نتایج جستجو برای: regioselective synthesis
تعداد نتایج: 410958 فیلتر نتایج به سال:
A phenylethynyl Fischer carbene complex was used as a traceless directing group for the regioselective cycloaddition of dithiolethiones to arylacetylene, which constitutes the first synthesis of E-dithiafulvene thione or dithioesters.
The regioselective, orthogonal functionalisation of 4,10-dichlorochrysene enables the synthesis of a variety of 2,8,4,10-"A2B2"-tetrasubstituted chrysenes. Such compounds exhibit broadened UV-vis absorption spectra, decreased band gap and higher HOMO levels compared to the parent chrysene.
An efficient approach for the synthesis of pyrrolo[3,2-c]quinolines (the core nucleus of the natural product martinellic acid) from protected 2-alkynylanilines via the regioselective formation of pyrroles followed by Heck and intramolecular Michael addition has been described.
A one-pot indole synthesis consisting of a highly regioselective TiCl(4)-catalyzed hydroamination and a 5-endo Heck cyclization starting from 2-chloroaniline is described, using an in-situ generated, sterically hindered imidazol-2-ylidene palladium complex.
A convenient Cu(I)-catalyzed cycloaddition of electron rich internal aryl alkynes and diazoacetates was discovered for the chemoselective and regioselective synthesis of tetra-substituted furans and cyclopropenes in moderate isolated yields (18-67%), and alkyne conversion (29-73%).
A highly enantioselective synthesis of homopropargylic alcohols is achieved by using the new helical chiral 2,2'-bipyridine N-monoxide catalyst and allenyltrichlorosilane. This method can be further extended to the enantio- and regioselective propargylation of N-acylhydrazones.
[reaction: see text] An enantiospecific synthesis of a coccinellied alkaloid, (-)-adalinine, was established starting from (S)-(-)-pyroglutamic acid, where a stereoselective Michael addition and a samarium iodide-promoted regioselective carbon-nitrogen bond cleavage reaction were involved as the key reactions.
A novel Pd-catalyzed regioselective intramolecular aminofluorination of unactivated alkenes has been developed, which is an efficient method for the synthesis of a variety of monofluoromethylated nitrogen-containing heterocycles.
A novel and facile cascade Biginelli-like assembly employing enaminone, aldehyde and urea/thiourea has been developed, which provides a highly chemo- and regioselective synthesis of new dihydropyrimidinones, 1,3-thiazines and chromones by altering particular functional groups in the reactants.
Efficient syntheses of four aminocyclitols are reported. Each synthesis is accomplished in eight steps starting from D-(-)-quinic acid. The key step involves a highly regioselective ring opening of epoxides by sodium azide.
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