Allylic trimethoxysilanes

Allylic trimethoxysilanes are activated by a catalytic combination of CuCl and TBAF.118 The mechanism of this reaction is not entirely clear, but it seems to involve fluoride activation of the silane. These reactions are stereoconvergent for the isomeric 2-butenyl silanes, indicating that reaction occurs through an acyclic TS. 

The complex -Tol-BINAP-AgF (/>-Tol-BINAP - 2,2 -bis(di-/)-tolylphosphanyl)-l,l -binapthyl) catalyzes the asymmetric addition of allylic trimethoxysilanes to aldehydes (Equation (7)).7 3 The process can provide various optically active homoallylic alcohols with high enantioselectivity (up to 96% ee) and a remarkable 7 and anti- selectivities are observed for the reaction with crotylsilanes, irrespective of the configuration of the double bond ... 

Wadamoto and Yamamoto have modified the chiral silver catalyst system and achieved catalytic enantioselective addition of aUyltrimethoxysilane to ketones [45]. For example, the reaction of 1-naphthaldehyde (29) with 2 equiv of (27) in the presence of 5 mol% of (R)-DIFLUORPHOS, 5mol%ofAgF, and 1 equiv ofMeOH in THF at —78 °C for 12 hours provides the tertiary homoallylic alcohol (30) in 98% yield with 95% ee (Scheme 18.11). Use of y-substituted allylic trimethoxysilanes... 

Catalytic enantioselective protonation of prochiral ketone enolates is a beneficial route to optically active carbonyl compounds possessing a tertiary asymmetric carbon at the a-position. In the asymmetric protonation of trimethylsilyl enolates with methanol, BINAP-AgF has been found to act as a chiral catalyst [90,91], which is also known to catalyze asymmetric allylation of aldehydes with allylic trimethoxysilanes [42] as well as asymmetric aldol reaction with trimethoxysilyl enolates [54]. This protonation can be most effectively performed using 6 mol% ofBINAP and 10 mol% of... 

Yanagisawa A, Kageyama H, Nakatsuka Y, Asakawa K, Matsumoto Y, Yamamoto H. Enantioselective addition of allylic trimethoxysilanes to aldehydes catalyzed by p-Tol-BINAP - AgF. Angew. Chem. Int. Ed. 1999 38 3701-3703. 

In the first, developed by usj a layer of clay mineral particles is covered with the cationic polyelectrolyte poly(diallyldimethylammoniumchloride) (PDDA) and subsequently with the anionic, noncentrosymmetric dye 4- 4[A -allyl,A -methylamino]phenylazo benzene sulpho-nic acid (NAMC). Thus, the monolayer consists of clay/ PDDA/NAMO. It is supported on a glass substrate, derivatized with 3-aminopropyl-trimethoxysilane (APTS)... 

Chromium sulfate (ic) crosslinking agent Acrylic acid/acrylamide copolymer Allylglycidyl ether alcohol resin Allyl isocyanate Aluminum acetylacetonate N-2-Aminoethyl-3-aminopropyl trimethoxysilane Ammonium persulfate t-Amyl peroxyacetate Bis (triethoxysilyl) ethane Chromic acetylacetonate Cobalt acetate (ous). 

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