N-Methylanilinium trifluoroacetate-promoted Prins reaction of α-methylene-α-tetralone dimers: generation of new molecular scaffolds

α-Methylene-α-tetralone dimers (8-10) are shown to undergo a diastereoselective Prins reaction with paraformaldehyde in the presence of N-methylanilinium trifluoroacetate resulting in 2, 4, and 5. The structure of the new scaffold 2 was confirmed by X-ray crystallographic analysis.