39755-02-7Relevant academic research and scientific papers
DMSO-Enabled Selective Radical O?H Activation of 1,3(4)-Diols
Han, Bing,Jiao, Ning,Jin, Rui,Liu, Guoquan,Liu, Jianzhong,Zhang, Ziyao,Zhu, Yuchao
supporting information, p. 19851 - 19856 (2020/09/04)
Control of selectivity is one of the central topics in organic chemistry. Although unprecedented alkoxyl-radical-induced transformations have drawn a lot of attention, compared to selective C?H activation, selective radical O?H activation remains less explored. Herein, we report a novel selective radical O?H activation strategy of diols by combining spatial effects with proton-coupled electron transfer (PCET). It was found that DMSO is an essential reagent that enables the regioselective transformation of diols. Mechanistic studies indicated the existence of the alkoxyl radical and the selective interaction between DMSO and hydroxyl groups. Moreover, the distal C?C cleavage was realized by this selective alkoxyl-radical-initiation protocol.
Probing the Effects of Heterocyclic Functionality in [(Benzene)Ru(TsDPENR)Cl] Catalysts for Asymmetric Transfer Hydrogenation
Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
, p. 7223 - 7227 (2019/10/08)
A range of TsDPEN catalysts containing heterocyclic groups on the amine nitrogen atom were prepared and evaluated in the asymmetric transfer hydrogenation of ketones. Bidentate and tridentate ligands demonstrated a mutual exclusivity directly related to their function as catalysts. A broad series of ketones were reduced with these new catalysts, permitting the ready identification of an optimal catalyst for each substrate and revealing the subtle effects that changes to nearby donor groups can exhibit.
Photochemistry of nonconjugated diketones: internal self-quenching and energy transfer
Wagner, Peter J.,Frerking, Harlan W. Jr.
, p. 2047 - 2061 (2007/10/03)
The triplet state behavior of nine α,ο-dibenzoylalkanes indicates the occurrence of a rapid quenching interaction between the two carbonyl groups.This quenching is fastest (k=3E7 s-1) in dibenzoylbutane, is slightly slower (ca.E7 s-1) in dibenzoylethane, dibenzoylpentane, and 2,2-dibenzoylpropane, but is absent in 1,3-dibenzoylpropane.It also occurs in several "mixed" 1,4-diaroylbutanes incorporating p-ethylbenzoyl or p-methoxybenzoyl chromophores.This internal self-quenching is interpreted as the intramolecular counterpart of the well-know bimolecular self-quenching of aryl ketones, although no exact mechanism can be proposed.Such internal quenching does not occur as rapidly, if at all, in three "turned around" diketones: δ-(p-acetylphenyl)valerophenone, δ-(p-acetylphenoxy)valerophenone, and γ-(p-acetylphenoxy)butyrophenone.This fact, together with the varying rates of internal self-quenching in the dibenzoylalkanes, indicates the necessity for a very specific and close orientation of the two carbonyl groups for self-quenching.In the mixed diketones containing a p-alkylbenzoyl group, triplet excitation appears to be fully equilibrated between the two chromophores.However, in those containing a p-methoxybenzoyl group, excitation does not fully equilibrate before triplet decay, as evidenced by different quenching efficiencies for products from the two carbonyls.Analysis indicates intramolecular energy transfer rate constants -1.These are sufficiently lower than in other bichromophoric systems to suggest relatively slow energy hopping in the polymers of phenyl vinyl ketone.Key words: nonconjugated diketones, dibenzoylalkanes, sefl-quenching, energy transfer, triplet ketones.
