نتایج جستجو برای: phenacyl isoquinolinium ylide
تعداد نتایج: 762 فیلتر نتایج به سال:
A dynamic azomethine ylide system was established using Sc(OTf)3 and Ag/Taniaphos as catalysts. The system was subsequently kinetically resolved in a tandem 1,3-dipolar cycloaddition process where the silver complex acted as both a reaction catalyst and an external selector, resulting in the formation of an exclusive pyrrolidine product in good yield and enantiopurity.
Diastereoselectivity in reactions of aryl-stabilised ammonium ylides are highly sensitive to the nature of the amine and the ylide substituent. DFT calculations are consistent with a mechanism in which reversibility in betaine formation [despite the high energy (and therefore instability) of ammonium ylides] is finely balanced due to the high barrier to ring closure.
4-Nitrobenzylidenedimethylsulfurane 4-Nitrobenzylidenedimethylsulfurane, a semi-stabilized sulfonium ylide has been generated by the attack of methylsulfinyl carbanion in dimethyl sulfoxide and reacted with a series of substituted benzaldehydes, furfural and benzylideneacetophenone to afford <mns-l,2-disubstituted epoxides in fair to good yields. The structural assignments of the products are b...
Generation and cycloaddition of less- or non-stabilized azomethine ylides, or nitrile ylide equivalents, via unprecedented 1,4-stannatropy of N-(tributylstannylmethyl)thioamides were achieved. The reactions with dipolarophiles, such as electron-deficient alkenes and alkynes, afforded corresponding pyrrolidine and pyrrole derivatives effectively.
The synthesis of the compound that has been proposed to be the natural product sclerophytin F has been completed from a known vinylogous carbonate. The synthetic strategy relied upon rearrangement of a catalytically generated ylide-like intermediate to produce an oxabicyclo[6.2.1]-5-undecen-9-one and an intermolecular Diels-Alder reaction to construct the complete tricyclic core found in the na...
Lithiation of 1,2-dichloroor 1,2,3-trichloroferrocene with lithium tetramethylpiperidinide, followed by transmetallation with ZnCl2 and Pd(II)-catalyzed coupling with 2-bromopyridine, yield the pyridylferrocenes [CpFe{C5H2−nCl2+n(2-C5H4N)}] (2a, b, n = 0 or 1) as brown oils of low stability. Recrystallization of 2b produced a small number of X-ray quality crystals, which could be shown to have ...
Fifteen cyclic and acylic carbenes have been calculated with density functional theory at the BP86/def2-TZVPP level. The strength of the internal X→p(π) π-donation of heteroatoms and carbon which are bonded to the C(II) atom is estimated with the help of NBO calculations and with an energy decomposition analysis. The investigated molecules include N-heterocyclic carbenes (NHCs), the cyclic alky...
The development of new synthetic fluorination reactions has important implications in medicinal, agricultural, and materials chemistries. Given the prevalence and accessibility of alcohols, methods to convert alcohols to trifluoromethanes are desirable. However, this transformation typically requires four-step processes, specialty chemicals, and/or stoichiometric metals to access the trifluorom...
A highly efficient gold(I)-catalyzed Overman rearrangement of allylic trichloroacetimidates to allylic trichloroacetamides in water is reported. With this environmentally benign and scalable protocol, a series of C3-alkyl substituted allylic trichloroacetamides were synthesized in good to high yields.
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