Simple proline derivatives as recoverable catalysts for the large-scale stoichiometric aldol reactions

2012 ◽  
Vol 2 (5) ◽  
pp. 1068 ◽  
Author(s):  
Shi Li ◽  
Chuanlong Wu ◽  
Xiaoqin Long ◽  
Xiangkai Fu ◽  
Guodong Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Aldol Reactions ◽  
Recoverable Catalysts ◽  
Proline Derivatives

ChemInform Abstract: Simple Proline Derivatives as Recoverable Catalysts for the Large-Scale Stoichiometric Aldol Reactions.

ChemInform ◽  
2012 ◽  
Vol 43 (39) ◽  
pp. no-no
Author(s):  
Shi Li ◽  
Chuanlong Wu ◽  
Xiaoqin Long ◽  
Xiangkai Fu ◽  
Guodong Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Aldol Reactions ◽  
Recoverable Catalysts ◽  
Proline Derivatives

ChemInform Abstract: Highly Efficient Direct Large-Scale Stoichiometric Aldol Reactions Catalyzed by a New Diamine Salt in the Presence of Water.

ChemInform ◽  
2012 ◽  
Vol 43 (30) ◽  
pp. no-no
Author(s):  
Jing Huang ◽  
Guodong Chen ◽  
Xiangkai Fu ◽  
Cao Li ◽  
Chuanlong Wu ◽  
...  
Keyword(s):  
Large Scale ◽  
Aldol Reactions ◽  
Highly Efficient

New Mechanistic Approach in the Enamine-Based Asymmetric Organocatalysis

2021 ◽  
Author(s):  
András A. Gurka
Keyword(s):  
Water Molecule ◽  
Transition State ◽  
Aqueous Media ◽  
Initial Step ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Mechanistic Approach ◽  
Asymmetric Organocatalysis ◽  
Organocatalytic Reactions ◽  
Proline Derivatives

Abstract During the course of my research in asymmetric organocatalysis the inversion of enantioselectivity was observed in the asymmetric aldol reactions of acetone with different aldehydes catalyzed by amphiphilic proline derivatives in aqueous media varying only achiral components. It was not possible to explain the explored dual stereocontrol with the existing models, therefore I proposed a new mechanism for asymmetric aldol reactions catalyzed by l-amino acid derivatives in aqueous media and explained the explored phenomenon of inversion of enantioselectivity with different structures of micelle-stabilized transition state described as a metal-free version of the Zimmermann-Traxler model with explicit participation of a water molecule. Contrary to the existing models, according to the proposed mechanism the formation of new bonds proceeds directly in the transition state stabilized by a water molecule without the additional step of product iminium ion hydrolysis. The proposed mechanism has universal character, it is consistent with experimental results and general theoretical conceptions and it is applicable to all enamine-based asymmetric organocatalytic reactions carried out not only in aqueous, but in organic media as well, because the initial step of catalytic cycle, which involves the formation of an enamine from the carbonyl compound and proline (derivative), liberates one water molecule.

scholarly journals Earthworms as a Biocatalyst: In Asymmetric Aldol Reactions

2017 ◽  
Vol 22 (9) ◽  
pp. 1162-1167
Author(s):  
Guo-Yan Zhang ◽  
Yan-Li Chen ◽  
Hai-Hong Li ◽  
Zhi Guan ◽  
Yan-Hong He
Keyword(s):  
Crude Extract ◽  
Industrial Production ◽  
Carbonyl Compounds ◽  
Large Scale ◽  
Environmentally Friendly ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Excellent Yield ◽  
Wide Range ◽  
Potential Possibility

A crude extract from earthworms was used as an environmentally friendly and easily accessible biocatalyst for asymmetric direct aldol reactions. The β-hydroxy carbonyl compounds could be prepared in yields of up to 94%, with ee values of up to 98% and dr of up to >99:1. A wide range of substrates could participate in the reaction. This earthworm catalyst was also efficient in the large-scale reaction, providing product in excellent yield and good selectivity. The protocol as an example gives inspiration for the development of sustainable catalysts from nature, which also provides a potential possibility for application of earthworm catalyst in industrial production.

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