Guiding a divergent reaction by photochemical control: bichromatic selective access to levulinates and butenolides

Sutar, Revannath L.; Sen, Saumik; Eivgi, Or; Segalovich, Gal; Schapiro, Igor; Reany, Ofer; Lemcoff, N. Gabriel

doi:10.1039/c7sc05094a

Cited by 26 publications

(9 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This latency property presents many advantages. For example, selective catalytic sequences can be guided by UV light in chromatic orthogonal methodologies . Processes such as ring-opening metathesis polymerization (ROMP) can be performed with higher precision and ease of handling .…”

Section: Introductionmentioning

confidence: 99%

Influence of Anionic Ligand Exchange in Latent Sulfur-Chelated Ruthenium Precatalysts

et al. 2018

Self Cite

View full text Add to dashboard Cite

Four new cis-dianionic S-chelated ruthenium benzylidenes were synthesized by chloride ligand exchange. The special cis-dianionic conformation of these complexes contributed to a particularly facile anion exchange process, producing room-temperature-latent precatalysts. Their catalytic activity was strongly influenced by the solvent used. The latent iodide complex very efficiently promoted ring-closing metathesis by heating in toluene. Conversely, carboxylate ligands produced quite poor catalysts, but could abstract chlorides from chlorinated solvents to transform into active precatalysts. In tetrahydrofuran (THF), the S-chelated dichloro complex was shown to promote cycloisomerization instead of metathesis; however, the metathesis activity in THF could be recovered in the presence of phenylacetylene as a cocatalyst. Under the same conditions, all the other complexes required addition of LiCl to mimic this dichotomous behavior.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of Anionic Ligand Exchange in Latent Sulfur-Chelated Ruthenium Precatalysts

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…This was demonstrated with bis-phenol-A and 1,6 hexane diolbased linkers and with the sunscreen applied either internally or externally ( Figure 3). The successful suppression of the photocleavage of supersilyl ethers inspired us to apply this strategy to affect other photochemical reactions [45]. The cross-metathesis (CM) product of allylic and The successful suppression of the photocleavage of supersilyl ethers inspired us to apply this strategy to affect other photochemical reactions [45].…”

Section: Development Of the Methodsmentioning

confidence: 99%

“…The successful suppression of the photocleavage of supersilyl ethers inspired us to apply this strategy to affect other photochemical reactions [45]. The cross-metathesis (CM) product of allylic and The successful suppression of the photocleavage of supersilyl ethers inspired us to apply this strategy to affect other photochemical reactions [45]. The cross-metathesis (CM) product of allylic and acrylic substrates may undergo two competing photochemical reactions when exposed to 254 nm light to form γ-butenolides or levulinate esters (Scheme 3).…”

Section: Development Of the Methodsmentioning

confidence: 99%

“…The successful suppression of the photocleavage of supersilyl ethers inspired us to apply this strategy to affect other photochemical reactions [ 45 ]. The cross-metathesis (CM) product of allylic and acrylic substrates may undergo two competing photochemical reactions when exposed to 254 nm light to form γ-butenolides or levulinate esters ( Scheme 3 ).…”

Section: Development Of the Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Sunscreen-Assisted Selective Photochemical Transformations

Eivgi

Lemcoff

2020

Molecules

Self Cite

View full text Add to dashboard Cite

In this review, we describe a simple and general procedure to accomplish selective photochemical reaction sequences for two chromophores that are responsive to similar light frequencies. The essence of the method is based on the exploitation of differences in the molar absorptivity at certain wavelengths of the photosensitive groups, which is enhanced by utilizing light-absorbing auxiliary filter molecules, or “sunscreens”. Thus, the filter molecule hinders the reaction pathway of the least absorbing molecule or group, allowing for the selective reaction of the other. The method was applied to various photochemical reactions, from photolabile protecting group removal to catalytic photoinduced olefin metathesis in different wavelengths and using different sunscreen molecules. Additionally, the sunscreens were shown to be effective also when applied externally to the reaction mixture, avoiding any potential chemical interactions between sunscreen and substrates and circumventing the need to remove the light-filtering molecules from the reaction mixture, adding to the simplicity and generality of the method.

show abstract

“…In recent years, 1,n photochemical hydrogen atom transfer (HAT) reactions are receiving considerable attention mainly because they provide excellent opportunities for the straightforward activation of chemically inert aliphatic C−H bonds [9] . For example, a divergent light‐mediated methodology for the synthesis of levulinates via photoinduced cross‐metathesis followed by a photochemical 1,5‐hydrogen atom transfer in the presence of phenanthrene as modulator [9a] …”

Section: Introductionmentioning

confidence: 99%

Metal‐Free Photochemical Olefin Isomerization of Unsaturated Ketones via 1,5‐Hydrogen Atom Transfer

Manikandan

Phatake

Lemcoff

2022

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

The photochemical isomerization of α,β‐ to β,γ‐unsaturated ketones through a 1,5‐hydrogen atom transfer mechanism under mild conditions with high efficiency and selectivity is reported. The reaction is carried out in the absence of metal catalysts or other additives, and its stereoselectivity can be tuned by selecting appropriate solvent mixtures. The reaction‘s scope and tolerance towards functional groups, including light‐sensitive halogens, free acids and alcohols, were studied, providing reliable access to a wide variety of β,γ‐unsaturated ketones. This methodology details the deconjugation of a wide range of unsaturated ketones and, when combined with olefin metathesis, provides an efficient process for either dehomologation or one‐carbon double‐bond migration of terminal alkenes.

show abstract

Guiding a divergent reaction by photochemical control: bichromatic selective access to levulinates and butenolides

Abstract: Allylic and acrylic substrates may be efficiently transformed by a sequential bichromatic photochemical process into derivatives of levulinates or butenolides with high selectivity when phenanthrene is used as a regulator.

Cited by 26 publications

References 69 publications

Influence of Anionic Ligand Exchange in Latent Sulfur-Chelated Ruthenium Precatalysts

Influence of Anionic Ligand Exchange in Latent Sulfur-Chelated Ruthenium Precatalysts

Sunscreen-Assisted Selective Photochemical Transformations

Metal‐Free Photochemical Olefin Isomerization of Unsaturated Ketones via 1,5‐Hydrogen Atom Transfer

Contact Info

Product

Resources

About