نتایج جستجو برای: chemoselectivity
تعداد نتایج: 401 فیلتر نتایج به سال:
Catalytic chemoselective reactions of innately less reactive functionalities over more are described. A cooperative catalyst comprising a soft Lewis acid/hard Brønsted base enabled activation hydroxyl group an amino group, allowing for nucleophilic addition to electron-deficient olefins. The reaction could be applicable variety alcohols, including pharmaceuticals, without requiring tedious prot...
This Perspective illustrates the defining characteristics of free radical chemistry, beginning with its rich and storied history. Studies from our laboratory are discussed along with recent developments emanating from others in this burgeoning area. The practicality and chemoselectivity of radical reactions enable rapid access to molecules of relevance to drug discovery, agrochemistry, material...
Rate and equilibrium constants for the reaction between N-aryl triazolium N-heterocyclic carbene (NHC) precatalysts and substituted benzaldehyde derivatives to form 3-(hydroxybenzyl)azolium adducts under both catalytic and stoichiometric conditions have been measured. Kinetic analysis and reaction profile fitting of both the forward and reverse reactions, plus onwards reaction to the Breslow in...
With [Ru(p-cymene)Cl(2)](2) as catalyst, diazo-β-ketoanilides would undergo intramolecular carbenoid arene C-H bond functionalization to afford 3-alkylideneoxindoles in up to 92% yields. The reaction occurs under mild conditions and exhibits excellent chemoselectivity. The lack of primary KIE (k(H)/k(D) ~ 1) suggests that the reaction should not proceed by rate-limiting C-H bond cleavage; a mec...
[reaction: see text] The relative quantum yields and chemical efficiencies of crystalline p,p'-disubstituted 1,3-diphenyl-2-propanones with 4-MeO, 4-Me, 4-F, 4-CF3, and 3,4-diMeO groups were determined by parallel irradiation of polycrystalline samples. Variations in quantum yields that span a factor of 4 are analyzed in terms of the effects of substituents on the stability of the benzylic radi...
Graphite oxide as a heterogeneous and recyclable solid acid catalyzed a simple and efficient method for the synthesis of β -amino alcohols by ring opening of epoxides with amines. This method is effective with various aromatic and aliphatic amines under solvent-free conditions. The corresponding β -amino alcohols are obtained in high yields (56%–95%) and short reaction times (15–30 min) with hi...
The Suzuki-Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported Pd-NHC complex catalyst has been realized for the first time. The polymer-supported catalyst can be re-used several times still retaining high activity for this transformation. Various aryltriazenes were investigated as electrophilic substrates at room temperature to ...
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