetric Aldol Reaction ◽  
Reaction In Water

New di- or triamide organocatalysts derived from (L)-proline were synthesized and successfully used in the direct asymmetric aldol reaction of aliphatic ketones and aromatic aldehydes in water at 0 °C in the presence of benzoic acid as co-catalyst. (S)-methyl-2-((S)-3-hydroxy-2-((S)-3-pyrrolidine-2-carboxamido)propanamido)-3-phenylpropanoate (7c) as organocatalyst showed best results under these reaction conditions, and good diastereoselectivities (up to 99%), enantioselectivities (up to 98%) and yields (up to 91%) were observed.

Pro-Phe derivatives as organocatalysts in asymmetric aldol reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Merve Karaoglu ◽  
Feray Aydogan ◽  
Cigdem Yolacan
Keyword(s):  
Aldol Reaction ◽  
Aromatic Aldehydes ◽  
Biologically Active ◽  
Asymmetric Aldol ◽  
Catalytic Activities ◽  
Bond Forming ◽  
Nitrobenzoic Acid ◽  
Aliphatic Ketones ◽  
Asymmetric Aldol Reaction ◽  
Optically Pure

: The aldol reaction which is the most important one among the C-C bond forming reactions, is widely used by synthetic organic chemists to obtain β-hydroxycarbonyl compounds which are important starting components for biologically active compounds in optically pure form. In this research, five Pro-Phe derivatives were synthesized by simple amidation reactions and characterized by their spectral data. Their catalytic activities in asymmetric aldol reaction were investigated. The catalytic activity studies were performed with aliphatic ketones and various aromatic aldehydes. Especially, (S)-methyl 3-mercapto-2-((S)-3-phenyl-2-((S)-pyrrolidine-2-carboxamido)propanamido)propanoate showed good catalytic activities in water at 0 oC in the presence of p-nitrobenzoic acid cocatalyst. The enantioselectivities were upto 90.4%, the diastereomeric ratios were upto 97/3 and yields were 99%. The results showed that these organocatalysts were promising organocatalysts for aldol reaction. Besides, this catalyst showed its best catalytic activities in water which is also important contribution to green chemistry requirements.

(S,S,S)-Perhydroindolic Acid: Efficient Catalyst for Direct Asymmetric Aldol Reaction from Aromatic Aldehydes.

ChemInform ◽  
2007 ◽  
Vol 38 (3) ◽  
Author(s):  
Xiaoping Tang ◽  
Benoit Liegault ◽  
Jean-Luc Renaud ◽  
Christian Bruneau
Keyword(s):  
Aldol Reaction ◽  
Aromatic Aldehydes ◽  
Efficient Catalyst ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction

Enhanced Activity and Stereoselectivity of Polystyrene-Supported Proline-Based Organic Catalysts for Direct Asymmetric Aldol Reaction in Water

2009 ◽  
Vol 2009 (31) ◽  
pp. 5437-5444 ◽  
Author(s):  
Michelangelo Gruttadauria ◽  
Anna Maria Pia Salvo ◽  
Francesco Giacalone ◽  
Paola Agrigento ◽  
Renato Noto
Keyword(s):  
Aldol Reaction ◽  
Asymmetric Aldol ◽  
Enhanced Activity ◽  
Asymmetric Aldol Reaction ◽  
Reaction In Water ◽  
Organic Catalysts

scholarly journals Bioinspired Polymer-Bound Organocatalysts for Direct Asymmetric Aldol Reaction: Experimental and Computational Studies

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 398
Author(s):  
Ganhong Du ◽  
Jun Ling ◽  
Fangyu Hu ◽  
Keyuan Liu ◽  
Long Ye ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Aldol Reaction ◽  
Catalytic Efficiency ◽  
Aromatic Aldehydes ◽  
Relative Energy ◽  
Catalyst Loading ◽  
Polymer Backbone ◽  
Asymmetric Aldol ◽  
Tertiary Amide ◽  
Asymmetric Aldol Reaction

A series of poly(2-oxazoline) (POX) derivatives bearing prolinamide pendants were designed as organocatalysts and evaluated in the direct asymmetric aldol reaction between aromatic aldehydes and cyclic ketones. The structural variation of the alkyl spacer connecting the polymer backbone with the catalytic unit was applied so as to deduce structure–performance relationships combined with comparable experiments from model catalysts. Results showed that the POX-bound prolinamides can promote the aldol reaction more effectively as compared to their small-molecular and non-POX-bound analogs. The catalyst P3 containing the pyrrolidine moiety closer to the tertiary amide backbone exhibited the overall best catalytic efficiency, affording anti-products in 84% yield with 89% ee in the representative aldol addition of cyclohexanone to 4-nitrobenzaldehyde at a 10 mol.% catalyst loading. Furthermore, the influence of trifluoroacetic acid as an additive on the asymmetric transformation was investigated. Theoretical calculations revealed that the protonation of the aldehyde carbonyl group switched the activation mode of the aldol acceptor through hydrogen bond interactions, thereby changing the relative energy barrier of the enamine/aldehyde reaction transition states, which accounted well for the significant improvement in the enantioselectivity of the acidic additives observed experimentally.

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