نتایج جستجو برای: silanes

تعداد نتایج: 586  

Journal: :Angewandte Chemie 2021

We report the first catalytic enantioselective conjugate addition of allyl groups to α,β-unsaturated aldehydes. The chemistry exploits visible-light-excitation chiral iminium ions activate silanes towards formation allylic radicals, which are then intercepted stereoselectively. underlying radical mechanism this process overcomes poor regio- and chemoselectivity that traditionally affects allyla...

Journal: :Journal of the American Chemical Society 2004
Isaac M Rutenberg Oren A Scherman Robert H Grubbs Weirong Jiang Eric Garfunkel Zhenan Bao

The use of surface-initiated ring-opening metathesis polymerization (SI-ROMP) for producing polymer dielectric layers is reported. Surface tethering of the catalyst to Au or Si/SiO2 surfaces is accomplished via self-assembled monolayers of thiols or silanes containing reactive olefins. Subsequent SI-ROMP of norbornene can be conducted under mild conditions. Pentacene semiconducting layers and g...

Journal: :Science 2008
Christos Douvris Oleg V Ozerov

Carbon-fluorine bonds are among the most unreactive functionalities in chemistry. Interest in their activation arises in part from the high global warming potentials of anthropogenic polyfluoroorganic compounds. Conversion to carbon-hydrogen bonds (hydrodefluorination) is the simplest modification of carbon-fluorine bonds, but efficient catalytic hydrodefluorination of perfluoroalkyl groups has...

2006
Bernd Wrackmeyer Ezzat Khan Rhett Kempe

The 1,2-hydroboration of various alkyn-1-yl(chloro)silanes (3 – 7), derived from 1-hexyne (a) and ethynylbenzene (b), using 9-borabicyclo[3.3.1]nonane, 9-BBN, affords selectively alkene derivatives in which the dialkylboryl and chlorosilyl groups are in geminal positions at the C=C bond. The molecular structure of (Z)-α-(9-borabicyclo[3.3.1]non-9-yl)-α-dichloro(phenyl)silyl-styrene (11b) was de...

2011
Nando Gartmann Dominik Brühwiler

Aminopropylalkoxysilanes are frequently used for the functionalization of mesoporous silica. The analysis of amino group distributions on arrays of silica nanochannels by a combination of nitrogen sorption and confocal laser scanning microscopy provides valuable insight into the mechanisms underlying the interaction of these silanes with mesoporous silica surfaces. Tendencies towards external s...

Journal: :Organic Letters 2021

We report here an efficient and highly straightforward access to α-difluoromethylated ketones through a visible light-mediated difluoromethylation of readily available enol silanes. The method, which takes advantage the polyvalence Hu’s reagent, N-tosyl-S-difluoromethyl-S-phenylsulfoximine, used as CHF2 radical precursor under catalytic photoredox conditions, is practical, scalable, provides co...

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