نتایج جستجو برای: regioselective
تعداد نتایج: 2974 فیلتر نتایج به سال:
The regioselective and enantioselective Michael addition between azlactones and o-hydroxy chalcone derivatives is reported. Enantiomerically enriched N,O-aminals with two continuous stereogenic centers are exclusively obtained in moderate to good yields with excellent diastereoselectivities and good to excellent enantioselectivities. The experimental results show that an o-hydroxy group on the ...
The regioselective synthesis of fullerene multiadducts was achieved from commercially available reagents in one pot over two steps. The configuration of the isolated regioisomers was determined using various NMR methods, UV-vis spectroscopy and electrochemical analysis with the structure of one isomer confirmed by single crystal X-ray analysis. Interesting variation in regioselectivity was obse...
A carbene-catalyzed highly regioselective and enantioselective 1,4-addition reaction between isothioureas enals has been achieved under oxidative conditions.
Biobased exo-methylene-conjugated dienes underwent regioselective living cationic polymerization to result in well-defined homo- and copolymers with good thermal properties.
Regioselective synthesis of novel N2- and N4-substituted 7-methylpyrazolo[4,5-e][1,2,4]thiadiazines.
The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one1,1-dioxide (5) was synthesized and its novel mono N2- or N4-substituted derivatives 6 and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios of NaH and alkyl halides. Based on the regioselective alkylation conditions found a facile one-pot synthesis of N2,N4-disubstituted pyrazolo[4,5-e][1,2,4] t...
A mild, efficient and regioselective method for para-amination of activated arenes has been developed through a combination of iron and copper catalysis. A diverse range of products were obtained from an operationally simple one-pot, two-step procedure involving bromination of the aryl substrate with the powerful Lewis acid iron(III) triflimide, followed by a copper(I)-catalysed N-arylation rea...
Epoxides undergo regioselective ring opening with various nucleophiles using catalytic amount of nano magnesium oxide and water as solvent under mild reaction conditions. The remarkable features of this method are improved yields, high regioselectivity, and green chemistry agreement.
Radical translocation facilitates the regioselective ?-amination of 2-alkyl-substituted azacycles, leading to 1,3-diamines including alkaloidal natural product tetraponerine T8.
A regioselective approach for the synthesis of pyrrolopyridinones and pyrroloazepinones is reported employing an Ugi reaction followed by a gold(I) or platinum(II) catalyzed intramolecular hydroarylation.
Phenyl- and ethyl-magnesium bromides undergo regioselective asymmetric allylic substitution with high enantioselectivity under the catalysis of chiral amidophosphane-copper(I) complexes.
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