The conjugate addition of enantiomerically pure lithium amides as chiral ammonia equivalents part III: 2012–2017

Davies, Stephen G.; Fletcher, Ai M.; Roberts, Paul M.; Thomson, James E.

doi:10.1016/j.tetasy.2017.10.031

Cited by 23 publications

(9 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Asymmetric synthesis using alkali metal complexes is an important and widely researched area. − Reaction pathways often depend on the alkali metal, with the metal identity having a significant impact on their thermodynamics. Understanding how alkali metals interact with organic molecules is crucial to their application as reagents and catalysts in synthesis.…”

Section: Introductionmentioning

confidence: 99%

Isomers of Alkali Metal (Methylbenzyl)allylamides: A Theoretical Perspective

et al. 2020

View full text Add to dashboard Cite

Recent studies of alkali metal N-(α-methylbenzyl)allylamides containing lithium, sodium, and potassium have shown unique rearrangements in NMR experiments. It was found that lithium isomers favored the formation of aza-allyl and aza-enolate complexes that could exist in a solution for a substantial amount of time. As the radius of the metal ion increases going from lithium to potassium, so does the preference for the formation of the imine structure. For sodium, the aza-allyl complex could still be isolated, whereas the imine structure was only found to be stable on the scale of several hours for potassium. In this work, ab initio calculations were used to shed light on this phenomenon. Decomposition of intermolecular interaction energies of the aza-allyl, aza-enolate, and imine complexes showed that for lithium, the formation of aza-allyl and aza-enolate complexes was driven by electrostatic interactions. For potassium, the dispersion component of the metal interaction with the ligand proved to be more important for the stability of the imine structure. The presence of the imine formation in potassium and partially in sodium was found to be due to the reduced electrostatic nature of these larger metals. The assignment of the experimental NMR spectra was further confirmed with the natural bond order (NBO) analysis as well as the partial charge calculations. Analysis of orbital energies, specifically those of the highest occupied molecular orbitals (HOMOs), as well as the deformation energies of each of the ligands, were also considered. Through these procedures, an understanding of the tendency for each metal to have a unique isomerization pathway was gained.

show abstract

Section: Introductionmentioning

confidence: 99%

Isomers of Alkali Metal (Methylbenzyl)allylamides: A Theoretical Perspective

et al. 2020

View full text Add to dashboard Cite

show abstract

“…However, these reports have mainly focused on the use of strong Michael donors such as primary or secondary aliphatic and aromatic amines. The most comprehensive review articles on this subject have been published for the last decade [1–6] …”

Section: Introductionmentioning

confidence: 99%

Weak Nucleophiles in the Aza‐Michael Reaction

Rulev

2023

Adv Synth Catal

View full text Add to dashboard Cite

The 1,4‐conjugated addition of nitrogen centered nucleophiles to electron‐deficient alkenes is one of the most significant and widely used reactions in modern synthetic organic chemistry. To date, various protocols for the aza‐Michael reaction have been developed. However, these reports mainly focus on the use of strong Michael donors. In recent years, the conjugate addition of weak nitrogen nucleophiles to various Michael acceptors gained increasing popularity. Impressive progress in this area has been achieved by the use of more efficient catalyst systems. This review aims to provide a critical analysis of the results obtained in reactions of weak nucleophiles (azoles, pyrroles, indoles, carbamates, purines, amides, hydrazides, uraciles etc) with electron‐deficient alkenes which were reported over the past twelve years.

show abstract

“…Other strategies include ring closure protocols [14] or functional group transformations of other cyclobutane derivatives [15] . Although the aza‐Michael addition of lithium amides to unsaturated esters is an established method for the preparation of β‐amino acids, [16] we are aware of only one application thereof for the preparation of an ACBC [17] . One of the challenges in this approach lies in the controlled preparation and manipulation of esters of cyclobutene‐1‐carboxylic acid [18] .…”

Section: Introductionmentioning

confidence: 99%

β‐N‐Heterocyclic Cyclobutane Carboximides: Synthesis through a Tandem Base‐Catalyzed Amidation/aza‐Michael Addition Protocol and Facile Transformations

et al. 2023

View full text Add to dashboard Cite

A stereoselective one-pot double derivatization of cyclobutene-1-carboxylic acid via a mild organic base catalyzed amidation/ aza-Michael addition of benzo[d]oxazol-2(3H)-ones has been developed. This unprecedented tandem reaction provides access to novel β-N-heterocyclic cyclobutane carboximide derivatives with a trans geometry. The carboximide moiety reacts smoothly with nucleophiles, allowing access to diverse derivatives of trans-β-N-heterocyclic cyclobutanecarboxylic acid, including peptidomimetic structures.

show abstract

The conjugate addition of enantiomerically pure lithium amides as chiral ammonia equivalents part III: 2012–2017

Cited by 23 publications

References 97 publications

Isomers of Alkali Metal (Methylbenzyl)allylamides: A Theoretical Perspective

Isomers of Alkali Metal (Methylbenzyl)allylamides: A Theoretical Perspective

Weak Nucleophiles in the Aza‐Michael Reaction

β‐N‐Heterocyclic Cyclobutane Carboximides: Synthesis through a Tandem Base‐Catalyzed Amidation/aza‐Michael Addition Protocol and Facile Transformations

Contact Info

Product

Resources

About