940-49-8Relevant academic research and scientific papers
Photo-triggered hydrogen atom transfer from an iridium hydride complex to unactivated olefins
Guo, Xingwei,Pfund, Bj?rn,Schreier, Mirjam R.,Wenger, Oliver S.
, p. 8582 - 8594 (2020/09/07)
Many photoactive metal complexes can act as electron donors or acceptors upon photoexcitation, but hydrogen atom transfer (HAT) reactivity is rare. We discovered that a typical representative of a widely used class of iridium hydride complexes acts as an H-atom donor to unactivated olefins upon irradiation at 470 nm in the presence of tertiary alkyl amines as sacrificial electron and proton sources. The catalytic hydrogenation of simple olefins served as a test ground to establish this new photo-reactivity of iridium hydrides. Substrates that are very difficult to activate by photoinduced electron transfer were readily hydrogenated, and structure-reactivity relationships established with 12 different olefins are in line with typical HAT reactivity, reflecting the relative stabilities of radical intermediates formed by HAT. Radical clock, H/D isotope labeling, and transient absorption experiments provide further mechanistic insight and corroborate the interpretation of the overall reactivity in terms of photo-triggered hydrogen atom transfer (photo-HAT). The catalytically active species is identified as an Ir(ii) hydride with an IrII-H bond dissociation free energy around 44 kcal mol-1, which is formed after reductive 3MLCT excited-state quenching of the corresponding Ir(iii) hydride, i.e. the actual HAT step occurs on the ground-state potential energy surface. The photo-HAT reactivity presented here represents a conceptually novel approach to photocatalysis with metal complexes, which is fundamentally different from the many prior studies relying on photoinduced electron transfer. This journal is
One carbon homologation of halides to benzyl ethers
Taber, Douglass F.,Paquette, Craig M.,Reddy, P. Ganapati
supporting information; experimental part, p. 2462 - 2463 (2009/08/09)
The preparation of one carbon homologated benzyl ethers from alkyl and aromatic halides is reported. The coupling reaction is rapid and efficient at room temperature.
Alkylation on graphite in the absence of Lewis acids
Sereda, Grigoriy A.
, p. 7265 - 7267 (2007/10/03)
Graphite is introduced as a convenient catalyst for alkylation of aromatic compounds and alcohols by benzyl, tertiary alkyl, and secondary alkyl halides in the absence of strong Lewis acids. Primary alkyl halides are not active under the reaction conditions.
Self-decomposition of K-, K+(15-crown-5)2 tetrahydrofuran solution via organometallic intermediates
Grobelny, Zbigniew,Stolarzewicz, Andrzej,Maercker, Adalbert
, p. 65 - 70 (2007/10/03)
Self-decomposition of K-, K+(15-crown-5)2 tetrahydrofuran solution results in dipotassium tetraethylene glycoxide and ethylene as the main reaction products. Dipotassium triethylene glycoxide, potassium tetraethylene glyco
Efficient reductive etherification of carbonyl compounds with alkoxytrimethylsilanes
Hatakeyama, Susumi,Mori, Hisato,Kitano, Kaori,Yamada, Hidetoshi,Nishizawa, Mugio
, p. 4367 - 4370 (2007/10/02)
An efficient TMSOTf catalyzed ether synthesis from carbonyl compounds and alkoxytrimethylsilanes via triethylsilane-reduction is described.
Rearrangement of Aromatic Acetals Over Solid Acid Catalysts
Xavier, N.,Arulraj, S. J.
, p. 519 - 522 (2007/10/02)
The reactions of aromatic acetals (1a-6a) catalysed by aluminium phosphate (AP) yield the corresponding esters (b), ethers (c) and the parent aldehydes (d).Similar reactions over aluminium sulphate (AS) give only esters (b) and the aldehydes (d).Probable mechanisms have been suggested for the reactions.The catalysts have been characterized by various studies.The specific poisoning of the catalysts have been done with NH3 and CO2 and the product formation on the poisoned catalyst provides support to the suggested mechanisms.
