نتایج جستجو برای: unsymmetric
تعداد نتایج: 521 فیلتر نتایج به سال:
The set Λ consists of infinitely many linear real–valued functionals λ that usually take the form of point evaluations of functions or derivatives at points inside a domain or on some boundary or interface layer. If several differential or boundary operators are involved, we simply put everything into a single set Λ of functionals of various types. We call (1) a generalized interpolation proble...
In this paper, adaptive control is proposed for master-slave teleoperation systems with dynamical uncertainties and unsymmetric time-varying delays in communication channels. With the technique of force-motion transformation based on impedance model, we can convert the objective of force reflection into motion synchronization. Using partial feedback linearization, the whole teleoperation dynami...
Catalytic Tsuji-Trost allylation has become a ubiquitous method for allylation of active methylene compounds.[1] While monoallylation products are typically formed, bisallylation of malonates and related ketone enolates leads to 1,6-dienes.[2] Given the utility of these 1,6heptadienes in metal-catalyzed cycloisomerization reactions,[3] it would be beneficial if one could perform controlled bisa...
Diaryliodonium salts are demonstrated as efficient arylating agents of aliphatic alcohols under metal-free conditions. The reaction proceeds at room temperature within 90 min to give alkyl aryl ethers in good to excellent yields. Aryl groups with electron-withdrawing substituents are transferred most efficiently, and unsymmetric iodonium salts give chemoselective arylations. The methodology has...
One-pot synthesis of symmetric 1,4-disubstituted 1,3-diynes from iodoarenes and propiolic acid via Sonogashira reaction followed by Pd-catalyzed decarboxylative homocoupling is developed in high yields. Also, this system allows the one-pot synthesis of unsymmetric 1,4-disubstituted 1,3-diynes by cross-coupling of two different 3-substituted propiolic acids.
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