Formation and structure of a fluorinated [2.2]paracyclophan-1-ene

The Unexpected Formation of 9,9,10,10-Tetrafluoro-1,2,4,12-tetraphenyl[2.2]paracyclophan-1-ene

“…When purified 8 was exposed to further analogous conditions, only 15% of the starting material remained, accompanied by numerous (>10) unidentified products. GC–MS analysis of the complex product mixture indicated that the other unidentified products were dimeric or higher oligomeric materials, which seems to be in agreement with the results of the previously described magnesium-promoted defluorinative silylation reaction . In our above reactions, we were not able to observe the presence of intermediate 9 (the expected 19 F NMR signal for such bridge vinylic fluorines is around δ F = −118 ppm), nor did we detect any paracyclophan-1,9-diene-based structures.…”

“…The proposed mechanism contains the first example of a Grignard reagent causing reductive defluorination of a fluoroalkyl group. This reaction, along with the previously reported Mg- 19 and Zn-promoted 7 reductive defluorination reactions, clearly demonstrates the ability to perform chemistry on the tetrafluorethylene bridges of such fluorinated paracyclophanes and its future potential, which to this point have been relatively unexplored.…”

“…However, this investigation also alerted us to the formation of an additional, unexpected molecule that fact was the major isolated product of this reaction. The new product exhibited two AB quartet patterns in the 19 F NMR spectrum, characteristic of a disubstituted OFP derivative (yet different from the expected compound 7), 15 but the electron ionization mass spectrum of the new product lacked the characteristic "split in half" xylylene fragmentation pattern typical for such paracyclophanes. 1,14 On the contrary, this product displayed only a dominant peak at m/z 582 with minimal fragmentation.…”

“…In that same publication, we reported that extended exposure of 1 to zinc in refluxing THF increased the yield of 3 to 14%. More recently, a magnesium-promoted defluorinative silylation reaction of 1 was reported by Amii, Uneyama, and co-workers, who were able to attain an X-ray crystal structure of the trimethylsilylated pentafluoro[2.2]­paracyclophan-1-ene product 4 . This highly strained molecular structure revealed a remarkably long CF 2 –CF 2 bond length of 1.64 Å.…”

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

“…2) was typically produced by Hofmann elimination [5–6]. As reported, the uniform coating properties of parylene films were improved by introducing halogen atoms to the structure of the parent [2.2]paracyclophane [7]. Therefore, the two chloride atoms on the benzene ring make parylene D superior to parylene N and parylene C. There are some creative strategies for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane (Fig.…”