31469-15-5Relevant articles and documents
Addition of ketene silyl acetals to the triplet excited state of C60 via photoinduced electron transfer leading to the fullereneacetates
Mikami,Matsumoto,Ishida,Takamuku,Suenobu,Fukuzumi
, p. 11134 - 11141 (1995)
The photochemical carbon-carbon bond formation of C60 with ketene silyl acetals is described to give a new way for fullerene functionalization chemistry. The photoaddition of ketene silyl acetals to C60 occurs efficiently under irradiation of the visible light in benzene as well as benzonitrile to yield the fullereneacetates. The comparison of the observed rate constants determined from the dependence of the quantum yields on the concentrations of ketene silyl acetals as well as the quenching of triplet excited state of C60 by ketene silyl acetals with those predicted for the electron transfer processes indicates that the photoaddition proceeds via photoinduced electron transfer from ketene silyl acetals to the triplet excited state of C60. The negative shift in the one-electron reduction potentials by the adduct formation of C60 is examined by the cyclic voltammetry measurements. The factors to control the formation of mono- and bisadducts of C60 are clarified based on the rates of photoinduced electron transfer from ketene silyl acetals to the triplet excited states of C60 and the adducts.
Chiral Modification of the Tetrakis(pentafluorophenyl)borate Anion with Myrtanyl Groups
Pommerening, Phillip,Oestreich, Martin
, p. 7240 - 7246 (2019)
The synthesis and characterization of chiral [B(C6F5)4]– derivatives bearing a myrtanyl group instead of a fluoro substituent in the para position are described. These new chiral borates were isolated as their bench-stable lithium, sodium, and cesium salts. The corresponding trityl salts were prepared and tested as catalysts in representative counteranion-directed Diels–Alder reactions and Mukaiyama aldol additions but no enantioselectivity was obtained. Preformation of a chalcone-derived silylcarboxonium ion with the chiral borate as counteranion did not lead to any asymmetric induction in a reaction with cyclohexa-1,3-diene.
Silanediol versus chlorosilanol: Hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes
Fox, Falco,Neud?rfl, J?rg M.,Goldfuss, Bernd
supporting information, p. 167 - 186 (2019/01/30)
Biphenyl-2,2’-bisfenchyloxydichlorosilane (7, BIFOXSiCl2) is synthesized and employed as precursor for the new silanols biphenyl-2,2’-bisfenchyloxychlorosilanol (8, BIFOXSiCl(OH)) and biphenyl-2,2’-bisfenchyloxysilanediol (9, BIFOXSi(OH)2
The Catalytic Asymmetric Mukaiyama–Michael Reaction of Silyl Ketene Acetals with α,β-Unsaturated Methyl Esters
Gatzenmeier, Tim,Kaib, Philip S. J.,Lingnau, Julia B.,Goddard, Richard,List, Benjamin
supporting information, p. 2464 - 2468 (2018/02/06)
α,β-Unsaturated esters are readily available but challenging substrates to activate in asymmetric catalysis. We now describe an efficient, general, and highly enantioselective Mukaiyama–Michael reaction of silyl ketene acetals with α,β-unsaturated methyl esters that is catalyzed by a silylium imidodiphosphorimidate (IDPi) Lewis acid.