Diastereoselectivity in the boron aldol reaction of α-alkoxy and α,β-bis-alkoxy methyl ketones

2019 ◽  
Vol 17 (12) ◽  
pp. 3167-3180 ◽  
Author(s):  
Alessandra A. G. Fernandes ◽  
Ives A. Leonarczyk ◽  
Marco A. B. Ferreira ◽  
Luiz Carlos Dias
Keyword(s):  
Synergistic Effect ◽  
Aldol Reaction ◽  
Asymmetric Induction ◽  
Aldol Reactions ◽  
Methyl Ketones

We investigated the asymmetric induction in boron enolate aldol reactions of α-alkoxy and α,β-bisalkoxy methyl ketones and elucidated the synergistic effect between the stereocenters.

ChemInform Abstract: 1,4-Asymmetric Induction in the Titanium-Mediated Aldol Reactions of α-Benzyloxy Methyl Ketones.

ChemInform ◽  
2008 ◽  
Vol 39 (47) ◽  
Author(s):  
Miquel Pellicena ◽  
Joan G. Solsona ◽  
Pedro Romea ◽  
Felix Urpi
Keyword(s):  
Asymmetric Induction ◽  
Aldol Reactions ◽  
Methyl Ketones

1,4-Asymmetric induction in the titanium-mediated aldol reactions of α-benzyloxy methyl ketones

2008 ◽  
Vol 49 (36) ◽  
pp. 5265-5267 ◽  
Author(s):  
Miquel Pellicena ◽  
Joan G. Solsona ◽  
Pedro Romea ◽  
Fèlix Urpí
Keyword(s):  
Asymmetric Induction ◽  
Aldol Reactions ◽  
Methyl Ketones

Nanosheet-Enhanced Asymmetric Induction of Chiral α-Amino Acids in Catalytic Aldol Reaction

2012 ◽  
Vol 18 (48) ◽  
pp. 15323-15329 ◽  
Author(s):  
Li-Wei Zhao ◽  
Hui-Min Shi ◽  
Jiu-Zhao Wang ◽  
Jing He
Keyword(s):  
Amino Acids ◽  
Aldol Reaction ◽  
Asymmetric Induction

Alternating chiral selectivity of aldol reactions under the confined space of mesoporous silica

2015 ◽  
Vol 51 (96) ◽  
pp. 17116-17119 ◽  
Author(s):  
Chewei Yeh ◽  
Yan-Ru Sun ◽  
Shing-Jong Huang ◽  
Yeun-Min Tsai ◽  
Soofin Cheng
Keyword(s):  
Mesoporous Silica ◽  
Aldol Reaction ◽  
Recyclable Catalyst ◽  
Aldol Reactions ◽  
Water Medium ◽  
Confined Space ◽  
Asymmetric Aldol ◽  
Co Catalysts ◽  
Asymmetric Aldol Reaction ◽  
Chiral Selectivity

The chiral selectivities were altered and high diastereo- and enantio-selectivities of the products were obtained in water medium without adding acid co-catalysts when a primary–tertiary diamine catalyst was immobilized on mesoporous SBA-15 to form a recyclable catalyst for the direct asymmetric aldol reaction of cyclohexanone with p-nitrobenzaldehyde.

Synthesis of 1,2-Diamine Bifunctional Catalysts for the Direct Aldol Reaction Through Probing the Remote Amide Hydrogen

2019 ◽  
Vol 6 (2) ◽  
pp. 171-176
Author(s):  
Rajasekhar Dodda ◽  
Sampak Samanta ◽  
Matthew Su ◽  
John Cong-Gui Zhao
Keyword(s):  
Hydrogen Bonding ◽  
Catalytic Activity ◽  
Aldol Reaction ◽  
Catalytic Efficiency ◽  
Aldol Reactions ◽  
Catalyst Loading ◽  
Bifunctional Catalysts ◽  
Amide Hydrogen ◽  
Highly Efficient ◽  
Direct Aldol Reaction

Background: While proline can catalyze the asymmetric direct aldol reactions, its catalytic activity and catalyst turnover are both low. To improve the catalytic efficiency, many prolinebased organocatalysts have been developed. In this regard, prolinamide-based bifunctional catalysts have been demonstrated by us and others to be highly efficient catalysts for the direct aldol reactions. Results: Using the β-acetamido- and β-tosylamidoprolinamide catalysts, the highly enantio- and diastereoselective direct aldol reactions between enolizable ketones and aldehydes were achieved (up to >99% ee, 98:2 dr). A low catalyst loading of only 2-5 mol % of the β-tosylamidoprolinamide catalyst was needed to obtain the desired aldol products in good to high yields and high stereoselectivities. Methods: By carefully adjusting the hydrogen bonding ability of the remote β-amide hydrogen of the 1,2-diamine-based prolinamide bifunctional catalysts, the catalytic activity and the asymmetric induction of these catalysts were significantly improved for the direct aldol reaction between aldehydes and enolizable ketones. Conclusion: Some highly efficient 1,2-diamine-based bifunctional prolinamide catalysts have been developed through probing the remote β-amide hydrogen for its hydrogen bonding capability. These catalysts are easy to synthesize and high enantioselectivities may be achieved at very low catalyst loadings.

Proline-Catalyzed Asymmetric Aldol Reaction Between Methyl Ketones and 1-Aryl-2,2,2-trifluoroethanones.

ChemInform ◽  
2005 ◽  
Vol 36 (38) ◽  
Author(s):  
Li-Hua Qiu ◽  
Zong-Xuan Shen ◽  
Chang-Qing Shi ◽  
Yan-Hua Liu ◽  
Ya-Wen Zhang
Keyword(s):  
Aldol Reaction ◽  
Methyl Ketones ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction
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