Synthesis and characterization of tetramethylammonium trifluorosulfate.

[Me(4) N](+) [SO(2) F(3) ](-) , the first example of a [SO(2) F(3) ](-) salt, has been prepared from Me(4) NF and SO(2) F(2) . The colorless, microcrystalline solid was characterized by its infrared and Raman spectra. The trigonal bipyramidal structure of C(2v) symmetry of the [SO(2) F(3) ](-) anion is predicted by ab initio calculations. Two oxygen atoms with d(SO)=143.2 pm and one fluorine atom with d(SF)=157.9 pm occupy the equatorial plane. The two fluorine atoms in the axial position with d(SF)=168.5 pm are repulsed by the two oxygen atoms forming a bent axis with ∡(F(ax) SF(ax) )=165.2°.

A domino annulation reaction under Willgerodt-Kindler conditions.

Butanone side chains at arenes and hetarenes, efficiently introduced by a Heck-type reaction, are transformed to annulated thieno[3,2-b]thiophenes in a domino redox process under Willgerodt-Kindler conditions. A nucleophilic aromatic substitution with an intermediary thioenolate is a reasonable key step of this process.

Isoindoles and dihydroisoquinolines by gold-catalyzed intramolecular hydroamination of alkynes.

The title compounds are enantioselectively synthesized in just two preparative steps, making use of the Ugi-four-component reaction with an amino acid as chiral component, followed by a gold-catalyzed hydroamination.