نتایج جستجو برای: Benzoin
تعداد نتایج: 326 فیلتر نتایج به سال:
N-Heterocyclic carbenes (NHCs) have emerged as a powerful class of organocatalysts that mediate a variety of organic transformations. The Benzoin reaction constitutes one of the earliest known carbon-carbon bond-forming reactions catalysed by NHCs. The rapid growth of NHC catalysis in general has resulted in the development of a variety of benzoin and benzoin-type reactions. An overview of such...
Cross benzoin condensation using room temperature ionic liquids, namely 1-butyl-3-methylimidazolium bromide ([Bmim][Br]), acted as catalyzed and a solvent under NaOH base condition to afford desired cross-benzoin products 4a-i in satistactory yields (60-70%.) Homo-benzoin 5a-d 6a also were occurred side reactions 9-18% yields.
Hydroacylation reactions and aza-benzoin reactions have attracted considerable attention from experimental chemists. Recently, Wang et al. reported an interesting reaction of N-heterocyclic carbene (NHC)-catalyzed addition of aldehyde to enamide, in which both hydroacylation and aza-benzoin reactions may be involved. Thus, understanding the competing relationship between them is of great intere...
Benzoin, a popular photoinitiator for free radical polymerization of vinyl monomers, was improved by introduction of two methyl thioether substituents. This new benzoin derivative showed an about 50 times higher light absorption in the near-UV spectral region and performed better than the unsubstituted benzoin in polymerization experiments in bulk solutions or films of acrylate monomers when lo...
Benzoin (and neither the Breslow intermediate nor the NHC-aldehyde tetrahedral adduct) has been unambiguously identified as the oxidised species in aerobic NHC-catalysed aldehyde esterifications.
In this letter, a method of generating spatially defined electrospun microarchitectures by direct photolithographic patterning of electrospun films is described. A photoinitiator, benzoin methyl ether, is incorporated into a solid thermoplastic electrospun polyurethane matrix selectively photo-cross-linked by standard photolithographic methods. Subsequent development in an organic solvent yield...
Benzoin alkyl ethers encapsulated in a cisoid conformation within water-soluble p-sulfonatocalix[8]arenes preferentially yield the Norrish Type II reaction product deoxybenzoin.
We disclose the first catalytic activation of carbohydrates as formaldehyde equivalents to generate acyl anions as one-carbon nucleophilic units for a Stetter reaction. The activation involves N-heterocyclic carbene (NHC)-catalyzed C-C bond cleavage of carbohydrates via a retro-benzoin-type process to generate the acyl anion intermediates. This Stetter reaction constitutes the first success in ...
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