A highly stable and easy to synthesize aluminium complex bearing a flexible N2O2-donor salabza ligand (N,N'-bis(salicylene)-2-aminobenzylamine) in combination with tetrabutylammonium bromide forms an active binary catalytic system for the cycloaddition of CO2 to epoxides (TOFs 120-3434 h(-1)) under mild conditions (10 bar, 80 °C) and low catalyst loadings (0.05-0.2 mol%). Kinetic experiments ha...

Benzonitrile oxide (la) reach with 1,1,2,2,3,3-hexamethyl-4,5-bis(methylene)cyclopen~e (5) to give a mixture of the 1,3-dipolar cycloaddition product 8 and the oxime 9. This reaction is 26 times slower than the corresponding reaction of la with 1,2-bis(methylene)cyclopentane (15), which exclusively yields the 2-isoxazoline 19. With the assumption that the oxime 9 is generated by a stepwise proc...

Bioorthogonal reactions are chemical reactions that neither interact with nor interfere with a biological system. The participating functional groups must be inert to biological moieties, must selectively reactive with each other under biocompatible conditions, and, for in vivo applications, must be nontoxic to cells and organisms. Additionally, it is helpful if one reactive group is small and ...

A highly reactive Ag(I)-catalyzed [3 + 2] cycloaddition of azomethine ylides is founded using AgOAc as the catalytic precursor and phosphines as ligands. Using a new bis-ferrocenyl amide phosphine (FAP) as the ligand, we found that high enantioselectivities (up to 97% ee) have been achieved in the [3 + 2] cycloaddition of azomethine ylides. Up to four stereogenic centers can be established in t...

Cycloaddition reactions are among the most powerful methods for the synthesis of complex compounds. In particular, the development and application of the 1,3-dipolar cycloaddition, an important member of this reaction class, has grown immensely due to its powerful ability to efficiently build various five-membered heterocycles. Azomethine ylides are commonly used as dipoles for the synthesis of...

The Cu(I)-catalysed 1,3-dipolar "click" cycloaddition is utilised as an efficient reaction for the preparation of novel fluorene-based conjugated polymers.

Phosphine-catalyzed [3+2]cycloaddition reactions of electron-deficient allenes and alkynes with a,b-unsaturated carbonyl compounds can give access to important highly functionalized cyclopentenes. The seminal example of such a transformation was first reported by Lu et al. in 1995, and its asymmetric version in 1997 by the group of Zhang. However, it took another ten years before the potential ...

The de novo synthesis of pyridines from smaller molecules has attracted a lot of interest since pyridine is one of the most important heterocyclic structural motifs in numerous areas of organic chemistry. Many developed syntheses, such as the Kr hnke or the Hantzsch reaction, rely on condensation reactions of smaller molecules, but a number of synthetic approaches including cycloaddition reacti...