1,3‐Dithienium and 1,3‐Dithiolenium Salts. IX. Reactions of 1,3‐Dithiane‐2‐ylium Tetrafluoroborates with C‐Nucleophiles 1,3‐Dithian‐2‐ylium tetrafluoroborates (1), which can be easily obtained by variable methods, react in good to excellent yields with variable C‐nucleophiles to new geminal disubstituted 1,3‐dithianes. The latter compounds are potential precursors of interesting synthetic building blocks. Reactions are described with 2‐lithio‐1,3‐dithianes 2, sodium cyanide 4, sodium salts of the nitro alkanes 7 and CH‐acids of the type of the 1,3‐dicarbonyl compounds 9. The reduction of 3‐oxo‐2‐(2‐phenyl‐1,3‐dithian‐2‐yl)‐ethoxybutanoat–following a diastereoselective pathway – leads to the Cram product 11. Further presented is the crystal structure of 2‐phenyl‐1,3‐dithiane‐2‐ylium tetrafluoroborate (1b).

1,3-Dithienium and 1,3-Dithiolenium Salts. Part 9. Reactions of 1,3-Dithiane-2-ylium Tetrafluoroborates with C-Nucleophiles. -New geminal disubstituted 1,3-dithianes, e.g. (III), (V), and (VII), are obtained by the title reaction. These compounds are potential precursors of interesting synthetic building blocks. The structure of the salt (Ia) is determined by X-ray analysis. -(LINKER, M.; REUTER, G.; FRENZEN, G.; MAURER, M.; GOSSELCK, J.; STAHL, I.; J. Prakt. Chem./Chem.