Corrigendum to “New class of bifunctional thioureas from l-proline: highly enantioselective Michael addition of 1,3-dicarbonyls to nitroolefins” [Tetrahedron: Asymmetry 25 (2014) 568–577]

Vinayagam, Poopathy; Vishwanath, Manjunatha; Kesavan, Venkitasamy

doi:10.1016/j.tetasy.2014.08.004

Cited by 7 publications

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“…Thiourea 3 g as well as Takemoto's thiourea 3 h facilitated the formation of expected product 6 a in better yields and similar enantioselectivities (70 %, entries 7–8). Pleasingly„ proline‐derived thiourea ( 3 i ), which was developed in our lab, yielded the expected product in 80 % yield with an enantiomeric excess of 91 %. To ascertain the structural requirement of thiourea 3 i in effective asymmetric induction, pyrrolidine‐ring‐containing thioureas ( 3 j , 3 k ) were also explored in this transformation.…”

Section: Resultsmentioning

confidence: 99%

Organocatalytic Enantioselective Assembly of Spirooxindole‐naphthopyrans through Tandem Friedel–Crafts Type/Hemiketalization

et al. 2016

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A new synthetic strategy to construct spirooxindole‐naphthopyran scaffold has been demonstrated via Friedel–Crafts type/hemiketalization of oxindole α‐ketoester with 2‐naphthol. Under the established reaction condition, quaternary chiral center at C3‐position of oxindole has been created with very good asymmetric induction up to 98 % for a broad range of substrates. DFT calculations, which account for the stereochemical outcome, were performed.

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Section: Resultsmentioning

confidence: 99%

Organocatalytic Enantioselective Assembly of Spirooxindole‐naphthopyrans through Tandem Friedel–Crafts Type/Hemiketalization

et al. 2016

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Addition Reactions: Polar Addition

Kočovský

2017

Organic Reaction Mechanisms · 2014

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Synthesis and Evaluation of (S)‐Proline‐Containing α,β‐Dipeptides as Organocatalysts in Solvent‐Free Asymmetric Aldol Reactions Under Ball‐Milling Conditions

2014

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With the aim of developing sustainable enantioselective reactions, the organocatalytic activity of three proline‐based α,β‐dipeptides was evaluated in the asymmetric aldol reaction between cyclohexanone and 4‐nitrobenzaldehyde according to three contrasting experimental protocols: (1) solvent‐free, under high‐speed ball milling (HSBM) activation, (2) neat conditions with conventional stirring, and (3) in solution with conventional stirring. The HSBM technique, providing “green” solvent‐free reaction conditions, proved to be the synthetic strategy of choice, proceeding in shorter reaction times and affording the aldol products with higher stereoselectivity. The organocatalytic activity of two of the α,β‐dipeptides was then compared in the solvent‐free asymmetric aldol reaction under ball‐milling activation in order to establish the influence of a stereogenic center in the β‐amino acid residue on the stereoinducing ability of the organocatalyst. The organocatalyst with one stereogenic center and the organocatalyst with two stereogenic centers exhibit similar efficiency in the asymmetric aldol reaction between cyclohexanone and 4‐nitrobenzaldehyde, affording the aldol product in excellent yield, and with high anti diastereoselectivity and good enantioselectivity. Thus, the presence of a second stereogenic center in the α,β‐dipeptide organocatalysts does not result in a more stereoselective reaction relative to that induced by the α,β‐dipeptide organocatalyst with one stereogenic center.

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Corrigendum to “New class of bifunctional thioureas from l-proline: highly enantioselective Michael addition of 1,3-dicarbonyls to nitroolefins” [Tetrahedron: Asymmetry 25 (2014) 568–577]

Cited by 7 publications

References 1 publication

Organocatalytic Enantioselective Assembly of Spirooxindole‐naphthopyrans through Tandem Friedel–Crafts Type/Hemiketalization

Organocatalytic Enantioselective Assembly of Spirooxindole‐naphthopyrans through Tandem Friedel–Crafts Type/Hemiketalization

Addition Reactions: Polar Addition

Synthesis and Evaluation of (S)‐Proline‐Containing α,β‐Dipeptides as Organocatalysts in Solvent‐Free Asymmetric Aldol Reactions Under Ball‐Milling Conditions

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