Gold-Catalyzed Oxidative Coupling of Arylsilanes and Arenes: Origin of Selectivity and Improved Precatalyst
作者:Liam T. Ball、Guy C. Lloyd-Jones、Christopher A. Russell
DOI:10.1021/ja408712e
日期:2014.1.8
substitution of the arylsilane and the arene by Au(III) precedes product-forming reductive elimination and subsequent cycle-closing reoxidation of the metal. Despite the fundamental mechanistic similarities between the two auration events, high selectivity is observed for heterocoupling (C-Si then C-H auration) over homocoupling of either the arylsilane or the arene (C-Si then C-Si, or C-H then C-H auration);
Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
作者:Jan H. Kuhlmann、Mustafa Uygur、Olga García Mancheño
DOI:10.1021/acs.orglett.2c00288
日期:2022.3.4
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)–Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient
Visible Light Thiyl Radical‐Mediated Desilylation of Arylsilanes
作者:Jan H. Kuhlmann、Jan H. Dickoff、Olga García Mancheño
DOI:10.1002/chem.202203347
日期:2023.2.24
available and cheap disulfides proved to be excellent thiyl-radical sources for the mild desilylation of arylsilanes under visible-light irradiation. This method relying in a radical chain mechanism shows a broad applicability and functional group tolerance, allowing for the effective reaction of simple arylsilanes, as well as complex structures and therapeutic derivatives.
Gas-phase alkylation of phenyltrimethylsilanes. Using the trimethylsilyl group to probe proton shifts in gaseous arenium ions
作者:Marina Attina、Fulvio Cacace、Andreina Ricci
DOI:10.1021/ja00016a003
日期:1991.7
The reactivity of (trimethylsilyl)benzene (TSB) and (trimethylsilyl)toluenes (TST) toward i-C3H7+ and (CH3)2F+ has been studied in the gas phase in the interval from 0.6 to 3040 Torr and from 37.5 to 100-degrees-C by mass spectrometric and radiolytic techniques. The systematic investigation of the dependence of the relative rate of the alkylation and alkyldesilylation processes promoted by i-C3H7+ on the nature and the concentration of gaseous bases has allowed an evaluation of the rate constant of the isomerization via proton 1,2-shifts of the alkylated adducts from TSB into the corresponding ions protonated ipso to the SiMe3 group. The results, i.e., k(i) = 1.6 X 10(9) s-1 at 310 K and E(i) almost-equal-to 9.5 kcal mol-1, represent the first experimental evaluation of the kinetic parameters of proton 1,2-shifts within gaseous arenium ions, generally too fast to be monitored by mass spectrometric techniques, and are in excellent agreement with theoretical and solution-chemistry studies of the model C6H7+ ion. The selectivity of the alkylation of TSB and of m- and p-TST is discussed, particularly as regards direct ipso substitution and the steric hindrance to deprotonation of the ortho-isopropylated adducts.