Synthesis, structure, and first reactions of a new class of thiacyclophanes

摘要

In our effort to prepare m. ncyclophanes carrying functional groups in their molecular bridges, the thiacyclophanes 14, 19, 20, and 21 have been prepared by simple routes from the pseudo-gem dibromide 10a and the corresponding bis-thiol 10b. The triply-bridged bis-thia-cyclophanes 14, and 19-21 were characterized by their spectroscopic data as well as by X-ray structural analyses. The meta-isomer 20 was oxidized to the bis-sulfone 23, which on flash vacuum pyrolysis (FVP) yielded a product mixture presumably containing the hydrocarbon 26 with a cleaved molecular bridge. Subjecting 23 to Ramberg-Backlund conditions (CCl4, NaOH, phase transfer catalysis) provided the chloride 24 in poor yield (9), a 2.2 paracyclophane in which the new molecular bridge is fully conjugated.