The synthesis of a family of O-silylcarbamates from the corresponding silylamines has been achieved simply by heating the silylamine in supercritical carbon dioxide (scCO2), and these O-silylcarbamates have been shown to be effective precursors for the synthesis of a range of symmetrical and unsymmetrical ureas.

The synthesis of unsymmetrical 2,5-disubstituted thiophenes by selective and sequential palladium-catalyzed cross-coupling reactions of indium organometallics with 2,5-dibromothiophene is reported. Following an iterative coupling sequence, α-oligothiophenes were synthesized in good yields and with high atom economy.

A diblock copolymer is designed to have incompatible blocks, unsymmetrical block lengths, and a reversible linkage. This copolymer self-assembles into nanostructured cylindrical morphology in thin films. Removal of the nanosized cylinders by breaking the reversible linkage then affords nanoporous membranes featuring a chemically reactive functionality in the pores.

A novel Lewis acid InBr3-catalyzed direct cross-coupling reaction of arylboronic acids with diorgano diselenides and ditellurides without any additive has been developed. The reactions generated the corresponding unsymmetrical diorgano monoselenides and monotellurides in good to excellent yields. The method has advantages of broad substrate scope, simple operation, mild reaction conditions and ...

Using Ag2CO3 as an additive, we developed the Pd-catalyzed intermolecular C-H/C-H cross-coupling of pyridine N-oxides with five-membered heterocycles such as 1-benzyl-1,2,3-triazoles, thiophens and furans. This protocol provides an efficient and regioselective approach for the synthesis of unsymmetrical biheteroaryl molecules.

5-Alkenyl-15-alkynylporphyrins have been obtained unexpectedly by [2 + 2] acid-catalyzed condensation of dipyrrylmethane and TMS propynal in addition to 5,15-dialkynylporphyrin, and the unsymmetrical porphyrin can be converted to a butadiyne-linked dimer by selective desilylation of the alkynyl TMS.

Stable, water-soluble aminosugar staurosporine, K-252a and rebeccamycin analogs have been prepared by nucleophilic opening of C(2)-symmetric N-activated bis-aziridines by bis-indolylmaleimides. This divergent strategy allows the synthesis of unsymmetrical substituted derivatives and provides an easy access to the piperidine and pyrrolidine analogs.

The transformation of enynes under cobalt-catalysis leads to symmetrical benzannulation products in dichloromethane. In tetrahydrofuran the cobalt-catalysed reactions afforded the unprecedented unsymmetrical benzannulation products in moderate to good yields and good regioselectivities. In addition, cyclotrimerisation of the alkyne subunit can be realised when electron-deficient enynes are appl...

A new tetra-dentate unsymmetrical Schiff base, C(15)H(10)N(4)O, has been synthesized from 4,5-dicyano-o-phenyl-enediamine and o-vanillin in refluxing ethanol. The dihedral angle between the two benzene rings is 39.0 (1)°. There are intra-molecular O-H⋯N and weak inter-molecular N-H⋯O and N-H⋯N inter-actions.

The synthesis of imidazolinium salts from the reaction of formamidines and (2-bromoethyl)diphenylsulfonium triflate is described. A variety of symmetrical and unsymmetrical imidazolinium triflate salts were synthesized in high yield in short reaction times under mild conditions. Aromatic and aliphatic N-substituents work well. The reaction is proposed to proceed via generation of a vinyl sulfon...