The Reduction of Tetracyclone¹

Molecular Structure and Photodecarbonylation of 2,3,4,5‐ Tetraphenylcyclopentanone

“…The structure of 8 proposed by Sonntag et al (1953) was based upon infrared and ultraviolet absorption spectral data which indicated the presence of a nonconjugated carbonyl group. In agreement with their report, we observe ultraviolet absorption maxima at 308 nm (E = 260) and 260 nm (E = 680), assigned to carbonyl n , r * and benzene r ,~* transitions.…”

“…Chemicals. Clemmensen reduction of 5.1 g tetracyclone (Aldrich Chemical Co., Milwaukee, WI) according to the method of Sonntag et al (1953) afforded after recrystallization from ethanol and hexane 0.24 g (5"/0) of 2,3,4,5tetraphenylcyclopentanone: mp 174-177" (lit. 176"); UV (cyclohexane) 230 nm (E = 680), 308 nm (E = 260); 90 MHz ' H NMR (CDCI,) 6 4.24 (s, 4 H), 6.8-7.4 (m, 20 H), with 0.22 equiv Eu(fod), (Aldrich) 6 4.45 (d, 2 H, J = 6 Hz).…”

“…Our interest in 1,2,4,5-tetraphenyIbutanediyl (5) was rekindled by the failure to observe cation radical [2+1] cycloaddition reactions for 1 or 2 (Lewis et al, 1985), a process which occurs for numerous 1aryl-and 1,l-diarylolefins (Mattes and Farid, 1983;Lewis and Kojima, 1988a Sonntag et al (1953) that reduction of tetracyclone under Clemmensen conditions yields 2,3,4,5-tetraphenylcyclopentanone, 8. We report here the elucidation of the stereochemistry of 8 by means of x-ray crystallography and the investigation of its photodecarbonylation.…”

Protonation of Tetraphenyl‐ and 2,3,4‐Triphenylcyclopentadienone – An NMR and X‐ray Crystallographic Study

“…A different approach involved the reaction of tetraphenylcyclopentadienone (tetracyclone) with aluminum trichloride in the expectation that coordination of the electrophile to the ketonic oxygen atom would generate the required cation. In the first report, by Allen and VanAllan in 1943, it was claimed that the product was 2,3,4,5‐tetraphenylcyclopentan‐1‐one ( 8 ); once again, this claim was rebutted, and the product was instead established as 9,11‐diphenyl‐9 H ,11 H ‐cyclopenta[ l ]phenanthren‐10‐one ( 9 ), whereby the initially generated positive charge was delocalized onto the most distant phenyl ring, as in 10 , thus initiating the formation of the tetracyclic framework (Scheme ). However, the relative orientation of the phenyl rings in 9 was undetermined until 2002 when Pascal unequivocally characterized both the cis and trans isomers in an X‐ray crystallographic study …”

The Reaction of Diphenyliodonium Ion with Hydroxide Ion1

“…Experimental Materials.-Diphenyliodonium iodate was made essentially by the method of Lucas and Kennedy. 6 The chloride was made from this by precipitation from solution with sodium chloride and recrystallization from alcohol. Anal.…”