15971-76-3Relevant articles and documents
King,Efraty
, p. 3773,3776, 3778 (1972)
The Photoisomerization of 1,2,3,4,5-Pentamethyl-5-vinyl-1,3-cyclopentadiene
Burger, Ulrich,Etienne, Robert
, p. 2057 - 2062 (1984)
The title compound 1 is shown to give, both upon direct irradiation at 254 nm and upon acetophenone-sensitized photolysis at 300 nm, the syn-vinyl-pentamethylhousene 5, which spontaneously rearranges in a -sigmatropic process to give the bicycloheptadiene skeleton 2.Based on the photochemical behaviour of selectively deuterated starting material, the suggestion is made that the direct photolysis produces the vinylhousene skeleton by a classic electrocyclization, whereas the sensitized reaction reaches the same target via a di-?-methane rearrangement.The bicycloheptadiene derivative 2 gives pentamethylhomoprismane 3 upon prolonged irradiation at 254 nm.
Photolysis of the Carbon-Hydrogen Bond in Pentamethylcyclopentadiene. Properties of the Pentamethylcyclopentadienyl Radical
Davies, Alwyn G.,Lusztyk, Janusz
, p. 692 - 696 (2007/10/02)
Irradiation of pentamethylcyclopentadiene (A) in liquid solution with u.v. light results in homolysis of the ring C-H bond to give the pentamethylcyclopentadienyl radical (B) , and atomic hydrogen which abstracts hydrogen from a second molecule of (A) to give molecular hydrogen and a second radical (B).The radicals (B) self-react at a diffusion-controlled rate (2kt 2 x 1E9 l mol-1 s-1 in hexane at 25 degC) by two different routes.The first, which is thermally and photolytically reversible, is the combination to give the dehydrodimer (C), and the second, which is irreversible, is the disproportionation to give the parent cyclopentadiene (A) and the tetramethylfulvene (D).
