Asymmetric Induction by a Remote Chiral Substituent – Computationally Determined Stereodifferentiation in Michael Additions of α‐Lithiated Allyl Sulfones

Belostotskii, Anatoly M.; Albeck, Amnon; Häßner, Alfred

doi:10.1002/ejoc.200700245

Cited by 11 publications

(3 citation statements)

References 35 publications

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“…Computational analysis of the Li complex 556 shows two conformers A and B (Scheme b). Conformer A with a 3.23 Å distance of aryl···Li + bond is much more stable than conformer B . This resulted in a decrease in the chemical reactivity of conformer 556a - A , and therefore, the preferential stereochemical selection seems to arise from the reaction with conformer 556a - B .…”

Section: Metal Cation-assisted Reactionsmentioning

confidence: 99%

Cation−π Interactions in Organic Synthesis

2018

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The cation−π interaction is an attractive noncovalent interaction between a cation and a π system. Due to the stronger interaction energy than those of the other π interactions, such as π–π and CH−π interactions, the cation−π interaction has recently been recognized as a new tool for controlling the regio- and stereoselectivities in various types of organic reactions. This review attempts to cover a variety of organic reactions controlled by cation−π interactions, which includes not only recent examples but also those reported before the term “cation−π interaction” was defined in 1990. This review will provide comprehensive knowledge on the role of cation−π interactions in organic synthesis.

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Section: Metal Cation-assisted Reactionsmentioning

confidence: 99%

Cation−π Interactions in Organic Synthesis

2018

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“…Though the precise geometry of the aromatic ring during chelation with the lithiated species is as yet unknown, it evidently plays an important role in determining the approach of the carbanion to the conjugate acceptor and thus the stereoselectivity of the conjugate addition. Preliminary ab initio calculations [ 17 ] for the energetics of approach of 1 to 2 (in the case Ar = Ph) are consistent with these results: the calculations indicate that a remote aromatic substituent in lithiated 1 , in its lowest energy conformation, can come into close proximity (ca. 3.2 Å) with the lithium cation ( Fig.…”

Section: Resultsmentioning

confidence: 61%

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

Levinger¹,

Nair²,

Häßner³

2008

Beilstein J. Org. Chem.

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The impact of a remote aromatic nucleus on the stereochemical outcome of the conjugate addition of α-sulfonylallylic carbanions to an α,β-unsaturated ester was investigated. α-Regioselectivity coupled with anti-diastereoselectivity is accompanied by a prominent preference for relative configuration 3 over 4. The 9-anthryl moiety has shown itself greatly superior over all other groups in this bias. A lithium ion-aromatic π interaction has been postulated as decisive for the remote transmission of chirality.

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“…Past modelling studies of α-sulfonyl anion chemistry typically account for the metal counterion [48][49][50][51][52][53], although there are exceptions [45,54,55]. This assessment engages a lithium counterion with the α-sulfonyl anion, as part of the transition state for addition to the aldehyde and for the chemistry thereafter.…”

Section: Oxathiin Ring Formationmentioning

confidence: 99%

The Synthesis and Base-Induced Breakdown of Triaryl 1,4-Oxathiins—An Experimental and DFT Study

Nicol,

Sing,

Luu

et al. 2023

Molecules

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1,4-Oxathiins are valued for a breadth of bioactivities and are known commercial fungicides. This article explores a novel preparation of 2,3,6-trisubstituted 1,4-oxathiin-S,S-dioxides via the reaction of benzyl 1-alkynyl sulfones and aryl aldehydes under basic conditions. A total of 20 examples possessing exclusively a trans arrangement of the 2,3-diaryl substituents are exhibited; the products demonstrate a variation of functional groups on the aryl ring attached to the heterocyclic ring system. The preparation is hindered by the base sensitivity of the products, and a ring-opened by-product typically contaminates the reaction mixture. A DFT assessment of the overall system includes a lithium counterion and offers possible pathways for the incorporation of the aldehyde, the cyclization step and the requisite proton transfers. In addition, the DFT work reveals options for the ring opening chemistry. It appears the trans 2,3-diaryl selectivity is set during the cyclization stage of the reaction sequence. The practical work uncovers a new reaction pathway to create a family of novel 1,4-oxathiin-S,S-dioxides whereas the computational work offers an understanding of the structures and possible mechanisms involved.

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Asymmetric Induction by a Remote Chiral Substituent – Computationally Determined Stereodifferentiation in Michael Additions of α‐Lithiated Allyl Sulfones

Cited by 11 publications

References 35 publications

Cation−π Interactions in Organic Synthesis

Cation−π Interactions in Organic Synthesis

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

The Synthesis and Base-Induced Breakdown of Triaryl 1,4-Oxathiins—An Experimental and DFT Study

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