Highly regiocontrolled Pd-catalyzed cross-coupling reaction of terminal alkynes and allenylphosphine oxides

The cross-coupling of a variety of terminal alkynes 1 with allenylphosphine oxides 2 catalyzed by a Pd(OAc)(2)-TDMPP system provided conjugated endo-enynes 3 solely, while the TCPC-catalyzed reaction of the same regents led to the exclusive formation of exo-isomers 4. The mechanistic rationale for these selective transformations was proposed. Synthetic usefulness of the prepared exo-enyne 4 was demonstrated in the synthesis of multisubstituted diarylbenzylphosphine oxides 5 via the Pd-catalyzed [4+2]-benzannulation reaction.     

Arylation of Rhodium(II) Azavinyl Carbenes with Boronic Acids

A highly efficient and stereoselective arylation of in situ-generated azavinyl carbenes affording 2,2-diaryl enamines at ambient temperatures has been developed. These transition-metal carbenes are directly produced from readily available and stable 1-sulfonyl-1,2,3-triazoles in the presence of a rhodium carboxylate catalyst. In several cases, the enamines generated in this reaction can be cyclized into substituted indoles employing copper catalysis.     

Discrete diffraction in a cascade-induced anisotropic lattice

The features of anisotropic discrete diffraction in a cascade-induced lattice formed by two crossed pump waves in a quadratically nonlinear medium have been studied. The transition from the diffraction of a signal beam in free space to discrete diffraction with the further capture in a waveguide in a defocusing lattice by the increasing of the pump wave intensity has been traced.     

Specific Features of Synthesis,Structure, Magnetometry,and NMR Spectroscopy of Different-Type Nanowires

Physics of the Solid State - Nanowires of different types (homogeneous (made of iron) and heterogeneous (layered)), obtained by the template synthesis method, have been investigated. A technique...     

Direct palladium-catalyzed arylation of cyclopropenes

The first examples of direct palladium-catalyzed arylation and heteroarylation of cyclopropenes have been demonstrated. This method allows for efficient synthesis of various tetrasubstituted cyclopropenes, incuding nonracemic cyclopropenes, which are not available via known asymmetric cyclopropenation methods. Mechanistic studies strongly suggest an electrophilic path for this Heck-type transformation.     

Cross-section measurements for the 58,60,61Ni(n,a)55,57,58Fe reactions at 8.50,9.50 and 10.50 MeV neutron energies

Cross sections of the 58,60,61Ni(n,α)55,57,58Fe reactions were measured at 8.50,9.50 and 10.50 MeV neut-ron energies based on the HI-13 tandem accelerator of Ch...     

Rhodium-catalyzed transannulation of 1,2,3-triazoles with nitriles

Stable and readily available 1-sulfonyl triazoles are converted to the corresponding imidazoles in good to excellent yields via a rhodium(II)-catalyzed reaction with nitriles. Rhodium iminocarbenoids are proposed intermediates.     

Sila morita-Baylis-Hillman reaction of cyclopropenes

The first example of sila-Morita-Bayis-Hillman reaction between 1-silylcyclopropenes and carbonyl compounds has been demonstrated. This novel phosphine-catalyzed transformation features a 1,3-Brook rearrangement/elimination cascade and provides convenient access to a variety of 1-(silyloxymethyl)cyclopropenes, which are not easily available via traditional methods.     

Direct Pd-catalyzed arylation of 1,2,3-triazoles

A highly efficient method for the synthesis of multisubstituted 1,2,3-triazoles via a direct Pd-catalyzed C-5 arylation has been developed.