76358-44-6Relevant academic research and scientific papers
P-Silylation of Arenes via Organic Photoredox Catalysis: Use of p-Silylated Arenes for Exclusive o-Silylation, o-Acylation, and o-Alkylation Reactions
Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Pushpendra,Mondal, Pradip Kumar
supporting information, p. 7730 - 7734 (2021/10/25)
Photocatalytic regiospecific p-silylation of arenes has been achieved by the coupling of in situ generated silyl radical with arene radical cation. The strategy involves reductive activation of PhSe-SiR3 and single electron transfer from the electron rich
Generation and Mesolysis of PhSeSiR3.-: Mechanistic Studies by Laser Flash Photolysis and Application for Bimolecular Group Transfer Radical Reactions
Pandey, Ganesh,Sesha Poleswara Rao,Palit,Mittal
, p. 3968 - 3978 (2007/10/03)
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET promoted reductive activation of selenosilane 1a to its radical anion 1a.-. PET activation of 1a is achieved through a photosystem comprising a light-absorbing electron-rich aromatic (ERA), such as DMN or DMA, as an electron donor and ascorbic acid as a co-oxidant. The evidence for the ET from excited singlet states of DMN as well as DMA to 1a is suggested by estimating negative ΔGet (-51 and -43.46 kcal mol-1, respectively) values and nearly diffusion- controlled fluorescence quenching rate constants (kqTR) 0.36 × 1010 M-1 s-1 and 0.28 × 1010 M-1 s-1, respectively, from time-resolved fluorescence quenching study. The transient absorption spectra of DMN.+, DMA.+, and 1a.- are obtained initially by pulse radiolysis in order to correlate the time- resolved absorption spectral data. Laser flash photolysis studies in the nanosecond time domain have confirmed the generation of 1a.-, DMN.+, and DMA.+, supporting the participation of the triplet state of DMN or DMA in the ET reaction. Mesolytic cleavage of 1a.- produced a silyl radical and a phenyl selenide anion. The preparative PET activation of 1a in acetonitrile in the presence of DMN or DMA leads to the formation of 5 and 6, confirming the fragmentation pattern of la.-. The overall ET rate constants (kr(DMN) = 0.99 × 1010 M-1 s-1 and kr(DMA) = 1.62 × 1010 M-1 s-1) and limiting quantum yields (φlim(DMN) = 0.034 and φlim(DMA) = 0.12) are estimated from the inverse plot (1/[1a] vs 1/φdis) obtained by measuring the dependence of photodissociation quantum yields of 1a at its maximum concentration in the presence of DMN or DMA. Silicon-centered radical species generated from the mesolysis of 1a.- are utilized for initiating a radical reaction by the abstraction of halogen atom from -C-X (X = Cl, Br) bonds, while PhSe-1 terminates the radical sequences via PhSeSePh. This concept is successfully applied for the bimolecular group transfer (BMGT) radical reactions and intermolecular radical chain addition reactions.
Silyl Halides from (Phenylseleno)silanes. Reaction with Oxiranes and Alcohols To Give Hydrolytically Stable Silyl Ethers.
Detty, Michael R.,Seidler, Mark D.
, p. 1283 - 1292 (2007/10/02)
The preparation of (phenylseleno)silanes and their reactions with halogens (Cl2, Br2, I2) to give silyl halides and diphenyl diselenide are described.Highly hindered tert-butyldimethyl and tert-butyl diphenylsilyl halides were easily prepared.The reaction of silyl bromides and iodides with oxiranes followed by diazabicyclononane treatment gave allylic alcohol silyl ethers.Tertiary alcohols reacted rapidly with silyliodides to give hydrolytically stable silyl ethers.Treatment of the silyl ethers with tetra-n-butylammonium fluoride gave the free alcohols withoutrearrangement or isomerization.
